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Fomites and Infection Control
Charles P. Gerba
Departments of Soil, Water and Environmental
Science
and
Epidemiology and Environmental Health
Univeristy of Arizona
Tucson, AZ
Conflict of Interest Statement
 Clorox
- Research funding and consulting
 GOJO Industries – Research funding and
consulting
 Purethread – Research funding
 Allied Bio Science – Research funding
 Waterlogic – Research funding
2
Objectives
 How
are common infections transmitted?
 The role of hands in spreading microbes.
 The difference between cleaning and
hygiene
 Germ geography –where the germs are
 Interventions to prevent the spread of
microbes
 Disinfectants – what’s new
Percentage of Disease Due to Transmission Route
Person to
Person
Animal to
Human
Drinking
Water
?%
?%
?%
?%
?%
?%
Aerosols
?%
Food
Fomite
Recreation
Life in the 21st Century








Most of our time is spend indoors (80 - 90%)
More people work in offices than ever before
We travel more than ever before
We spend less time cleaning than the last
generation (50% less than 50 years ago)
We are less clean (e.g. laundry practices)
We spend more time in public places
We are more mobile and have more electronic
equipment (e.g. cell phones, ipods)
We share more common surfaces (fomites) with
more people than ever before in history
Cleaning vs. Hygiene
Cleaning is the removal
of unwanted matter
Hygiene is reducing the
risks of infection
6
Role of Fomites in Transmission of a Disease
Person picks up pathogen
through contaminated fomite
Pathogen falls on fomites
e.g. phone, computer
Person touches nose or eyes
with contaminated fingers and
becomes infected with pathogen
Sick person sneezes, coughs and pathogens fall on fomite or get aerosolized
7
Mouthing Events in Children (per hour)
-81 times under two years
-42 times two thru five years
-A child swallows the about of dirt on six kitchen
floor tiles per day
Hand Contact in Adults
 Adults
hour



touch their face 15.5 times per
2.5 eyes
5 nose
8 lip
Germ Geography
Identifying Critical
Control Points
Home/Work/Play/Shopping
Coliform Bacteria and E. coli

Coliform bacteria and
E. coli are found in
feces and their
presence on surfaces
indicates
contamination by
feces and the
potential presence of
disease causing
microorganisms
Germs at Home
2
Geometric mean per cm or per mL
Enteric Bacteria (Coliforms) in
the Home by Location
7
6
5
4
3
2
1
0
-1
-2
Sponge Kitchen
Sink
Bath
Sink
Cutting
Board
Kitchen
Floor
Bath
Floor
Bath
Counter
Toilet
Seat
The Importance of Cleaning
Tools in the Spread of Germs
Germs in Your Laundry
Exposure from Laundry

Changes in practices
in the U.S



Hot water used only
5% of the time. Most
use cold water
Only 12 minute wash
Dry for only 30
minutes
Occurrence of Coliforms and
Fecal Coliforms in Wash Water After
Laundering
Fecal Coliform
Coliform Arithmetic
Arithmetic Average
Average
Type of
Clothing
Washer
Load
Underwear 5.2 x 106
Jeans
Per
Item
Washer
Load
Per
Item
4.5 x 105
5.6 x 105 7.4 x 104
7.2 x 105 1.07 x 105
1.5 x 104 2.24 x 103
Bath Towels 1.2 x 106 1.77 x 103
<1.6 x 104
ND
Feces in the Laundry

Average pair of
underwear contains
0.1 grams of feces
 Rotavirus and
adenovirus 1010-11
virus per gram of
feces
 Salmonella 1010 per
gram of feces
Hospital Scrubs
Summary of Heterotrophic Plate Count for different
classifications of scrubs
Type of scrub
Number of
garments
Average
CFU/sq cm
Range
CFU/sq cm
Unwashed
hospital
18
180
5 - 473
Homelaundered
26
143
1 - 848
Hospitallaundered
20
4
1 - 27
New disposable
16
16
1 - 118
New cloth
10
35
1 - 145
20
Bacteria in Home Laundered
Scrubs







GRAM NEGATIVE
Enterobacter cloacae
Klebsiella
pneumoniae
Klebsiella oxytoca
Raoultella terrigena
Pantoea species
Serratia rubidaea





