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COLLEGE OF HEALTH SCIENCES
This is to certify that the doctoral dissertation by
Laurence Franken
has been found to be complete and satisfactory in all respects,
and that any and all revisions required by
the review committee have been made.
Review Committee
Dr. Chester Jones, Committee Chairperson, Public Health Faculty
Dr. Shana Morrell, Committee Member, Public Health Faculty
Dr. Gary Burkholder, University Reviewer, Public Health Faculty
Chief Academic Officer
David Clinefelter, Ph.D.
Walden University
2011
Abstract
Advanced Oxidation Treatment in a Health Care Building for Reducing Microbiological
Populations in the Air and on Surfaces
by
Laurence J. Franken
M.S.P.H., Walden University, 2006
M.S., Baker University, 1995
B.S., Kansas State University, 1989
Dissertation Submitted in Partial Fulfillment
of the Requirements for the Degree of
Doctor of Philosophy
Public Health
Walden University
August 2011
Abstract
The purpose of this study was to determine whether a daily 12-hour advanced oxidation
treatment, using a photohydroionization reactor, significantly reduced microbiological
populations in the air and on surfaces in an applied health care setting. Microorganisms
found in health care facilities have been linked to disease including asthma, body, lung,
and skin infections. The conceptual framework includes development of the impact of
microbial organisms on population health as well as treatment options. Little data exists
on the efficacy of advanced oxidation treatment in the health care setting. The research
questions addressed whether the intervention reduced mold in the air and Staphylococcus
aureus, Methicillin-resistant Staphylococcus aureus (MRSA), and Pseudomonas species
on contact surfaces. The study used an experimental design, with samples collected on
Day 0 for the control and Days 5, 10, 20, and 30 of the intervention. Validated cultural
media was used to measure microbiological levels in the building. Results of multiple
regression models showed a statistically significant relationship (p <.05) between
advanced oxidation treatment and the reduction of mold, Staphylococcus aureus, and
Pseudomonas species. The treatment resulted in greater than 90% reductions in mold,
MRSA, and Staphylococcus aureus in the measured areas. Implications for positive
social change include providing data on best practices for building engineers, infection
control, and occupational health professionals to help them make health care facilities
safer for susceptible populations, thus reducing the spread of infectious diseases and
lowering heath care costs overall.
Advanced Oxidation Treatment in a Health Care Building for Reducing Microbiological
Populations in the Air and on Surfaces
by
Laurence J. Franken
M.S.P.H., Walden University, 2006
M.S., Baker University, 1995
B.S., Kansas State University, 1989
Dissertation Submitted in Partial Fulfillment
of the Requirements for the Degree of
Doctor of Philosophy
Public Health
Walden University
August 2011
UMI Number: 3469899
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Acknowledgements
I would like to thank all of those who helped me accomplish this academic goal.
This includes a special thank you to my research committee – Dr. Chester Jones,
chairperson, and committee members – Dr. Shana Morrell and Dr. James Marsden for
their knowledge and guidance in helping me to complete the dissertation process. I would
also like to thank the staff of Kansas City, Kansas / Wyandotte County Health
Department who were instrumental in making this research possible. Finally, I would like
to thank my wife Kimberly and son Owen, for their support and encouragement
throughout this journey.
ii
Table of Contents
Chapter 1: Introduction ........................................................................................................1
Indoor Microorganisms and Human Health ..................................................................2
Advanced Oxidation and Antimicrobial Intervention....................................................8
Statement of Problem ...................................................................................................10
Nature of the Study ......................................................................................................11
Research Questions and Hypotheses ...........................................................................11
Purpose of Study ..........................................................................................................13
Theoretical Base...........................................................................................................14
Definitions of Terms and Variables .............................................................................15
Assumptions.................................................................................................................16
Scope ............................................................................................................................17
Delimitations ................................................................................................................17
Limitations ...................................................................................................................19
Significance of Study ...................................................................................................20
Summary ......................................................................................................................21
Chapter 2: Literature Review .............................................................................................23
Introduction ..................................................................................................................23
Sources of Contamination in Health Care Facilities ....................................................24
Indoor Air Contamination and Mold ...........................................................................30
Bacterial Contaminants on Surfaces ............................................................................34
Staphylococcus aureus .........................................................................................36
iii
Antimicrobial Resistance Bacteria and MRSA....................................................38
Pseudomonas species ...........................................................................................41
Impact of Microbiological Contaminants of Health Care Workers .............................47
Intervention Used For Reducing Microbiological Contaminants ................................52
Surveillance of Microorganisms in Health Care Facilities ..................................52
Conventional Cleaning and Disinfection .............................................................54
Ventilation and Air Cleaners ...............................................................................56
Advanced Oxidation ............................................................................................60
Methods Used for Evaluating Indoor Microorganisms ...............................................70
Summary ......................................................................................................................72
Chapter 3: Methodology ....................................................................................................74
Introduction ..................................................................................................................74
Design and Approach ...................................................................................................74
Sample Population and Setting ....................................................................................77
Testing Locations in Building ..............................................................................79
Air Sampling ........................................................................................................80
Surface Sampling .................................................................................................80
Instrumentation and Materials .....................................................................................82
Treatment .....................................................................................................................83
Data Collection ............................................................................................................85
Air Samples ..........................................................................................................86
Contact Surface Samples .....................................................................................87
iv
Analysis of Data ...........................................................................................................89
Research Questions ..............................................................................................89
Hypotheses ...........................................................................................................90
Data Labeling and Statistical Analysis ................................................................91
Threats to Validity .......................................................................................................95
Ethical Considerations .................................................................................................97
Measures to Protect Building Occupants .............................................................97
Summary ......................................................................................................................99
Chapter 4: Results ............................................................................................................100
Descriptive Analysis ..................................................................................................101
Research Questions and Hypotheses .........................................................................106
Research Question 1 ..........................................................................................106
Hypothesis 1.......................................................................................................107
Research Question 2 ..........................................................................................109
Hypothesis 2.......................................................................................................109
Research Question 3 ..........................................................................................112
Hypothesis 3.......................................................................................................112
Research Question 4 ..........................................................................................114
Hypothesis 4.......................................................................................................114
Regression Analysis ...................................................................................................116
Threats to Validity .....................................................................................................119
Chapter 5: Summary, Recommendations, and Conclusions ............................................121
v
Overview of Study and Summary of Findings ..........................................................121
Findings and Alternative Antimicrobial Interventions ..............................................125
Implications for Social Change ..................................................................................127
Recommendations ......................................................................................................127
Recommendations for Action ............................................................................127
Recommendations for Further Research ............................................................129
Conclusions ................................................................................................................131
References.... ....................................................................................................................133
Appendix A: Wyandotte County Public Health Building Floor Plan ..............................165
Appendix B: Consent Letter to Conduct Study In Health Department ...........................166
Appendix C: First Email Letter to Health Department Mangers .....................................167
Appendix D: Second Email Letter to Health Department Mangers ................................168
Curriculum Vitae .............................................................................................................169
vi
List of Tables
Table 1. Average Recovered Airborne Mold Counts and Standard
Deviation by Time (Day) and Location .............................................................101
Table 2. Average Recovered Airborne Mold Counts and Standard
Deviation by Time (Day) and Sampling Distance (Feet) ..................................102
Table 3. Percentage of Microorganisms Recovered on Study Surface
Types Prior to Treatment ...................................................................................103
Table 4. Average Recovered Staphylococcus aureus Counts and Standard
Deviation by Time (Day) and Location / Zone ..................................................103
Table 5. Average Recovered MRSA Counts and Standard Deviation by
Time (Day) and Location / Zone .......................................................................104
Table 6. Average Recovered Pseudomonas spp. Counts and Standard
Deviation by Time (Day) and Location / Zone ..................................................105
vii
List of Figures
Figure 1. Average log reduction in airborne mold counts by time and
distance ..............................................................................................................107
Figure 2. Average log reduction in airborne mold counts by testing
location and time ................................................................................................109
Figure 3. Average log reduction in surface MRSA counts by time and
distance .............................................................................................................111
Figure 4. Average log reduction in surface Staphylococcus aureus counts
by time and distance...........................................................................................113
Figure 5. Average log reduction in surface Pseudomonas spp. counts by
time and distance................................................................................................115
viii
1
Chapter 1: Introduction
This study addressed questions on the efficacy of reducing potentially harmful
mold and bacteria in a health care facility using an antimicrobial treatment. The impact of
microorganisms on human health has been well documented and is a topic that has
received much attention in recent years (Diekema & Smith, 2007). The adverse health
effects associated with microorganisms are generally related to infection, but can also
contribute to asthma and allergies (Kim et al. 2007). Susceptible persons including ill,
immune-compromised, children, and elderly may be at higher risk of infection than
healthy adults (Durston, 2007; Hota, 2004; Jacob et al., 2002). In more severe cases of
contamination, anyone occupying the building may be at risk of adverse health effects as
a result of the exposure (Menzies, Tamblyn, Nunes, Hanley, & Tamblyn, 1996).
In chapter 2, methods for remediation of indoor microorganisms using current
technologies are discussed along with advantages and disadvantages of each process. The
chapter also examines advanced oxidation as an indoor antimicrobial treatment, detailing
benefits of the technology over other processes. Chapter 2 also includes a review of the
literature on disease-causing microorganisms found in indoor environments and the
impact these organisms have on human health. This includes sections on airborne mold
and microbiological surface contaminants found in buildings. Much of the literature
presented is related to health care environments where the impact of microbiological
contaminants is of concern.
Indoor Microorganisms and Human Health
Mold, a member of the fungi family, is a common indoor air contaminant found in
almost every building including health care facilities (Neely & Orloff, 2001; Price,
2
Simmons, Crow, & Ahearn, 2005). Health effects associated with mold have been well
documented especially in persons who are more susceptible such as children (Jacob et al.,
2002). Molds are also known to cause various allergic diseases such as allergic rhinitis
and allergic asthma (Kim et al., 2007). It is estimated that 8.2% of the United States
population currently suffer from asthma (Akinbami, Moorman, & Liu, 2011). In children,
asthma is an even greater concern with a prevalence rate at almost 9% in children under
15 years of age (Center for Disease Control and Prevention [CDC], 2008a). Indoor
exposure to mold has also been linked to an increased risk of developing atopic
symptoms and allergic sensitization in children (Jacob et al., 2002). Children are a major
demographic for many health care facilities including the facility used for this study.
Along with asthma, mold can cause infections of the lungs, body, and blood
(Graw, Woolson, & Huddleston, 2010; Hsiue, Ruan, Kup, Huang, & Hsueh, 2010; Jones
Recer, Hwang, & Lin, 2011; Ortega et al., 2010). In persons who are already ill, or have a
weak immune system, the risk of infection from mold is increased (Hille, 2007). Chronic
sinusitis, an inflammation of the nose and sinus cavity, affects nearly 37 million persons
in the United States (Mayo Clinic, 1999). Mold, along with other fungi, are believed to
the single biggest cause of these infections (Mayo Clinic, 1999). While research has
focused on identifying health effects linked with mold exposure, there is limited
information available on technology to effectively remove or reduce mold from indoor
air.
Bacteria can be found on most indoor surfaces and may be readily transmitted
throughout a building (Bures, Fishbain, Uyehara, Parker, & Berg, 2000). While the
majority of bacteria found in buildings are harmless, there are some organisms including
3
Staphylococcus aureus and Pseudomonas spp. that can cause disease (Hasanagic, 2008;
Hindron et al., 2008; Scott, Duty, & McCue, 2009). In health care buildings, the threat of
bacterial infection from either direct or indirect environmental contacts can be an even
greater concern, especially for susceptible persons (Hota, 2004).
Staphylococcus aureus is a gram positive-bacteria common to indoor
environments and a primary cause of skin and soft tissue infections, accounting for over
45% of all cases (Minnesota Department of Health, 2007; Rennie, Jones, & Mutnick,
2003). Enterotoxin produced by strains of Staphylococcus aureus can cause bacterial
gastroenteritis, a disease with associated symptoms such as vomiting and diarrhea
(Balaban & Rasooly, 2000). In the United States Staphylococcus aureus is responsible for
causing 500,000 health care infections annually (Bowersox, 1999). The most severe
impact from Staphylococcus aureus infections may be linked with susceptible
populations. A five-fold increase in influenza-associated deaths was observed in children
with coinfections with Staphylococcus aureus, suggesting that children suffering from
influenza may be at increased risk of a coinfection with Staphylococcus aureus (CDC,
2008c).
Another bacterium that has emerged in recent decades is Methicillin-resistant
Staphylococcus aureus (MRSA). MRSA is a common indoor microorganism that is
linked to serious skin and soft tissue infections and pneumonia. Since it was first
discovered, MRSA has steadily grown in importance to the point where it is now a major
health care and community health issue (Raygada & Levine, 2009). In 2005, MRSA
accounted for 278,000 hospital infections, an increase of over 100% since 1999 (Klein &
Smith, 2007). Persons infected by antimicrobial resistant bacteria like MRSA are more
4
likely to require additional medical treatment that may be less effective, more toxic, and
more expensive (Chotani, Roghmann, & Perl, 2004). As with other types of bacteria,
there is a lack of knowledge on interventions for the reduction of MRSA in heath care
facilities, as well as the general community.
The transmission of Staphylococcus aureus and MRSA from person to person can
occur directly through skin to skin contact or indirectly by surface to skin contact
(Ecolab, 2009). Early research from the 1980s suggested that these infections mainly
occurred through direct skin to skin contact (Maki, Alvarado, Hassemer, & Zilz, 1982).
However, more recent studies have shown that indirect transfers of these microorganisms
through contaminated surfaces are a significant source of transmission (Dancer, 1999;
Hota, 2004; Neely & Maley, 2000; Kagan, Aiello, & Larson, 2002). Contact surfaces
often associated with these infections include those of common objects such as office
equipment, fabrics, door knobs, medical devices, and light switches (Neely & Maley,
2000; Ecolab, 2009). A concern of Staphylococcus aureus and MRSA in a health care
setting is how easily it can be transmitted by patients, health care workers, and contact
surfaces (Raygada & Levine, 2009; Sonya, Lawson, & Loritsch, 2002).
Pseudomonas species are a gram negative, rod-shaped bacterium that is one of the
most common disease-causing microorganisms found in health care environments
(Hindron et al., 2008). Pseudomonas spp. accounts for 8% of all health care infections
and is the second leading cause of microbiological outbreaks in health care facilities
(Gastmeier et al., 2005; Hidron et al., 2008). Pseudomonas spp. are associated with a
number of illnesses including infection of the skin, body, eyes, lungs, and urinary tract
(Donaln, 2001; Hall-Stoodley et al., 2006)
5
Pseudomonas spp. commonly found in health care buildings, as well as most
occupied buildings. This is based on limited nutritional requirements needed for the
organism to survive and adaptability to different environments (Karlowsky et al., 2003).
A concern with this microorganism is its ability to stay in an environment for extended
periods of time. When transmitted onto common indoor surfaces, Pseudomonas spp. have
shown the ability to survive for up to 16 months (Kramer, Schwebke, & Kamp, 2006;
Martinez, Pascual, & Perea, 1990; Neely, 2000). Once the organism contaminates a
contact surface, it can then be transmitted to patients and staff through hand contact with
the contaminated surface (Kagan et al., 2002; Rusin, Maxwell, & Gerber, 2002; Scott et
al., 2009). This may be a concern in health care facilities where susceptible persons are
seen on a regular basis.
Indoor contaminants such as mold and bacteria are a potential public health
concern due to the risk of infectious disease and exposure of toxic agents (Kujundzic et
al., 2005). This health risk may be higher in persons who are more susceptible to disease
than healthy adults (Jacob et al., 2002). This would include persons who are immunecompromised, ill, young, and elderly, as they may not have the ability to fight off the
infection or toxins (Durston, 2007). Infection rates for persons who are susceptible to
these microorganisms are high and appear to be continuing to climb (CDC, 2008b). More
knowledge on interventions that can help reduce the risk of disease from these
contaminants is needed, especially for susceptible populations.
It is estimated that as many as 70% of the U.S. and Canadian populations work
indoors (Menzies, Hanley, Rand, & Milton, 2003). The risk to workers who occupy these
buildings is high as they have extended periods of exposure to whatever contaminant is
6
present (Menzies et al., 2003). Symptoms such as headaches, muscle pain, and
respiratory illness have been associated with persons living and working in contaminated
buildings (Gyntelberg et al., 1994; Samuel & Strachan, 2006). These symptoms may be
linked to environmental factors such as certain microorganisms found indoors (Menzies
et al., 2003). In a health care setting, workers have an added concern of being exposed to
even more dangerous microorganisms such as MRSA (Johnston et al, 2006).
Much of the literature on disease caused by microorganisms has been devoted to
hospital-acquired infection. A gap in literature exists on the effects of indoor
microorganisms for most other types of health care buildings including outpatient clinics,
physician‟s offices, and assisted-living facilities. While the prevention of indoor
microorganisms is important in a hospital setting, it is also critical for other health care
facilities where the threat of infection has grown over the past decade (Johnston et al.,
2006; Raygada & Levine, 2009). A possible reason for the increased risk for infection in
nonhospital health care facilities may be related to these facilities receiving limited
guidance on infection control practices including effective cleaning, disinfection, and
surveillance (Abramson, et al, 2000; Johnston et al., 2006). Persons suffering from
infectious disease, including skin infection and gastrointestinal illness, are found at both
hospital and nonhospital health care settings, possibly aiding in the transmission of
microbes between facilities.
The indoor microbiological contaminants are expensive, costing the United States
billions of dollars each year through employee sick days and increased medical costs
(Menzies, 2003). The total cost of the contaminants may be difficult to quantify, as less
severe illnesses such as headache or fatigue may result in the loss of productivity and in
7
the case of health care workers, patients receiving less than optimal service (Gaba &
Howard, 2002).
There are many factors contributing to the presence of indoor contaminants.
Among these are reduced ventilation, inadequate cleaning, inadequate disinfection, and
old or poorly constructed buildings (Tilton, 2003). Once inside a building, indoor
contaminants can be easily transmitted from person to person through contact surfaces
including medical equipment, computers, and employee hands (Neely & Sittig, 2002).
This study contributes to the body of knowledge by adding data on the efficacy of an
antimicrobial system at reducing indoor microbiological populations.
Literature on indoor bacteria is directed at identification of potential avenues for
infection. This would include common contact surfaces such as those found in exam
rooms, patient rooms, waiting rooms, bathrooms, and office areas (Bures et al., 2000;
Donlan, 2001; Lawson, Saur, & Loritsch, 2002; Neely et al., 2005; Scott et al., 2009). A
gap in knowledge exists on interventions that can effectively reduce bacteria on these
surfaces in health care buildings.
Advanced Oxidation and Antimicrobial Interventions
The advanced oxidation process is an antimicrobial technology that is purported
to offer a safe and effective means for reducing indoor microbiological contaminants in
the air and on surfaces in health care facilities. The advanced oxidation system works by
treating the indoor environment with multiple oxidizers including ultraviolet light,
hydrogen peroxide, and ozone at low levels (Fink, 2004; Gamage & Zhang, 2010). In
chapters 2 and 3, there is a more detailed discussion on the advanced oxidation process.
8
Originally the advanced oxidation process was developed as a way to remove
contaminants from water (Camel & Bermond, 1998). The technology has now progressed
to where the antimicrobial treatment can be applied to an indoor environment. The RGF
Environmental Group has developed a patent pending advanced oxidation device, air
purification system (APS), which utilizes a photohydroionization (PHI) reaction.
“Photohydroionization reactors employ a broad spectrum high intensity UV light targeted
on a quad metallic catalyst ultraviolet (UV) target in a moist atmosphere” (Fink, 2004, p.
1). Used as an indoor antimicrobial treatment the PHI technology may have the potential
to reduce microbial levels in the air, as well as on contact surface.
The PHI reaction possesses antimicrobial properties, however, data is lacking
with respect to its effectiveness in an applied real-world setting (Ortega, Franken,
Hatesohl, & Marsden, 2007). The research study determined whether this technology has
potential as an antimicrobial intervention, which is a critical step in it gaining acceptance
by infection control, environmental health, and occupational health professionals
(National Science Foundation, 1994; Reybrouck, 1998).
The gap in knowledge on the PHI advanced oxidation process includes the
treatment‟s effectiveness in a health care environment. An applied research study in a
health care facility fills a gap in knowledge by addressing issues common to practical
application including length of treatment, distance from the treatment, strain of
microorganisms found, contaminant levels, constant reinoculation of microorganisms,
treatment across rooms, environmental conditions such as surface soils, temperature, and
humidity. This research would also help in identifying another antimicrobial intervention
9
for building engineers, infection control, and occupational health professionals, who are
responsible for keeping health care facilities safe from potential harmful microorganisms.
There are other environmental interventions for the reduction of indoor
microbiological populations in the air and on surfaces in an occupied building.
Treatments that have been studied include ultraviolet (UV) germicidal lamps, air filters,
and ionizers (Hick, 2007; Kogan, Harto, Hesse, & Sparks, 2007; Rudnick & First, 2007).
UV lamps destroy microorganisms, but are only effective where the UV light comes in
close contact with the contaminant (Kujundzic, Hernandez, & Miller, 2007). The UV
germicidal lamps also have a safety issue, as direct exposure to the UV light can be
harmful to humans. Air filtration systems are used by many types of organizations,
including health care organizations, to clean the air of harmful microorganisms. While air
filtration can be effective, there are a several major limitations of air filters for removing
indoor contaminants (Clausen, 2004). First, the air filters only remove contaminants from
the air and have little effect on surface contaminants. Second, the filters must be changed
regularly or the filters become ineffective. Finally, cost of maintaining a micro air
filtration system can be high. Electrostatic precipitators (ionizers) are another common
intervention that has shown to be effective in reducing indoor contaminants, but does not
reduce surface microorganism (Kogan et al., 2007; Mazur & Kim, 2006). Ionizers also
require frequent cleaning or the system may become a breeding ground for
microorganisms (Mazur & Kim, 2006).
The most common way to reduce microbiological populations on surfaces is to
use conventional cleaning and disinfection methods with strong chemicals that often
require repeated applications (Kuhn et al., 2003). While conventional methods serve an
10
important role in the overall prevention plan, the effectiveness of these practices appear
limited (Kuhn et al., 2003). Conventional methods have also been known to cause further
spread of microorganisms and help produce resistant strains (Dharan et al., 1999; Kuhn et
al., 2003). There is a gap in knowledge of the effectiveness of alternative interventions
which can be easily applied to an indoor environment that do not aid in the development
of resistant strains or the further spread of bacteria. These interventions are discussed
further in chapter 2.
Statement of the Problem
The problem addressed by this study is whether an advanced oxidation treatment
can significantly reduce microbiological populations in the air and on surfaces in a health
care building. Effective interventions should reduce or eliminate microorganisms in
buildings where susceptible persons may be present. Currently, indoor contaminants such
as mold can be found in the air of most buildings (Gots, Layton, & Pirages, 2003; Price et
al., 2005). Bacteria including MRSA, Staphylococcus aureus, and Pseudomonas species
may be found on many common surfaces throughout buildings (Huange, Mehta, Weed, &
Price; 2006; Kusumaningrum, Riboldi, Hazeleger, & Beumer, 2003; Neely, 2000; Neely
& Maley, 2000; Scott et al., 2009). There are few treatments available outside of
conventional cleaning and disinfection practices that can effectively reduce or eliminate
these contaminants (French et al., 2004). Exposure to these microorganisms may lead to
infection or disease, especially if persons are susceptible such as children, ill, elderly, or
immune-compromised (Utrup, Werner, & Frey, 2005).
11
Nature of the Study
This quantitative, experimental study evaluated the effects of a daily advanced
oxidation treatment of an indoor environment at a local health department building, to
reduce microbiological population. A total of 90 control and 120 intervention samples of
the building air, and 108 control and 144 intervention samples of the building surfaces
were collected over a 7 week period. The population for this study consisted of common
indoor microorganisms and included mold in the air, and MRSA, Staphylococcus aureus,
and Pseudomonas species on common contact surfaces. Indoor microbiological
contaminants are commonly found in occupied buildings (Griffith, Cooper, Gilmore,
Davies, & Lewis, 2000: Price et al., 2005). In health care facilities these contaminants
pose a treat of disease to the susceptible populations present (Durston, 2007; Hota, 2004;
Utrup et al., 2005). Keeping the indoor environment as clean as possible is one method
for health care organizations to limit the risk patients and staff of contracting an infection,
as a result of exposure to these contaminants (Dancer, 2004; Dharan et al., 1999;
Johnston et al. 2006). In this study the reduction in counts between the control and
experimental groups were compared to answer four research questions and hypotheses. A
more detailed discussion of each of the research questions and hypotheses can be found
in chapter 3.
Research Questions and Hypotheses
Research Question 1. Does an advanced oxidation treatment, applied to the indoor
environment of a health care facility for 12 hours daily, reduce mold mean counts or
detectable mold in the air by at least 90%, as measured by microbiological cultural
plating of indoor air on YM Agar?
12
H01 - Mold mean counts in the air, as measured by microbiological cultural
plating of indoor air on YM Agar, will not be affected by daily 12 hour advanced
oxidation treatments of the indoor environment.
Ha1 - Mold mean counts will be reduced in the air, as measured by
microbiological cultural plating of indoor air on YM Agar, after daily 12-hour advanced
oxidation treatments of the indoor environment.
