Evaluation of a Pulsed Xenon Ultraviolet Disinfection System for Reduction of Healthcare-Associated Pathogens in Hospital Rooms

Transcription

1 Infection Control & Hospitl Epidemiology Additionl services for Infection Control & Hospitl Epidemiology: Emil lerts: Click here Subscriptions: Click here Commercil reprints: Click here Terms of use : Click here Evlution of Pulsed Xenon Ultrviolet Disinfection System for Reduction of Helthcre-Associted Pthogens in Hospitl Rooms Michelle M. Nerndzic, Priyleel Thot, Thriveen Snkr C., Annette Jencson, Jennifer L. Cdnum, Amy J. Ry, Robert A. Slt, Richrd R. Wtkins nd Curtis J. Donskey Infection Control & Hospitl Epidemiology / Volume 36 / Issue 02 / Februry 2015, pp DOI: /ice , Published online: 05 Jnury 2015 Link to this rticle: How to cite this rticle: Michelle M. Nerndzic, Priyleel Thot, Thriveen Snkr C., Annette Jencson, Jennifer L. Cdnum, Amy J. Ry, Robert A. Slt, Richrd R. Wtkins nd Curtis J. Donskey (2015). Evlution of Pulsed Xenon Ultrviolet Disinfection System for Reduction of Helthcre-Associted Pthogens in Hospitl Rooms. Infection Control & Hospitl Epidemiology, 36, pp doi: /ice Request Permissions : Click here Downloded from IP ddress: on 20 Feb 2015

2 infection control & hospitl epidemiology februry 2015, vol. 36, no. 2 originl rticle Evlution of Pulsed Xenon Ultrviolet Disinfection System for Reduction of Helthcre-Associted Pthogens in Hospitl Rooms Michelle M. Nerndzic, BS; 1 Priyleel Thot, MD; 2 Thriveen Snkr C., MBA; 2 Annette Jencson, MT, CIC; 1 Jennifer L. Cdnum, BS; 2 Amy J. Ry, MD; 2,3 Robert A. Slt, MD; 2,3 Richrd R. Wtkins, MD; 4 Curtis J. Donskey, MD 2,3,5 objective. To determine the effectiveness of pulsed xenon ultrviolet (PX-UV) disinfection device for reduction in recovery of helthcressocited pthogens. setting. Two cute-cre hospitls. methods. We exmined the effectiveness of PX-UV for killing of Clostridium difficile spores, methicillin-resistnt Stphylococcus ureus (MRSA), nd vncomycin-resistnt Enterococcus (VRE) on glss crriers nd evluted the impct of pthogen concentrtion, distnce from the device, orgnic lod, nd shding from the direct field of rdition on killing efficcy. We compred the effectiveness of PX-UV nd ultrviolet-c (UV-C) irrdition, ech delivered for 10 minutes t 4 feet. In hospitl rooms, the frequency of ntive pthogen contmintion on high-touch surfces ws ssessed before nd fter 10 minutes of PX-UV irrdition. results. On crriers, irrdition delivered for 10 minutes t 4 feet from the PX-UV device reduced recovery of C. difficile spores, MRSA, nd VRE by 0.55 ± 0.34, 1.85 ± 0.49, nd 0.6 ± 0.25 log 10 colony-forming units (CFU)/cm 2, respectively. Incresing distnce from the PX-UV device drmticlly reduced killing efficcy, wheres pthogen concentrtion, orgnic lod, nd shding did not. Continuous UV-C chieved significntly greter log 10 CFU reductions thn PX-UV irrdition on glss crriers. On frequently touched surfces, PX-UV significntly reduced the frequency of positive C. difficile, VRE, nd MRSA culture results. conclusions. The PX-UV device reduced recovery of MRSA, C. difficile, nd VRE on glss crriers nd on frequently touched surfces in hospitl rooms with 10-minute UV exposure time. PX-UV ws not more effective thn continuous UV-C in reducing pthogen recovery on glss slides, suggesting tht both forms of UV hve some effectiveness t reltively short exposure times. Infect Control Hosp Epidemiol 2015;36(2): Automted room disinfection technologies re incresingly being used s n djunct to stndrd clening nd disinfection in helthcre fcilities. Ultrviolet (UV) rdition devices hve been most widely dopted owing to the efficiency nd welldocumented efficcy of UV irrdition. 