GRAM POSTIVE
Staph. lugdunensis
Micrococcus luteus
Curtobacterium
luteum
Sanguibacter
incohoensis
Scrubs
 Hospital-laundered
scrubs had
significantly fewer (p=0.044) HPC bacteria
than home-laundered scrubs
 Ten percent (3/29) of unwashed scrubs
tested positive for E. coli
 Mold commonly found on all types of
scrubs
22
Study of Bacteria in Reusable
Cleaning Cloths in Hospitals
 Collected
three cloths each from 10
different hospitals in Arizona
 Tested cloths by wetting in trypticase soak
broth and then squeezing out the liquid
and testing for total bacteria, coliform
bacteria, spore formers, MRSA and C.
difficile
Average Number of Bacteria in Towels used
to Clean Patient’s Rooms (before use)
Hospital
Total Bacteria
Coliforms*
1
2
3
12,600
63
6,310
1
0
2
4
7,943
0
5
6
7
8
9
10
31,622
100,000
1,000
5,012
6,310
398
0
20
0
0
0
25
*E. coli was identified in two towels
Effect of Cleaning Cloth Material
on Bacteria in the Cloth
Organism
Total
bacteria
Coliforms
Molds
Cotton
1,995
Microfiber
24,547
P-value
0.01
1
1
6
47
0.0002
0.001
Effect of Disinfectant Application
Method
Organism
Total
bacteria
Coliforms
Mold
Spores
Soaked
2,239
Sprayed
104,713
P-value
0.01
1
1
15
18
2,188
4,074
>0.0001
>0.0001
0.04
Bacteria Identified in Cleaning
Cloths
 Pseudomonas
luteola
 Klebsiella oxytoca
 Klebsiella pneumoniae
 Serratia plymuthica
 Pasteurella pneumotropica
 Aerommoas hydrophilia
 Pantoea sp
 Escherichia coli
Conclusions
 Reuseable
cleaning/towels/cloth can
contain opportunistic pathogenic bacteria
 Washing practices can effect microbial
loads in reusable cleaning clothes/towels
 Microfiber clothes contain more bacteria
than cotton
 A wide range of enteric bacterial types are
present in cleaning clothes
Home Laundering of
Professional Clothing
Bleach as directed should yield 200
ppm bleach
Hot Water
Dry for 45
minutes
European Washing Machines
Wash at ~180 oF – 140 min wash cycle
Germs at Work
Number of Germs per Square Inch
Bacteria in Offices
32
Parainfluenza on Office Fomites Fall
2004
Percentage of Fomites Positive for Parainfluenza
70
60
Conference
Rooms
50
Offices
40
Cubicals
30
20
10
0
New York
San
Fransico
Atlanta
Chicago
Tucson
Total
Comparison of Offices that Use Disinfectant versus
Offices that Don't Use Disinfectant
Average Bacteria
1.00E+05
1.00E+04
1.00E+03
1.00E+02
1.00E+01
Don't Use Disinfectant
Use Disinfectant
Germs at School
School Study (Grade K thru 12)- 2009
Figure 1
Top Three Contaminated Sites in All Schools
Total Bacteria/approximate 100 cm sq
1.00E+07
4.77E+06
1.70E+06
8.60E+05
1.00E+06
1.00E+05
1.00E+04
Average
Toilet Seat
1.00E+03
1.00E+02
Cafeteria Table
Computer Mouse
Desk
Sites with the Highest Percent of Coliforms in
all Schools – it’s not the Restroom!!
Site
Desk
Computer Mouse
Cafeteria Table
Library Table
Bathroom Sink Faucets
Water Fountain
Keyboard
Bathroom Paper Towel
Handle
Percent of sites positive for
Coliforms
59
57
55
53
36
33
33
29
Impact of Disinfectant Wipes on
Absenteeism -Seattle
 Study


Two school semesters
3rd and 4th graders
 Intervention

Children’s desk wiped with a disinfectant wipe
at the end of each school day
 Results


50% reduction in absenteeism
From Bright et al, 2010; J. School Nursing
Shopping with Germs
Coliform Bacteria in Reusable
Grocery Shopping Bags
49%
51%
Coliforms
Yes
No
Reusable Shopping Bags
 E.
coli detected in
30% of the bags
 No Salmonella
detected
E. coli Isolation from Shopping Carts
 Maine
80%
 Atlanta 79%
 Chicago 70%
 Tucson 0%
 Los Angeles 10%
 Recent
study has associated Salmonella
and Campylobacter infections in children
and placement in shopping carts
The Forgotten Fomites
Critical Control Points

Phone / mobile phone

TV remote

Computer keyboard

Computer mouse

Sink taps / handles

Sponges / cleaning
cloths

Laundry
44
Most Common Disinfectants used in Homes,
Public Places and Hospitals/Health Care
Facitlies
 Quats (take 10 minutes)
 Chlorine Bleach
 Hydrogen Peroxide
Occurrence of Coliforms (%) in
Your Dentist’s Office
phone
64
mouse
53
0
desk
52
63
keyboard
faucet
handle
67
light
handle
0
18
handsets
70
arm rests
door
knobs
76
50
22
drawer pulls
Impact of Hydrogen Peroxide Wipes
Sample Site
Dental Office
Pre intervention
Post intervention
Keyboard
>1.61E+03 (100->2.42E+03)
<1
Mouse
>1.84E+03 (100->2.42E+03)
<1
Dentist chair arm
>1.62E+03 (100->2.42E+03)
<1
Patient chair arm
>3.38E+03 (100->2.42E+03)
<1
<1*
<1
Receptionist counter tops
>1.68E+03 (100->2.42E+03)
<1
Bathroom door knob
>5.50E+03 (310->2.42E+03)
<1
<1*
<1
Office phones
>2.14E+03 (110->2.42E+03)
<1
Office door knobs
>1.58E+03 (100->2.42E+03)
<1
Dental tool handles
Dentist light
Quat Wipe / Hand Sanitizer
Intervention
In an Office Building

