Evaluation of Discharge Room
Cleaning using UV Technology:
Focus on Clostridium difficile
Alison Gibson D.O.
Fellow, Pediatric Infectious Diseases
University of Michigan
Disclosures
• This study was funded by a $12,000 award from the Patient
Safety Committee of University of Michigan Health System
• Both of the UV devices used in our study were provided to
the institution by Xenex and iPT during the outcomes study,
the Xenex device was then rented to complete the
environmental culturing study
• I have no other conflicts of interest or relationships with
industry
This is a confidential Quality Improvement and Assurance/peer review document of the University of Michigan Hospitals and Health Centers. Unauthorized disclosure or
duplication is absolutely prohibited. This document is protected from disclosure pursuant to the provisions of MCL 333.20175; MCL 333.21515; MCL 331.531; MCL 331.533
or such other statutes that may be applicable.
Objectives
• How does UV work?
• What literature do we have to support the
use of UV?
• Why did UofM choose to pursue UV and how
did we utilize it?
• Outcomes study
• Environmental culturing study
• Future Directions
Automated Room Disinfection
• Ultraviolet (UV)
– UV-C (mercury bulbs)
– PPX-UV (pulsed xenon bulbs)
• Hydrogen peroxide vapor (HPV)
• Neither of these technologies replace manual
cleaning, and therefore both add additional
time before room turnover
Tru-D Lumalier (UV-C)
Xenex (PPX-UV)
Bioquell (HPV)
http://www.hpnonline.com/inside/201109/1109-CS-RoomDisinfection.html
http://bionews-tx.com/wpcontent/uploads/2013/04/xenex-device.jpg
http://www.bioquell.com/en-us/markets/product-selector/bioquell-q10/
UV – Science
• Breaks DNA bonds by inducing pyrimidine or
thymine dimers (1,2,3,4,5)
http://mashable.com/category/dna/
UV – Safety
• No health or safety concerns returning to room
• Direct prolonged light exposure can cause
temporary corneal and conjunctival irritation (1,2,3,4,5)
http://www.clinicaladvisor.com/what-to-do-whenthe-eyes-have-it/article/121816/
UV – Utilization
• Easy to use, no room modifications
• Shorter treatment time (depending on device and
room size, compared to HPV)
• Expenses associated with machine and bulb
replacement
• Safe with electronic room devices and other room
materials (1,2,3,4,5)
UV - Efficacy
• 2-4 log10 reduction of spores
• May allow resistant organisms to develop due to sublethal dose
• Efficacy dependent on intensity of emitted light (old
bulb vs. new bulb), exposure time,
placement/obstructions, air movement
• Less effective out of direct line of sight
• Less effective further from the source (cannot use in
large areas) (1,2,3,4,5)
UV-C vs. PPX-UV
UV-C (Ex.Tru-D Lumalier, iPT)
PPX-UV (Ex. Xenex)
• 200-280nm, Tru-D emits at
254nm
• Breaks DNA bonds but not at
the ideal wavelength (265nm),
so occurs more slowly
• Continuous dose at germicidal
wavelength
• Longer treatment times (34100min per cycle) (1,2,4,5)
• 200-320nm broad spectrum
• More efficient (faster) because
more broad spectrum
• Additional benefits of
photosplitting, photohydration,
and photocrosslinking, all of
which contributes to faster
treatment times
• Pulse dose at broad
wavelength including
germicidal range
• Shorter treatment times (5-10
min per cycle) (1,2,5)
Published UV Data
Study
Device
Cleaning
Method
Culture
Method
Results
Anderson et al.
(2013)6
Tru-D Lumalier
UV
Rodac touch
plates
1.16 log
reduction in
colony counts
Boyce et al.
(2011)7
Tru-D Lumalier
UV
Pre-inoculated
plates
1.7-2.9 log
reduction in
colony counts
Sitzlar et al.
(2013)8
Tru-D Lumalier
Routine cleaning Surface
followed by UV swabbing
Reduction in
positive cultures
from 57% to
35%
Levin et al.
(2013)9
PPX-UV
Bleach followed
by UV
Reduction in
HO-CDI rate
from 9.46 to
4.45/10,000 PDs
None
Why did we choose to pursue use of a
UV system?
• C. difficile rates are above the national and
state averages
• Tried to implement daily bleach cleans of hightouch surfaces
• Appeal of a device less vulnerable to human
error
UV light trials
• Trialed two different lights [PPX-UV (Xenex)
and UV-C (iPT)] on three units each and
followed HO-CDI rates
– Trial 1 was 5 months
– Trial 2 was 10 months
UV Utilization
• Adjunct to bleach for discharge room cleans
• 2 - 4 cycles per room, 5-10 min each plus set up and
take down
• Device was operated by EVS personnel trained by our
institution
• Spot cleaning of public areas/work areas (family rooms,
bathrooms, etc.)
http://bionews-tx.com/news/2014/10/08/xenex-uv-emitting-room-disinfectionrobots-ready-to-tackle-ebola-and-other-contamination/
iPT (UV-C)
http://www.infectionpreventiontechnologies.com/irsModel320
0m.php
Xenex (PPX-UV)
http://bionews-tx.com/wp-content/uploads/2013/04/xenex-device.jpg
Healthcare Facility Onset C. difficile Rates During UV-C
Trial
C. difficile Rate (Cases/10,000 Patient-Days)
30
25
20
UV Trial
15
5 mths prior to trial (p = .3360)
Same time period previous year (p = .3793)
10
5
*None of the units showed a statistically significant change
in C. difficile rate, with the exception of 8DNS which
showed a significantly worse rate when compared to the
previous 5 months
0
5D
8C
8DNS
Hospital Unit
Total
Healthcare Facility Onset C. difficle Rates During PPX-UV
Trial
C. difficile rate (cases/10,000 patient-days)
35
30
25
20
UV Trial
10 mths prior to trial (p = .9576)
15
Same time period previous year (p = .5738)
10
5
*no individual units reached a statistically
significant difference in C. difficile rate
0
5B
6D
4D
Hospital Unit
Total
UV Utilization
Barriers to UV Utilization
• Prolonged room turnover time
• Only can be used at discharge in single
occupant rooms
• Burden of initial investment to provide
sufficient machines to cover all C.diff or
contact isolation or every discharge
• Burden of training and maintaining additional
EVS personnel to run the devices
Why we chose to pursue this study
• No improvement in C. difficile outcomes after
utilizing UV technology
– Were we utilizing the device correctly?