1 7 Severl UV room disinfection devices re now being mrketed. Most of these devices use low pressure mercury gs bulbs, but recently pulsed xenon flsh bulbs hve lso been incorported into disinfection systems. UV rdition hs pek germicidl effectiveness in the wvelength rnge from 240 to 280 nm. 1 7 Mercury gs bulbs primrily emit UV-C t 254 nm, wheres xenon gs bulbs produce brod spectrum of rdition tht encompsses the UV ( nm) nd visible ( nm) spectr The UV-C rdition emitted by low pressure mercury bulbs is delivered in continuous strem tht grdully ccumultes to lethl doses depending on durtion of exposure nd distnce from the primry field of rdition. 1 7 The brod-rnge UV delivered by xenon bulbs is emitted in short, high-intensity pulses, possibly requiring shorter durtion of exposure to chieve lethl doses Given the incresing use of UV devices nd vritions in recommended cycle times, there is need for evlutions of the rel-world performnce nd comprtive effectiveness of different devices. We previously demonstrted tht mobile, utomted room disinfection device tht utilizes mercury bulbs for emitting UV-C rdition is effective for reducing the frequency of positive methicillin-resistnt Stphylococcus ureus (MRSA), vncomycin-resistnt Enterococcus (VRE), nd Clostridium difficile culture results on high-touch surfces in hospitl rooms (Tru-D Rpid Room Disinfection device; Lumlier). 13 For disinfection of vegettive bcteri nd C. difficile spores, the mnufcturer recommends cycles in stndrd Affilitions: 1. Reserch Service, Louis Stokes Clevelnd Veterns Affirs Medicl Center, Clevelnd, Ohio; 2. Cse Western Reserve University School of Medicine, Clevelnd, Ohio; 3. Deprtment of Medicine, University Hospitls Cse Medicl Center, Clevelnd, Ohio; 4. Akron Generl Medicl Center, Akron, Ohio; 5. Geritric Reserch, Eduction nd Clinicl Center, Clevelnd Veterns Affirs Medicl Center, Clevelnd, Ohio. Received July 11, 2014; ccepted October 14, 2014; electroniclly published Jnury 5, by The Society for Helthcre Epidemiology of Americ. All rights reserved X/2015/ DOI: /ice

3 xenon uv disinfection of nosocomil pthogens 193 hospitl rooms of pproximtely 15 nd 45 minutes, respectively. Here we exmined the effectiveness of mobile, utomted pulsed xenon ultrviolet (PX-UV) device (Xenex; Xenex Disinfection Services) t substntilly shorter disinfection cycle (10 minutes, s suggested by mnufcturer). The efficcy of the device ws ssessed for killing of MRSA, VRE, nd C. difficile spores on crriers plced in hospitl rooms nd for reducing nturlly occurring contmintion on high-touch surfces in hospitl rooms. methods C. difficile, MRSA, nd VRE Strins Two clinicl isoltes ech of C. difficile, MRSA, nd VRE were studied. The MRSA strins were pulsed-field gel electrophoresis type USA300 nd USA800. The VRE strins were VnA-type isolte (C37) nd VnB-type isolte (C68). The C. difficile strins were VA 17, restriction endonuclese nlysis type BI strin, nd VA 11, restriction endonuclese nlysis type J strin. Preprtion of C. difficile Spores Spores were prepred s previously described. 14 Spores were stored t 4 C in sterile distilled wter until use. Prior to testing, spore preps were confirmed by phse contrst microscopy nd mlchite green stining to be t lest 99% dormnt, bright-phse spores. Microbiology VRE, MRSA, nd C. difficile were cultured on selective medi s previously described. 13,15 For specimens collected with sterile, premoistened swbs, the swbs were pplied directly to the surfce of the pproprite selective gr. To detect lower levels of C. difficile spores, 10 ml of pre-reduced cycloserinecefoxitin-brucell broth contining 0.1% turocholic cid nd lysozyme 5 mg/ml (CDBB) ws poured into sterile culture tube contining specimens collected with sterile guze pds. 15 Positive broth cultures were subcultured onto selective gr for identifiction of C. difficile. To quntify totl heterotrophic bcteri, swbs were plted on trypticse soy gr contining 5% sheep blood nd incubted t 37 C for 48 hours. VRE nd MRSA colonies with unique morphology were subjected to identifiction nd susceptibility testing in ccordnce with Clinicl Lbortories Stndrds Institute guidelines. 