Research Question 2. Does an advanced oxidation treatment, applied to the
indoor environment of a health care facility for 12 hours daily, reduce MethicillinResistant Staphylococcus aureus (MRSA) mean counts or detectable MRSA on surfaces
by at least 90%, as measured by microbiological cultural plating of swabbed surfaces on
MRSA agar?
H02 - Methicillin-Resistant Staphylococcus aureus (MRSA) on surfaces, as
measured by microbiological plate counts of surface swabs of MRSA agar, will not be
affected after daily 12 hour advanced oxidation treatments of the indoor environment.
Ha2 - Methicillin-Resistant Staphylococcus aureus (MRSA) counts will be
reduced on surfaces, as measured by microbiological plate counts of surface swabs of
MRSA agar, after daily 12-hour advanced oxidation treatments of the indoor
environment.
Research Question 3. Does an advanced oxidation treatment, applied to the indoor
environment of a health care facility for 12 hours daily, reduce Staphylococcus aureus
mean counts or detectable Staphylococcus aureus on surfaces by at least 90%, as
measured by microbiological plate counts of swabbed surface diluents on Baird Parker
Agar?
13
H03 - Staphylococcus aureus mean counts on surfaces, as measured by
microbiological plate counts of surface swab diluents on Baird Parker Agar, will not be
affected after daily 12 hour advanced oxidation treatments of the indoor environment.
Ha3 - Staphylococcus aureus counts will be reduced on surfaces, as measured by
microbiological plate counts of surface swab diluents on Baird Parker Agar, after daily
12-hour advanced oxidation treatments of the indoor environment.
Research Question 4. Does an advanced oxidation treatment, applied to the indoor
environment of a health care facility for 12 hours daily, reduce Pseudomonas spp. counts
or detectable Pseudomonas spp. on surfaces by at least 90%, as measured by
microbiological plate counts of swabbed surface diluents on Pseudomonas Isolation
Agar?
H04 - Pseudomonas spp. counts on surfaces, as measured by microbiological plate
counts of surface swab diluents on Pseudomonas Isolation Agar, will not be affected after
daily 12 hour advanced oxidation treatments of the indoor environment.
Ha4 - Pseudomonas spp. counts will be reduced on surfaces, as measured by
microbiological plate counts of surface swab diluents on Pseudomonas Isolation agar,
after daily 12-hour advanced oxidation treatments of the indoor environment.
Purpose of Study
The purpose of this study was to test the efficacy of an advanced oxidation
treatment for reducing specific microbiological populations in a health care building. This
study included the measurement of mold counts in the air and bacteria counts (MRSA,
Pseudomonas spp., and Staphylococcus aureus) on surfaces. There is currently a lack of
information available on the effectiveness of advanced oxidation technology for use in
14
remediation of indoor contaminants in an occupied indoor setting. The advanced
oxidation system used in this study supplied the environment with a daily treatment of
oxidizers at low levels. This was the first independent study to evaluate the effectiveness
of an advanced oxidation technology for reducing microbiological populations in an
applied health care setting. The setting for the study is a health department building
located in a large Midwest city. Within the building a patient waiting area, exam rooms,
and bathroom air and surfaces will be evaluated for microbiological levels before and
after the advanced oxidation intervention.
The independent variable for this study was defined as the daily 12-hour
application of an advanced oxidation treatment in a health care facility. The dependent
variables are defined as the number of mold counts found in air samples and bacterial
counts for MRSA, Pseudomonas spp., and Staphylococcus aureus found on surfaces. The
control and intervening variables included microbiological plate counts on media specific
for selection of mold, MRSA, Staphylococcus aureus, and Pseudomonas spp.
Theoretical Base
Microorganisms are a normal part of indoor environments and can contribute to
adverse health effects in building occupants (Mendell et al., 2002; Neely, 2000). It has
been hypothesized that by reducing the levels of these indoor microorganisms, the risk of
adverse health effects to occupants will be decreased (Menzies et al., 2003). One way to
possibly reduce microbiological populations is through the use of oxidizers, which
destroys the organism through a process called cell lysing, where the cell wall is ruptured,
thereby killing the organism (Pope, Eichler, Coates, Kramer, & Soracco, 1984). The use
of multiply oxidizers also known as advanced oxidation for the reduction of
15
environmental contaminants was first theorized by Bolton, Bircher, Tumas, & Tolman
(1996). These researchers put forth the idea that multiple oxidizers used at low levels can
destroy organic contaminants such as mold and bacteria in the air and on surfaces. Ortega
et al. (2007) confirmed this theory that advanced oxidation process had antimicrobial
properties in a basic laboratory study. The application of the advanced oxidation process
in an occupied building is based on the theory by Daniels (2007) that these systems can
be applied to commercial, industrial, and residential buildings as a means to reduce
indoor contaminants and improve indoor environmental quality. Daniels (2007) also
proposed that the application of advanced oxidation systems in buildings is an important
intervention in the control of unusual events such as infectious disease outbreaks. This
study builds on this theory by identifying the benefits of the advanced oxidation
technology in an applied health care setting where indoor microbiological contaminants
pose a risk to patients and health care workers (Johnston et al., 2006; Raygada & Levine,
2009).
Definition of Terms and Variables
Advanced oxidation is defined here as the production of hydroxyl radicals in
sufficient quantity to affect decontamination (Glaze & Kang, & Chapin, 1987). A
common method of producing these highly reactive hydroxyl radicals is the combination
of ozone (O3), hydrogen peroxide (H2O2), and ultraviolet (UV) radiation.
Conventional cleaning is defined here as the removal of visible soil from objects
and surfaces, and is normally accomplished manually or mechanically using water with
detergents or enzymatic products (Rutala & Weber, 2008)
16
Conventional disinfection is defined here as a process that eliminates many, or all
pathogenic microorganisms, except bacterial spores, on inanimate objects (Rutala &
Weber, 2008).
Critical surfaces is defined as a surface, which carries a high risk of infection if it
becomes contaminated, or comes in contact with mucous membranes, or non-intact skin
(Rutala & Weber, 2008).
Noncritical surface is defined as surface that may come in contact with intact
skin, but not mucous membranes (Rutala & Weber, 2008).
Photohydroionization (PHI) is a unique form of advanced oxidation that consists
of a high-intensity broad spectrum UV tube (100-300nm) in a hydrated catalytic matrix
cell (quad-metallic). “Low-level ozone is produced in the cell, the majority of which is
converted into airborne hydro peroxides, super oxide ions, ozonide ions, and hydroxides”
(Fink, 2004, p. 7).
Sponge-stick is a device used for aseptically collecting microorganisms from
surfaces. The sponge-stick consists of a sterile sponge attached to a removable plastic
stick, and is manufactured by 3M Corporation, St. Paul, MN.
Assumptions
It is assumed that the study building is generally comparable to other health care
buildings. Microorganisms found in the health care facility are believed to be
contaminants common to most health care buildings. It is understood that surfaces found
in the health department are comparable to those found in other health care facilities. The
health department‟s ventilation and air handling system is assumed to be analogous to
other buildings. This includes windows which are designed to remain closed at all times.
17
It is assumed that other health care facilities use cleaning and disinfection methods
similar to those used by the health department. It is assumed that the study building has
patient traffic levels similar those of other health care buildings. In the application of an
antimicrobial intervention, it is presumed that advanced oxidation devices can be
installed in any health care building and at equal levels throughout the facility. Room
sizes of the health department building are considered to be comparable to room sizes of
other health care facilities.
Scope
The scope of this study was limited to evaluating an antimicrobial intervention in
a health care facility. This includes testing for microorganism in the indoor air and on
common contact surfaces. The intervention included an advanced oxidation treatment
applied over a 1-month period with microbiological testing on Days 5, 10, 20, and 30.
Testing consisted of analysis of microorganisms in the air and on contact surfaces. Air
samples were collected before and after the intervention to determine the effectiveness at
reducing mold populations. Contact surface samples were collected before and after the
intervention to determine the effectiveness at reducing MRSA, Staphylococcus aureus,
and Pseudomonas spp. populations. It is likely that all the microorganisms mentioned
above would be found throughout the building.
Delimitations
The study was confined to microbiological testing of the air and surfaces of a
health care facility with outpatient clinics. A number of alternative study locations were
considered. Testing in another type of health care building such as a hospital or an
assisted living facility was considered, but was not selected for several reasons. First, the
18
use of these facilities was not feasible due to access and availability. Second, these
facilities may not have as high of microbiological levels, as outpatient clinics are often
cleaned less frequently and have fewer infection control resources (Johnston et al., 2006).
Third, the large building size of the hospitals and assisted living facilities considered for
this study made them impractical for the application of this intervention. There were only
a limited number of advanced oxidation units available to the researcher to conduct the
study. Conducting the study in a nonhealth care setting such as an office building or a
school would be beneficial, but was not considered, as health care facilities offer added
potential for this intervention.
Testing the effect of advanced oxidation against other common health care
microorganisms such as Clostridium difficile, Enterobacteriaceae, and VancomyocinResistant Enterococci were not considered, as those organisms may not be present in the
study building. Considering that this is the first study of its kind using advanced
oxidation, it is important to test the intervention on some of the most prevalent
microorganisms, such as MRSA, Staphylococcus aureus, Pseudomonas spp., and mold.
Mycobacterium tuberculosis was not considered due to employee safety issues and
variable consistency of the microorganism being present in the building. Testing the
effectiveness of the advanced oxidation treatment against viruses such as influenza would
be beneficial, but is not practical for this study. Virus testing is highly seasonal and
requires expertise in testing that is not available for this study. Testing of noncontact
surfaces in the building for microbiological populations was not considered, as these
areas would be unlikely to contribute to the spread of disease. Noncontact areas include
areas such as walls, floors, and ceilings.
19
Limitations
A limitation of this study was low levels of certain microbiological populations
which made it difficult to show the maximum effectiveness of the advanced oxidation
treatment. Lower microbiological counts can make it more of a challenge to show
statistical variation between control and intervention groups. A possible limitation of the
study, which did not prove to be an issue, involved cofounders from outside sources
possibly affecting microbiological levels in the building. For example, outdoor mold or
mold from other parts of the building could have caused an increase in mold in the test
areas. A limitation of the study that was addressed in the study design involved the
control over other antimicrobial interventions that could have affected microbiological
counts in test areas. For example, surfaces selected for this study were not regularly
cleaned, but could have been a threat to validity if these areas were manually cleaned
during one of the treatments. Another potential limitation that was addressed in the study
design included objects identified for surface testing needing to remain in their assigned
testing zone throughout the duration of the study. If an object identified for testing were
moved from one zone to another, this could have threatened the study validity, as the
object surface may have received a change in treatment as a result of the move. A
possible limitation of this study was control over environmental conditions, such as
temperature and humidity, which could have impacted microbiological counts in the
building. These variables were addressed in the data analysis discussed further in chapter
4.
20
Significance of Study
The significance of the study is the opportunity for increased environmental
quality in health care settings where susceptible populations are at risk of disease from
microbial contaminants in the air and on surfaces. The reduction of indoor contaminants
in the air and on surfaces needs to be addressed as it is a growing public health concern
that impacts the health of millions (Kujundzic et al., 2005). Indoor microbiological
contaminants have been found to be associated with common disease such as asthma,
allergies, skin infections, and gastrointestinal illness (Jabob et al., 2002; Liu et al., 2008;
Smedje, Norback, & Edling, 1997; Stevenson, 2008). This study took place in an
outpatient health care setting where the prevention of infections in small children,
pregnant women, ill, and immune-compromised patients is an important objective
(Campos-Outcalt, 2004). Contaminated, noncritical contact surfaces common to these
facilities can be routes of infection through transmission from hands to eyes, nose, mouth,
or opening on the skin (Bloomfield, Aiello, Cookson, O‟Boyle, & Larson, 2007; Johnston
et al., 2006; Poland, Tosh, & Jacobson, 2005; Rusin, Maxwell, & Gerba, 2002).
Microbiological contamination can also be transferred from noncritical contact surfaces
to critical contact surfaces by health care workers or patients (Matlow & Morris, 2009;
Rutala & Weber, 2001). Health care facilities are major users of antimicrobials to reduce
microbiological population (Maillard, 2005). Before an antimicrobial can gain acceptance
in a health care facility, the technology needs to be proven effective in practical situations
(Reybrouck, 1998). This study may be generalizable to other occupied buildings for
reducing the risk of illness from known indoor contaminants, also referred to, as building
related illness (EPA, 2008a). This study advanced social change by increasing awareness,
21
knowledge, and understanding of the benefits of reduced microbiological contaminants in
all health care facilities including both hospital and nonhospital settings. This research
provides health care organizations a method for reducing costs, and if effective, may
result in fewer facility-acquired infections, reduced absenteeism, and improved
performance of workers. Advanced oxidation has advantages over other antimicrobial
interventions including labor-free application and treatment of the entire environment
including the air and all exposed surfaces. The application of an effective antimicrobial
intervention, using an advanced oxidation, would encourage building engineers, infection
control, and occupational professionals to make indoor environments safer for occupants
and create social change (Mendell et al., 2002). These stakeholders can help to ensure
that patients and health care workers are safe from microbiological contaminants found in
health care buildings.
Summary
There is a need for additional interventions to stop the spread of disease by
reducing microbiological population in health care facilities. Mold found in the air in
health care buildings may contribute to disease, especially in susceptible populations
(Hille, 2007). Bacteria found on surfaces may increase the risk of infection for patients
and health care workers (Utrup et al., 2005). Current practices for the control and
prevention of potentially harmful microorganisms found in health care facilities may not
be sufficient and in some cases may even spread harmful bacteria (Dharan et al., 1999;
Kuhn et al., 2003). This study investigated the use of an indoor environmental cleaning
technology that might aid in reducing or eliminating these microorganisms.
22
In chapter 2, current prevention measures to stop the spread of disease from
indoor microbiological contaminants are reviewed along with a discussion on literature
regarding the use of PHI advanced oxidation technology for reducing microbiological
populations. The literature review includes a discussion of similar research methods used
to study indoor microbiological populations. The chapter also examines recent scholarly
literature regarding the impact of indoor microorganisms on human health in the air and
on surfaces in health care facilities. Sources of airborne mold are identified along with a
discussion on the adverse health effects these contaminants have on occupants. Literature
is reviewed on bacterial contaminants found on common health care surfaces and the
impact these contaminants have on human health.
Chapter 3 includes a description of the methodology used to answer the research
questions. This includes a description on the use of ANOVA analysis and regression
analysis as a valid means to analyze the effect between the advanced oxidation treatment
and the reduction of microbiological population in the building. The chapter includes a
review of the study design, sample population, advanced oxidation treatment, procedures,
measures, data analysis, and ethical considerations.
Chapter 4 is comprised of descriptive and statistical analysis of count reductions
for each of the study microorganisms according to proximity to the treatment and length
of exposure. Chapter 5 consists of conclusions on the efficacy of the advanced oxidation
technology in a health care facility, based on the study results. The final chapter also
includes recommendations for the application of the technology in a health care facility
and for further research.
23
Chapter 2: Literature Review
Introduction
The chapter presents a brief overview of how surfaces and air can become
contaminated in the health care setting, the types of surface and air microbes relevant to
health care settings, and a review of research conducted on various interventions used to
reduce indoor microorganisms in the air and on surfaces. Interventions studied include
surveillance, conventional cleaning, disinfection, air filtration, use of electrostatic
precipitators, and ultraviolet germicidal light. Mechanisms of action and previous
research on the advanced oxidation process and the PHI Advanced Oxidation Technology
are discussed. The chapter concludes with a discussion on research methods commonly
used to measure indoor microbiological contaminants.
The strategy used for this literature review focused on the evaluation of peerreviewed journals that addressed issues relating to environmental health, infectious
disease, and public health. Web-based informational sites such as the Centers for Disease
Control and Prevention (CDC) and the U.S. Environmental Protection Agency were also
used to help in understanding the impact of poor indoor air quality. Word searches on
these web sites to better understand the problem of microorganisms found in health care
facilities included: indoor air quality, health care infection, outbreak, mold,
Staphylococcus aureus, MRSA, and Pseudomonas species. Word searches used to
identify interventions to treat indoor environments included: conventional cleaning,
disinfection, air filters, ionizers, surveillance, hydrogen peroxide, ozone, ultraviolet light,
and advanced oxidation. Studies directed at reducing microbiological levels in occupied
indoor environments and on oxidative technology were included in the literature search.
24
Studies evaluating outdoor microbiological contaminants and antimicrobial interventions
designed for unoccupied buildings were excluded. This strategy helped to focus the
review on research studies applicable to the one proposed in this paper.
Sources of Contamination in Health Care Facilities
On average, persons spend about 95% of their time inside buildings where they
are at risk of exposure when indoor contaminants are present (Hedge 2000; Ott &
Roberts, 1998). In health care facilities, environmental contaminant exposure is even
more relevant, as the population is typically susceptible to these contaminants (Beggs,
2003). The spread of communicable disease through indoor contaminants is an important
health issue and has been well documented (Beggs, 2003; Johnson, Croghan, &
Crawford, 2003; Li et al., 2007). Microbial contaminants in the air and on surfaces can
contribute to the spread of disease (Menzies, 2003). While microorganisms found in any
occupied building may be a concern, in health care facilities these same microorganisms
have additional opportunity to cause adverse health effects as a result of the susceptible
populations being present (Durston, 2007; Hota, 2004; Jacob et al., 2002).
Hospitals, assisted living facilities, and surgical centers can expose occupants to a
number of potentially dangerous environmental microorganisms often as a result of
invasive procedures, contaminated medical devices, or from other contaminated
environmental surfaces (Matlow & Morris, 2009). These facilities are impacted by
microorganisms that are both specific to healthcare-associated and community-associated
infection (Raygada & Levine, 2009). While many of these facilities have extensive
cleaning and disinfection programs along with infection control specialists, they still
25
appear to be challenged in preventing the spread of infection inside their buildings
(Fabregas & Bello, 2003; White, Dancer, & Robertson, 2007).
Health care facilities including outpatient clinics, physician‟s offices, dental
offices, and physical therapy centers can also be sources for the spread of disease from
indoor contaminants through minor medical procedures and environmental contacts
(Matlow & Morris, 2009). These facilities have recently seen an increase in infectious
disease from indoor microorganisms possibly as a result of continued spread of
community associated antimicrobial-resistant microorganisms and from less stringent
infection control practices (Gaygada & Levine, 2009). Outpatient clinics and physician‟s
offices also have limited treatment options for these infections and often must deal with
the same susceptible populations as hospitals (Matlow & Morris, 2009). The proposed
research study was conducted in outpatient clinics located in a local health department.
Patients seen in this facility includes persons who may be susceptible to disease such as
children, pregnant woman, and those who are ill, immune-compromised, or elderly
(Durston, 2007; Hota, 2004; Jacob et al., 2002).
There is a need for additional interventions such as advanced oxidation that can
help to reduce indoor microorganism levels, as health care buildings are constantly being
reinoculated. Building design, materials used in construction, and upkeep all contribute to
contaminant levels in these facilities (Mendell et al., 2002). During the past several
decades, indoor contaminant levels have become a rising health issue, as engineers have
worked to create buildings that have increased climate control capabilities for occupant
comfort and reduced energy costs. While these efforts have helped reduce energy usage,
they may also be causing increased levels of microbiological contaminants. A study
26
conducted by Engvall, Norrby, and Norback (2003) found that buildings renovated for
better energy efficiencies were more likely to be associated with an increase in adverse
health conditions. The study by Engvall et al. (2003) detailed causes of indoor
contaminants, but did not address potential interventions used to reduce their levels in
buildings. As health care facilities go through routine remolding, building engineers may
want to consider interventions such as advanced oxidation, which can counter the effects
of increased indoor contaminants caused by the building design changes.
Buildings that have unknown indoor contaminants at levels high enough to cause
health concerns are often said to be suffering from sick building syndrome (SBS). SBS is
a broad term that has been used to describe the significance of contaminants in buildings.
SBS is considered any building that causes health problems such as allergies, rashes,
respiratory problems, dizziness, loss of concentration, and headaches (Gyntelberg et al.,
1994; Samuel & Strachan, 2006). The causes can derive from a wide range of sources,
but poor ventilation is attributed to many indoor illnesses (Bahnfleth & Kowalski, 2005).
Li and associates (2007) reviewed the impact of building ventilation systems on human
health. An expert panel of medical and environmental health experts reviewed original
research studies on this topic over the previous 45 years. The panel found convincing
evidence to support the association between the spread of infectious disease and poor
ventilation in a building. Ventilation systems aid in the spread of disease by giving
microorganisms a means to travel to different locations in a facility. There are two ways
that ventilation systems can aid in the spread of these microorganisms. First, when ducts
are not cleaned regularly they can release small particles into the air (Tranter, 2005).
Microorganisms attached to these particles or by themselves can easily travel throughout
27
a building by air movement infecting anyone in the facility (Lueng & Chan, 2006).
Second, inadequate ventilation can increase contaminant levels by not bringing in enough
outdoor air to dilute emissions from indoor sources (Engvall et al., 2003). Energy
efficiency efforts have limited the amount of fresh air circulated throughout buildings,
making it more difficult for infection control managers and building engineers to prevent
disease (Engvall et al., 2003).
Factors such as how old the source is and whether it is properly maintained are
also significant (Tilton, 2003). Buildings used for health care facilities can vary in age
and may include older buildings. Older buildings seem to be at risk of having increased
levels of indoor microbiological contaminants through structural decay such as leaky
pipes and old, outdated ventilation systems (McGovern, 2002; Meklin et al., 2003). Even
newer health care buildings may be a source for indoor microorganisms if poorly
maintained or inadequately designed (Narui et al., 2009). Infection control professionals
and building engineers need viable interventions to reduce microbiological levels that can
be easily applied to any type of building.
Patients entering a health care facility can be important contributors in the
transmission of potentially harmful microorganism in health care buildings. There is
evidence that up to 80% of health care infections are caused by the microbial flora that
patients bring with them to the health care facilities (Tilton, 2003). Patients can spread
these microorganisms throughout a building by everyday activities such as coughing,
talking, and touching of objects or other occupants (Lis, Pacha, & Idzik, 2009, p. 177).
This micro-flora can then take advantage of the new environment and spread the risk of
disease throughout the building (Sing, 2001). Currently, there appears to be a lack of
28
interventions designed to reduce this disease risk that patients bring with them into a
health care facility (Hitt, 2011). Only a limited number of hospital and assisted living
facilities are performing screening of patients for potentially harmful microorganisms and
those who are typically only screen patients who are at highest risk of being carriers
(Diekema & Edmonds, 2007).
Health care workers are a potentially concerning source for the spread of
microorganisms in health care buildings, as they may affect the health of patients they are
treating (Poland et al., 2005). Health care workers can transfer microorganism to patients
through direct skin to skin contact or indirectly though contact with an object or surface
that the worker may have contaminated (Johnston et al., 2006).
Poor hand hygiene practices by health care workers and patients may be an
important factor in the spread of microbiological contaminants in a building (Bischoff,
Reynolds, Sessler, Edmond, & Wenzel, 2000). Dirty hands can give microbes a quick and
easy means to travel to surfaces throughout a health care building (Gamage & Zhang,
2010). Education on the importance of good hand hygiene would seem to be an effective
way to increase hand washing, but some research has shown it to have little effect.
Bischoff et al. (2000) found that a hand hygiene education intervention was ineffective at
improving hand washing in a health care facility. This would indicate that contact
surfaces in health care facilities may be constantly exposed to microorganisms by
occupants. Interventions which aid in keeping the indoor environment clean, like the
advanced oxidation treatment, could help reduce the spread of microbes by patients and
health care workers.
29
Objects brought into a building may also be a source for microorganisms to enter
a health care facility. This may include used medical or office equipment brought into the
facility that has been contaminated with a potentially harmful microorganism (Donlan,
2001; Neely et al., 2005). Contaminated food can also be a source for microorganisms
inside a health care facility affecting patients and staff, either through consumption of the
food or by contaminating the environment (Welinder-Olsson, et al., 2004).
Another factor impacting control and prevention measures for health care
infections may be the lack of resources. Infection control managers are challenged to
prevent the spread of disease inside their health care facility often with limited support
and staff (Fabregas & Bello, 2003). Microorganisms within the health care facility have
multiple routes, which promote the spread of infectious disease. These routes of infection
within the health care facility are often related to cutbacks in staffing, which places a
greater burden on the medical staff to not only treat patients, but keep from spreading
infection (Chotani et al., 2004). Infection control managers must also compete for
available funds and resources. Even though health care infection rates continue to
increase there is a competition with other higher profile health issues such as bioterrorism
and pandemic influenza (Chase, 2006).
The following sections of this chapter detail variables that contribute to indoor
microorganisms. Microbes reviewed in the chapter are common indoor contaminants that
impact the health of persons in many health care facilities. This includes mold that can be
commonly found in the air and MRSA, Staphylococcus aureus, and Pseudomonas
species found on surfaces.
30
Indoor Air Contamination and Mold
Mold is a common cause of indoor air contamination in many buildings including
health care facilities (Price et al., 2005). Mold is part of the fungi family of
microorganisms, which also include yeast. There are thousands of known species of
molds; some are used in production of foods and medicines while other species are
known to be opportunistic pathogens (Ryan & Ray, 2004). Mold also gives off spores and
mycotoxins that cause irritation, allergic reactions, or disease, especially in immunecompromised persons (Bahnfleth & Kowalski., 2005). Airborne mold has been found to
be associated with common diseases including asthma and chronic sinusitis. Chronic
sinusitis is an inflammation of the nose and sinus cavity that affects over 16% of
Americans (Mayo Clinic, 1999). Dennis (2003) found that patients suffering from
chronic sinusitis who had recurring exposure to airborne mold had an increased risk of
having sinusitis symptoms. Dennis also found that by reducing the level of mold
exposure to less than four colonies per 1-hour agar gravity plate exposure, patients were
less likely to suffer symptoms.