• Were enough rooms being treated?
– Was it actually decreasing environmental C. difficile
burden?
– Is environmental contamination at discharge our
primary issue?
The Study
Our goal was to compare the effectiveness of manual cleaning with
quaternary ammonium cleaner (Virex), manual cleaning with bleach,
and PPX-UV cleaning both separately and in combination
Obtained cultures from confirmed C. difficile positive rooms at
discharge and throughout the cleaning process
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Bed rail
Tray table
Remote
Toilet seat
Toilet rim
Sink faucet
Light switch
Keyboard
Soiled Room
Culture #1
Bleach Clean
Culture #2
PPX-UV
Clean
Culture #3
Ready for
Admission
Soiled Room
Culture #1
QA Clean
Culture #2
PPX-UV
Clean
Culture #3
Bleach Clean
Technicalities of swabbing and
culturing
• Sites were swabbed using pre-moistened sterile swabs
(EnviroMax Plus)
• Swabs were inoculated in enrichment broth (TCCFB)
and incubated anaerobically for 24-48 hours
• Broth was plated on selective media (CCFA-HT) and
incubated anaerobically for 24-48 hours
• Multiple colonies which were morphologically similar
to/consistent with C.difficile were selected from each
plate for PCR
• PCR was used to detect toxin genes tcdA, tcdB, cdtA/cdtB
• Representative isolates from each room were PCR
ribotyped
C. difficile Reduction with Bleach
Followed by PPX-UV
C. difficile Reduction with QA Followed
By PPX-UV
Conclusions
• Bleach effectively eradicated C. difficile from multiple
surfaces (p = .011)
• PPX-UV light could not show an additive benefit
when utilized after bleach cleaning (p = .343)
• Manual cleaning with a QA product followed by PPXUV did reduce positive C. difficile cultures (p = .008)
• Manual cleaning with a QA product followed by PPXUV is possibly not as effective for C. difficile
eradication as bleach alone (p = .063)
In the Meantime…
• Nerandzic et al. (2015):
– Xenex (PPX-UV) device and Tru-D Lumalier (UV-C) device
– C. diff, MRSA, and VRE from pre-inoculated plates
• Pathogen load did not impact killing, but distance from source did
• C. diff at 4ft was only 0.5 log10 reduction with PPX-UV
• UV-C was superior to PPX-UV for reduction of all 3 organisms
with the same concentrations of organisms and distance from
source (1 log10 for C. diff)
– Room contamination
• Tested PPX-UV alone and bleach + PPX-UV
• Saw statistically significant reductions in culture positivity with
PPX-UV, but not with bleach + PPX-UV, and did not assess for
statistically significant difference between the two methods (10)
In the Meantime…
• Ghantoji et al. (2015):
– Xenex PPX-UV device
– Environmental cultures were collected before and
after environmental cleaning with activated
hydrogen peroxide followed by bleach (26/74 
18/74)
– And with activated hydrogen peroxide followed by
PPX-UV (29/70  16/70)
– No statistically significant difference in C. difficile
positive cultures, z = 0.058 (11)
Comparing Our Study
Positive cultures pre-
Positive cultures post-
Study
bleach (%)
bleach (%)
Gibson et al.
17/80 (21%)
1/80 (1%)
Ghantoji et al.11
26/74 (35%)
18/74 (24%)a
Nerandzic et al. 10
22/113 (19%)
9/113 (8%)b
aCultures
bCultures
were obtained pre- and post- combination of activated hydrogen peroxide followed by bleach
were obtained pre- and post- combination of standard clean including bleach followed by PPX-UV
Remaining Questions
• Is environmental contamination at discharge a
primary contributor to C. difficile transmission
at our institution?
• Does UV-C/PPX-UV have a place in an
infection prevention program?
• What amount of bacterial environmental
burden is permissible?
Future Directions
 When an excessive number of cases occur on a unit
(5 in a rolling 4 week period), multi-pronged
approach including:
 bleach cleaning
 ATP assessment
 contact precautions re-enforcement and monitoring
 Possible utilization of hydrogen peroxide vapor
(Bioquell)
 Focusing on other aspects of C. difficile prevention
besides the terminal clean
Thanks
• Patient Safety Committee of the University of
Michigan Health System
• The Young Lab
– Kavitha Santhosh
– Vincent Young MD, PhD
– Krishna Rao MD
• Infection Prevention
– Amanda Valyko MPH, CIC
– Laraine Washer MD
– Terri Stillwell MD, MPH
References
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Am J Infect Control. 2013 May;41(5 Suppl):S36-41.
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7. Boyce JM, Havill NL, Moore BA. “Terminal decontamination of patient rooms using an automated mobile UV light unit.”
Infect Control Hosp Epidemiol. 2011 Aug;32(8):737-42.
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11. Ghantoji SS, Stibich M, Stachowiak J, et al. “Non-inferiority of pulsed xenon UV light versus bleach for reducing
environmental Clostridium difficile contamination on high-touch surfaces in Clostridium difficile infection isolation rooms.” J
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