Download A. Visibility under normal and ultraviolet light

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Use of polyethylene microspheres to simulate
hospital acquired infections: A teaching
strategy for healthcare students and workers
Lydia Wigglesworth-Ballard

Abstract—Hospital acquired infections are still a major
problem in the United States despite infection control measures
that have been put in place. The bacteria that cause most hospital
acquired infections are constantly mutating and are becoming
increasingly difficult to treat due to antibiotic resistance. This
has created challenges for many hospitals and other clinical
settings and many insurance companies will no longer cover the
cost for these types of infections. The guidelines that have been
put in place by the Center for Disease Control and Prevention
says that hand washing is the most important method in the fight
against the spread of infections. However, hand washing
compliance and techniques still fall short of these guidelines.
Ultraviolet polyethylene microspheres were developed and tested
to determine if its behavior was sufficient to simulate the spread
of hospital acquired infections and to determine if the
microspheres could be used as a teaching strategy to incorporate
into the curriculum for healthcare education and for infection
control training in hospitals and clinical settings.
The
microspheres were able to simulate the spread of bacteria
through direct and indirect contact on different surfaces and had
the ability to be washed off under specific hand washing
guidelines. Due to the positive results the use of microspheres as a
simulator during instruction should be explored further in order
to improve hand washing techniques and compliance.
Index Terms—Infection Control, Training, Hospital acquired
infections, Simulation
I. INTRODUCTION
Hospital acquired infections (HAIs) are still a problem in
hospitals today despite the increased surveillance and infection
control programs. HAIs are infections that patients acquired
while receiving care or treatment for another condition while
in a health care setting. According to the Center for Disease
Control and Prevention, 1 out of 20 patients will acquire a
HAI, which will result in 26 to 33 billion in excess healthcare
costs [1]. This is very important due to the fact that Medicare
will no longer cover costs incurred for HAIs. Many other
insurance companies are following Medicare’s lead and are
beginning to implement the same cost cutting measures.
Bacteria cause a majority of HAIs. Bacteria can arise as an
endogenous infection from permanent bacteria that is part of
L. Wigglesworth-Ballad is a doctoral student in Health Services Research
in the College of Community and Environmental Sciences, Old Dominion
University, Norfolk, VA 23529 USA (email: [email protected]).
the normal flora of the patient or as an exogenous infection
from bacteria of another patient or hospital staff. In the second
case the bacteria is transmitted via direct contact and indirect
contact with body fluids and contaminated surfaces and
airborne droplets. The spread of the bacteria is caused by
patient-to-patient contact or via the carriage on a healthcare
worker’s hand with someone who is colonized and may not
necessarily be symptomatic. Some of the more common and
noteworthy HAIs, include Methicillin-resistant Staphylococcus
aureus (MRSA), Clostridium difficile (C. difficile),
Vancomyocin resistant enterococcus (VRE), imipinemresistant Pseudomonas aeruginosa (IRPA) and Klebsiella
pnuemoniae. Infections can present themselves as urinary tract
infections, respiratory infections, infections of surgical
wounds, and skin infections. Infections caused by MRSA have
become more prevalent today than ever and has become one of
the most frequent causes of skin and soft tissue infections in
the United States [2]. It has been well documented that many
bacteria that cause HAIs can live on hospital surfaces for days,
weeks, and sometimes months. C. difficile has been reported
to occur on surfaces in close proximity to patients such as
bedpans, blood pressure cuffs, stethoscopes, walls, and floors
with a survival rate for up to 5 months [3]. The hospital patient
population is usually weaker and already in a poor state of
health, this makes them more susceptible to getting the
infections and more likely to die from them, in some cases.
Hand washing is the best method in reducing the spread of
these infections.
The Center for Disease Control and
Prevention has posted prevention guidelines to include
isolation, handwashing, use of gloves, use of disposable
supplies, and surface sanitation as methods to prevent
transmission of HAIs [4]. As with any set of guidelines, if not
done properly the outcome may not be favorable. Despite the
infection control measures that are in place, HAIs continue to
infect many patients. Those mostly affected are the elderly,
premature babies, and those with a deficient immune system.
In addition, HAIs also lead to prolonged hospital stays and
increased morbidity and mortality.