Asthma is a disease that affects both adults and children, and is easily aggravated
by indoor air contaminants such as mold (Smedje et al., 1997). The relationship between
indoor air contaminants and asthma is complex, but an association between indoor mold
and asthma has been shown. In a nested case-referent study by Thorn, Brisman, and
Toren (2001), an increased odds ratio for asthma was observed with exposure to mold in
adults 20-50 years of age.
In children, asthma is an especially concerning health issue as it is one of the most
common chronic diseases (CDC, 2008a; Jones et al., 2011). Mold exposure has been
31
found to be associated with asthma in children. In a study by Kim et al. (2007) of school
aged children, asthma was significantly associated with exposure to higher concentrations
of mold and mold produced organic compounds. The authors also found this association
existed despite any visible evidence of mold growth. This would suggest that health care
facilities with high, nonvisible mold levels may be placing children at greater risk for
asthma.
Mold exposure in childhood may have an impact on human health that lasts
throughout adulthood. According to Bjorksten (1999), exposure to indoor mold early in
life may be a factor in sensitizing genetically susceptible individuals to this allergen later
in life, resulting in the development of asthma. This would suggest that building
engineers and health care facilities take serious the impact that indoor mold may have,
especially when infants and small children are present.
Mold in a building may be linked to other environmental contaminants commonly
found in buildings. There are a number of contaminants found in indoor air that can
activate allergic symptoms in persons of these dust may be one of the most common
(Kildeso, Tornvig, Skov, & Schneider, 1998; Tranter, 2005). Dust in buildings typically
contains fine particles from a number of different sources including mold (Tanter, 2005).
Kildeso et al. (1998) investigated levels of airborne dust in buildings and found that it had
a direct correlation to the dust and dirt found on the surfaces of the occupied building.
These researchers also discovered that even with thorough cleaning of surfaces, there was
still dust present in the air (Kildeso et al., 1998). This study supports that additional
interventions are needed in reducing mold counts in the air that cannot be reduced
through conventional cleaning methods.
32
A few of the more common indoor mold strains associated with disease are
Chaetomium species, Penicillium species, and Stachybotrys species (Wilson et al.,
2004). A study by Cooley, Wong, Jumper, and Straus, (1998) found that Penicillium and
Stachybotrys molds had the highest prevalence in 48 schools where indoor air complaints
had been recorded. Exposure to mycotoxins can cause symptoms that include coughing,
wheezing, runny nose, irritated eyes or throat, skin rash, and diarrhea. The study by
Cooley et al. (1998) showed an association between mold and indoor air complaints, but
did not address at what levels the mycotoxins need be present in the air to cause these
symptoms.
Stachybotrys, also known as black mold can be found in homes or buildings long
after repairs to eliminate leaks of moisture are completed. The reason for this extended
contamination period is directly related to the organisms ability to survive. Wilson et al.
(2004) found that in spite of being without moisture this organism remained toxic for up
to 2 years in standard drywall. This research would support the theory that a continuous
air treatment such as the one used in this study may be beneficial in reducing the health
risks, which these types of contaminants pose.
As mentioned above, the impact of mold on human health is well documented
(Bahnfleth & Kowalski, 2005; Wilson et al., 2004). According to Gots et al. (2003), what
is not yet fully understood is at what level of exposure these organisms become
dangerous to occupants. In the article by Gots et al. (2003), published literature on fungi
levels in 149 commercial buildings, and 820 residential buildings were reviewed. The
authors found that the commercial buildings had an average indoor fungi count of 233
colony forming units (CFU) per cubic meter and the residential buildings had an average
33
count of 1,252 CFU. The authors noted that a large portion of both the commercial and
residential buildings had fungi counts higher than 500 CFU per cubic meter. This is the
level where remediation is often recommended when occupants complain about negative
health effects (Gots et al., 2003).
Mold is a contributor to health care infections including those of the lung, body,
and blood. Research has shown an association between exposure to indoor mold and the
risk of respiratory infection (Chauhan & Johnston, 2003; Smith, Samet, Romieu, &
Bruce, 2000; Hsiue et al., 2010). In health care facilities, the risk of infection may be
increased for persons who are already ill or have a weak immune system (Hille, 2007).
The mold species Candida has been associated with infections of the body, especially in
persons with underlying health conditions such as diabetes (Graw et al., 2010; Heald et
al., 2001). Candida is also the fourth leading cause of blood stream infections in the
United States (Gudlaugsson et al., 2003; Ortega et al., 2010). Data has shown that
patients who acquire candidemia are likely to die during hospitalization as a result of the
infection, and the prevention of health care infections caused by Candida species should
be a high priority for any health care facility (Gudlaugsson et al., 2003)..
Mold, found outside of buildings may also be contributing to the risk of sick
building syndrome. Cooley et al. (1998) found that certain types of mold (Penicillium &
Stachybotrys) were more prevalent outside buildings associated with SBS. The
breakdown of outdoor fungus, which the authors found linked to SBS buildings included
Cladosporium (81.5%), Penicillium (5.2%), Chrysosporium (4.9%), Alternaria (2.8%),
and Aspergillus (1.1%; Cooley et al., 1998, p. 579). This research indicates that outdoor
mold may increase the risk of elevated levels of mold found indoors. Interventions such
34
as the advanced oxidation treatment may be beneficial in keeping mold counts reduced
when outdoor levels are elevated.
To better understand the impact mold has on human health at various exposure
levels animal studies have been performed. A study published by Schwab, Cooley,
Jumper, Graham, and Straus (2004) evaluating mice exposed to Penicillium chrysogenum
showed how high levels of this organism could produce strong allergic reactions. In a
study by Cooley, Wong, Jumper, Hutson, Schwab, & Straus (2000), a related
microbiological strain, Penicillium chrysogenum conidia produced similar allergic
reactions in mice. Both studies indicate that the presence of some of the most common
fungus found in buildings and homes produce allergic reactions.
The presence of air borne contaminants like mold represent a growing public
health problem as they may be a linked to the spread of infectious disease (Kunjundzic et
al., 2005; Leung & Chan 2006). While research has shown that airborne microorganisms
may cause serious health issues for occupants, there is a gap in knowledge about what
levels are safe (Fabian, Miller, Reponen, & Hernandez, 2005). In a health care facility
safe levels may need to be even lower than other occupied building based on the highly
susceptible populations that are present. Considering the adverse health effects associated
with airborne mold, initiative to keep levels as low as possible should be a priority of
infection control mangers and building engineers in health care facilities.
Bacterial Contaminants on Surfaces
Bacteria can be found on just about any surface in a building (Griffith et al.,
2000). Many of these organisms are harmless. However, many can adversely affect the
health of occupants (Menzies et al., 2003). In health care facilities where susceptible
35
persons are present, the risk of disease can be a concern (Utrup et al., 2005). Health care
workers are also at an increased risk of infection from these surface microorganisms
(Johnston et al., 2006). What levels of surface microorganisms are safe in a health care
facility is still not established, but reducing their levels as low as possible should be a
priority (Dancer, 2004).
Health care facility surfaces are classified as either critical or noncritical surfaces.
Critical surfaces pose a high risk for infection if they become contaminated through
contact with mucous membranes, nonintact skin, or some other contaminated surface
(Rutala & Weber, 2008). Noncritical surfaces are those that may come in contact with
intact skin, but not mucous membranes, and are also a potential source for the spread of
infection (Rutala & Weber, 2008). Contaminated, noncritical contact surfaces are
common to health care facilities and can be routes of infection through persons touching
that surface with their hand than touching their eyes, nose, mouth, or opening on the skin
(Bloomfield et al., 2007; Johnston et al., 2006; Poland et al., 2005; Rusin et al., 2002).
Microbiological contamination can also be transferred from noncritical contact surfaces
to critical contact surfaces by health care workers or patients (Matlow & Morris, 2009;
Rutala & Weber, 2001).
Bacteria can survive for extended periods of time on common noncritical surfaces
found throughout most health care facilities (Hota, 2004; Kramer et al., 2006; Neely &
Maley, 2000). Once an object such as a desktop, doorknob, or an exam table becomes
contaminated with a bacterial strain, all it takes is a simple touch of that object by a
person and the bacteria has spread (Johnston et al., 2006; Neely et al., 2005). In a study
by Rusin, Maxwell, and Gerba (2002), the ability to transfer bacteria from a contact
36
surface to hand and from hand to the lips was evaluated. The researchers found that over
a million bacterial cells can be transferred from hard nonporous surfaces to the hand by
sampling touching that surface. The transfer of bacteria from the hands to the lips was
just as high as from the surface to the hands. In the following sections, common indoor
surface bacteria including Staphylococcus aureus, MRSA, and Pseudomonas spp. are
discussed.
Staphylococcus aureus
Staphylococcus aureus is a gram-positive bacterium that was first discovered in
1880 by Sir Alexander Ogston (Lowy, 1998). The organism has had adverse impact on
human health causing approximately 500,000 infections annually (Bowersox, 1999).
Staphylococcus aureus is typically associated with skin and soft tissue infections, but can
also contribute to respiratory and gastrointestinal disease (Balaban & Rasooly, 2000;
Riechelmann et al., 2005).
There are several different types of skin infection associated with Staphylococcus
aureus including boils, impetigo, cellulitis, and scalded skin syndrome (Mayo Clinic,
2009). Boils or skin abscesses are the most common skin infection caused by
Staphylococcus aureus bacteria. The disease develops in hair follicles or where the skin
has been broken such as a cut or scratch. Impetigo is a contagious form of the bacteria
that causes a painful rash and is common in children and infants. Cellulitis is an infection
that occurs typically on the lower part of the leg and is more common in elderly persons.
Scalded skin syndrome (SSS) is a disease found in children and some adults. The
disease is caused by exfoliative toxins produced by Staphylococcus aureus bacteria.
Symptoms associated with SSS include redness of the skin, fever, and blistering (Ladhani
37
& Evans, 1998). The incidence of the SSS may not be accurately known as a result of
inadequate reporting, but the disease may still be an important health issue. It is believed
that exfoliative producing Staphylococcus aureus bacteria may be common in health
facilities, especially those which minister to new born infants (Landhani, Joannou,
Lochrie, Eavans, & Poston 1999).
In a health care facility, the impact of Staphylococcus aureus may be amplified by
multiple avenues for infection. For example, there may be a link between the presence of
bacterial contaminant and the risk of respiratory disease. In a study by Riechelmann et al.
(2005), nasal lavages of 22 patients with house dust mite allergy and 18 healthy controls
were tested for the number of colony forming units of Staphylococcus aureus. The
researchers found persons with the dust mite allergy were more frequent carriers of
Staphylococcus aureus bacteria than the healthy controls.
The complications from Staphylococcus aureus infections have been linked with
influenza-associated mortality in school aged children. In January 2008, the CDC
released an alert, warning health care providers of the possibility of coinfections of
Staphylococcus aureus, and influenza. Children with co-infections were found to be more
likely to have pneumonia and acute respiratory distress syndrome (ARDS). CDC data
from the 2006-2007 influenza season showed a five-fold increase over the previous 2
years in pediatric influenza-associated deaths due to coinfections with Staphylococcus
aureus (CDC, 2008c).
Staphylococcus aureus can produce a number of dangerous toxins that cause
various diseases in humans. Enterotoxins SEs is a family of Staphylococcus aureus
produced toxins that can cause bacterial gastroenteritis, a disease with associated
38
symptoms such as vomiting and diarrhea (Balaban & Rasooly, 2000). Staphylococcus
aureus enterotoxin B (SEB) was tested for its effects on bronchial allergic inflammation
(Hellings et al., 2006). Hellings et al. induced the features of allergic asthma in mice then
performed applications of nasal and bronchial SEB on three different occasions to the
mice. The authors found that the nasal and bronchial SEB aggravated several features of
asthma in the mice. The role of bacterial contaminant and noninfectious disease may not
yet be completely understood, but there does appear to be a link, as observed in the
studies mentioned above.
Exposure to Staphylococcus aureus bacteria in a health care facility can originate
from health care workers, other patients, and even contact surfaces. In a study by Neely
& Maley (2000), Staphylococcus aureus was able to survive on common fabrics
including cotton, terry, polyester, polyethylene, and blended fabric for at least 24 hours.
On polyester fabric, the microorganism was able to live for almost three months. On
other common surfaces such stainless steel, Staphylococcus aureus can survive for at
least 4 days at room temperature (Kusumaningrum et al., 2003). Common objects found
in health care facilities can also be carriers of Staphylococcus aureus. In a 2002 study by
Singh, Kaur, Gardner, and Treen, Staphylococcus aureus was present on 21% of
healthcare workers‟ pagers.
Antimicrobial Resistant Bacteria and MRSA
The ability of potentially harmful bacteria to quickly adapt to its environment may
be one of the biggest challenges facing health care organizations (Chase, 2006). Bacteria
can gain resistance to antibiotics and chemical disinfectants rendering them ineffective to
39
stop the spread of the organism. In health care facilities, these resistant strains can then
take advantage of susceptible populations and cause infection (Matlow & Morris, 2009).
There are several ways bacteria gain resistance to antimicrobials (Lewis, 2005).
Resistance may develop when an antimicrobial attacks a group of bacterial cells that are
susceptible to that agent. Cells that have some resistance may survive resulting in reduced
competition and that bacteria‟s ability to flourish. Bacteria can also inherit resistance
genes from their forerunners (Livermore, 2002). Genetic mutations are another way that
bacteria can form resistance. Bacterial mutations may spontaneously produce a new
resistance trait or strengthen an existing one. Finally, bacteria can acquire resistance
genes from other bacterial cells in the vicinity in a process called transformation (Lewis,
2005).
There is concern with the development of resistant strains of bacteria (Chase,
2006). Resistant strains can emerge from either health care or community settings,
making it difficult for infection control professions to fight (Raygada & Levine, 2009). In
a study by Liu et al. (2008), it was determined that nearly 1 in 300 San Francisco
residents suffered from a MRSA infection with the infections occurring both in the health
care setting and the general community. There is a need for additional interventions that
can be used in the prevention of resistant strains of bacteria in any environment.
The CDC lists Methicillin-Resistant Staphylococcus aureus (MRSA) as one of the
most commonly encountered multidrug-resistant organisms in healthcare facilities (CDC,
2000). MRSA is also one of the earliest known antibiotic resistant organisms. The
antibiotic methicillin was first invented in 1960, and by 1961 some Staphylococcus
aureus strains had already developed a resistance to the drug (Chase, 2006). The first
40
epidemics from MRSA infections occurred in the early 1980s in London and quickly
spread to other hospitals (Duckworth, Lothian, & Williams, 1988). As of 2006 it was
estimated that 1% of the U.S. population carry drug-resistant Staphylococcus without
symptoms (Chase, 2006). Carriers can spread the disease and suddenly become acutely
ill. There are approximately 130,000 hospitalizations a year caused by resistant
Staphylococcus bacteria (Chase, 2006).
MRSA is becoming a common infectious agent not only in health care facilities,
but in any environment (Raygada & Levine, 2009). There are two types of MRSA,
healthcare-associated (HA-MRSA) and community-associated (CA-MRSA). While the
two types of MRSA vary in terms of epidemiology and genetic design, both can have
serious health implications for persons infected (Raygada & Levine, 2009). CA-MRSA
has been quickly emerging over the past 10 years and now can be found in almost any
type of occupied building including health care facilities. HA-MRSA, which has been
commonly found in U.S. health care facilities for several decades, is slowly being
overtaken by CA-MRSA in these facilities (Popovich, Weinstein, & Hota, 2008).
The most common infections associated with the MRSA are skin and soft tissue
infections (Avdic & Cosgrove, 2008). At the outset of a MRSA skin infection a person
may experience small red bumps or a rash. Within a few days, the area can grow more
painful with larger deep red bumps along with the formation of pus-filled abscesses and
fever (Mayo Clinic, 2008). The bacteria can also infect and cause more serious illness of
other parts of body including joints, bloodstream, and lungs (Amander, Cumberland,
Bott, & Chissell, 2011; Chu, Wu, Drasin, & Barack, 2010; Wisplinghoff et al., 2004). In
some cases these infections can become life threatening.
41
MRSA, like many microorganisms can be easily spread throughout a health care
facility. A study by Shiomori et al. (2002) showed that strains of antibiotic resistant
bacteria can become transmitted to other areas through such routine activities as bedmaking. Researchers have also shown that there is a significant correlation between the
presence of MRSA collected from hospital room samples and the number of patients
infected with the organism (Wilson, Huang, & McLean, 2004).
MRSA can survive for extended periods of time on many different types of
surfaces. In a controlled laboratory study by Huange et al. (2006), MRSA was inoculated
onto common health care surfaces and tested to determine how long it could survive. The
researchers found that MRSA was able to survive 11 days on plastic patient chairs, 12
days on a laminated tabletop, and 9 days on a cloth curtain. In another study, researchers
tested to see if some noncritical surfaces of a health care facility carried MRSA. The
researchers were able to recover MRSA from health care worker keyboards and faucet
handles. The study showed that all contact surfaces of a health care facility need to be
considered potent reservoirs for harmful bacteria (Bures et al., 2000).
Pseudomonas species
Pseudomonas is a gram negative, rod shaped, motile species of bacteria, which
grows best in the presence of oxygen. Members of the genus Pseudomonas can cause
disease on just about any part of the body, but in health care facilities, infections are
usually associated with eyes, urinary tract, central nervous system, bloodstream, skin, and
lungs (Foca et al., 2000). Pseudomonas spp. are generally found throughout occupied
buildings including healthcare facilities where it is considered an opportunistic pathogen
(Hindron et al., 2008).
42
Pseudomonas species, which are most commonly associated with health care
infections, include Pseudomonas oryziharbitans, Pseudomonas luteola, and
Pseudomonas aeruginosa. Illnesses caused by Pseudomonas oryziharbitans and
Pseudomonas luteola are less common, but have been linked to infections of the body,
blood, and eyes (Chihab, Alaoui, & Mohamed Amar, 2004; Levitski-Heikkila & Ullian,
2005; Yu & Foster, 2002). Pseudomonas aeruginosa is the species responsible for the
majority of Pseudomonas infections and is also one of the most common microorganisms
found in health care facilities (Hindron et al., 2008; Foca et al., 2000).
There are many different microorganisms that can cause infection in a health care
facility, however, only a few organisms are responsible for the majority of illness.
Pseudomonas spp. are one of these organisms and as such is considered an important
indoor contaminant (Gastmeier et al., 2005; Hindron et al., 2008). In a 2008 study,
Hindron and associates evaluated 462 heath care facilities throughout the United States to
determine the prevalence of different pathogenic microorganisms associated with health
care infections. Over 28,000 healthcare-associated infections from 25,384 patients were
studied. The researchers found that Pseudomonas spp. were the responsible infectious
agent in 8% of those infections.
Outbreaks of an infectious disease in a health care facility can be a serious
concern, especially when susceptible persons may be present (Gastmeier et al., 2005).
Pseudomonas spp. found in these facilities has been shown to be a major contributor to
infectious outbreaks. In a retrospective study by Gastmeier and colleagues (2005), 1,022
health care facility outbreaks were evaluated. Gastmeier et al. found that Pseudomonas
spp. were the second leading cause of disease outbreak accounting for 9% of all
43
outbreaks. The application of an antimicrobial treatment of the entire health care
environment, like the one proposed in this study, may help in reducing the risk of
outbreaks associated with Pseudomonas bacteria.
Pseudomonas spp. can cause a variety of skin infections on any part of the body
(Foca et al., 2000). In health care facilities, soft-tissue skin infections caused by
Pseudomonas spp. are typically associated with nonintact skin, but can also occur on
healthy intact skin (Agger & Mardan, 1995; Foca et al., 2000). Factors leading to skin
infections are typically related to a breakdown or tearing of the skin, which may result
from burns, trauma, or dermatitis (Brook, 2002). In a study by Rennie, Jones, and
Mutnick (2003), 24 health care facilities in the United States and Canada were evaluated
to determine which microbiological pathogens are most associated with skin and soft
tissue infections. The researchers found that Pseudomonas spp. accounted for almost
11% of all skin and soft tissue infections.
Pseudomonas spp. can cause infections in the human eye and has been related to
outbreaks in health care facilities (Brito, Oliveira, Matos, Abdallah, & Filho, 2003).
Conjunctivitis, also known as pink eye, is a common infection of the eye (Brito, et al,
2003). In healthy adults the disease usually only causes minor discomfort, but in infants
the disease can cause serious damage to the eye and lead to infections of other body sites
(Brito et al., 2003; Grundmann, Kropec, & Harting, 1993). Haas, Larson, Ross, See, and
Saiman (2005) conducted a 2-year study of two health care facilities located in New York
City to determine the prevalence of health care acquired conjunctivitis in infants. The
researchers found that conjunctivitis occurred in 5% of infants treated in those facilities
44
over that time period. Improved hygiene practices in health care facilities have been
suggested as a means to reduce the risk of this disease (Hass et al., 2005).
Respiratory infections can be a serious problem for acute and long term patient
care facilities (Garau & Gomez, 2003; Karlowsky et al., 2003). Health complications
from disease such as pneumonia can have mortality rates as high as 33%, in these settings
(CDC, 2004). Pseudomonas aeruginosa is considered the leading cause of health care
acquired pneumonia, which accounts for 15% of all health care associated infections
(CDC, 2004; Garau & Gomez, 2003; Karlowsky et al., 2003). In preventing pneumonia,
the CDC (2010) recommends keeping hands of health care workers and family members
clean. This is because bacteria can be transferred from one surface to another via the
hands (Rutala & Weber, 2001; Scott et al., 2009). Keeping indoor surfaces clean may
help in reducing the risk of inadvertently transferring surface dwelling Pseudomonas spp.
to patients.
A serious health condition linked with Pseudomonas aeruginosa is meningitis and
brain abscesses (Huang, Lu, Chuang, Tsai, Chang, Chen, et al., 2007). The disease occurs
when the bacteria gains access to the central nervous system through the inner ear, head
trauma, invasive procedure, or cross contamination from another site of infection
(Quiney, Mitchell, Djazeri, & Evans, 1989; Reefhuis et al., 2003). While Pseudomonas
spp. may not be the main biological agent associated with meningitis, it is still important
based on the high mortality associated with the infection. Huang et al. (2007) evaluated
29 Pseudomonas spp. associated cases of meningitis in adults aged 17 to 86 years old.
Huang et al. found an overall mortality rate of 40% from these cases. The researchers
also noted the rapid development of antibiotic resistant strains of the bacteria as a
45
contributing factor in the high mortality rates. Keeping Pseudomonas spp. levels reduced
in health care facilities may help to reduce the risk of infection linked with exposure to
the microorganism in health care facilities where invasive procedures may be preformed
and where antibiotic-resistant strains may be present.
As mentioned above, Pseudomonas spp. are well known for the ability to gain
resistance to antimicrobials (Huang et al., 2007). Hidron et al. (2008) found that
antimicrobial-resistant Pseudomonas spp. were responsible for as many as 2% of all
healthcare associated infections, including nonresistant antibiotic infections. Strains of
Pseudomonas spp. are known to be resistant to several different classes of antimicrobials
including ampicillin, amoxicillin-clavulanate, antistaphylococcal penicillins,
tetracyclines, macrolides, rifampin, and chloramphenicol (Karlowsky et al., 2003). Based
on the high level of resistance which Pseudomonas spp. have to so many different
antibiotics, it would seem to be vital that health care organizations keep counts as low as
possible inside their facilities.
There are over 100,000 cases of bloodstream infections every year in the United
States, many of which are caused by Pseudomonas species (CDC 2002; Maki, Kluger, &
Crnich, 2006). Pseudomonas spp. associated blood infections can be serious and in many
cases even deadly. A retrospective study by Grisaru-Soen et al. (2000) looked at 70
seriously ill patients with a secondary blood infection caused by Pseudomonas
aeruginosa. The authors observed a high mortality rate of 20%, with the highest mortality
associated with young infants who seem most susceptible to this organism. These
infections often occur when bacteria are given access to the bloodstream from
contaminated medical devises (Donlan, 2001). Medical equipment can be easily
46
contaminated by health care workers who transfer Pseudomonas bacteria from one
surface to another (Donlan, 2001; Neely et al., 2005; Scott et al., 2009).
Urinary tract infections are an important issue for any health care provider (CDC,
2002). Pseudomonas spp. are often associated with surfaces of catheters, which can be an
avenue for urinary tract infections (Khoury, Lam, Ellis, & Costerton, 1992). While
Pseudomonas infections are less commonly associated with noncritical surfaces, there is
a risk of cross contamination that should be considered when trying to stop the spread of
infection (Kramer et al., 2006). Pseudomonas spp. have the potential to be transmitted
from noncritical surfaces to critical surfaces by health care workers and patients (Kramer
et al., 2006). Routine disinfection of all contact surfaces should be part of any infection
control program (Rutala & Weber, 2001).
A negative characteristic of Pseudomonas is the organism‟s ability to live for
extended periods of time in the health care environment. The main reason why it is able
to do this is due to the limited nutrient requirements needed for its‟ survival (Karlowsky
et al., 2003). In a study by Kramer et al. (2006), literature on the survival of health care
pathogens was evaluated for all years available on MedLine, up to December, 2005.