16 C. difficile ws confirmed on the bsis of odor nd ppernce of colonies nd by positive rection using C. difficile ltex gglutintion (Microgen Bioproducts). The Pulsed Ultrviolet Disinfection Device Figure 1 is photogrph of the PX-UV device (Xenex; Xenex Disinfection Services). The device contins xenon gs flsh bulb tht opertes t 2 Hz nd emits brod spectrum of figure 1. Photogrph of the Xenex pulsed xenon ultrviolet device. rdition covering the UV-C spectrum of 200 to 280 nm s well s the visible light spectrum. The device is designed for mnipultion by single opertor nd is pproximtely 1.6 ft wide by 2.3 ft long by 3.3 ft high nd weighs 150 pounds. It is operted remotely outside the room nd includes motion sensors, which turn off the device if the door is opened. The device is wheeled into strtegic position locted ner high-touch surfces in the room nd set to irrdite for 5 to 7 minutes s suggested by the mnufcturer. Then, the device is wheeled to second loction in the room nd run for n dditionl 5 to 7 minutes. The disinfection process tkes pproximtely 15 to 20 minutes, which includes setup, rdition cycles, nd repositioning. The Impct of Pthogen Concentrtion nd Orgnic Lod on the Efficcy of PX-UV Disinfection on Crriers in Hospitl Rooms Initil experiments were conducted to determine whether pthogen concentrtion (ie, colony-forming units [CFU] per cm 2 ) or orgnic lod influenced the disinfection efficcy of the PX-UV device. Ten µl liquots of C. difficile spores, MRSA, nd VRE suspended in phosphte buffered sline were inoculted onto glss microscope slides nd spred to cover 1-cm 2 re. For ech pthogen, the inoculum pplied to the slide ws djusted such tht 2 to 5 or more log 10 CFU/cm 2 were recovered from the positive control specimens fter desicction. For subset of smples, the orgnisms were suspended in 5% fetl clf serum. The slides were plced on tble positioned centrlly over the bed in hospitl room, 4 feet within the direct field of rdition delivered by the PX-UV device. Bseline slides were left untreted outside of the room (ie, positive controls). The PX-UV device ws run for totl of 10 minutes, 5 minutes on the left side of the bed nd 5 minutes on the right, s suggested

4 194 infection control & hospitl epidemiology februry 2015, vol. 36, no. 2 by the mnufcturer nd stndrd protocol in the fcility utilizing the device. To quntify vible orgnisms, the slides were submersed in 25 ml of sterile phosphte buffered sline nd vortexed vigorously, nd dilutions of the suspensions were plted onto selective medi. Following 48 hours of incubtion, log 10 CFU reductions were clculted by compring the log 10 CFU recovered from slides fter PX-UV disinfection to untreted controls. All experiments were performed 3 times. The Impct of Distnce on the Efficcy of PX-UV Disinfection on Crriers in Hospitl Rooms The killing efficcy of the PX-UV device ws evluted t incresing distnces from the primry field of rdition. Slides were prepred nd processed s described previously. However, the inoculum ws ltered such tht ech glss slide yielded 5 log 10 CFU t bseline. Additionlly, slides were plced 6 inches, 4 feet, nd 10 feet within the direct field of rdition, nd lso 4 feet shded from direct rdition (under bedside tble). Comprison of Pulsed Xenon Versus Continuous Mercury UV for Killing of Pthogens We compred the efficcy of PX-UV versus UV-C delivered by mercury bulbs for reduction of pthogens inoculted onto slides in similrly sized hospitl rooms. This comprison ws performed in seprte fcilities becuse the devices were housed in seprte hospitls. The experiments were performed in similr rooms with equivlent dimensions, nd the experimentl smples were plced t the sme distnces from the UV devices. Slides were prepred s described previously; the inoculum ws ltered such tht ech glss slide yielded 5 log 10 CFU t bseline. The slides were plced 4 feet from ech device within the direct field of rdition. The UV-C ws delivered by the Tru-D device (Lumlier); ech device ws run for totl of 10 minutes. Slides were processed s described previously. The experiments were performed 3 times. Disinfection of Environmentl