Add a bacterial virus
to the entrance door
handle of an
office building
with 80 persons

Collect samples after
2, 4 and 7 hours of
fomites and hands
48
The Virus
Bacteriophage MS-2
-~23 nm in diameter
-single stranded RNA
-no lipid layer
-similar in shape and size to the cold
virus (rhinovirus)vand norovirus
-commonly used as a
model for disinfectant
testing
Add bacteriophage to one
persons hand?* 80 persons in
building
*Person did not
know hand was
contaminated
Virus detection on office workers hands/fomites
after times indicated. (MS-2 virus was added to one
person’s hand at the beginning of the work day)
First place virus
detected is the
coffee break room
Intervention
+ hygiene
education
52% of 80 employee’s agreed to participate
Impact of intervention on Occurrence of
Virus on Employee's Hands
Results
 The
number of people with viruses on their
hands was reduced 80 to 50%.
 The occurrence of viruses in communal
work areas (fomites) was reduced by more
than 80% after four hours and by 70%100% after seven hours
UV Dose (µW*sec/cm2) vs. Distance
0 Ft
3 Ft
5 Ft
8 Ft
Distance
from
Ground
217,185
35,604
10,743
2,593
4 Ft
166,152
68,241
42,428
5,133
2 Ft
208,500
64,087
19,879
5,103
0 Ft
Distance from Device
UV Inactivation of MRSA
Log Reduction of MRSA
0.00
0
Average Log
Reduction
2.03
3.07
3.46
Standard Deviation
0.52
0.72
0.55
17,594-17,768
4.22
0.48
35,014-35,845
4.20
0.58
Formica
UV Exposure
(μWs/cm2)
1,193-1,632
5,543-6,370
10,951-12,502
15,762-18,872
30,433-37,032
Fabric
UV Exposure
(μWs/cm2)
121,155-126,407
236,256-285,395
Average Log
Reduction
0.89
2.55
3.17
3.28
3.70
Average Log
Reduction
0.39
1.11
Standard Deviation
1.12
0.74
0.07
0.12
0.16
Standard Deviation
0.24
0.24
10,000
20,000
30,000
40,000
-0.50
-1.00
Average Log Reduction
Stainless Steel
UV Exposure
(μWs/cm2)
1,558-1,615
5,788-6,540
11,948-12,637
-1.50
-2.00
-2.50
Stainless Steel
-3.00
Formica
-3.50
-4.00
-4.50
-5.00
UV Exposure (μWs/cm2)
• Results are an
average of triplicate
experiments using a
collimated beam set
up
Log Reduction of Clostridium
difficile spores on stainless steel
UV
LOG
Exposure
REDUCTIO
(μW/sec/cm
N
2)
0
0
4000
2.09
8000
2.57
12000
2.63
16000
3.19
20000
3.21
STD
DEV
0.18
0.23
0.2
0.09
0.1
0.62
+
Evaluation of
combination of UV and
H2O2
Combinations of
disinfectants
 UV
disinfection for hard surfaces
followed by hydrogen peroxide
wipe to evaluate if there is any
synergy
 Test
organisms:
MS2
C.
difficile spores
Methods for H2O2 and
(UV+H2O2)
After inoculating,
expose the dry
tile to varying
times and
distances of UV
(if necessary, for
UV and Synergy)
After
exposure to
UV (not
applicable for
just H2O2),
H2O2 was
squeezed
onto the tile.
After covering
the tile with
liquid and
allowing to sit
for 50 seconds,
the tile was
wiped for 10
seconds.
MRSA with and without Hydrogen
Peroxide
Log Reduction
Stainless
Steel
Formica
Polyester
Control
0.0
0.0
0.0
UV Horizontal
2.9
4.9
0.8
UV Vertical
5.3
4.4
1.0
UV + H2O2 Horizontal
> 5.4
> 4.9
> 5.8
UV + H2O2 Vertical
> 5.4
4.9
5.8
Stainless steel
Formica
Key takeaway: H2O2 + UV is more effective than UV alone. The difference is most
pronounced on the soft surface.
Polyester
The Future

Self Sanitizing Surfaces
• Copper – toxic to many bacteria and viruses.
Recent studies show a 40 to 50% reduction in
Hospital acquired infections
• Titanium dioxide – uses light energy to kill
microorganism. A “Thin film reactor” coating
• Silinated sanitizers/disinfection . Disinfectants
chemically bound to
•
hard surfaces
Summary


Fomites will continue play a major role in
disease transmission now and into the
future
Good hygiene is not cleaning more, but
focused and targeted use of disinfectants
and cleaning tools
Questions?