Kramer et al. found that Pseudomonas spp. were adaptable to most inanimate surfaces
and in some cases could survive up to 16 months. Neely (2000) tested the ability
Pseudomonas spp. to survive on common health care surfaces such as fabrics and
plastics. Neely found that at inoculation levels of just 100 colony-forming units,
Pseudomonas spp. could survive for several weeks at ambient room temperature.
Considering the large number of susceptible persons that visit health care facilities, the
47
risk of contamination from these microorganisms would seem to make antimicrobial
treatments of all contact surfaces a priority for infection control managers.
Pseudomonas spp. can be found on almost any health care surface due to the
ability to survive in harsh environments, and because of the number of persons who are
carriers of the organism (Karlowsky et al., 2003; Scott et al., 2009). In recent study by
Scott and associates (2009), 24 common indoor surfaces were tested for the presence of
Pseudomonas. The organism was recovered on all of the surfaces at some level, but was
most prevalent on sinks, faucet handles, counter tops, drains, door handles, light switches,
and telephones (Scott et al., 2009).
Impact of Microbiological Contaminants on Health Care Workers
Microorganisms can affect anyone who occupies a contaminated facility,
including health care workers (Johnston et al., 2006). Employee health and well being has
been found to be linked to factors such as retention, recruitment, absenteeism, reduced
healthcare costs, improved productivity, and employee job satisfaction (Hillier, Fewell,
Cann, & Shepard, 2005; Samet & Spengler, 2003). Continually dealing with
microorganisms that can cause even mild health conditions such as allergies, respiratory
infection, or minor skin infections can negatively impact an employee‟s sense of well
being (Mendell et al., 2002).
Worker related illnesses, such as those mentioned above, are usually not life
threatening and as a result are often ignored (Singh, 2001). This has resulted in a lack of
interventions directed at improving worker environments. According to Mendell et al.
(2002), “there currently is no comprehensive research effort to provide a scientific basis
for improving indoor work environments in the United States” (p. 1430). Health care
48
facilities would appear to be settings where workers may be placed at an increased risk of
disease based on their exposure to indoor microbiological contaminants.
The association between the levels of indoor contaminants and their health effects
have become better understood through research studies conducted over the past couple
decades. For example, a 1996 cross-sectional study looked at the association between the
levels of indoor contaminants and reporting of symptoms by workers in a nonindustrial
office building (Menzies et al., 1996). Menzies et al. found that as contaminant exposure
levels increased for workers, the more likely they were to report adverse health effects.
This study looked at less severe symptoms including headache, fatigue, and allergies.
Health care workers would have the added exposure to even more dangerous
microorganism from contaminated patients (Lis et al., 2009).
Absenteeism is a problem that affects most organizations including health care
organizations. Absenteeism costs organizations billions of dollars every year (Sherman,
1990). In health care facilities, the impact on employee absenteeism may not only be
limited to increased cost, but also to the quality of care patients receive (Gaba & Howard,
2002). When health care workers are not feeling their best, the service they provide to the
patient may suffer as a result. Even mild symptoms that have been associated with indoor
microbiological contaminants such as headache, fatigue, and atopic symptoms may
contribute to this issue (Menzies et al., 2003).
Mold, a prevalent indoor air contaminant, may contribute to adverse health effects
of health care workers (Thorn et al., 2001). A study by Milton, Glencross, and Walters
(2000) looked at historical data of 3,700 employees and found that the rate of employee
sick leave was significantly associated with air quality. Milton et al. found that increasing
49
the supply of outdoor air to a building decreased the morbidity and lost productivity.
Absenteeism rates have also been shown to be associated with indoor air quality. Rosen
and Richardson (1999) found that cleaning the air reduced employee absenteeism by as
much as 55%. Milton and colleagues (2000) estimated that on a national level, the cost of
lost productivity from poor air quality could be as high as $22 billion per year.
Employee performance may be negatively impacted by the presence of indoor
microorganisms. A study by Wargocki, Wyon, and Fanger (2004) looked at the response
rate of nurses working at a call-center. In the building where the nurses worked, replacing
dirty air filters with clean air filters resulted in nurses being able to respond to calls more
effectively with less talk time. This research would indicate that by keeping the indoor
environment clean of microbiological contaminants, worker performance would be
improved. In a health care setting this may also mean better service for patients.
Surface bacteria found in health care facilities may be putting workers at risk of
infection. In a study by Johnston et al. (2006), health care workers were evaluated for
their risk of contracting skin infections from surfaces in an outpatient clinic. The authors
found that not only were there numerous surfaces contaminated with infectious agents
such as MRSA, but that health care workers were contracting infections from these
exposures. An antimicrobial intervention like advanced oxidation may be beneficial at
reducing bacteria on the many surfaces of a health care facility, as the system treats all
exposed surfaces.
Reoccurring headaches are one of the many symptoms associated with buildings
that have microbiological contaminants (Menzies et al., 2003). These headaches can have
a negative impact on the workers‟ performance. In a study by Kroff, Stewart, Simom, and
50
Lipton (1998), 122 persons who met the criteria for routine migraine headache sufferers
were evaluated over a 3-month period. The authors found that these persons missed
substantial amounts of work and had reduced performance while at work due to
headaches.
Health care workers suffering from allergies may be affected by indoor
microbiological contaminants. In a research article by Lamb et al. (2006), 8,000
employees at 47 different locations were studied to determine the effect allergic rhinitis
had on workplace productivity over a 12 month period. Lamb et al. found that more than
half (55%) of the employees reported experiencing allergic rhinitis symptoms and were
absent an average of 3.6 days due to this condition.
The ability to stay focused on the job and not allow fatigue to affect job
performance would seem to be crucial to health care workers and their patients. It has
been established that indoor air contaminants can cause persons to develop chronic
fatigue syndrome (Chester & Levine, 1994). This condition may potentially lead to
serious safety issues for patients as fatigued health care workers may be more likely to
make mistakes (Gaba et al., 2002).
Research on interventions used to clean indoor environments has shown there are
a number of benefits to workers. Seppanen and Fisk (2005) found that remediation of
indoor contaminants reduced medical care costs, reduced sick leave, increased
performance, and lowered employee turnover. The remediation also lowered costs of
building maintenance due to fewer complaints from occupants. Advanced oxidation
treatment would seem to be a potential remediation for health care workers that both
infection control and occupational health professions should consider.
51
Health care workers have to deal with not only health risks associated with
infectious patients, but also buildings that may contribute to their risk. A cross-sectional
observational study conducted by Menzies, Fanning, Yuan, and Fitzgerald (2000) found
that inadequate ventilation in a Canadian hospital was associated to an increased risk for
contracting a bacterial infection in health care workers. Fisk and Rosenfeld (1997) also
found that poorly designed buildings can contribute significantly to the risk of spreading
respiratory disease within that facility. These studies demonstrate just how critical air
quality is in a patient care facility.
Absenteeism of health care workers poses a concern, as these professionals are
ultimately responsible for the care of persons in the community suffering from illness and
disease (Johnson et al., 2003). In 2005, a national survey on the work and health of nurses
was conducted in Canada. The survey found that these health care workers had one of
the highest rates of absenteeism of any workers in Canadian workforce (Canada‟s
National Statistics Agency, 2006). According to Johnson et al. (2003), the ramifications
of health care worker‟s absences can be directly seen in increased overtime and staff cost.
Indirect effects of absenteeism would be reduced quality of patient care, disruption of
services, and pain and suffering of those absent. These findings would suggest that public
health initiatives need to be directed at finding interventions that may help reduce health
care worker absenteeism. This study looked at how persons working and living in health
care facilities can have their wellness affected by indoor microbiological contaminants
and interventions available to reduce these contaminants.
Small (2003) suggested that “medical staff be made aware of potential hazards
from indoor contaminants that buildings may harbor as a result of poor maintenance or
52
design” (p. 523). Health care workers may also want to know that health care
organizations are making an effort to remediate these health risks. The application of
antimicrobial technology such as the advanced oxidation treatment would be a potential
intervention that could be applied to these buildings. The following section reviews
interventions for reducing contaminants in health care facilities.
Interventions for Reducing Indoor Microbiological Contaminants
Surveillance of Microorganisms in Health Care Facilities
Surveillance and monitoring programs for preventing the spread of antimicrobialresistant organisms are common in many health care facilities. Surveillance programs
typically include the use of microbiological samples which are taken from staff, patients,
medical equipment, and the environment (Diekeme & Edmonds, 2007). Environmental
testing may include both contact surfaces and building air. The effectiveness of these
surveillance programs at preventing the spread of disease is still being debated (Raygada
& Levine, 2009). Even if these programs prove to be effective, alone they may not be
enough to stop the spread of the infection, as surveillance only tells where contamination
exists. Health care organizations still need to treat the identified areas to destroy the
microbiological contaminants.
In a recent article by Diekema and Edmonds (2007), the current strategies for
surveillance of multidrug-resistant organisms were reviewed. The authors found that the
active surveillance initiatives helped in identifying sources of some, but not all health
care infection. The authors also found that there were negatives consequences associated
with surveillance testing. Surveillance may add to patient health care costs through
additional testing and cause patients to receive reduced contact with health care
53
employees. Health care workers may be reluctant to spend time in rooms or facility
locations that are identified as contaminated through surveillance testing. This can result
in a reduction of patient contact by as much as 50% (Diekema & Edmonds, 2007; Saint,
Higgins, Nallamothu, & Chenoweth, 2003). An advanced oxidation intervention may
help to keep patient contact levels high, as health care workers feel the environment is
safer as a result of the antimicrobial application.
In setting up surveillance programs, there is a dilemma as to which organisms the
health care facility should be looking to find. New strains of resistant microorganisms are
constantly developing, and testing for every potential organism would be difficult and
expensive (White, Cray, & Chiller, 2006). This is why it may be necessary to develop
interventions like advanced oxidation that can control the spread of any new strains of
resistant microorganisms without relying on expensive surveillance programs.
Another limitation of surveillance programs is that they can miss the presence of
some types of microorganisms as a result of misclassification of the illnesses. According
to Menzies et al. (1996), misclassification is a potential problem as illnesses acquired as a
result of microbiological contaminants can mistakenly be reported as something else. One
of the common misclassifications for Staphylococcus aureus resistant bacteria is to
classify the illness as a spider or insect bite (Chase, 2006).
The majority of microbiological surveillance programs are implemented in
hospitals. While these programs are beneficial in hospital settings, they may not be
practical for use in other health care facilities such as outpatient clinics and physician
offices (Rhinehart, 2001). For example, outpatient clinics typically do not conduct
microbiological surveillance testing of patients, indoor air, or contact surfaces because of
54
high patient turnover and cost (Johnston et al., 2006). As opposed to hospitals that may
find benefit in surveillance programs, nonhospital health care facilities may want to focus
on interventions such as one tested in this study.
Another drawback to surveillance systems is the time it takes to get results.
Microbiological testing is slow and can take up to 48 hours to get results, allowing for
extended exposure to the contaminant before it can be remediated (Chase, 2006).
Prevention measures may then need to be on going to limit this risk. Advanced oxidation
is an antimicrobial treatment that can be applied continuously so that contaminated
sources are constantly being treated.
Conventional Cleaning and Disinfection
Conventional cleaning and disinfection is the use of chemicals, often in a wet
form, to remove soil and destroy microorganism on contact surfaces. When used properly
conventional cleaning and disinfection can be an effective intervention for reducing
surface microbes (Dharan et al., 1999). However, there are several disadvantages that can
limit the effectiveness of the treatment.
Surface applications of cleaning detergents typically need to be wiped across a
surface to loosen and remove soils, and microbes. In some cases the detergent being
wiped across a surface can actually help to spread bacteria to other areas (Dharan et al.,
1999). The advanced oxidation process can not spread bacteria to other surfaces like
conventional cleaning.
Conventional cleaning and disinfection is not effective long term and must be
conducted often to keep up with the constant reinoculation of surfaces that occurs in
health care buildings (Dharan et al., 1999; Gamage & Zhang, 2010; French et al., 2004).
55
There are a couple of reasons why constantly cleaning and disinfection of a health care
facility using conventional methods is not practical. First, it would increase exposure
levels of chemicals for patients and staff, many of which may be harmful to humans. In a
recent article by Paton (2009), the use of common health care cleaners and disinfectants
were found to be negatively correlated with asthma in health care workers. Second, the
cost in added chemicals and man power may make the increased cleaning frequencies
very expensive.
Conventional methods must be standardized so that each application is as
effective as the previous (Dharan et al., 1999). Variation may occur in cleaning and
disinfection from person to person or from application to application. In a study by
Dharan and associates (1999), uncontrolled conventional cleaning and disinfection of
surfaces did not always effectively reduce microbes on surfaces, and in some cases even
spread the organisms. An advanced oxidation treatment would supply a standard
antimicrobial agent to all surfaces. There is no risk of variation between applications or
from human interaction as the system works as a hands-off process.
Conventional cleaning and disinfection methods may also be contributing to the
development of new strains of antimicrobial organisms. In health care facilities across the
country there has been a rise in the number of infections resulting from resistant strains of
bacteria (Beatty, Anderson, & Camins, 2007). Contributing to the rise in the number of
resistant strains of bacteria may be the use of disinfectants, which have increased over the
past decade (Fraise, 2002).
The concern with using antimicrobial cleaners and disinfectants to fight bacterial
infections is that the bacteria may develop resistance to that agent making them even
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more difficult to destroy. A study by Fawley et al. (2007) looked at the efficacy of five
common cleaning agents and/or germicides at eliminating epidemic strains of resistant
bacteria. Fawley et al. found that when used at the recommended concentrations, not only
were most of the products ineffective at inactivating the microorganism, but that some
even caused an increase in sporulation rates (Fawley et al., 2007). Unlike the many
conventional cleaning and disinfection methods, the advanced oxidation process should
not produce resistant strains of microorganisms (Pope et al., 1984).
Conventional cleaning and disinfection methods serve an important role in the
reduction of bacteria on surfaces and should be part of any health care organizations
infection control program (French et al, 2004). However, conventional cleaning alone
may not be enough to keep microbiological counts at safe levels (French et al., 2004). In
a study by French et al. (2004), conventional methods did reduce microbiological
populations in a health care facility, but not all microbes were destroyed. The advanced
oxidation treatment has the potential to work in conjunction with conventional methods
to keep surface bacteria levels reduced. In between routine conventional cleaning and
disinfection of surfaces, the advanced oxidation treatments may help in destroying
microbes on those surfaces.
Ventilation and Air Cleaners
Prevention and control of indoor microorganisms may be difficult because of the
number of different modes of contamination. Spengler and Sexton (1983) list the main
strategies for reducing indoor air contaminants: source control, ventilation, air cleaning,
and source modification (p. 13). Source control is considered the most effective of the
intervention methods because it eliminates the sources of pollutants or reduces their
57
emissions. Identifying the source of the pollutant is the first step to source control, but in
many cases this is difficult to do because contaminants are sometimes hard to find
(Alsmo & Holmberg, 2010). Source modification can serve an important role in the
reduction of some of the more serious indoor contaminant. According to Spengler and
Sexton (1983), “source modification is the reduction of pollutant emissions through
containment of the emissions through the use of barriers or sealants” (p. 13). For
example, sealing off a damp basement or sub floor area that is emitting mold could help
to reduce airborne mold counts throughout the rest of the building. Not all sources of
microbiological contamination may be obvious so the use of barriers and sealants may
not always be effective (EPA, 2008b). Advanced oxidation systems do not need to have
the contaminant sources identified to help reduce microbiological levels.
Ventilation is effective because it brings outside air indoors. This is typically
achieved by opening windows and doors, turning on exhaust fans, or through the use of
mechanical ventilation systems (EPA, 1993). Buildings with ventilation systems that
have increased levels of outdoor air have been shown to have a positive effect on
occupant health (Milton et al., 2000). A limitation to the use of ventilation centers on the
costs for heating or cooling incoming air (Bahnfleth & Kowalski, 2005). For this reason it
may not be practical for many health care facilities to increase ventilation to include more
outside air. This is why systems like advanced oxidation may be beneficial, as they can
help to clean the air allowing building engineers to use cheaper, recirculated indoor air.
Indoor environmental cleaning systems such as filters, ionizers, electrostatic
precipitators, and UV light have been studied for use for reducing indoor air pollution.
One of the most common filtering methods is HEPA (high efficiency particulate air)
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filtration. HEPA filters work by forcing large volumes of air through a membrane to
achieve high-efficiency particulate filtration. An advantage of the HEPA filters is that
they can effectively filter out particles as small as 0.03 microns in the air. Research has
shown that bacterial counts in the air are reduced when used in certain indoor
environments (Kujundzic et al., 2005). A study by Kogan et al. (2007) looked at the
effectiveness of HEPA air cleaner systems and found that they can reduce concentrations
of the pollutants, as well as increase the time it takes to reach a particular room
concentration. The drawback to HEPA systems is that the filters can act as a breeding
ground for bacteria and mold if not changed out regularly. HEPA filters can be less
effective when used in large spaces (Hick, 2007). It would also seem unlikely that a
HEPA system would aid in disinfecting of indoor contact surfaces as the process only
focuses on removing contaminants from the air.
Filters used for cleaning indoor air often incorporate the use of carbon
impregnated filter fabric or granulated carbon. These filters usually have a foam or fabric
filter to hold the media. Carbon has the capability of acting as a physical filter trapping
particulates, and on a chemical basis, by reacting with some odors and heavy gases.
Research has shown that when properly maintained, filters can help in the reduction of
symptoms associated with sick building syndrome (Wargocki et al., 2004). A downside
to using filters is that they typically require frequent filter changes as they can become
overloaded with particles blocking air flow. If filters are not changed regularly they can
act as a breeding ground for microorganisms (Clausen, 2004). In contrast, the APS
advanced oxidation system only needs to be plugged into a wall outlet and left alone. The
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only maintenance for the system is changing of the oxidizer bulb, which can last for years
without a problem.
Electrostatic precipitators (ionizers) have been used by industry for many years to
clean up smoke stack emissions of particulate (Graham, 2007). They operate by
electrically charging a field between metal plates. The air is charged with an electrical
charge similar to static electricity. The charged particulates collect and coagulate on a
second set of charged plates where they build up, then fall onto a collection tray.
Research has shown that electrostatic precipitators are effective at reducing the level of
indoor air pollutants including microorganisms (Kogan et al., 2007). Ionizers have been
found to be beneficial in reducing absenteeism rates. Rosen and Richardson (1999)
conducted a controlled trial where an electrostatic air cleaning system was installed in a
Swedish daycare to reduce airborne particles such as mold and bacteria. The researchers
found that not only did the air cleaning system reduce the levels of indoor contaminants,
but it also resulted in absenteeism rates decreasing by 55% (Rosen & Richardson, 1999).
The disadvantage of this type of air cleaner is that they require frequent cleaning and only
cleans the air that passes through the filter. Air from the building that doesn‟t come in
contact with the ionizer will not be cleaned. Particle buildup on the charged plates can
also act as a breeding ground for bacteria (Mazur & Kim, 2006). As mentioned above, the
advanced oxidation system requires very little maintenance, cleans the indoor air
regardless if it comes in contact with the oxidation processing unit, and does not
contribute to indoor microbiological contaminant levels.
Negative ion generators are used to remove particulates from the air and to
neutralize the effects of excess positive ions. Negative ions are produced electrically and
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travel through the air until they attract airborne particulates. The particulates coagulate
until they are too heavy to drift and settle to the floor. The benefits of using ion
generators may not yet fully understood. Manufactures claim that negative ion generators
are effective at improving air quality by removing such contaminants as smoke from the
air. Daniell, Camp, and Horstman (1991) conducted a study on the use of a negative ion
generator on office building air contaminants and the reporting of symptoms in office
workers. The authors found that there was no effect on employee likelihood of reporting
symptoms as a result of the ion generators use. This study would indicate that ion
generators may not be effective interventions for use in health care facilities.
All of the interventions mentioned above are designed for reducing
microbiological levels in the air. Surface microorganisms may still need to be addressed,
requiring health care organizations to use multiple interventions to reduce
microbiological levels. The advanced oxidation system on the other hand has the
potential to reduce surface, as well as airborne microorganisms (Fink, 2004).
Advanced Oxidation
Advanced oxidation technology is a term used to describe the use of multiple
oxidizers to disinfect (Glaze et al., 1987). Photohydroionization (PHI) is an advanced
oxidation process developed by RGF Environmental Group, Inc., West Palm Beach,
Florida. In this study, the technology is being evaluated for the first time in an applied
research setting. The PHI process incorporates the use of ultraviolet light, ozone, and
peroxide at low levels. This technology has been designed to not exceed the
recommended federal safety limit for ozone of 0.08 parts per million (ppm) in an
occupied room. In a laboratory study, the system was shown to have antimicrobial
61
properties, which may make it an effective indoor treatment for reducing microbiological
levels (Ortega et al., 2007).
As mentioned above, the PHI advanced oxidation process combines the use of
ozone, ultraviolet radiation, and peroxides. All three are potent oxidizers, and each is
known to be an effective antimicrobial. The benefit of combining the three is an
increased oxidation that can more effectively clean the environment (Martins, 1998). The
potential use of advanced oxidation was first described in an article by Bolton, Bircher,
Tumas, and Tolman (1996), in which they stated:
Advanced oxidation processes (AOPs), which involve the in-situ generation of
highly potent chemical oxidants such as the hydroxyl radical (·OH), have recently
emerged as an important class of technologies for accelerating the oxidation and hence
destruction of a wide range of contaminants in polluted water and air. (p. 2)
Looking at the three main oxidizers (ultraviolet light, ozone, & hydrogen
peroxide) used in the advanced oxidation process there are advantages and disadvantages
to each. Following are listed some different studies on each of those oxidizers. Ultraviolet
(UV) light radiation systems have been used as a sanitizer by the medical profession for
years. UV light can sanitize air by destroying bacteria that is passed directly in its path.
Advantages of UV germicidal technology include no reduction in airflow and installation
in either a central air system or an individual room unit. A drawback of UV light is it
needs direct close contact with a calculated exposure time and the rays must be shielded
from human exposure, as the light can be harmful to a person‟s skin and eyes (Weiss,
Weiss, Weiss, & Weiss, 2007).
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In a research study conducted by Kujundzic et al. (2007), UV germicidal
irradiation was evaluated for its ability to inactivate airborne fungal spores and bacteria.
The researchers found that the UV treatment was effective at reducing spore counts by
75% and bacterial counts by 87%. In this study ultraviolet lamps were enclosed in the
ventilation ductwork eliminating the risk of exposure to persons in the building.
Ultraviolet germicidal irradiation may also be of benefit in older buildings where
major changes to air handing systems may not be practical or cost effective. Rudnick and
First (2007) noted, “Compared with increasing outdoor air ventilation rate, ultraviolet
germicidal irradiation is an attractive technology for lowering concentrations of airborne
microorganisms, and thereby reducing the risk of airborne transmission of disease” (p.
352).
Wekhof, Trompeter, and Franken (2001) evaluated the use of germicidal
ultraviolet light for the control of health care acquired infections. The authors noted that
pulsed ultraviolet light may be an effective intervention to improve air quality, as
microorganisms are susceptible to certain UV wavelengths. The system could be installed
for decontamination of high risk areas such as surgical sites and infectious patient rooms
(Wekhof et al., 2001). Another study using germicidal ultraviolet light found that it may
be effective at preventing the spread of certain infectious diseases, especially multidrugresistant tuberculosis, which is a growing concern in many health care facilities (Miller &
Macher, 2000).
Ozone has become a popular method used for indoor air treatment and is typically
conducted in gaseous form (Khurana, Chynoweth, & Teixeria, 2003). In this state, the
ozone is colorless with a characteristic odor. Ozone consists of an oxygen molecule
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containing three atoms instead of two, like the oxygen humans and animals breathe. The
extra atom of ozone is known as a loose radical that looks for organics to attach to and
thereby oxidize. Ozone is an oxidizing gas that oxidizes all organics it comes in contact
with, and reverts back to oxygen after oxidation occurs. At the appropriate levels ozone
can destroy microorganisms (Lim, Kim, Lee, & Ko, 2010). Ozone units can be installed
in central air handling units without causing reduced air flow. Ozone comes with safe
usage limits and exposure levels must be controlled to meet government guidelines.
Ozone has been used for over the past twenty years by cleaning and disaster
restoration companies. These companies have utilized ozone to disinfect homes, schools,
and other buildings by destroying mold, mildew, and fungi (Rice, 2002). The
effectiveness of these treatments have been questioned by some researchers as there has
been a lack of understanding of what levels are needed to effectively remove
contaminants (Boeniger, 1995). Research on ozone technology has established that levels
somewhere below 9 ppm are necessary for sick buildings or professional disinfection
(Khurana et al., 2003). The U. S. Environmental Protection Agency (2005) has set the
standard exposure limits for ozone of 0.08 ppm for 8 hours, and 0.12 ppm for 1 hour. The
lower the ozone concentration, the safer it is for human exposure.
Low level ozone applications have been found to be effective at reducing
populations of certain bacteria. A study by Berrington and Pedler (1998) found that a
gaseous ozone generator used in hospital rooms was effective at reducing Staphylococcus
aureus at low levels, but only in the vicinity of the generator. The study also showed that
the ozone was less effective at destroying Methicillin Resistant Staphylococcus aureus
than Methicillin-Sensitive Staphylococcus aureus.
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In a study by Klanova and Lajcikova (2006) ozone gas was tested as a possible
application for the reduction of potentially dangerous microorganisms. The researchers
found that the ozone was effective at reducing populations of Escherichia coli,
Pseudomonas aeruginosa, MRSA, and Candida albicans. In addition to the reduction of
airborne microorganisms the authors also noted that the ozone application can also be
effective in reaching less accessible solid surfaces (Klanova & Lajcikova, 2006, p. 84).