Surfces in Hospitl Rooms The efficcy of the PX-UV device ws ssessed in rooms (~10 20 feet) of dischrged ptients in tertiry cre fcility. In phse 1, the PX-UV device ws run in rooms tht hd not yet been clened. In phse 2, the device ws run fter stndrd terminl clening by environmentl services personnel tht included use of blech for high-touch surfces in ll dischrge rooms; subset of the rooms hd previously been occupied by ptients with C. difficile infection. Swbs nd guze pds premoistened with sline were used to collect cultures for MRSA, VRE, C. difficile, nd totl heterotrophic bcteri from hightouch surfces (ie, cll light, bedside tble, telephone, chir, intrvenous poles, portble keybords, nd bed ril) before nd fter use of the PX-UV device for 10 minutes (5 minutes on ech side of the bed). An pproximtely cm re ws cultured before PX-UV disinfection nd djcent res of the sme size were cultured fter disinfection. Specimens were cultured nd identified s described previously. Dt Anlysis Dt were nlyzed using STATA, version 9.0 (SttCorp). Continuous dt were nlyzed using pired t tests nd ctegoricl dt were ssessed using the Fisher exct test. results Figure 2 shows the men log 10 CFU/cm 2 reductions of 2 strins of C. difficile, MRSA, nd VRE on glss slides fter the use of the PX-UV device. There were no significnt differences between the log 10 CFU reductions of the 2 strins of ech pthogen tested. Therefore, in subsequent experiments, dt for the 2 strins ws pooled. Pthogen concentrtion did not hve significnt impct on the killing efficcy of the PX-UV device. Irrdition delivered 4 feet from the PX-UV device for 10 minutes reduced C. difficile spores by 0.55 ± 0.34 log 10 CFU/ cm 2, MRSA by 1.85 ± 0.49 log 10 CFU/cm 2, nd VRE by 0.6 ± 0.25 log 10 CFU/cm 2. Orgnic lod (5% fetl clf serum) did not significntly impct the efficcy of the PX-UV device (dt not shown). As shown in Figure 3, the efficcy of PX-UV decresed s distnce from the device incresed. For ech pthogen, significntly less reduction ws chieved t 4 feet versus 6 inches nd t 10 feet versus 4 feet (P <.05 for ech comprison). At 4 feet from the device, shding the orgnisms from the direct field of rdition did not hve significnt impct on efficcy (P >.05 for ech comprison). At 10 feet from the device, the log 10 CFU reduction ws less thn 1 log 10 CFU/cm 2 for ech pthogen. Figure 4 shows the men log 10 CFU/cm 2 reductions of C. difficile, MRSA, nd VRE on slides fter the use of the UV-C nd PX-UV devices for 10 minutes t distnce of 4 feet from the devices. The UV-C device chieved significntly greter log 10 CFU reductions thn the PX-UV device (P <.001 for ech pthogen). Tble 1 provides summry of the results of 2 phses of PX- UV disinfection on high-touch surfces in hospitl rooms. For 16 rooms tht were cultured before nd fter use of PX-UV without clening (phse 1), PX-UV resulted in sttisticlly significnt reductions in the percentges of sites positive for ech of the 3 pthogens, the number of CFU recovered for ech pthogen, nd the heterotrophic plte counts. For 24 rooms tht were cultured before nd fter stndrd clening plus PX-UV (phse 2), there were lso sttisticlly significnt reductions in percentges of sites positive for ech of the pthogens, the number of CFU recovered, nd the heterotrophic plte counts. discussion We found tht the PX-UV device reduced recovery of MRSA, C. difficile, nd VRE on crriers nd on frequently touched