Overuse of antibiotics and constant mutation of bacteria has
caused some bacteria to become resistant to antibiotic
treatments making them more difficult to treat. These are clear
reasons why there is a need to explore other methods for
teaching students who will be entering into healthcare fields
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and to train those who are already in the field in infection
control. Simulation is a teaching strategy and an evaluation
tool that should be explored and incorporated into the
instruction in healthcare education. The simulation would
involve using a substance to mimic the behavior of HAIs. This
simulator would be used as a part of hand washing and
infection control instruction and provide a realistic and visual
view of how bacteria are spread. This could be more effective
in engaging the student rather than the hand washing
instruction alone. In reviewing the literature most studies
investigating infection control in hospitals involve nursing
students. This could be due to the fact that they are the
primary contact with the patients and more so than other
healthcare workers. In a study investigating integrating
simulation to teach patient safety it was found that nursing
student failed to wash their hands at required times or
performed the hand washing unsatisfactorily 45% of the time
[5]. In another study some nursing students perceived barriers
to hand hygiene compliance as long hours, understaffing, skin
conditions that are irritated by frequent hand washing, lack of
knowledge, lack of role models, and that gloves provide a false
sense of comfort as a replacement for proper hand hygiene [6].
The goal of this study was to have a product developed that
can behave in a similar manner as HAIs and can successfully
simulate the spread in a clinical environment by meeting
certain criteria. This product needs to supersede those
products that are already out on the market and needs to have
the capability to be manipulated for different settings and
scenarios in order to incorporated into healthcare instruction.
II. GERM-SIMULATED PRODUCT REVIEW
In a multidisciplinary pilot study performed by Old
Dominion University titled Investigation of Instruction and
Learning in a Virtual Intensive Care Unit, the investigators
tested seven germ-simulation substances that are currently on
the market [7]. All seven products were tested to determine if
they met the criteria set forth in the study. These criteria
included visibility under normal and ultraviolet light, ability to
be spread through casual human contact, ability to be spread
after a significant period of time, ability to be washed off, and
the ability to be photographed immediately after the study
(approximately 1 hour) and then again after a significant
amount of time later (approximately 4 hours). The study
involved using human simulator mannequins It was determined
that the Glo Germ powder was the best at meeting all the
criteria for further use in their study. This study led to further
exploration of germ-simulated substances that could be a more
effective tool for teaching infection control which resulted in
the development of the polyethylene microspheres.
A. Glo GermTM powder
The Glo Germ powder was determined to be appropriate for
the Old Dominion study, but there were a few properties of
this product that could be improved upon to make the use of a
germ simulated more efficient and effective. The two main
issues that arose during the study was the visibility under
normal light and difficulty in washing the substance off the
mannequins. The Glo Germ in small amounts could be seen
slightly under normal light on the mannequins. This was not
ideal because the sole purpose is for the substance to not be
seen at all, just as there is the inability to see bacteria. In order
to clean the Glo germ substance off of the surfaces the
manufactures recommendations were followed, but some of
the substance could not be properly removed under their
guidelines, which makes it less efficient for repeated use. A
product was later found to clean the Glo Germ substance
better, but it still did not remove all traces of the substance
completely.
B. Polyethylene microspheres
Polyethylene microspheres is a product created through a
polymerization process of ethylene. It is the same substance
that the average household plastics are made of. These
microspheres have many forms and have been used in
cosmetics, medical devices for diagnostic purposes, and as a
drug delivery method. This substance can also be manipulated
by chemical reactions and electromagnetic forces [8]. The
Food and Drug Administration has listed polyethylene as a
safe ingredient for use in chewing gum and as an indirect food
additive. The Cosmetic Ingredient Review (CIR) Expert panel
has deemed Polyethylene safe for use in cosmetics [8].
The microspheres used in this investigation were custom
developed. They are spherical in shape, can be colored to
blend in with the environment and are visible under a 365nm
ultraviolet light, also known as black light (see Fig. 1). They
were screened to prevent dust and debris in the sample. When
placed on objects as directed by the manufacturer, the
microspheres should not be visible under normal light.
Fig 1: Microspheres under ultraviolet light
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III. METHODS
IV. RESULTS
A. Visibility under normal and ultraviolet light
The microspheres were color matched for use with patient
simulator mannequins. The substance was placed on human
skin and simulated skin to determine if the substance was
visible under normal light and ultraviolet light. The substance
was placed on the skin using a small paintbrush as suggested
by the manufacturer. A small sample of the microspheres was
also placed on a variety of surfaces, which include a variety of
porous and non-porous surfaces and also of varying colors and
textures to determine visibility under normal and ultraviolet
light.
A. Visibility under normal and ultraviolet light
The microspheres blended very well and was not detectable
under normal light on both human skin and on the simulated
skin (see Fig. 2). Although the microspheres were color
matched to the simulated skin, the color used also blended well
on all the surfaces used in this study, which varied from a dry
erase board, which is white, to a office chair, which is black.