It has been reported that the anti-microbial activity of ozone is based on its strong
oxidizing effect, which damage the cell membrane (Pope et al., 1984). Ozone kills
bacteria within a few seconds by a process known as cell lysing. Ozone molecularly
ruptures the cellular membrane, disperses the cell's cytoplasm, and makes microbial
survival impossible. As a result, microorganisms cannot develop ozone resistant strains,
eliminating the need to change biocides periodically (Pope et al., 1984).
As mentioned earlier, safety must always be addressed when using ozone
technology for use indoors with human exposure. A study by Boeniger (1995) found that
ozone air cleaners are a potential health risk if used indoors at high levels. Boeniger‟s
research does raise awareness to the dangers of indoor ozone systems that produce ozone
at levels above the EPA recommended 0.08 ppm in an occupied room. The ozone levels
produced by the advanced oxidation system used in this study have been designed so
levels cannot exceed the recommended Federal safe limits for ozone (0.08 ppm) in an
occupied room (Fink, 2004; U.S. Environmental Protection Agency, 2005).
Another of the oxidative agents produced at low levels by the PHI process is
hydrogen peroxide. Hydrogen peroxide is made up of hydrogen and oxygen and has
strong oxidative properties. It is typically a manufactured chemical, but it can also be
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found at low levels in the air we breathe. Hydrogen peroxide has a limited life span when
aerosolized, as it will easily break down to water and oxygen. Hydrogen peroxide has
been used for many years in household products such as hair care products, laundry
additives, and minor medical treatments (ARSDR, 2002). It is generally recognized as a
safe (GRAS) antimicrobial agent and an oxidizing agent by the U.S. Food and Drug
Administration (2001).
The use of hydrogen peroxide as an antimicrobial treatment is believed to be safe
and effective, especially when compared to other germicidal agents (Falagas, Thomaidis,
Kotsantis, Sgouros, Samonis, & Karageorgopoulos, 2011; Rochon & Sullivan, 1999). A
2007 study conducted using aerosolized hydrogen peroxide showed the potential benefit
of the intervention in reducing growth of pathogenic microorganisms. In the study,
Mycobacterium tuberculosis was placed on the surface of stainless steel discs and then
exposed to hydrogen peroxide vapor. The treatment was effective at completely
inhibiting growth of the bacteria after a 30-minute exposure time (Hall, Otter, Chewins,
& Wenenack, 2007).
In another study, aerosolized hydrogen peroxide was shown to be effective at
reducing bacterial levels on contaminated eggs. In the study, Sander and Wilson (1998)
found that eggs fogged with a 3% solution of hydrogen peroxide and water produced a
significant reduction in the level of Staphylococcus aureus when compared to eggs
fogged with water only. The authors also observed that the hydrogen peroxide treatment
had no negative effect on the livability or health of the chickens.
Vaporized hydrogen peroxide has been tested for use in health care facilities and
has shown potential as an antimicrobial. A study by French et al. (2004) found that
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vaporized hydrogen peroxide could greatly reduce MRSA counts in a hospital setting.
The authors noted that the vaporized hydrogen peroxide treatment was an effective
disinfectant on all surfaces in the rooms tested.
The use of advanced oxidation has shown to be effective at reducing
microbiological populations in drinking water (Camel & Bromond, 1998). Other research
on the technology as an antimicrobial agent has been limited, but promising. In a 2006
laboratory study, an advanced oxidation process was effective at reducing potential
airborne microbiological contaminants (Vohra, Goswami, Deshpande, & Block, 2005).
This was a controlled laboratory study where the researchers used a higher concentration
of oxidizers focused on a specific area. In a real-world setting, there may be additional
challenges including limited oxidizer concentration for occupant safety, dilution of
oxidizers as a result of ventilation, and constant recontamination.
An important component of the advanced oxidation process includes titanium
dioxide as the photocatalyst for the production of oxidative gases. This component is also
a factor in the photohyroionization (PHI) process evaluated in this research study.
Research on titanium dioxide as the photocatalyst for advanced oxidation processes used
for indoor disinfectant has been limited, but results have been promising. A laboratory
study by Vohra et al. (2005) found that titanium dioxide, along with ultraviolet light
could produce oxidative gases that inactivate Bacillus cereus bacterial spores on
aluminum and polyester surfaces. In another controlled research study, airborne
Staphylococcus epidermidis levels were reduced by 92 % and fungi levels were reduced
by up to 95 % after an 8 hour treatment, using white light bulbs spray-coated with
titanium dioxide (Chuaybamroong, Thunyasirinon, Supothina, Sribenjalux, & Wu, 2011).
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The PHI process differs from these advanced oxidation processes through the addition of
hydrated tri-metallic hydrophilic coating of rhodium, silver, and copper on a fixed
support grid, impregnated with titanium dioxide, as the photocatalyst.
The use of titanium dioxide as the photocatalyst in the advanced oxidation process
has been proposed by researchers for disinfection of health care environments. Gamage
and Zhang (2010) noted that the technology has the potential to reduce indoor biological
contaminants in health care settings, both in the air and on surfaces. Studies presented by
Gamage and Zhang were limited to controlled laboratory research on photocatalytic
disinfection processes. As with the PHI process, there is a lack of knowledge for realworld application of this advanced oxidation technology.
Before any antimicrobial technology can gain acceptance it needs to follow
standard protocols for proving effectiveness (Reybrouck, 1998). The first step is to
conduct basic laboratory research to show that the technology possesses antimicrobial
properties. The technology must then be challenged in a practical, real-world situation to
determine if it is effective for that specific application (NSF, 1994; Reybrouck, 1998).
This is referred to as an applied research study.
The only peer-reviewed research on the PHI advanced oxidation technology is a
basic laboratory study, which was designed to determine if the system had any
antimicrobial properties. In the study, researchers challenged the technology against
common indoor agents such as Escherichia coli, Listeria monocytogenes, Streptococcus
pneumonia, Pseudomonas aeruginosa, Bacillus globigii, Staphylococcus aureus,
Candida albicans, and Stachybotrys chartarum (Ortega et al., 2007). The researchers
used stainless steel coupons inoculated with these microorganisms and treated with the
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advanced oxidation generator in an environmental chamber. The study showed that the
treatment reduced microbial populations on stainless steel surfaces within 2 hours under
ambient conditions. Testing was also conducted after 6 and 24 hours of treatment with
longer exposure times resulting in greater microbial reductions. The unit reduced all
microorganisms tested by at least 90% after 24 hr exposure on stainless-steel surfaces.
The advanced oxidation treatment produced only low concentrations of ozone (0.02
ppm), well below the allowable limits. The study also verified that low levels of oxidative
gases produced by the treatment have the potential to be an effective surface disinfectant.
The Ortega et al. (2007) study was limited to only evaluating the PHI advanced
oxidation technology‟s antimicrobial properties and not for its use in an applied realworld setting. While the system may work to reduce pure microorganisms on clean,
sterile stainless-steel surfaces in a small environmental chamber, it does not give
evidence that the system will work in a practical real-world environment. Microbes found
in the real-world environment typically do not exist as pure cultures and are often mixed
with other strains of microorganisms (Guerrero, Piqueras, & Berlanga, 2002). Microbes
used in the Ortega et al. (2007) study were grown in nutrient broth, which is not
representative of how microorganisms are found in a real world environment. Surfaces
found in the real world are usually not sterile and often not clean. Microorganisms on
dirty surfaces may be protected with the soil acting as a barrier between the microbes and
the advanced oxidation treatment. There are many different types of surfaces other than
stainless steel found in the real world environment, which could influence the survival of
the microorganisms (Huange et al., 2006; Neely, 2000).
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As described above the PHI advanced oxidation technology has shown to be
effective at reducing microbiological population on surfaces in a laboratory setting
(Ortega et al., 2007). Less understood is the treatment‟s ability to reduce microbes in the
air. The technology has the potential to reduce airborne microorganisms in a health care
setting based on the antimicrobial abilities of its oxidative agents mentioned above (Fink,
2004; Vohra et al., 2006). This study helped in better understanding the potential
applications of advanced oxidation at reducing microbiological populations on surfaces
and in the air.
The Ortega et al. (2007) study tested the effectiveness of the PHI technology
within only a couple feet of the advanced oxidation unit. A gap in knowledge exists on
the use of this technology for reducing microbiological populations over greater
distances, which would be more representative of indoor environments. This would
include variations in effectiveness that may occur from one room to another, as well as
distance from the reactor. It would seem to be critical that the effective range of this
technology be well understood before infection control managers, building engineers, and
occupational health professionals consider using in health care facilities.
Currently there is not a good understanding of what indoor microbiological levels
are safe for human occupants, but keeping these populations as low as possible would be
an important objective for health care facilities (Dancer, 2004; Otto & Nehis-Lowe,
2001). Crnich & Maki (2002) stated, “the challenge for the future will be to identify new
preventative technologies and to begin to more-widely adapt those technologies that have
already been shown to be efficacious and cost effective” (p. 1362). This would add to the
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idea that an ongoing intervention such as an advanced oxidation treatment would be
beneficial in many different buildings, but especially health care facilities.
Methods Used for Evaluating Indoor Microorganisms
The method used exclusively for evaluating microbiological populations in an
indoor environment is experimental design. A majority of the research presented in this
literature review was conducted using this method. An important advantage in using an
experimental method is the control over the variables making it easier to determine a
cause and effect relationship. This includes control over the intervention exposure levels,
which is critical in showing this relationship (Baas, Stefanowicz, Kilmek, Laskowski, &
Koolijman, 2010).
There have been a number of different experimental designs used in
microbiological studies of indoor environments. In a several recent studies (Neely, 2000;
Neely & Maley, 2000; Neely & Orloff, 2000), experimental design method was used to
test the survival of microbiological contaminants on common health care surfaces. The
researchers inoculated coupons, made up of common surface types, in a laboratory setting
with known levels of microbiological agents. The researchers conducted microbiological
testing routinely over a period of time to determine survival time of the organisms. The
method allowed the researchers to have control over study variables including room
temperature. The design was effective, but lacked randomization as researchers selected
microbiological strains and inoculation levels used in the study.
White et al. (2007) used an experimental design method for a microbiological
study of conventional cleaning practices of air tight health care facility surfaces.
Microbiological testing was performed at ten designated locations before and after an
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antimicrobial intervention. Three replications of the study were conducted over a two
week period for each intervention. Unlike the studies mentioned above, which used
researcher selected microbiological strains, this study used microorganisms already
present within the health care facility. This study design allowed the researchers to
evaluate the intervention in a real world setting as opposed to a controlled laboratory
environment, making it more a random design.
Menzies and associates (2003), in an assessment of an indoor air cleaning system,
used an experimental design to evaluate the intervention. The researchers conducted
microbiological testing of the building‟s air over a six month period. Testing was
conducted on three different days prior to the intervention and on three days during the
intervention. The data from the control and intervention groups were then compared.
Besides testing for differences between the control and intervention groups, the design
allowed researchers to determine if longer exposure time to the intervention resulted in a
greater reduction of microbiological populations.
The current study determined the relationship between an indoor antimicrobial
intervention and microbiological populations. The study method was a traditional
experimental design, similar to those mentioned above, with control and intervention
groups. The effect of the treatment was measured by comparing the observed effects from
the control group with those of the intervention groups. As with White et al. (2007), this
study incorporated randomization of study populations by using microflora already
present within the building. As with the Menzies et al. study (2003), this study also
determined if there is an increase in the reduction of microbiological populations based
on the length of exposure to the intervention. Unlike the Ortega et al (2007) experimental
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study, which was limited by the laboratory setting, this study was an applied study,
meaning the study was conducted in a real-world environment. This allowed for a
determination of the effectiveness of the intervention over greater distances, as large open
areas in a health care building were used for the evaluation.
Summary
This chapter identified sources of microbiological contamination in a health care
facility. This included such factors as the buildings age, design, and ventilation systems.
Occupants, including patients and health care workers were also identified as potential
sources for microbiological contaminant (Poland et al., 2005). Literature was also
presented on the harmful effects that microorganisms can cause to occupants of health
care facilities. Patients, as well as health care workers, may be at risk from exposure to
these contaminants (Thorn et al., 2001). Mold found in the air was shown to be associated
with adverse health effects ranging from asthma to infection. Adverse health effects were
found to be associated with other indoor microorganisms including Staphylococcus
aureus, MRSA, and Pseudomonas. All of these microorganisms have been found to
survive on common surfaces found in health care facilities.
Interventions used for reducing microbiological populations were reviewed in this
chapter. Microbiological surveillance of heath care facilities were identified as an
intervention for prevention of microorganisms in the air and on surfaces. The
effectiveness of surveillance programs appear limited, and may be beneficial only in
selected health care facilities (Raygada & Levine, 2009). Conventional cleaning and
disinfection was found to be an important method for reducing microbes on surfaces.
While the intervention can be effective, it also has limitations and may be best used in
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conjunction with other interventions such as advanced oxidation (French et al., 2004).
Current air cleaning interventions include increased ventilation, air filtration, ionizers,
and negative ion generators. These interventions have restrictions that advanced
oxidation does not including extensive maintenance requirements, ineffective
antimicrobial properties, and potential for seeding microorganisms (Fink, 2004). Based
on the review of these interventions, there seems to be a lack of knowledge on effective
antimicrobial treatments that can be used in health care facilities.
Oxidizers produced by the advanced oxidation process include ultraviolet light,
hydrogen peroxide, and ozone. Literature presented in the chapter identified the
advantages, and disadvantages of each oxidizer, as well as the benefits of combing these
agents. The advanced oxidation process was shown to be effective in a laboratory setting,
but a lack of knowledge exists on the technologies use in a real world environment
(Ortega et al., 2007). Literature was presented on the possible limited range oxidizers
have in a room, as antimicrobial effectiveness may be lower the further away a person is
from the system (Berrington & Pedler, 1998). Research presented in this chapter on the
advanced oxidation showed that the process is effective in reducing microbial
populations in as little as 24 hours (Ortega, 2007). The following chapter describes the
method used to test the effectiveness of an advanced oxidation system at reducing
microbiological levels in the air and on surfaces in a health care facility.
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Chapter 3: Methodology
Introduction
Chapter 2 presented information on some of the many sources of indoor
microbiological contamination in health care buildings. Common indoor microbiological
contaminants described in chapter 2 include mold found in the air, and Staphylococcus
aureus, Methicillin-resistant Staphylococcus aureus, and Pseudomonas found on
surfaces. In this chapter, a study is presented to quantitatively and statistically analyze the
effectiveness of the advanced oxidation system at reducing those microbiological
populations. The literature review also identified variables that may contribute to the
effectiveness of the advanced oxidation including exposure levels and proximity to the
treatment.
This chapter includes an explanation of the research design and approach
employed for the study. The sample population and setting are provided along with
sampling methods used in the study. A detailed description of the advanced oxidation
treatment in the building is given. Testing method and materials used for the
microbiological analysis are reviewed followed by data collection and analysis. Finally,
ethical consideration and measures to protect building occupants and their rights are
discussed.
Design and Approach
The study was an experimental design. The advanced oxidation treatment was
tested for effectiveness at reducing microbiological populations in a health care building.
In chapter 1, the problems associated with microbiological contaminants in health care
facilities were discussed, as well as the lack of effective interventions to reduce these
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populations. Advanced oxidation of the indoor environment is a new intervention that
may help reduce microbiological contaminants. The experimental design consisted of
control and intervention groups to determine if a statistical difference exists after the use
of the advanced oxidation treatment.
The experimental design was selected, as it is an effective way to support
causality. As shown in the literature review, experimental design is a commonly used
method for similar microbiological studies. This study tested the hypothesis that an
advanced oxidation treatment will reduce mold in the air, and MRSA, Staphylococcus
aureus, and Pseudomonas found on surfaces. Chapter 2 described the health concerns
associated with each of the organisms listed above, as well as the many common health
care surfaces where these organisms can be found. The independent variable was the
advanced oxidation treatment and the dependent variables were the microbiological
counts for mold, MRSA, Staphylococcus aureus, and Pseudomonas. The experimental
design method also allowed for better control of confounding variables that may have
affected the study (Creswell, 2003). In this study, it was important to have a similar
microbial population for both the intervention and control treatments.
The study design addressed the effectiveness of the intervention at various
exposure levels. As described in chapter 2, there is a gap in knowledge on the
effectiveness of advanced oxidation technology over distances more than a couple of feet
(Ortega et al., 2007). There is a possibility that a proximity effect exists, as areas closer to
the advanced oxidation unit may have a greater decrease in microbiological populations
than areas further away. There is a lack of knowledge in the literature on the effectiveness
of advanced oxidation technology over distances. A study on a related technology
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showed ozone was less effective just a few feet away from the source than right next to
the unit (Berrington & Pedler, 1998). For this study, an area encompassing 40 feet from
each advanced oxidation unit was chosen to test the efficacy of the treatment. This
distance was selected based on the manufacturer‟s recommendation for the APS unit,
room sizes of the study facility, testing locations, and placement of the APS units to limit
crossover of the antimicrobial treatment from multiple units. Considering these factors,
four APS units were placed evenly throughout the first level of the study building.
To test the effect of distance, airborne microorganisms were evaluated at 5, 10,
20, 30, and 40 feet from the advanced oxidation unit. To test the effect of distance on
surface microorganisms, two zones were used. Zone 1 was 0 to 20 feet and Zone 2 was
20 to 40 feet, from the advanced oxidation unit.
Exposure time to the advanced oxidation treatment was shown to be a possible
factor in the interventions effectiveness. In the literature review, the Ortega and
associates (2007) laboratory study showed that longer exposure times aided in the
antimicrobial efficacy of the advanced oxidation treatment. In that study, 24 hours of
continuous exposure to the intervention was needed to effectively reduce microorganisms
in a laboratory setting (Ortega et al., 2007). In this study, the advanced oxidation
treatment was applied for only half the amount of time (12 hours/day) and was applied in
a real-world situation on multiple surface types. Taking into account these more stringent
testing conditions and the lack of knowledge on time needed to reduce microbial
populations, the advanced oxidation treatment was evaluated on Days 0, 5, 10, 20, and 30
of the intervention.
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Sample Population and Setting
Microbiological populations were surveyed in two outpatient clinics in the
Wyandotte County Health Department building located in Kansas City, Kansas. The
study populations consisted of mold, MRSA, Staphylococcus aureus, and Pseudomonas
species. These microorganisms were chosen as a representative sample of organisms that
may be found within the building, to test the effectiveness of the advanced oxidation
treatment against. It would not be practical to test for every type of microorganism, so
common indoor microbiological contaminants were selected.
Mold is a typical indoor air contaminant and was likely to be found in this
building (EPA, 1991; Gots et al. 2003; McNeel & Kreutzer, 1996; Price et al., 2005).
According to the Centers for Disease Control and Prevention (2009), airborne molds are
common in buildings, and homes. Staphylococcus aureus and Pseudomonas spp. are
common indoor microorganisms and were expected to be recovered from surfaces in the
building (Kramer et al., 2006; Ladhani, Joannou, Lochrie, Evans, & Poston, 1999; Neely,
2000; Neely & Maley, 2000; Scott et al., 2009). MRSA is an emerging healthcare and
community associated microbiological contaminant. It was anticipated that the
microorganism would be present on contact surfaces in the facility (Huange et al., 2006).
According to Ladhani et al. (1999), “health care environments remain one of the most
common sources of Staphylococcus aureus, mainly due to inadequate adherence to
infection control practices” (p. 227). In a study by Bouillard, Michel, Dramaix, and
Devleeschouwer (2005), researchers evaluated indoor surfaces of office buildings to
determine which microorganisms were most common. The researchers found that strains
of Staphylococcus aureus and Pseudomonas spp. were common to surfaces of indoor
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environments and posed a potential health risk to occupants. Control testing was
conducted prior to the application of the intervention to confirm the presence of each of
the microorganisms.
The study setting was conducted on the first level of a three level health care
building. This level contains a pediatric clinic and family planning/prenatal clinic. These
outpatient clinics are open from 8:30 a.m. to 5:00 p.m. Monday, Tuesday, Wednesday,
Friday, and 8:30 a.m. to 7:00 p.m. on Thursday. The building was built in 1972 and
designed to allow limited outside air ventilation, including windows that cannot be
readily opened by occupants. Heating and cooling of the building is maintained by a
central HVAC system located on the roof of the facility. The temperature in the building
is maintained at approximately 72° F year round. There is one main entrance on the first
level used by everyone who enters or exists the building. There is one emergency exit
located on the first floor, but it is not used for routine entrance or exit from the building.
There are 53 health department employees stationed on the first level of the building.
There are approximately 65,000 patient visits annually of this building level.
The study included noncritical health care surfaces commonly found in patient
clinics (e.g., exam tables, waiting room chairs, telephones). According to CamposOutcalt (2004), “Outpatient clinical settings are a prime location for the spread of
infectious diseases, to staff and patients” (p. 285). While not the emphasis of this study,
the clinics also have critical contact surfaces (e.g., needles/syringes for venipuncture and
injections, intrauterine devices, speculums). A critical surface is defined as surface which
carries a high risk of infection if it becomes contaminated, comes in contact with mucous
membranes, or nonintact skin. Critical surfaces are usually medical devices of some kind.
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A noncritical surface is defined as a surface that may come in contact with intact skin, but
not mucous membranes. While this research was directed at reducing microorganisms on
common noncritical health care surfaces, there is also the potential benefit of reduced risk
from cross contamination to critical surfaces (Rutala & Weber, 2001). According to
researchers, noncritical contact surfaces need to be kept clean, as microorganisms can
easily be transferred by a person touching one contact surface and then another (Poland,
Tosh, & Jacobson, 2005; Johnston et al., 2006)
Testing Locations in Building
Four advanced oxidations (APS) units were placed on the first level of the
building. One unit was placed in each of the three microbiological test sites listed below.
A fourth site was located in the nurse office area, located on the south side of the
building. The microbiological test sites included (Appendix A):
North patient waiting room
Pediatric exam rooms
General clinic exam rooms
The rooms used in the study are occupied almost continuously throughout the
time the clinics are open. The north patient waiting area typically has approximately 60
patient visits a day, not including family members. On average, pediatrics has
approximately 20 patient visits a day. This does not include family members that often
accompany patients. On average, the general clinic sees approximately 16 patient visits a
day.
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Air Sampling
The air samples were collected by a mechanical air sampler, which randomly
pulls air from the room. Each sample included 100 liters of air filtered onto
microbiological media selective for mold. Two air samples were collected at 5, 10, 20,
30, and 40 feet from each of the three advanced oxidation units, for a total of 30 samples.
Samples were collected on three different days for the control treatment, and four for the
intervention treatment, for a total of 210 samples for both treatments. To determine if this
sample population was large enough to observe a significant difference G*Power priori
analysis was performed (Erdfelder et al., 1996). Based on an alpha error level of 5%, and
a moderate effect size of 0.5, a total sample size of at least 176 is needed. Based on these
parameters, 210 samples should be large enough so that the null hypothesis is not
incorrectly rejected.
Surface Sampling
Bacterial swabs were collected on the first level of the building at the locations
listed above. Samples collected from the control treatment were compared with samples
from the intervention treatment. Two testing zones for each unit location were evaluated
to determine if microbiological populations were reduced on surfaces closer to the
advanced oxidation unit than surfaces further away. Zone 1 included a 20-feet radius
from the unit, without obstruction from a closed door or wall. Zone 2 included the area
between 20 to 40 feet of the unit, without obstruction from a closed door or wall. There
were six samples collected in each of the zones. Some zones contained more than one of
the sample objects listed below. To determine which item to sample each object was
assigned a number. A corresponding number was then written on a piece of paper and
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placed in a container. On test days a number from the container was pulled and the
corresponding item was sampled.
The north patient waiting room advanced oxidation unit was placed so both Zone
1 and Zone 2 samples could be collected from the same room. Samples collected from
Zone 1 in the north patient waiting room included: child‟s table, two child chairs, door
knob, and two adult chairs. Zone 2 of the north patient waiting area included: child‟s
table, two child chairs, door knob, and two adult chairs.
The pediatrics advanced oxidation unit was placed so that Zone 1 samples were
collected from Exam Room D and the patient bathroom, and included: counter top, chair,
bathroom sink, faucet handle, scale, door knob. Zone 2 included Patient Exam Rooms B
and C. Samples collected in Zone 1 of the pediatric patient exam rooms included: counter
top, telephone, door knob, exam table, faucet handle, and sink. To determine which
rooms to sample the researcher flipped a coin.
The general clinic advanced oxidation unit was placed so that Zone 1 included
Patient Exam Rooms 1 and 2. Samples in Zone 1 included: telephone, door knob, exam
table, faucet handle, sink, and counter top. Zone 2 samples were collected from Exam
Rooms 3 and 4, and included the same samples as Zone 1. Each of the patient exam
rooms contains the same objects. To determine which room the samples would be taken a
coin was flipped.
Control samples were collected on three separate days of the same week and
intervention samples were collected on Days 5, 10, 20, and 30 of the treatment. Each
surface sample collected included a microbiological swab of 100 cm2.
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Six surface samples were collected from each of the six zones for a total of 36
samples. Samples were collected on three different days for the control treatment and 4
days for the intervention treatment, for a total of 252 samples for both treatments. To
determine if this sample population was large enough to observe a significant difference,
G*Power priori analysis was performed (Erdfelder et al., 1996). Based on an alpha error
level of 5% and a moderate effect size of 0.5, a total sample size of at least 176 (i.e. sum
of control + treatment) is needed. Based on these parameters, 252 samples is large
enough so that the null hypothesis is not incorrectly rejected.