5 xenon uv disinfection of nosocomil pthogens 195 figure 2. The effect of pthogen concentrtion on the efficcy of the pulsed xenon ultrviolet (PX-UV) device. The log 10 CFU reduction/cm 2 of 2 strins ech of Clostridium difficile spores, methicillin-resistnt Stphylococcus ureus (MRSA), nd vncomycin-resistnt Enterococcus (VRE) inoculted onto crriers is shown. Crriers contined either >5, 5 nd >3, or 3 log 10 CFU of ech pthogen. The crriers were irrdited for 10 minutes t distnce of 4 feet from the PX-UV device. The mens of the dt from experiments conducted in triplicte re presented. Error brs indicte stndrd error. figure 3. The effect of distnce on the efficcy of the pulsed xenon ultrviolet (PX-UV) device. The log 10 CFU reduction/cm 2 of Clostridium difficile spores, methicillinresistnt Stphylococcus ureus (MRSA), nd vncomycin-resistnt Enterococcus (VRE) t incresing distnces nd shded from the direct field of rdition delivered by the PX-UV device is shown. Crriers contined 5 log 10 CFU of ech pthogen. The crriers were irrdited for 10 minutes t distnce of 6 in, 4 feet, 4 feet shded, nd 10 ft from the PX-UV device. The mens of the dt from experiments conducted in triplicte re presented. Error brs indicte stndrd error. surfces in hospitl rooms with 10-minute exposure time. Incresing the distnce from the device drmticlly reduced the killing efficcy of PX-UV irrdition, wheres pthogen concentrtion, orgnic lod, nd shding from the direct field of rdition did not. PX-UV ws less effective thn continuous UV-C in reducing pthogen recovery on glss slides with 10- minute exposure time in similr hospitl rooms. Our findings re consistent with previous studies demonstrting the efficcy of PX-UV disinfection for reduction of VRE, MRSA, nd heterotrophic bcteri from surfces in helthcre fcilities. 8,11 In ddition, our study provides 2 ssessments not included in previous publictions on PX-UV (ie, log reductions chieved by PX-UV on crriers nd comprison with continuous UV). Although the log reductions chieved by PX-UV on crriers t 10 minutes were reltively modest, this exposure time ws sufficient to reduce contmintion on rel-world surfces. We hve previously demonstrted tht contminted surfces in hospitl rooms yield reltively low concentrtions (<1 3 log 10 CFU per site smpled using swbs) of helthcre-ssocited pthogens. 13,17 This observtion is corroborted in the current study nd my contribute to the efficcy of the PX-UV device in relworld settings. The PX-UV device hs some importnt potentil dvntges over other UV disinfection devices. First, unlike continuous UV-C devices, xenon flsh lmps do not contin mercury.

6 196 infection control & hospitl epidemiology februry 2015, vol. 36, no. 2 figure 4. The efficcy of pulsed xenon ultrviolet (PX-UV) versus continuous mercury UV-C for killing of pthogens. A comprison of the log 10 CFU reduction/cm 2 of Clostridium difficile spores, methicillin-resistnt Stphylococcus ureus (MRSA), nd vncomycin-resistnt Enterococcus (VRE) by PX-UV nd continuous mercury UV-C is shown. Crriers contined 5 log 10 CFU of ech pthogen. The crriers were irrdited for 10 minutes t distnce of 4 feet from the devices. The mens of the dt from experiments conducted in triplicte re presented. Error brs indicte stndrd error. Therefore, there re no sfety hzrds ssocited with disposl or exposure to mercury. Second, the mnufcturer recommends reltively brief disinfection cycle (10 20 minutes per room versus up to 45 minutes for spore-killing cycles of some UV-C devices) which my fcilitte greter use of the devices. However, our results suggest tht continuous UV-C devices might be similrly effective or more effective thn PX-UV with 10-minute exposure time. Moreover, previous studies hve demonstrted tht optiml killing of C. difficile spores by UV-C is likely to be chieved with longer cycle times 13,18 ; for 2 continuous UV-C devices, reductions in C. difficile spores t 10, 20, nd 40 minutes of exposure were ~1, 2, nd 3 log 10 CFU, respectively. 18 Finlly, orgnic lod did not impct the efficcy of the PX-UV device. PX-UV hs previously been shown to be more effective t penetrting orgnic lod present in wste wter thn UV-C emitted by low pressure mercury bulbs. 10 Thus, it is possible tht the orgnic burden present on rel-world hospitl surfces might hve less impct on the killing efficcy of PX-UV thn UV-C. However, we hve previously demonstrted tht rel-world orgnic mteril collected from hospitl surfces only modestly reduced the effectiveness of continuous UV-C for killing of C. difficile spores. 