Under ultraviolet light the microspheres fluoresced brightly to
show a simulated contamination (see Fig. 3). There was a
clear distinction between the microspheres and other
fluorescing particles, such as lint.
B. Surface Adherence
The initial tests were done to test the behavior of the
microspheres in the environment. The microspheres were
tested for the ability to adhere to human skin and human
simulated skin and maintain a contact on solid surfaces such as
counter tops, walls, computer equipment and porous surfaces
such as fabrics.
C. Hand Washing and Surface Removal
The microspheres were tested for the ability to be removed
from hands using a quick 5-10 second wash and then again
using the guidelines on hand washing taught by the Old
Dominion University School of Nursing, which are based on
recommendations by the Center for Disease Control and
Prevention. The procedure consisted of six steps: turn on the
water, wet hands, apply soap, rub vigorously for 15-30
seconds, dry hands with paper towels, and then turn off water
with paper towel. The hand washing tests were performed
with a ring on one finger and medium length nails and then
repeated without the ring and very short nails. They were also
tested for the ability to be removed using alcohol based hand
gel. The manufacturer stated that the microspheres could be
removed from surfaces with water and paper towels. In
addition to following these instructions, household cleaner and
cleaning wipes were also tested on all surfaces.
D. Transfer capabilities
To determine direct and indirect transfer capabilities tests
were conducted by placing microspheres on the index finger
and continually touching a human simulated skin sample until
very little or no traces were detectable on the surface. Another
test consisted of placing the microspheres all over the hand
and performing various routines within an office setting that
involved touching multiple surfaces. The surfaces touched
were those that are involved during routine activities that
included typing on the computer, printing documents on the
printer and removing those documents, and writing and erasing
on a dry erase board.
Fig 2: Microspheres on simulated skin under normal light
Fig 3: Microsphere on simulated skin under ultraviolet light
There is the ability to see the microspheres under ultraviolet
light in low light conditions, but the more background daylight
there is the closer to the source the ultraviolet light needs to
be.
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B. Surface Adherence
The static forces produced by the surface of the
microspheres and tested surfaces were sufficient for the
microspheres to adhere to human skin, simulated skin, and
other surfaces used in this study that included table tops, walls,
chairs, and office supplies. The microspheres could not be
removed using a brushing or rubbing motion on the hands or
other surfaces; however, some microsphere particles could be
displaced from their original location under these conditions.
C. Hand Washing and Surface Removal
After placing the microspheres on the hands, washing was
performed using a quick 5 – 10 second wash to simulate an
improper hand washing. This resulted in some traces of the
microspheres remaining on the hands.
Nearly all of the
microspheres were removed when using the Old Dominion
University hand washing guidelines. When hand washing was
performed with the ring on and medium length nails small
traces remained under nails and in the crevices of the ring
when not paying close attention to those areas. The alcohol
based hand gel only displaced and spread the microspheres
around on the hands, but did not remove it. The microspheres
cleaned off very well on non-porous surfaces, but was more
difficult to remove from fabrics, which had to be machine
washed in order to remove efficiently. The microspheres
cleaned up very well on surfaces using cleaning wipes, water
and paper towels, and cleaning solution and paper towels.
When using a cleaning rag some of the microspheres
transferred onto the rag and remained until the rag was washed
in a washing machine. The cleaning wipes cleaned up very
well when used on a small surface area and disposed of,
otherwise the larger the area, the less effective using cleaning
wipes became. Using several wipes and disposing them
immediately after a few wiping motions resolved this issue.
D. Transfer Capabilities
The microspheres were able to transfer from hand to hand
and hand to surface by direct contact. When a surface was
touched by the hand, some of the microspheres remained on
the hand, which presents a behavior that is very similar to
bacteria, in that bacteria will not all transfer to another surface
with just one touch
The transfer test on the simulated skin, as shown in Fig. 4,
shows that the microspheres were able to transfer successfully
eight times with decreasing amounts of the substance with each
touch. The microspheres were also able to transfer with
subsequent touching up to eight times by touching various
objects within an office setting. The surfaces that were
touched in the office setting are comparable to a hospital
setting as these same surfaces such as the computer, printer,
and dry erase boards can be found in any hospital or clinical
setting
Fig. 4: Transfer of microspheres
V. DISCUSSION
The polyethylene microspheres behaved in the environment,
as expected, by spreading through direct and indirect contact
and by having the ability to be washed off hands and
environmental surfaces. The microspheres adhered to all the
surfaces used in this study, which shows its flexibility and
ability to be used on the many surfaces that may be found
within any setting. The surfaces used in this study are some of
the same surfaces that can be found in hospitals and other
clinical settings. The 5-second wash was used to determine if
the amount of microspheres removal would be any different
than using proper hand washing guidelines. The 5-second
hand wash removed less than the wash under the hand washing
guidelines, satisfying the criteria for the use of the
microspheres to simulate HAIs. The sole purpose of using
alcohol based hand gels is to kill the bacteria, but not to
remove them. When using the alcohol based hand gels the
microspheres were not removed from the hand, which is
similar to the behavior of bacteria. There is no way to test or
compare viability since the microspheres are a plastic material
and are not live. Therefore, under the current design of the
microspheres it should only be used for training in hand
washing techniques. The process to clean the microspheres off
of surfaces was quick and was removed efficiently with water
and soap that should be readily available within any setting.