Instrumentation and Materials
A microbiological survey was used as the instrument to measure the effectiveness
of the treatment for this study. The microbiological survey included the use of validated
microbiological media, and culturing methods (Difco & BBL Manual, 2007). Variables
measured included levels for mold, Staphylococcus aureus, MRSA, and Pseudomonas
species. These variables were analyzed based on distance from the treatment, number of
days of exposure, and treatment location. The microbiological survey included
environmental samples collected from the air and surfaces in the building. Environmental
samples were collected using validated collection techniques including a microbiological
SAS air sampler made by Bioscience International, Rockville, MD and sponge-sticks
moistened with 10 ml of sterile peptone solution made by 3M Corporation, Saint Paul,
MN. To check the reliability and validity of culturing methods, confirmation procedures
were used for each microbial test method.
Uninoculated microbiological media was also incubated along with the inoculated
plates to confirm that the media is not contaminated. Microbiological counts were
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calculated for each sample location and time. Mold counts were recorded as the number
of colony forming units (CFU) per liter of air. Staphylococcus aureus, MRSA, and
Pseudomonas spp. will be recorded as CFU per square centimeter. Raw data collected
from the microbiological survey was placed into tables and then transferred to excel
spreadsheets on the researcher‟s personal computer.
Treatment
This study tested the effectiveness of an advanced oxidation treatment on
reducing microbiological populations. The photohydroionization (PHI) reactor, also
known as the APS advanced oxidation system, was used for the study. The APS system
was developed by RGF Environmental Group and incorporates the use of ultraviolet
light, ozone, and hydrogen peroxide at low levels to help clean the air, and disinfect
contact surfaces. The APS system works by having a broad-spectrum dual wavelength
UV bulb at the core of a cylindrical cell. The cell consists of a hydrated tri-metalic
hydrophilic coating of rhodium, silver, and copper on a fixed support grid impregnated
with titanium dioxide as the photocatalyst. The hydrophilic coating promotes hydration.
Rhodium supports the conversion of unwanted oxidizing compounds and silver and
copper increase the rates of desirable reactions. The target titanium dioxide surface
catalyzes a hydroxyl radical reaction in the broad spectrum 100-300 nm dual-wavelength
UV energy water vapor to produce hydroxyl, superoxide, and hydroperoxy radicals that
create an aggressive advanced oxidation atmosphere (Daniels, 2007, p. 336; Fink, 2004).
The dimensions of the APS system are 13”H x 12.5”D x 37”L, and it weighs
approximately 50 lbs. The system delivers 500 cubic feet of air per minute. The device
contains a UV bulb, which is coated in a protective poly tube. Another safety feature is a
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metal casing surrounding the device to prevent breakage of the bulb and tampering with
the device (Fink, 2004).
The APS advanced oxidation units were plugged into standard 110 volt outlets,
and placed on the first level of the building in the north patient waiting room against the
east wall, outside the pediatrics patient exam rooms B and C against the south hallway
wall, outside general clinic exam rooms 1 and 2, and in the south side nurse office area
(Appendix A). The treatment dose for the advanced oxidation was based on the
manufacturer‟s (i.e. RGF Environmental Group, West Palm Beach, FL) recommendation
of approximately 2,000 to 5,000 square feet per APS plug-in device. The first level of
the building is approximately 12,000 square feet. Four APS units were placed in different
locations of the first level of the building, meaning there would be one unit for every
3,000 square feet. To better distribute the oxidizing gases, doors to each room in the
building were left open during treatment applications, except for doors that directly
separate different oxidation units. The advanced oxidation system was operational for 12
hours daily throughout the duration of the treatment. The APS system were turned on at
7:30 pm every evening, and turned off at 7:30 a.m. every morning. The system was not
operational during any of the clinic hours, which ran from 8:30 a.m. to 5:00 p.m.
Monday, Tuesday, Wednesday, and Friday. On Thursdays the clinics were open from
8:30 am to 7:00 pm. The clinics were closed on weekends.
The advanced oxidation system has the ETL stamp of approval given by ETL
Testing Laboratories, currently known as Intertex Testing Services, Miami, FL, meaning
the device is recognized as safe. Products with this approval must meet rigorous
standards for electrical safety and electromagnetic emissions. This certification mark
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shows that the product has been tested and has met the minimum requirements of a
widely recognized (i.e. consensus) United States product safety standard, that the
manufacturing site has been audited, and that the applicant has agreed to a program of
periodic factory follow-up inspections to verify continued conformance. The testing lab is
recognized by OSHA (Occupational Safety and Health Association) as a Nationally
Recognized Testing Laboratory (NRTL). The APS advanced oxidation technology has
been safely used as an air cleaner and surface disinfectant for over a decade without
supportive research to its actual effectiveness in occupied buildings. Throughout the
treatment the APS advanced oxidation system was turned on only during hours the health
department was closed, and no patients or employees were present.
There are no residues associated with the use of the APS unit as oxidative
gases will immediately dissipate once the unit is turned off. For example, the hydrogen
peroxide and ozone produced by the system will convert back into water and oxygen the
instant the unit is turned off, with no residue left behind (EPA, 2002). Even if a building
occupant were somehow accidentally exposed to the treatment, there was no risk of harm
as the oxidative gases produced by the system are limited by the system design. For
example, ozone produced by the unit cannot exceed 0.04 ppm (Fink, 2004). The U.S.
Environmental Protection Agency (2005) has set the standard exposure limits for ozone
of 0.08 ppm for 8 hours, and 0.12 ppm for 1 hour.
Data Collection
Two weeks prior to the beginning of the study, an email was sent to all
department managers asking them to limit their access to the building to only operational
hours (Appendix B). Managers of the study clinics received a second email asking them
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to refrain from having employees clean any of those surfaces listed above (Appendix C).
In the same email, the managers were asked to refrain from moving any of the objects in
the test zones.
At the start of the study I checked the testing areas once in the morning and once
in the afternoon to make certain that no object listed for testing was moved from one zone
to another. During the intervention treatment, I made certain that the four advanced
oxidation units were turned off in the morning and locked up in a storage room until the
clinic closes. In the evening, I removed the units from the storage room, place them back
in the designated locations, and turned the units on.
Air Samples
Control samples were collected on three different days during the same week with
the advanced oxidation units turned off. Air samples were collected beginning at 6:30
a.m. of each sample day. On the first level of the building I collected two air samples
from 5, 10, 20, 30, and 40 feet from each of the three advanced oxidation units. To make
certain that the sample distance from the unit was accurate I measured the distance using
a tape measure. The researcher collected three air samples from the second level, third
level, and outside of the building. The indoor samples were collected on the east side of
the building, the central area of the building, and the west side of the building. Outdoor
air samples were collected by the east building entrance, the west building entrance, and
on the north side of the building. Using an SAS air sampler, 100 liters of air was filtered
on YM Agar made by Acumedia, Lansing MI, and incubated at 30º C for 72 hours. After
incubation, samples were enumerated and data recorded as colony forming units (CFU)
per 100 liters of air.
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The intervention samples were collected on Days 5, 10, 20, and 30 after the daily
12-hour advanced oxidation treatments had begun. Air samples were collected beginning
at 6:30 a.m. on each sample day. On the first level of the building, I collected two air
samples from 5, 10, 20, 30, and 40 feet from each of the three advanced oxidation units.
To make certain that the sample distance from the unit was accurate the researcher
measured the distance using a tape measure. The researcher collected three air samples
from the second level, third level, and outside of the building. The indoor samples were
collected inside the east side of the building, central area of the building, and the west
side of the building. Outdoor air samples were collected by the east building entrance, the
west building entrance, and on the north side of the building. Using an SAS air sampler
100 liters of air was filtered on 15 x 100 mm YM Agar plates made by Acumedia,
Lansing, MI. Agar plates were then incubated at 30º C for 72 hours. Following
incubation, agar plates were enumerated and data recorded as colony forming units
(CFU) per 100 liters of air. Once enumeration was complete and data recorded, agar
plates were disposed of following sterilization by autoclaving. To confirm the presence of
mold recovered from YM Agar plates, cell morphology using optical microscopy, was
used on colonies recovered from control and intervention samples.
Contact Surface Samples
Control samples were collected over a three week period. The first week samples
were collected on a Monday. The second week the samples were collected on a Tuesday.
The third week samples were collected on a Wednesday. Surface samples were collected
beginning at 7:30 a.m. on each sample day. Samples were collected on surfaces identified
for each of the six sample zones, on the first level of the building. On each testing day the
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researcher randomly selected surfaces from the objects identified in each of the zones.
Approximately 100 cm2 surface area were aseptically swabbed using a sponge-stick made
by 3M Corporation, St. Paul, MN, moistened with 10 ml of 0.1% peptone water (PW). A
sterile 100 cm2 template was used to identify the appropriate surface area to swab.
Sample collection location was recorded by the researcher for every sample so that the
exact same sample location was not sampled more than once.
After samples were collected, they were brought to the health department
laboratory for platting. Sample diluent was shaken for 30 seconds and aseptically plated
onto selective media. To determine Staphylococcus aureus counts, diluent was plated
onto Baird-Parker Agar with Egg Yolk Tellurite made by Becton, Dickinson and
Company, Sparks, MD, and incubated at 35º C for 24 hours. To determine MRSA counts,
diluents were plated onto MRSA Agar made by Acumedia, Lansing, MI with Oxacillin
Sandoz, Inc., Princeton, NJ, and incubated at 35º C 40-48 hours. To determine
Pseudomonas spp. counts, diluent was plated onto Pseudomonas Isolation Agar made by
Acumedia, Lansing, MI, with glycerol made by Sigma Aldrich, St. Louis, MO, and
incubated at 35º C for 24-48 hours. After incubation, the microbiological plates were
enumerated and recorded as colony-forming units per 100 square centimeters. Once
enumeration was completed and data recorded, agar plates were disposed of following
autoclaving. To confirm the presence of the Staphylococcus aureus and MRSA bacteria,
the coagulas test made by Becton, Dickinson and Company, Sparks, MD was used.
Pseudomonas was confirmed using King B Agar made by EMD Chemical, Brookfield,
WI.
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Analysis of Data
This study utilized an experimental design with control and intervention groups.
The instruments used for measurement of the variables in this study allowed for the data
to be analyzed through analysis of variance (ANOVA) and regression analysis. The
independent variable was the advanced oxidation treatment and the dependent variables
are the microbiological counts for mold, Methicillin-Resistant Staphylococcus aureus
(MRSA), Staphylococcus aureus, and Pseudomonas species. The research questions and
hypotheses are listed below along with the statistical analysis used to answer each
question.
Research Questions
1. If an advanced oxidation treatment is applied to the indoor environment of a
health care facility for 12 hours daily, will mold mean counts or detectable mold in the air
decrease by at least 90%, as measured by microbiological cultural plating of indoor air on
YM Agar? Testing parameters include treatment location (Site A, B, and C), sample
distance from the advanced oxidation unit (5, 10, 20, 30, and 40 feet), and exposure time
(0, 5, 10, 20, and 30 days).
2. If an advanced oxidation treatment is applied to the indoor environment of a
health care facility for 12 hours daily, will Methicillin-Resistant Staphylococcus aureus
(MRSA) mean counts or detectable MRSA decrease by at least 90% on surfaces, as
measured by microbiological cultural plating of swabbed surfaces on MRSA agar?
Testing parameters include treatment location (A, B, and C), sample distance from the
advanced oxidation unit (Zone 1 and Zone 2), and exposure time (0, 5, 10, 20, and 30
days).
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3. If an advanced oxidation treatment is applied to the indoor environment of a
health care facility for 12 hours daily, will Staphylococcus aureus mean counts or
detectable Staphylococcus aureus decrease on surfaces by at least 90%, as measured by
microbiological plate counts of swabbed surface diluents on Baird Parker Agar? Testing
parameters include treatment location (A, B, and C), sample distance from the advanced
oxidation unit (Zone 1 and Zone 2), and exposure time (0, 5, 10, 20, and 30 days).
4. If an advanced oxidation treatment is applied to the indoor environment of a
health care facility for 12 hours daily, will Pseudomonas spp. mean counts or detectable
Pseudomonas spp. decrease on surfaces by at least 90%, as measured by microbiological
plate counts of swabbed surface diluents on Pseudomonas Isolation Agar? Testing
parameters include treatment location (A, B, and C), sample distance from the advanced
oxidation unit (Zone 1 and Zone 2), and exposure time (0, 5, 10, 20, and 30 days).
Hypotheses
H01 - Mold mean counts in the air, as measured by microbiological cultural
plating of indoor air on YM Agar, will not be affected by daily 12-hour advanced
oxidation treatments of the indoor environment.
Ha1 - Mold mean counts will be significantly decreased in the air, as measured by
microbiological cultural plating of indoor air on YM Agar, after daily 12-hour advanced
oxidation treatments of the indoor environment.
H02 - Methicillin-Resistant Staphylococcus aureus (MRSA) on surfaces, as
measured by microbiological plate counts of surface swabs of MRSA agar, will not be
affected after daily 12-hour advanced oxidation treatments of the indoor environment.
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Ha2 - Methicillin-Resistant Staphylococcus aureus (MRSA) mean counts will be
significantly decreased on surfaces, as measured by microbiological plate counts of
surface swabs of MRSA agar, after daily 12-hour advanced oxidation treatments of the
indoor environment.
H03 - Staphylococcus aureus mean counts on surfaces, as measured by
microbiological plate counts of surface swab diluents on Baird Parker Agar, will not be
affected after daily 12-hour advanced oxidation treatments of the indoor environment.
Ha3 - Staphylococcus aureus mean counts will be significantly decreased on
surfaces, as measured by microbiological plate counts of surface swab diluents on Baird
Parker Agar, after daily 12-hour advanced oxidation treatments of the indoor
environment.
H04 - Pseudomonas spp. mean counts on surfaces, as measured by microbiological
plate counts of surface swab diluents on Pseudomonas Isolation Agar, will not be
affected after daily 12-hour advanced oxidation treatments of the indoor environment.
Ha4 - Pseudomonas spp. mean counts will be significantly decreased on surfaces,
as measured by microbiological plate counts of surface swab diluents on Pseudomonas
Isolation Agar, after daily 12-hour advanced oxidation treatments of the indoor
environment.
Data Labeling and Statistical Analysis
Microbiological counts were recorded by hand onto paper and later entered into a
spreadsheet, which was stored on a personal computer. The information on the personal
computer was secured using a password known only by the researcher. Paper copies of
data were stored in a locked file cabinet, which could only be accessed by the researcher.
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Controls samples for mold were labeled by treatment location (A, B, and C),
testing day (0a, 0b, and 0c), and distance from advanced oxidation unit (5, 10, 20, 30, and
40 feet). Control samples for Staphylococcus aureus, MRSA, and Pseudomonas spp.
were labeled by treatment location (A, B, and C), testing day (0, 5, 10, 20, and 30), and
distance from the advanced oxidation unit (Zone 1 and Zone 2). Interventions samples for
mold were labeled by treatment location (A, B, and C), testing day (0a, 0b, and 0c), and
distance from the advanced oxidation unit (5, 10, 20, 30, and 40 feet). Control samples
for Staphylococcus aureus, MRSA, and Pseudomonas spp. were labeled by treatment
location (A, B, and C), testing day (0, 5, 10, 20, and 30), and distance for the advanced
oxidation unit (Zone 1 and Zone 2).
The three control test days (0a, 0b, and 0c) were treated as a covariate to give an
estimate of microbiological levels prior to the intervention, which was used for Day 0
counts. Descriptive statistics include graphs of mean counts with standard deviations for
each testing. Data analysis was conducted separately for each of the study
microorganisms (mold, Staphylococcus aureus, MRSA, and Pseudomonas spp.), and
included the following statistical analysis.
There was a possibility that one of the three advanced oxidation units could have
been more effective than the other units at reducing microbiological populations. There
was also a possibility of variation in treatment efficacy based on room sizes or
microbiological levels differing from one location in the building to another. To
determine if there was a statistical difference between the three advanced oxidation unit
locations (A, B, and C) a one-way ANOVA analysis was conducted using the mean
counts for the control and intervention testing locations.
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Proximity to the advanced oxidation units may result in varying levels of
effectiveness of the treatment. Areas closer to the units may experience greater reductions
in microbiological counts than those further away. Mold found in the air was analyzed
based on the mean counts for each distance from the unit (5, 10, 20, 30, and 40 feet) and
surface sample analysis was based on mean counts for each testing zone (Zone 1 and
Zone 2). To determine if there was a statistical difference as a result of proximity to the
advanced oxidation unit, a one-way between groups ANOVA analysis was conducted.
Day 0 data was used as the control group and Day 5, 10, 20, and 30 as the intervention
group. Regression analysis was used to model the relationship between the mold counts,
and sample proximity (5, 10, 20, 30, and 40 feet) to the advanced oxidation unit.
Days of exposure may positively impact the effectiveness of the advanced
oxidation treatment. To determine if longer treatment time resulted in a greater reduction
of microbiological populations, a one-way within groups ANOVA analysis, using mean
data from the control group (Day 0) and the intervention group (Day 5, 10, 20, and 30)
was performed. Regression analysis was used to model the relationship between
microbiological counts for each organism and exposure times (Day 0, 5, 10, 20, and 30).
All data analysis was performed using SAS statistical analysis software.
Statistical analysis was conducted by the researcher with data secured on a personal
computer that is password protected. The researcher maintained all paper copies of
results in a locked file cabinet to which only the research has access.
The data was analyzed using a general linear model in SAS. Within groups
analysis was performed using the control group and the intervention group. The
dependent variables ( yijk ) included microbiological counts (CFU) recovered from
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selective media. Analysis was performed for each of the microorganisms selected
individually (mold, Staphylococcus aureus, MRSA, and Enterobacteriacea). The model
included:
y ijk
y ijk
i
j
k
ij
ik
jk
ijk
bx ijk
ijkl
dependent variable, which represents the microbiological count for the
ith treatment jth time and kth distance
μ = intercept
αi = main effect of treatment
βj = main effect of time
δk = main effect of distance
αβij = 2-way interaction (treatment, time)
αδik = 2-way interaction (treatment, distance)
βδjk = 2-way interaction (distance, time)
αβδijk = 3-way interaction (treatment, distance, time)
b = denotes the slope of the ith effect of treatment, jth effect of time, kth effect
of distance for the covariate of preintervention at d 0
εijk = experimental error
The data was analyzed using regression in SAS. The dependent variable (y) included
microbiological plate counts (CFU). A separate regression analysis was performed for
each of the study microorganisms (mold, Staphylococcus aureus, MRSA, and
Pseudomonas spp.). The model included:
y = β0 + β1x1 + β2x2 + β3x1x2 + β4x12 + β5x22 + ε
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y = dependent variable
β0 = intercept
β1 = coefficient for time
β2= coefficient for distance
β3 = coefficient for time x distance
β4 = coefficient for time squared
β5 = coefficient for distance squared
x1 = data for time
x2 = data for distance
ε = experimental error
Threats to Validity
There was the potential that microbiological populations may not have been large
enough to distinguish a difference between treatments. To control for this threat, the
study was replicated at three different locations on the first level of the health care
building. If test locations did have one of the study microorganisms present, then that
location would have been excluded from testing of that microorganism. The building
selection may also have helped to reduce this threat to validity, as it is an older health
care facility (38 years old), built with energy efficiency measures such as reduced fresh
air ventilation that may aid in increasing microbial populations. The building also has six
outpatient clinics that may contribute to higher microbiological levels as a result of less
effective infection control practices (Abramson et al., 2000; Johnson, 2003). According
96
Abramson et al. (2000), outpatient clinics lack effective infectious disease control
guidelines and receive fewer updates on new infection control measures than hospitals.
Another threat to validity could have been outside mold levels affecting indoor
mold counts. To control for this threat, three outdoor air samples were collected on the
same days as the study samples. There was also the threat that air from the second and
third levels of the building could affect mold counts on the first level. To control for this
variable, three air samples were collected on the same days as the study samples.
The surfaces selected for this study are not regularly cleaned, but could have been
a threat to validity if these areas are cleaned during one of the treatments. To control for
this threat, the clinic managers were asked that none of the surfaces identified for testing
be cleaned throughout the duration of the study. Highly soiled surfaces could have
possible impacted the effectiveness of the antimicrobial treatment by creating a protective
barrier to protect the bacteria. To control for this variable, only surfaces that were visibly
free of soil were sampled.
Objects identified for surface testing needed to remain in their assigned testing
zone throughout the duration of the study. If an object identified for testing were to have
been moved from one zone to another, this would have been a threat to the study validity,
as the object surface may have received a change in treatment as a result of the move. To
control for this threat, the researcher informed the clinic managers to not move any object
identified for testing while the study is being conducted. The researcher also checked
daily to see that these objects are in their assigned location.
A threat to the study validity could result from a change in the environmental
conditions such as temperature and humidity. To control for this threat, the researcher
97
will record temperature and humidity levels daily in all three advanced oxidation unit
locations areas for the duration of the study.
Ethical Considerations
The director of the Wyandotte County Health Department gave approval for the
study to be conducted in the building, and was asked to sign a consent form for use of the
building and laboratory equipment. The study took place over a 3-month period so it was
important to have an organization willing to commit the use of their facility for a long
period of time. RGF Environmental agreed to provide the APS advance oxidation units
used on the first level of the building. Testing for microbiological populations required
the use of equipment such as autoclaves, incubators, and laboratory facilities that are
present at the building. The director gave approval for use of health department
equipment and facilities. No person associated with the RGF Environmental Group or the
Wyandotte County Health Department had a role in the design, data collection, data
analysis, data interpretation, or writing of the dissertation. There is no conflict of interest
with RGF Environmental Group as there is no potential for monetary gain, employment,
or any other benefit as a result of conducting this research.
Measures To Protect Building Occupants
There were no major ethical issues related to this research study as the
intervention was applied only during the time the building was vacated of all occupants.
Even if a person were to have entered the building during the intervention, there was no
risk of harm as the oxidative vapors produced by the system are far below levels
considered to be dangerous. The advanced oxidation process leaves no residues after the
treatment so there was no risk of harm to occupants who entered the building. The
98
manufacturer of the APS advanced oxidation system, RGF Environmental Group, has
obtained all necessary safety certifications to distribute this technology in the United
States (e.g. ETL Testing Laboratories, currently known as Intertex Testing Services,
Miami, FL). While the effectiveness of the technology is just now being determined, the
systems have been sold for commercial and residential use for over 5 years without a
single safety incident. The treatment section of this chapter gives a more detailed
description of safety features associated with this technology. The only concern would
have been if the advanced oxidation systems were abused by a person who was not
authorized to be in the building. There was remote chance that the ultraviolet bulb could
have broken. This would have resulted in a small amount of broken glass and mercury
leakage. To prevent breakage, the UV bulb is coated in a protective poly tube. Another
safety feature is the metal casing surrounding the device, which helps prevent breakage of
the bulb (Fink, 2004). The security access code needed to enter the building during off
hours is restricted to only the department managers and the researcher. The researcher
notified department mangers by email that access to the building is restricted during off
hours. The advanced oxidation units were turned on and off only by the researcher, who
checked the systems daily to make certain they are operating properly. When not in use
the advanced oxidation units were placed in a locked storage closet. The advanced
oxidation units were labeled “Do not touch, research study in progress.” At the end of the
study the advanced oxidation units were removed at the request of the director of the
health department. To help ensure the safety of occupants an IRB application was
completed and submitted to Walden University for review. The Walden University IRB
approval number for the study is 07-15-10-0263873.
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Summary
The study described in this chapter was designed to increase the understanding of
the advanced oxidation process‟s ability to reduce microbiological contaminants in the air
and on contact surfaces in an applied research setting. The experimental design described
allowed testing of the advanced oxidation process in multiple treatment sites in the
building. The design also increased knowledge on the effectiveness of the system over
various distances from the unit. Threats to validity, as well as any ethical concerns, were
thoroughly discussed. In the next chapter, results from this study are presented along with
discussion of how those results address research questions and hypotheses.
100
Chapter 4: Results
This chapter presents the results from the study, which was conducted to
determine the reduction of microbiological counts by an advanced oxidation treatment in
a health care facility located in Kansas City, Kansas. This included measurement of the
reduction of mold in the air and Staphylococcus aureus, Methicillin-Resistant
Staphylococcus aureus (MRSA), and Pseudomonas spp. on common noncritical contact
surfaces. The study employed an experimental research design that included control and
intervention groups.
Chapter 4 is divided into four sections. The first section presents the descriptive
data analysis of the variables included in the research study. The section includes
microbiological levels for each of the variables and standard deviations. The second
section includes log CFU (colony forming units) reductions in microbiological counts
and the results of the ANOVA analysis conducted for Research Questions 1 through 4.
The third section includes the results of the regression analysis performed using log CFU
reductions over distance and time for mold, and log reductions over time for MRSA,
Staphylococcus aureus, and Pseudomonas species. These analyses were conducted to
determine whether the independent variables (treatment time and distance from the
advanced oxidation unit) could be used to predict the effectiveness of the treatment. The
final section of the chapter will present data on potential threats to validity which include
building temperature, humidity, and mold counts both in other building levels and
outdoors.
The microbiological counts for airborne mold are presented to give the average
recovered levels at each treatment time (Day 0, 5, 10, 20, and 30) and distance (5, 10, 20,
101
30, and 40 feet). Microbiological counts for surface bacteria (Staphylococcus aureus,
MRSA, and Pseudomonas species) are presented to give average recovered levels at each
treatment time (Day 0, 5, 10, 20, and 30) and distance (Zone 1 and Zone 2). Additionally,
surface counts comprised an analysis of surface types tested which included: adult chair,
child chair, child table, countertop, door knob, exam table, faucet handle, scale, sink, and
telephone. Microbiological counts for each of the three study locations were also
compared (A = pediatrics, B = patient waiting room, and C = general clinic).
Descriptive Analysis
Average Day 0 mold counts were similar throughout the three study locations
(1.93 log CFU/100 L + 0.03) with the patient waiting room having slightly higher counts
than the other two treatment locations (Table 1). Mold counts decreased throughout the
course of study with average counts of 0.90 log CFU/100 L recovered after Day 30
(Table 1). The largest decrease in counts occurred in the patient waiting room with a 1.16
log CFU/100 L reduction after 30 days. Variation among the three testing locations
increased after Day 0, possibly as a result of the inconsistency of the treatment.
Table 1
Average Recovered Airborne Mold Counts and Standard Deviation by Time (Day) and
Location
Treatment
location
Peds
PWR
GC
Day 0
Log
CFU/
100 l
1.91
1.96
1.93
Day 5
Std
dev
.09
.08
.09
Log
CFU/
100 l
1.48
1.6
1.56
Day 10
Std
dev
.18
.18
.28
Log
CFU/
100 l
1.3
1.36
1.32
Day 20
Std
dev
.26
.17
.14
Log
CFU/
100 l
1.29
0.84
1.13
Day 30
Std
dev
.3
.06
.15
Log
CFU/
100 l
1.02
.8
.87
Std
dev
.16
.30
.11
102
Average Day 0 mold counts were similar within the 40 ft test area with an average
of 1.93 log CFU/100 L and ranged from 1.9 to 1.95 log CFU/100 L (Table 2). Mold
counts decreased for all sampling distances throughout the 30-day study, with the largest
decreases seen in samples collected at closer proximities to the PHI generator. Variation
increased slightly at all sampling distances after Day 0.
Table 2
Average Recovered Airborne Mold Counts and Standard Deviation by Time (Day) and
Sampling Distance (Feet)
Distance
5 ft
10 ft
20 ft
30 ft
40 ft
Day 0
Log
CFU/
100 l
1.94
1.94
1.90
1.92
1.95
Std
dev
.11
.06
.08
.11
.09
Day 5
Log
CFU/
100 l
1.50
1.55
1.51
1.49
1.67
Std
dev
.25
.2
.24
.23
.2
Day 10
Log
CFU/
100 l
1.32
1.28
1.18
1.33
1.52
Std
dev
.31
.29
.36
.27
.24
Day 20
Log
CFU/
100 l
0.94
1.14
1.06
1.09
1.20
Std
dev
.30
.24
.30
.23
.35
Day 30
Log
CFU/
100 l
0.90
0.66
1.02
0.92
0.99
Std
dev
.24
.35
.19
.24
.35
MRSA was recovered in 56% of samples prior to treatment, with the patient
waiting room having the highest frequency (58%). MRSA was recovered on every
surface type, but was most often found on sinks (83%) and door knobs (72%; Table 3). In
the six sample zones, Day 0 MRSA counts ranged from 1.47 to 2.59 log cfu/100 cm2,
with an average of 1.8 log CFU/100 cm2 (Table 4). The patient waiting room had the
highest counts of the three study locations. The higher levels of MRSA found in the
patient waiting room may be attributable to heavier visitor traffic in that area, while lower
counts were found in lighter visitor traffic areas, such as exam rooms.
After 30 days of the advanced oxidation treatment, samples testing positive for
MRSA decreased from 56% to 31%. Counts decreased throughout the study going from a
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Day 0 average of 1.8 log CFU/100 cm2 to a Day 30 average of 0.72 log CFU/100 cm2.
The patient waiting room Zone 1 had the largest reduction in counts of the six sample
zones, with a decrease of 1.8 log CFU/100 cm2.
Table 3
Percentage of Microorganisms Recovered on Study Surface Types Prior to Treatment
Surface type
Counter top
Adult chair
Child chair
Sink
Scale
Door knob
Child table
Telephone
Faucet handle
Exam table
Staphylococcus aureus
%
75%
80%
100%
83%
66%
89%
100%
78%
100%
55%
MRSA
%
33%
53%
58%
83%
33%
72%
67%
44%
67%
22%
Pseudomonas species
%
8%
7%
8%
92%
33%
16%
33%
22%
83%
0%
Table 4
Average Recovered MRSA Counts and Standard Deviation by Time (Day) and Location
/Zone
Distance
Peds Z1
Peds Z2
PWR Z1
PWR Z2
GC Z1
GC Z2
Day 0
Log
CFU/
100
cm2
1.75
1.47
2.59
2.06
1.88
1.59
Std
dev
1.52
1.58
1.75
1.72
1.80
1.61
Day 5
Log
CFU/
100
cm2
0.86
1.27
1.30
1.67
0.79
1.18
Std
dev
1.34
1.45
1.46
1.84
1.25
1.38
Day 10
Log
CFU/
100
cm2
1.03
1.19
0.61
0.78
0.80
1.41
Std
dev
1.16
1.43
1.00
1.21
1.34
1.60
Day 20
Log
CFU/
100
cm2
0.68
0.73
0.47
1.16
0.77
0.62
Std
dev
1.07
1.26
1.15
1.09
1.20
0.98
Day 30
Log
CFU/
100
cm2
.59
.8
.7
.77
.72
.76
Std
dev
0.97
1.27
1.12
1.27
1.13
1.18
Staphylococcus aureus was the most commonly found surface microorganism
tested, and recovered in 85% of pretreatment samples. Of the three study locations, the
patient waiting room had the highest occurrence of Staphylococcus aureus with 92%. The
104
patient waiting room also has the most visitor traffic of any of the three study locations,
which may account for the higher microbial counts. Staphylococcus aureus was
recovered on every surface type and was most often found on faucet handles, child‟s
chairs, and tables (Table 3). The child‟s chair and tables are located in only the patient
room, while faucets are located in four of the six sample zones. In the six sample zones
Day 0 counts for Staphylococcus aureus ranged from 2.69 to 3.34 log CFU/100 cm2, with
an average of 2.89 log CFU/100 cm2 (Table 5).
After 30 days of the advanced oxidation treatment, samples testing positive for
Staphylococcus aureus decreased from 85% to 53%. Plate counts also decreased
throughout the study, going from an average of 2.89 log CFU/100 cm2 at Day 0 to 1.3 log
CFU/100 cm2 after Day 30. Pediatrics Zone 1 had the largest reduction in counts of any
of the six testing zones, decreasing by 2.19 log CFU/100 cm2 after 30 days.
Table 5
Average Recovered Staphylococcus aureus Counts and Standard Deviation by Time
(Day) and Location / Zone
Distance
Peds Z1
Peds Z2
PWR Z1
PWR Z2
GC Z1
GC Z2
Day 0
Log
CFU/
100
cm2
3.34
2.84
2.86
2.85
2.78
2.69
Std
dev
0.98
1.62
1.38
1.04
1.38
1.55
Day 5
Log
CFU/
100
cm2
2.12
1.91
1.75
1.75
1.92
2.45
Std
dev
1.71
1.64
1.41
1.52
1.58
1.55
Day 10
Log
CFU/
100
cm2
1.50
2.82
1.21
1.86
1.28
1.21
Std
dev
1.32
1.45
1.40
1.45
1.58
1.36
Day 20
Log
CFU/
100
cm2
1.01
1.61
1.15
2.32
1.16
2.13
Std
dev
1.18
1.31
1.32
0.47
1.34
0.59
Day 30
Log
CFU/
100
cm2
1.01
1.61
1.11
1.36
1.18
1.57
Std
dev
1.15
1.78
1.26
1.53
0.98
1.72
Pseudomonas spp. were the least prevalent of the three surface microorganisms
studied and were recovered in only 29% of all pretreatment samples. General clinic and
105
pediatrics surfaces had the highest frequency (36%) of Pseudomonas species.
Pseudomonas spp. was recovered on every surface type except exam tables (Table 3).
Surfaces where Pseudomonas spp. was most often found were typically wetter and
included sinks (92%) and faucet handles (83%). Average Day 0 Pseudomonas spp.
counts were 0.96 log CFU/100 cm2 with pediatrics having the highest counts (Table 6).
After the 30 day advanced oxidation treatment, samples testing positive for
Pseudomonas spp. decreased from 29% to 17%. Counts decreased throughout the course
of the study, going from an average of 0.96 log CFU/100 cm2 at Day 0 to an average of
0.44 log CFU/100 cm2 after Day 30 (Table 6). The largest reduction in Pseudomonas spp.
plate counts occurred in Pediatrics Zone 1 and General Clinic Zone 2, which had a
decrease of 0.91 log CFU/100 cm2 after 30 days of the treatment. There were also no
detectable Pseudomonas in the patient waiting room Zone 1 or the general clinic Zone 1
after 30 days.
Table 6
Average Recovered Pseudomonas spp. Counts and Standard Deviation by Time (Day)
and Location / Zone
Distance
Peds Z1
Peds Z2
PWR Z1
PWR Z2
GC Z1
GC Z2
Day 0
Log
CFU/
100
cm2
1.23
1.37
0.39
0.42
0.90
1.42
Std
dev
1.82
1.82
1.15
0.97
1.55
1.70
Day 5
Log
CFU/
100
cm2
0.36
0.91
0.00
0.51
1.08
1.47
Std
dev
0.88
1.50
0.00
1.26
1.05
1.67
Day 10
Log
CFU/
100
cm2
0.00
0.75
0.39
0.35
0.46
0.87
Std
dev
0.00
1.22
0.96
0.85
1.11
1.41
Day 20
Log
CFU/
100
cm2
0.38
0.46
0.00
0.00
0.22
1.08
Std
dev
0.94
1.13
0.00
0.00
0.53
1.29
Day 30
Log
CFU/
100
Cm2
0.32
1.40
0.00
0.38
0.00
0.51
Std
dev
0.78
1.63
0.00
0.94
0.00
1.25
106
Research Questions and Hypotheses
This section will review the statistical analysis performed using SAS statistical
software developed by SAS Inst., Inc., Cary, NC. To determine if there were statistical
differences between the advanced oxidation unit treatment and the control, a general
linear model was used to calculate least squares means. The model included:
y ijk
i
j
k
ij
ik
jk
ijk
bx ijk
ijkl
μ = intercept
αi = main effect of treatment
βj = main effect of time
δk = main effect of distance
αβij = 2 way interaction (treatment, time)
αδik = 2 way interaction (treatment, distance)
βδjk = 2 way interaction (distance, time)
αβδijk = 3 way interaction (treatment, distance, time)
b = denotes the slope of the ith effect of treatment, jth effect of time, kth effect
of distance
εijk = experimental error
Differences were detected between the intervention and the control with a reduction in
microbiological counts in three of the four organisms studied.
Research Question 1
If an advanced oxidation treatment is applied to the indoor environment of a
health care facility for 12-hours daily, will mold mean counts or detectable mold in the
107
air decrease by at least 90%, as measured by microbiological cultural plating of indoor air
on YM Agar? Testing parameters include treatment location (Site A, B, and C), sample
distance from the advanced oxidation unit (5, 10, 20, 30, and 40 feet), and exposure time
(0, 5, 10, 20, and 30 days).
Hypothesis 1
Mold mean counts will be significantly decreased in the air, as measured by
microbiological cultural plating of indoor air on YM Agar, after daily 12-hour advanced
oxidation treatments of the indoor environment.
There was a significant difference (p < 0.01) between the control group (Day 0)
and the APS advanced oxidation treatment group over the 30-day study (Day 5, 10, 20,
and 30). Mold count reductions gradually increased throughout the course of the study
(Figure 1). However, it was not until Day 30 that mold counts reached a 90% reduction
level.
Figure 1. Average log reduction in airborne mold counts by time and distance
108
Sampling distance from the advanced oxidation units did not show a significant
difference (p = 0.17) in mold counts. For this analysis, mold counts from samples
collected at 5, 10, 20, 30, and 40 feet away from the generator were compared. While
analysis did not show significant difference, there still appeared to be a relationship
associated with the sampling distance and the effectiveness of the treatment. Samples
collected from 5 feet away from the generator reached a 90% reduction by Day 20 while
further sampling distances took 30 days or never reached the 90% reduction level (Figure
1). The null hypothesis was rejected as differences between the control and the
intervention groups were statistically significant.
There was a significant difference (p < 0.05) found between testing locations (A,
B, and C) over time (Day 5, 10, 20, and 30). This may be attributable to more open
spaces, which allowed the treatment to be more effectively distributed (Figure 2). The
patient waiting room (B), which consisted of only one large room, reached 90% reduction
in mold counts after Day 20 of the advanced oxidation treatment. Pediatrics and general
clinic (A and C) both consist of multiple rooms and had slower rates of mold reduction
(Figure 2).
109
Figure 2. Average log reduction in airborne mold counts by testing location and time
Research Question 2
If an advanced oxidation treatment is applied to the indoor environment of a
health care facility for 12-hours daily, will Methicillin-Resistant Staphylococcus aureus
(MRSA) mean counts or detectable MRSA decrease by at least 90% on surfaces, as
measured by microbiological cultural plating of swabbed surfaces on MRSA agar?
Testing parameters include treatment location (A, B, and C), sample distance from the
advanced oxidation unit (Zone 1 and Zone 2), and exposure time (0, 5, 10, 20, and 30
days).
Hypothesis 2
Methicillin-Resistant Staphylococcus aureus (MRSA) mean counts will be
significantly decreased on surfaces, as measured by microbiological plate counts of
surface swabs of MRSA agar, after daily 12-hour APS advanced oxidation treatments of
the indoor environment.
110
No significant differences (p > 0.05) were detected in the reduction of average
MRSA counts over time between the control (Day 0) and the intervention groups (Day 5,
10, 20, and 30). However, there was a relationship between the use of the advanced
oxidation treatment and average MRSA counts, as overall reductions increased during the
course of the 30 day study (Figure 2). The overall reduction in log CFU counts exceeded
90% after 20 days of the advanced oxidation treatment (1.07 log CFU). While the
average MRSA counts were not significantly lower in the intervention samples, they did
approach significance. It is possible that with an increased sample size, statistical
significance could be reached.
No significant differences (p > 0.05) were detected in MRSA counts between
sample Zones 1 and 2. For this analysis, average Day 0 log counts for Zone 1 samples
were compared with counts from Zone 2 over the 30 day study. It is important to note
that the proximity to the advanced oxidation treatment did show a relationship, as the
difference between the zones approached significance. There were also higher reductions
observed in Zone 1 samples, as compared to Zone 2 (Figure 3). A greater than 90%
reduction in average MRSA counts was seen in Zone 1 after just 10 days of the
intervention, while Zone 2 average counts never reached higher than 85%. The null
hypothesis was accepted as differences between the control group and the intervention
group were not statistically significant (Figure 3).
111
Figure 3. Average log reduction in surface MRSA counts by time and distance
No significant difference was found in MRSA counts between the three study
locations (p = 0.34). For this analysis, average log counts for each study location (A, B,
and C) were compared over the 30 day study. This would indicate that the advanced
oxidation treatment had a similar effect on each study location over the course of the
study.
There was a significant difference (p < 0.05) in MRSA counts for 8 of the 10
surface types, as a result of the advanced oxidation treatment. For this analysis, the
average log counts for each of the 10 sample surface types were compared over the 30
day study. Surfaces that did not show a significant difference in counts included the
child‟s chair (p = 0.15) and exam table (p = 0.98). The child chairs were one of the
visually dirtiest and most contaminated surfaces types tested, possibly limiting the
efficacy of the treatment. The exam tables had the lowest number (22 %) of recovered
112
MRSA of the 10 sample surface types. It is possible with higher initial levels of MRSA
on exam tables, significance could be obtained.
Research Question 3
If an advanced oxidation treatment is applied to the indoor environment of a
health care facility for 12 hours daily, will Staphylococcus aureus mean counts or
detectable Staphylococcus aureus decrease on surfaces by at least 90%, as measured by
microbiological plate counts of swabbed surface diluents on Baird Parker Agar? Testing
parameters include treatment location (A, B, and C), sample distance from the advanced
oxidation unit (Zone 1 and Zone 2), and exposure time (0, 5, 10, 20, and 30 days).
Hypothesis 3
Staphylococcus aureus mean counts will be significantly decreased on surfaces,
as measured by microbiological plate counts of surface swab diluents on Baird Parker
Agar, after daily 12-hour advanced oxidation treatments of the indoor environment.
There was a significant difference (p < 0.01) in the reduction of average
Staphylococcus aureus counts over time, between the control (Day 0) and the
intervention groups (Day 5, 10, 20, and 30). A significance reduction (p < 0.01) in counts
first occurred after Day 5 of the treatment, and remained significant throughout the rest of
the study. The overall Staphylococcus aureus count reductions increased throughout the
course of the 30 day study, ending with a 95% log reduction (Figure 4). The overall
reduction in log CFU exceeded 90% after 10, 20, and 30 days of the intervention. The
null hypothesis was rejected as differences between the control and the intervention
groups were statistically significant.
113
Figure 4. Average log reduction in surface Staphylococcus aureus counts by time and
distance
There was a significant difference (p < 0.01) between sample Zones 1 and 2. For
this analysis, Day 0 average Staphylococcus aureus counts for Zone 1 samples were
compared with counts form Zone 2 samples over the 30 day study. Samples collected
from closer proximity to the advanced oxidation treatment (Zone 1) had greater reduction
in Staphylococcus aureus counts than those collected further away (Figure 2). A greater
than 90% reduction in average counts was seen in Zone 1 after Day 5, 10, 20, and 30 of
the intervention, while Zone 2 average counts did not reach 90% until Day 30.
Study location (A, B, and C) did not appear to have an effect on Staphylococcus
aureus counts, as there was no significant difference (p = 0.35) between the three areas.
For this analysis, average Staphylococcus aureus counts for each of the three study
locations were compared over the 30 day study.
Nine out of the 10 sample surfaces types tested showed a significant difference (p
< 0.01) in Staphylococcus aureus counts, as a result of the advanced oxidation treatment.
114
For this analysis, the average log counts for each of the 10 surface types were compared
over the 30 day study. The only surface that did not show a significant difference (p =
0.52) was the exam tables, which had the lowest number (55%) of positive
Staphylococcus aureus sample sites. It is possible with higher initial levels of
Staphylococcus aureus on exam tables, significance could be obtained.
Research Question 4
If an advanced oxidation treatment is applied to the indoor environment of a
health care facility for 12 hours daily, will Pseudomonas spp. mean counts or detectable
Pseudomonas spp. decrease on surfaces by at least 90%, as measured by microbiological
plate counts of swabbed surface diluents on Pseudomonas Isolation Agar? Testing
parameters include treatment location (A, B, and C), sample distance from the advanced
oxidation unit (Zone 1 and Zone 2), and exposure time (0, 5, 10, 20, and 30 days).
Hypothesis 4
Pseudomonas mean counts will be significantly decreased on surfaces, as
measured by microbiological plate counts of surface swab diluents on Pseudomonas
Isolation Agar, after daily 12-hour advanced oxidation treatments of the indoor
environment.
There was a significant difference (p < 0.01) in the reduction of average
Pseudomonas counts over time between the control group (Day 0) and the intervention
group (Day 5, 10, 20, and 30). A significant difference (p < 0.01) was first observed after
Day 5 of the treatment, and remained significant throughout the rest of the study.
However, the overall reduction in log CFU never reached 90%, peaking at just 54% after
Day 20 (Figure 5). The limited count reductions could be attributable to low control
115
Pseudomonas spp. levels (Day 0), which averaged only 0.96 log CFU/100 cm2. It is
possible that with higher levels of Pseudomonas spp. in the control group, a 90%
reduction could be reached.
Figure 5. Average log reduction in surface Pseudomonas spp. counts by time and
distance
A significant difference (p < 0.01) was observed between the sample Zones 1 and
2. For this analysis, average log counts for Zone 1 samples were compared with Zone 2
counts, over the 30 day study. Samples collected from closer proximity to the advanced
oxidation treatment (Zone 1) had greater reductions in Pseudomonas spp. counts than
those collected further away (Figure 5). Zone 1 count reductions gradually increased
throughout the duration of the study, peaking 66% after Day 30. Zone 2 count reductions
were consistently lower than Zone 1, reaching a high of just 50% after Day 20 of the
advanced oxidation treatment. The null hypothesis was rejected as differences between
the control and the intervention groups were statistically significant.
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Between the three study locations (A, B, and C), there was no significant
difference (p = 0.46) in Pseudomonas spp. counts throughout the course of the study. For
this analysis, average log counts for each of the three study locations were compared over
the 30 day trial.
Only four of the 10 sample surface types showed a significant difference (P <
0.05) in Pseudomonas spp. counts, as a result of the advanced oxidation treatment. For
this analysis, counts from each surface type were compared over the 30 day study.
Surfaces that did not show a significant difference included an adult chair (p = 0.20),
child chair (p = 0.16), counter top (p = 0.80), scale (p = 0.71), telephone (p = 0.89), and
exam table (p = 0.95). As mentioned earlier in this chapter, Pseudomonas spp. was most
often recovered on wetter surfaces. These surfaces were dry with little, if any
Pseudomonas spp. present on them. It is possible that with higher initial levels of
Pseudomonas spp. on the surfaces mentioned above, a significant reduction could be
reached.
Regression Analysis
The data were analyzed using stepwise regression in SAS (SAS Inst., Inc., NC)
for each of the study microorganisms (mold, Staphylococcus aureus, MRSA, and
Pseudomonas spp.). The model used for the regression analysis included: distance, time,
sample type, and location.
There was a significant relationship between mold count reduction and the
advanced oxidation treatment time. For this analysis, average log mold counts were
compared over the 30 day study. The prediction equation used included the following:
Mold = Intercept + Time (-.0595) + Time2 + (.0011) + Location*Time (-.0025). Since the
117
relationship was significant, this indicates the likelihood of the mold counts being
reduced as a result of the advanced oxidation treat over time. The R2 was 0.7818,
meaning the application of the advanced oxidation treatment over time accounted for
78% of the variability in mold counts. Since there was a quadratic effect for time it was
determined that the point of inflection or diminishing return was 20 days.
There was a significant relationship between MRSA count reduction and the
advanced oxidation treatment time. For this analysis, average log mold counts were
compared over the 30-day study. The prediction equation used included the following:
MRSA = Intercept + Time (-.0961) + Zone*Sample (.0028) + Sample2 (-.0007) + Time2
(.0021). Since the relationship was significant, this indicates the likelihood of the mold
counts being reduced as a result of the advanced oxidation treat over time. However, the
R2 was 0.2975, meaning the application of the advanced oxidation treatment over time
accounted for just 30% of the variability in MRSA counts. The effect of sample indicates
that some of the surfaces were more impacted than others. This means that some items
had lower counts at the beginning than others so did not see as much of an effect. This
holds true for the different zones, which explains the interaction of the surfaces sampled
within each zone. As seen with mold there was a quadratic effect for time meaning a
point of inflection or leveling off of the counts was found at 20 days.
There was a significant relationship between Staphylococcus aureus count
reduction and the advanced oxidation treatment time. For this analysis, average log mold
counts were compared over the 30-day study. The prediction equation used included the
following: Staphylococcus aureus = Intercept + Sample2 (-.0102) + Time (-.1210) +
Time2 (.0026). Since the relationship was significant, this indicates the likelihood of the
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Staphylococcus aureus counts being reduced as a result of the advanced oxidation treat
over time. However, the R2 was only 0.3019, meaning the application of the advanced
oxidation treatment over time accounted for just 30% of the variability in Staphylococcus
aureus counts. The effect of sample indicates that some of the surfaces were more
impacted than others. This means that some items had lower counts at the beginning than
others, so did not see as much of an effect. This holds true for the different zones, which
explains the interaction of the surfaces sampled within each zone. Since there was a
quadratic effect for time it was determined that the point of inflection or diminishing
return was 20 days.
There was a significant relationship between Pseudomonas spp. count reduction
and the advanced oxidation treatment time. For this analysis, average log mold counts
were compared over the 30-day study. The prediction equation used included the
following: Pseudomonas spp. = Intercept + Sample2 (-.0102) + Time (-.1210) + Time2
(.0026). Since the relationship was significant, this indicates the likelihood of the mold
counts being reduced as a result of the advanced oxidation treat over time. However, the
R2 was only 0.1392, meaning the application of the advanced oxidation treatment over
time accounted for just 14% of the variability in Pseudomonas spp. counts. The effect of
sample indicates that some of the surfaces were more impacted than others. This means
that some items had lower counts at the beginning than others, so did not see as much of
an effect. This holds true for the different zones, which explains the interaction of the
surfaces sampled within each zone. Since there was a quadratic effect for time it was
determined that the point of inflection or diminishing return was 20 days.
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Threats to Validity
Potential confounding variables were evaluated to determine if there was a
possible effect on microbiological counts in treatment locations by an external variable.
Temperature and humidity data, collected from each study location showed no significant
affect on microbiological counts. Indoor ambient temperatures remained constant
throughout the course of the study and ranged from 70 to 73°F. Indoor humidity levels
were relatively high throughout the duration of the study and varied from only 58% to
65%.
Outdoor airborne mold and indoor airborne mold, from the second and third
building levels were tested on the same days as the treatment (Day 0, 5, 10, 20, and 30).