Table 1 shows that based on the microspheres behavior in the
environment, this material would be an effective way to
simulate HAIs.
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ACTION
DIRECT
SPREAD
INDIRECT
SPREAD
HAND WASHREMOVAL
ALCOLHOL
GELREMOVAL
ALCOHOL GEL
- KILLED
REMOVAL
WITH
CLEANING
PRODUCTS
KILLED WITH
CLEANING
PRODUCTS
REMOVAL
FROM
FABRICS
BACTERIA
Yes
MICROPSHERES
Yes
Yes
Yes
Yes
Yes
No
No
Most
No
Yes
Yes
Most
No
Machine wash
Machine wash
Table 1: Bacteria and microsphere comparison chart
There were no stains or residue left behind and the
microspheres are safe to use on the skin and on different
surfaces. The inability to see the microspheres when placed in
the environment also made it suitable due to the fact that
bacteria are not visible with the naked eye. In order get the
best possible view of the microspheres; the room light must be
turned off in order to visualize the spread under the ultraviolet
light. One of the limitations in this investigation was that due
to the limited range of the ultraviolet light it was not possible
to get a full view of the entire area of the spread. This could
be important when attempting to trace the spread and can be
resolved by using a larger source or several sources or
ultraviolet light.
VI. CONCLUSION
This investigation of the polyethylene microspheres shows
how this substance can play an important role in instruction for
infection control training. The results of these tests show that
the microspheres, when applied properly can be an efficient
tool because of the design of the product and the ease of clean
up. The visibility under ultraviolet light can provide a realistic
view of the bacterial spread process especially in an
environment where there are numerous patient-healthcare
worker contacts. This product has the capability to be
designed to fit the user’s needs by changing certain properties
such as the size and color in order to fit a variety of scenarios.
There are some important factors that would facilitate
instruction using the microspheres as a simulator. First factor
is having defined outcomes, which can be described as having
no microspheres spread to other areas from the source.
Second is repetitive practice, which would allow students to
repeat the scenarios as needed in order to improve on hand
washing skills and containment of the bacteria.
Third is
immediate feedback and reflection which would allow
facilitators to discuss with students the areas of strengths and
weaknesses, so that the student can begin to apply corrective
measures to improve hand washing techniques and infection
control. Other advantages to using the microspheres as a
simulator is that it doesn’t stain and is easy to clean up, which
makes it safe to use on patient simulators, it can be designed
and manipulated to fit different scenarios, and it provides a
safe and controlled environment where no patients can be
harmed.
Students need a method to confront the challenges of
infection control practices, mainly hand washing techniques,
which they will be faced with in the real world. In the real
world bacteria are not visible with the naked eye. The
microspheres provide a safe method to visualize the spread of
HAIs with the naked eye and under the right conditions in real
time. As a part of the instruction this can also be used as an
opportunity to measure and evaluate the students hand washing
techniques. Along with infection rates that are used to
measure hand hygiene, the instructor would be able to identify
the person or persons who spread the disease allowing for
more individualized corrective measures.
VII. FUTURE RESEARCH
Future research on this topic could further focus on
customizing the microspheres even further to simulate multiple
colonization sites and other visualization techniques. The
environmental sources of HAIs should also be explored and
the role it plays in transmission of hospital acquired infections.
The behavior of each of the hospital-acquired infections
should be studied more in depth individually because there are
some differences between them especially in the colonization
locations, viability on different surfaces, and concentration
needed to cause infection. This could play a role in how much
and to which area the microspheres should be applied to for
different training situations.
Integrating the microspheres into the curriculum for each of
the healthcare disciplines is important, but also using a
multidisciplinary approach is just as important as it gives a real
world situation that involves using all the healthcare personnel
that are involved in patient care.
ACKNOWLEDGMENT
This work was conducted with the assistance and support of
Dr. Holly Gaff and is gratefully appreciated. An appreciation
and thank you also to Dr. Ginger Watson and Ms. Jacqueline
Jackson for their assistance with this submission.
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