No differences were detected in colony counts for mold in the study locations (first
level). Outdoor airborne mold levels were high (>2.6 log CFU/100 L) throughout the
duration of the study, however did not cause any statistical differences.
This chapter presented data addressing each of the four research questions and
hypotheses. This included descriptive analysis of counts recovered from the three study
locations, ANOVA analysis to answer research questions, and regression analysis to
model the relationship between microbial counts and sample proximity to the advanced
oxidation unit. The next and final chapter includes a discussion of the findings presented
in chapter 4, along with their implications and social change significance. Chapter 5
concludes with recommendations for action and further study and final comments. These
include the placement of the advanced oxidation units to optimize operation in a health
care facility. Recommendations for further study are presented covering study limitations
and gaps that were identified from the research.
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Chapter 5: Summary, Recommendations, and Conclusions
The final chapter comprises four sections. The first section provides an overview
of the study and a summary of the findings. The second section includes a discussion of
the findings and implications in the context of previous research on indoor environmental
antimicrobial treatments. The third section includes a discussion of the social change
significance of the study. Section four presents recommendations for action and future
study.
Overview of Study and Summary of Findings
Microbiological contaminants are responsible for hundreds of thousands of health
care infections, costing health care providers billions of dollars annually (CDC, 2008c;
Hindron et al., 2008; Klein & Smith, 2007; Price et al., 2005). Contaminants such as
mold and bacteria are commonly found in almost every indoor environment (Huange et
al., 2006; Price et al., 2005; Scott et al., 2009). It is essential to reduce the health risk
posed by contaminants in buildings where susceptible populations are present (Durston,
2007; Hota, 2004; Jacob et al., 2002).
This study addressed the knowledge gap in the effective treatments to reduce
these indoor contaminants and whether an advanced oxidation treatment system can
significantly reduce microbiological populations in the air and on surfaces in a health
care building. The study was conducted on the first level of a three-level health building
located in Kansas City, Kansas. The study was conducted in three separate locations in
the building over a time period of 30 days. Research questions addressed the application
of the advanced oxidation treatment applied daily for 12 hours with testing occurring on
Days 0, 5, 10, 20, and 30. Testing focused on the reduction of counts in airborne mold
121
and MRSA, Staphylococcus aureus, and Pseudomonas spp. on surfaces. Prior research
has been limited to the use of single oxidizing agents, air filtration, and conventional
cleaning and disinfection methods (Clause, 2004; Kuhn et al., 2003; Kunjundzic et al.,
2007; Mazur & Kim, 2006).
The results of this study were that the APS advanced oxidation system was
effective at reducing indoor contaminants in the air, and on surfaces in a health care
facility. In pretreatment samples mold was recovered at similar levels throughout the
three treatment areas. Mold counts decreased significantly (p < 0.01) as a result of the 30day advanced oxidation treatment. A significant reduction (p < 0.01) in airborne mold
was first observed after Day 5 of the treatment. A 90% reduction in counts did not occur
until after Day 30 when a peak reduction of 94% was obtained. Proximity to the
advanced oxidation generator was also evaluated, but no significant relationship
observed. However, there did appear to be an association, as samples collected from the
closest sampling distance (5 ft) were the first to reach a 90% reduction. There was a
significant difference (p < 0.05) between study locations, with the patient waiting room
reaching a 90% reduction earlier than the other two study areas. This maybe attributable
to the patient waiting room being more open, consisting of only one large room, while the
other locations consisted of multiple rooms. Regression analysis showed that the
treatment was effective up to Day 20, after which time counts for airborne mold were
negligible (< 10 CFU/100 L). Further research, with higher initial mold levels is needed
to better understand total reduction capabilities of the technology and time duration for
effectiveness.
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MRSA was recovered on 56% of control samples, and on every surface type
tested. Sinks and door knobs were most likely of the 10 surface types to have MRSA
present. MRSA counts were highest in heavily trafficked areas such as the patient waiting
room. The advanced oxidation treatment did not significantly (p = 0.05) reduce MRSA
counts over the 30-day treatment. This may be attributable to the low level of MRSA
recovered in the study areas. Higher control level MRSA counts may have resulted in a
significant difference. An exposure time longer than 30 days may also be needed to show
a significant difference in counts. There is also a possibility that the advanced oxidation
treatment is less effective at reducing MRSA counts than other strains of Staphylococcus
aureus. There was also no significant difference (p = 0.05) associated with proximity to
the treatment. However, there did appear to be a positive relationship related to both the
treatment time and proximity, as both approached significance. The treatment resulted in
a 91% overall reduction in MRSA counts after 30 days. All surface types tested showed a
significant (p < 0.01) reduction in counts except for the exam tables and child chairs. The
treatment effectiveness peaked at Day 20, after that time the treatments ability to reduce
MRSA counts began to lessen. However, MRSA counts did continue to decrease
throughout the 30-day study.
Staphylococcus aureus was the most commonly found (85%) of the three surface
microorganisms tested, and was recovered on every surface type. The advanced oxidation
treatment significantly (p < 0.01) reduced Staphylococcus aureus counts in 5 days. A
greater than 90% reduction in counts first occurred after 10 days of treatment, with a peak
reduction of 95% at the end of the 30 days. Proximity to the treatment did impact
efficacy, as samples collected within 20 feet of the PHI generator had significantly (p <
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0.01) lower Staphylococcus aureus counts than samples collected further away. These
findings reinforce the hypothesis by Berrington and Pedler (1998) that oxidizers are most
effective in the vicinity nearest the generator. Nine out of 10 surfaces types tested showed
a significant reduction (p < 0.01) in Staphylococcus aureus counts. The patient exam
tables were the only surface type not to show a significant reduction in Staphylococcus
aureus counts, likely attributable to the low levels of the microorganism initially found
on that surface. Regression analysis showed that the treatment was most effective up to
Day 20, after which time effectiveness began to diminish. However, Staphylococcus
aureus counts countined to decrease throughout the course of the 30-day study.
Pseudomonas species were the least prevalent of the three surface
microorganisms studied, being recovered in only 29% of all pretreatment samples.
Pseudomonas spp. were most often recovered on wetter surfaces, such as sinks (92%)
and faucet handles (83%). This supports findings by Scott et al. (2009) who noted that
Pseudomonas spp. survive best in indoor environments where higher moisture levels are
present. The advanced oxidation treatment significantly reduced (p < 0.01) Pseudomonas
spp. counts after only 5 days. The overall reduction in log CFU never reached 90%,
peaking at just 54% after Day 20. Low levels of Pseudomonas spp. in the control samples
likely impacted the studies ability to show a 90% reduction in counts. Proximity to the
treatment did impact efficacy, as samples collected within 20 feet of the PHI generator
had significantly (p < 0.01) lower counts than samples collected further away. Only four
of the 10 surface types tested had significantly (p < 0.05) lower counts as a result of the
treatment. Surfaces that did not show a significant difference in counts had little or no
124
Pseudomonas spp. present on them at Day 0. The treatment was most effective up to Day
20, after which time there was no further reduction Pseudomonas spp. counts.
Findings and Alternative Antimicrobial Interventions
The study showed that the advanced oxidation treatment was effective at
significantly reducing indoor mold counts in the air. Other interventions including
increased ventilation, air filtration, and ionizers are also known to be effective at reducing
air borne contaminants including mold (Kujundzic et al., 2005; Milton et al., 2000; Rosen
& Richardson, 1999). Increasing ventilation would not have been an effective
intervention in this study, as the building has limited air flow with sealed windows.
Limited ventilation is not only an issue for this building, but for most health care facilities
with the current emphasis on energy conservation and climate control (Bahnfleth &
Kowalski, 2005). Both air filtration and ionizers require regular maintenance to ensure
the units are operating properly and are not a source of contamination (Clausen, 2004;
Mazur & Kim, 2006). The advanced oxidation systems required no maintenance during
this study, but would need to be checked periodically to make certain the UV bulb is
operating properly. The advanced oxidation system produced a low level noise when
operating, which may not be an issue with other interventions mentioned above. Multiple
advanced oxidation systems would also need to be placed throughout a building to
effectively reduce mold counts. This may not be the case with other interventions needing
only one central treatment location.
Understanding the effectiveness of the advanced oxidation system at reducing
surface microorganisms was an important aspect of this study. The advanced oxidation
system reduced counts in all three of the microorganisms tested (MRSA, Staphylococcus
125
aureus, & Pseudomonas spp.) with reductions of 0.52 to 1.55 log CFU after 30 days of
treatment. Conventional cleaning and disinfection is the most commonly used
antimicrobial intervention used by health care facilities (Dharan et al., 1999).
Conventional cleaning and disinfection can produce larger reductions in counts.
However, the literature review identified several important limitations for this
antimicrobial method relating to effectiveness and safety of the treatment.
From the literature review conventional cleaning and disinfection was found to
be: inconsistent at reducing surface counts, a potential source for the development of
antimicrobial bacterial strains, and a contributor to disease burden from the use of harsh
chemicals (Beatty et al., 2007; Dharan et al., 1999; Fraise, 2002; Paton, 2009). In this
study, the application of the advanced oxidation treatment was consistent with no
significant difference in microbial reductions between the three study locations. The
advanced oxidation process will not contribute to the development of antimicrobial
strains and leaves no harmful residue (EPA, 2002; Fink, 2004).
The most efficient use of the advanced oxidation system would be in conjunction
with conventional cleaning and disinfection, as a means for keeping counts reduced
between applications. In this study, surfaces tested were not conventionally cleaned or
disinfected throughout the duration of testing, relying only on the daily advanced
oxidation treatment to keep counts reduced. In health care facilities, advanced oxidation
systems could act as a control intervention to assure that conventionally cleaned surfaces
remain clean longer.
126
Implications for Social Change
The results of the study contribute to social change. It is evident from previously
published research described in chapter 2 that indoor microbiological contaminants are an
important public health problem, especially in health care facilities where susceptible
populations reside. This study provides evidence that an advanced oxidation treatment
can be used to significantly reduce counts of airborne and surface microorganisms in
these facilities. These findings are valuable to building engineers, infection control,
occupational health, and public health professionals in developing best practices for
making indoor environments healthier for occupants, especially those who are susceptible
to microbiological contaminants. Improved infection control practices will help patients,
visitors, and health care workers feel more confident about the cleanliness of the health
care facility and their reduced risk of contracting a health care acquired infection. The
research also gives health care organizations a potential method for reducing costs
through fewer facility-acquired infections, reduced absenteeism, and improved
performance of workers.
Recommendations
Recommendations for Action
This study used large, commercial photohyroionization (PHI) generators referred
to as air purification systems (APS) by the manufacturer. The units are designed to treat
large areas of 2,000 to 5,000 square feet. Study results indicated that the APS advanced
oxidation system is most effective in the area closest to the generator (0 to 20 feet).
Smaller PHI generators, designed to treat a single room could be placed more frequently
127
throughout a building, potentially giving more effective coverage. This would include
placing a unit in every occupied room or placing multiple units in larger rooms.
Placing units in every room would eliminate the risk of a closed door blocking
access to the advanced oxidation treatment. This study was conducted in the evenings,
when the building was vacant and the doors could easily be left open. If the treatment
were to be applied during normal office hours it would be difficult, if not impossible to
keep all doors continuously open; however, understanding the limitations of the unit is
important for strategizing locations of their placement.
Considering the systems are most effective in areas closest to the PHI units, it
would be beneficial to place them closer to critical areas. In a health care facility this may
include waiting rooms, where infectious organisms may be present as a result of ill
clients. Child play and reading areas may also be ideal area to place units as children are
known to shed harmful microorganisms (McDonald, 2005). Bathroom and food
preparation areas would also be potential sites in which to place advanced oxidation units
(Scott et al., 2009).
This study operated the advanced oxidation units only 12 hours a day, when the
building was empty. Operating the units for longer periods of time, or running them
continuously may result in faster and/or larger reduction in microbiological counts.
Operating the units for longer periods of time could mean the building is occupied during
the treatment. A potential drawback to operating the APS units when the building is
occupied is the noise and odor levels generated by the system. While neither appeared
excessive, it would be important to better understand occupant tolerance for these factors
before operating during regular business hours.
128
In health care environments keeping surfaces visually clean is typically a critical
step prior to disinfection (Goodman et al., 2008; Hota, 2004). This appears to also apply
when using the APS advanced oxidation system. The visually dirtiest surfaces, such as
the child chairs in the patient waiting room, were the most difficult to significantly reduce
microbial counts. Making certain that surfaces are visually free of soils may increase
probability of achieving a significant microbial reduction.
Recommendations for Further Research
The advanced oxidation treatment occurred over a 30-day period with constantly
increasing microbial reductions in all the study organisms except for Pseudomonas. This
is longer than previous peer reviewed research which evaluated the technology for just 24
hours (Ortega et al., 2007). To better understand the total reduction capabilities for those
microorganisms, a longer treatment evaluation period is recommended. Studying the
technology over an extended period of time would also increase knowledge of the long
term effectiveness of the treatment at keeping microorganisms suppressed.
It would be beneficial to test the effectiveness of the advanced oxidation treatment
again on Pseudomonas species. Levels of the microorganisms found in this study were
too low to effectively determine reduction capabilities of the treatment. Future research
should focus on testing of Pseudomonas spp. only on surfaces which are typically wetter
and more likely to contain the microorganism. This would include surfaces such sink,
faucets, floor drains, showers, and bath tubs.
The only microorganism tested that did not show a significant reduction in counts
was MRSA. However, there did appear to be a relationship as data approached
significance. Low levels of MRSA levels in the control samples may have contributed to
129
not being able to show a significant difference. Further research into the effectiveness of
the treatment against environmental MRSA would be beneficial in understanding this
technology. MRSA is an important indoor microbiological contaminant and the control of
which is a priority to health care organizations (Jarvis, 2010).
Moisture naturally found in the air, in the way of humidity, is an important
component to the photohydroionization process (Fink, 2004). This study was conducted
during the months of August and September, with indoor humidity at relatively high
levels (58-65%). A study conducted in different seasons of the year, when humidity
levels may be lower, may give a clearer understanding of the technology‟s seasonal
effectiveness.
Due to study constraints, the APS units were placed at only 3 feet off the ground.
Placing the units at higher levels could have an impact on the effectiveness of the
treatment, especially when applying the treatment of larger distances. Oxidizers such as
ozone are heavier than air and may not effectively penetrate higher areas in the study
rooms (Millar & Hodson, 2007). A study, in which the generators are placed at various
heights from the floor, would be beneficial in expanding the knowledge on the
applications of these systems.
This study was limited to testing of Staphylococcus aureus, MRSA, and
Pseudomonas spp. on surfaces and mold in the air. It would be beneficial to determine
the effectiveness of the technology on other common indoor contaminants which pose a
health risk to susceptible populations. This would include Enterobacteriaceae, a family
of bacteria that are a normal part of the human intestinal micro flora, which include
strains that can cause severe health effects in humans (Scott et al., 2009). Vancomycin-
130
Resistant Enterococcus (VRE) is another dangerous indoor contaminant that is especially
concerning in health care facilities where it accounts for as many as 80,000 infections
annually in the United States (Reik, Tenover, Klien, & McDonald, 2008).
Using aerobic bacterial counts as an indicator for the effectiveness of an advanced
oxidation treatment would be beneficial, especially in areas that may have lower levels or
unknown microbiological populations. Aerobic bacteria are a broad category of
microorganisms that have previously been used to evaluate the efficacy of disinfectants
(Dewaele, Ducatelle, Herman, Heyndrickx, & De Reu, 2011).
This study focused on the reduction of indoor microbiological contaminants. It
would increase knowledge of this technology if a study were conducted in a commercial
setting to determine the relationship between the treatment and the number of reported
adverse health effects of building occupants. This could include recording minor health
effects such as headache, fatigue, dizziness, and sore throat, as well as more serious
conditions such as skin infections, gastrointestinal illness, and upper-respiratory illness.
Research has shown a correlation between indoor microbiological levels and the health
and well being of occupants (Menzies et al., 2003).
Conclusions
Indoor microbiological contaminants are a serious public health issue in health
care facilities, especially considering that the indoor environments are constantly being
reinoculated by occupants and visitors. Current interventions to reduce or eliminate these
contaminants have been limited to the use of conventional cleaning methods,
surveillance, increased ventilation, air filtration, or air ionizers. While these interventions
have some level of effectiveness at reducing microbiological counts, alone they cannot
131
keep health care environments free of microbiological contaminants. The APS advanced
oxidation system is an intervention that has the capability to enhance current infection
control efforts. The effectiveness of the system at reducing common indoor
microorganisms in a practical setting was examined and found to significantly reduce
levels of airborne mold, and Staphylococcus aureus and Pseudomonas spp. on common
contact surfaces. The intervention was most effective on mold and Staphylococcus aureus
which had count reductions of 90% or greater after 30 days. Strategies for applying the
technology to most effectively reduce these indoor contaminants were also identified.
This included placing of units in areas or rooms where reducing microbiological levels
would be most beneficial, keeping doors to adjoining rooms open during the treatment to
allow for better exposure, applying the treatment 12 hours daily for at least 20 days,
placing the units at least 3 feet off the ground, and keeping surfaces visibly clean. The
advanced oxidation technology works best in conjunction with conventional cleaning and
disinfection, as a means of keeping microbial levels in the air and on surfaces reduced for
longer periods of time.
132
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165
Appendix A – First Level
Wyandotte County Public Health
Building Floor Plan
5
6
7
1
2
3
4
8
9
Zone 1
Zone 2
Advanced Oxidation
Units
Wyandotte County Health Department Building Floor Plan (Legend)
1. General Clinic - Exam Room 1
2. General Clinic - Exam Room 2
3. General Clinic - Exam Room 3
4. General Clinic - Exam Room 4
5. Pediatrics - Exam Room D / Patient Bathroom
6. Pediatrics - Exam Room C
7. Pediatrics - Exam Room B
8. North Patient Waiting Room
9. Nurse Office Area
166
Appendix B
Consent Letter to Conduct Study In Health Department Building
Unified Government of Wyandotte County and Kansas City, Kansas
Public Health Department
619 Ann Avenue
Kansas City, Kansas 66101
March 10, 2010
Dear Laurence Franken,
Based on my review of your research proposal, I give permission for you to conduct the
study entitled, Advanced Oxidation Treatment in a Health Care Facility for Reducing
Microbiological Populations in the Air and on Surfaces, within the Unified Government
of Wyandotte County / Kansas City, Kansas Public Health facility. As part of this study,
I authorize you to install the APS Advanced Oxidation System and conduct
microbiological testing. We reserve the right to withdraw from the study at any time if
our circumstances change.
I confirm that I am authorized to approve research in this setting.
I understand that the data collected will remain entirely confidential and may not be
provided to anyone outside of the research team without permission from the Walden
University IRB.
Sincerely,
Joseph M. Connor
Director Public Health Department
167
Appendix C
First Email Letter to Health Department Managers
DATE: _________
TO:
All Health Department Managers
RE:
Restricted Access to the Health Department Building
On (Study Start Date), I will begin a research study in the Health Department Building as
part of my Walden University doctorate dissertation. As part of the study, an
antimicrobial treatment will be applied during the hours of 7:30 pm to 7:30 am the next
day. While the technology is considered safe and poses no health risk to occupants, I am
asking that employees refrain from entering the building during these hours. The study
will end on (Study End Date), at which time full access to the building will again be
allowed.
Thank you for your cooperation,
Larry Franken
168
Appendix D
Second Email Letter to Health Department Managers
DATE: _________
TO:
All Health Department Managers
RE:
Research Study
On (Study Start Date), I will begin a research study in the Health Department Building,
as part of my Walden University doctorate dissertation. Managers on the first level of
the building are being asked to restrict movement of waiting room and exam room tables,
chairs, and patient scales until the study concludes on (Study End Date). Chemical
cleaning of chairs, tables, door knobs, and sink surfaces in the pediatrics clinic, general
clinic, and North patient waiting rooms should also be stopped throughout the duration of
the study. If one of these surfaces becomes grossly contaminated and must be cleaned,
please contact me as soon as possible. All Managers should remember to restrict access
of employees to the building during the hours of 7:30 pm until 7:30 am the next morning.
Thank you for your cooperation,
Larry Franken
169
CURRICULUM VITAE
NAME:
Laurence J. Franken, MS, MSPH
BUSINESS ADDRESS:
Department of Public Health
Emergency Preparedness and Public Health Education
Unified Government of Wyandotte County / Kansas City,
KS
EDUCATIONAL BACKGROUND:
Kansas State University
B.S. Animal Science Graduation: May 1989
1984 - 1989
Baker University
M.S. Management Graduation: May 1995
1993 - 1995
Walden University
M.S. Public Health Graduation: May 2006
Ph.D. Public Health & Epidemiology
2003 - Present
WORK EXPERIENCE:
Epidemiologist – Public Health Dept., Kansas City, KS
2008 - Present
Director of Microbiology – Triumph Foods, St. Joseph, MO
2007 - 2008
Corporate Microbiologist – MGP Ingredients, Atchison, KS
2005 - 2007
Research Coordinator – Kansas State University, Manhattan, KS
2002 - 2005
Research Microbiologist – Anheuser-Busch Inc., St. Louis, MO
1995 - 2001
Quality Improvement Manager – University of Kansas Hospital
Kansas City, KS
1991 - 1995
Research Scientist – CPI Corporation, Wichita, KS
1989 - 1991
170
ADVISORY POSITIONS:
-
Advisor – Kansas City Childhood Obesity Collaborative, 2011
Advisor – Cleveland College, M.S. in Health Promotion Program, 2011.
Co-Chairman – Epidemiology Surveillance Isolation and Quarantine Committee,
Kansas City Regional Homeland Security Council, 2010 – Present.
Coordinator - Kansas Region-15 Disease Surveillance Weekly Conference Call, 2008
Present
SELECTED MEDIA EXPERIENCE--Interviews on Public Health for Television /
Radio / Newspaper
-
Kansas City Star (Newspaper) – October, 2009
Fox 4 News (Television) Kansas City – July, 2009
KKFI (Radio) Kansas City – May, 2009
KKFI (Radio) Kansas City – January, 2009
MEMBERSHIP IN PROFESSIONAL SOCIETIES:
-
Lions Club International
Association of Professionals in Infection Control and Epidemiology
International Association of Food Protection
SELECTED PUBLICATIONS:
Ortega, M. T., Franken, L. J., Hatesohl, P. R., Marsden, J. L. (2007). Efficacy of
Ecoquest radiant catalytic ionization cell and breeze AT ozone generator at reducing
microbial populations on stainless steel surfaces. Journal of Rapid Methods and
Automation in Microbiology, 15(4), 359-368.
Franken, L. J., Marsden, J. L., Harvey, E. R., & Pearsall, C. (2005). Survey of cooking
practices and methods for beef steaks and roasts. Kansas State University Cattlemen’s
Day - Beef Cattle Research. 943, 115-117.
Franken, L. J., Van de Riet, M., Schasteen, E., & Pringle, A. (2000). A quantitative test
for evaluating the effectiveness of cleaning chemicals. Master Brewers Association
Technical Quarterly, 37(3) 41-47.
171
SHORT COURSES AND SEMINARS:
-
Mobile Preparedness Course, Strategic National Stockpile, CDC, 5/2011.
Strengthening Community Agro-security Planning, EDEN, 4/2011.
Public Health and Radiation Emergency Preparedness, CDC, 3/2011.
The Impact of Social Media on Incident Command System, Mid-America Regional
Council, 12/2010.
Advanced ICS Command Staff and General Staff-Complex Incidents, ICS-400,
FEMA, 11/2010.
Criminal and Forensic Epidemiology, FBI and CDC, 7/2010
Weapons of Mass Destruction – Respiratory Protection Program for Emergency
Response, Center for Domestic Preparedness, 6/2010.
Foreign Animal Disease Event: Roles and Responsibilities, Kansas Department of
Animal Health, 5/2010.
Protecting Human Research Participants, NIH, 10/2009.
Bioterrorism: Mass Prophylaxis Preparedness & Planning, Texas Engineering
Extension Service, 9, 2009.
Weapons of Mass Destruction, Center for Domestic Preparedness, Anniston,
Alabama, 1/2009.
Pandemic Influenza Preparedness and Planning, Center for Domestic Preparedness,
Anniston, Alabama, 1/2009.
Basic Life Support (CPR), American Heart Association, 6/2009.
ICS for Single Resources and Initial Incidents, ICS-200a, FEMA, 12/2008
ICS for Expanding Incidents, ICS-300, FEMA, 5/2008.
Incident Command System, ICS-100, FEMA, 5/2008.
National Incident Management System, ICS-700, FEMA, 4/2008.
State Disaster Management, IS-208, FEMA, 11/2006
Emergency Planning, IS-235 FEMA, 10/2006.
Principles of Emergency Management, ICS-230, FEMA, 9/2006
Livestock in Disasters, ICS-111, FEMA, 9/2006
Emergency Planning and Exercising, Center for Bio-defense, University of Medicine
and Dentistry of New Jersey, 1/2005.
Bio-safety Education, Midwest Regional Center of Excellence for Bio-defense and
Emerging Infectious Disease Research, St. Louis, MO, 11/2004.
ISO 17025 Laboratory Standards Training Los Angeles, CA, 6/2001.
TEACHING EXPERIENCE:
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Cleveland College of Graduate Studies, Health Promotion, Adjunct Faculty 2011.
Kansas State University, Department of Animal Science, Assistant Instructor and
Guest Lecturer, 2002 to 2005.
The University of Kansas, Department of Dietetics & Nutrition, Teaching Associate,
1991 to 1995.