19 The PX-UV device lso hs some potentil limittions. The efficcy of PX-UV ws drmticlly reduced s the distnce from the device ws incresed. Therefore, it is recommended tht commonly touched surfces (eg, bedside tble, cll button, telephone) be rrnged close to the device for optiml exposure to irrdition. Although the PX-UV device reduced contmintion on surfces, residul contmintion ws not uncommon. In contrst, technologies such s hydrogen peroxide vpor my be more effective in eliminting pthogens. 20,21 Further studies re needed to determine whether the level of reduction in contmintion provided by the PX-UV device is sufficient to reduce rtes of infection. Two recent qusiexperimentl studies hve reported reductions in rtes of C. difficile infection with the use of PX-UV. 9,22 Rndomized trils re needed to determine whether use of PX-UV or other UV devices is effective in reducing infection rtes. Our study hs some limittions. First, the use of swbs nd direct plting to quntify the concentrtions of bcteri is imprecise t higher concentrtions. In ddition, recovery nd relese of bcteri from swbs is less thn 100% nd therefore we my not hve detected lower levels of bcteri on surfces. However, methods were stndrdized for processing ll tble 1. Clostridium difficile, Methicillin-Resistnt Stphylococcus ureus (MRSA), Vncomycin-Resistnt Enterococcus (VRE), nd Totl Heterotrophic Plte Counts (HPC) on Hospitl Surfces before nd fter Pulsed Xenon Ultrviolet (PX-UV) Disinfection No. positive/no. smpled (%), Men CFU (rnge) C. difficile MRSA VRE HPC Phse 1 Before 13/112 (12), 11/112 (10), 4/112(4), 107/112 (96), 9(1 54) 21 (2 75) 522 (2 10,000) After PX-UV 3/112 (3) b 1/112 (0.9), b 0/112 (0) 94/112 (84), b 2 (2) b 0 (0) b 2 (2) b Phse 2 c Before 22/113 (19) 11/113 (10), 4/113 (4), 56/86 (65), 96 (2 300) 12 (3 30) 934 (1 10,000) After stndrd clening & PX-UV 9/113 (8) 2/113 (2), 1/113 (0.9), 36/86 (42), b 12 (4 21) b 1 (1) b 17 (1 186) b NOTE. CFU, colony-forming units. Broth enrichment positive only, no dt vilble for men CFU. b Indictes significnt reduction, P <.01. c In phse 2, totl of 42% of rooms housed ptients with C. difficile infection (in phse 1, no rooms housed such ptients).

7 xenon uv disinfection of nosocomil pthogens 197 smples so ny limittions in the methodology would be eqully shred by bseline nd experimentl groups. Second, becuse the PX-UV nd continuous UV-C devices were housed in seprte hospitls, it ws not fesible to perform the comprtive evlution in the sme room. We cnnot completely rule out the possibility tht some of the differences in results for the 2 devices were due to unpprecited differences in room chrcteristics. However, the experiments were performed in similr rooms with equivlent dimensions, nd we found similr results for the PX-UV device when testing ws done in 3 different rooms. Finlly, for the evlution of pthogen reduction in hospitl rooms, we did not monitor the thoroughness of stndrd environmentl disinfection prctices. cknowledgments Finncil support. Deprtment of Veterns Affirs (Merit Review grnt to C.J.D.) nd Agency for Helthcre Reserch nd Qulity (grnt H44 to C.J.D). Potentil conflicts of interest. All uthors report no conflicts of interest relevnt to this rticle. Address correspondence to Michelle M. Nerndzic, BS, Clevelnd VA Medicl Center, Est Blvd., Clevelnd, OH (michellenerndzi@im.com). references 1. Conner-Kerr TA, Sullivn PK, Gillrd J, Jones RM. The effects of ultrviolet rdition on ntibiotic-resistnt bcteri in vitro. Ostomy Wound Mnge 1998;44: Griego VM, Spence KD. Inctivtion of Bcillus thuringiensis spores by ultrviolet nd visible light. Appl Env Microbiol 1977;35: Hercik F. Action of ultrviolet light on spores nd vegettive forms of Bcillus megtherium sp. J Gen Physiol 1936;20: Setlow P. Spores of Bcillus subtilis: their resistnce to nd killing by rdition, het nd chemicls. JApplMicrobiol2006;101: Setlow P. Resistnce of spores of Bcillus species to ultrviolet light. Environ Mol Mutgen 2001;38: Thi TP, Kest DH, Cmpbell KE, Woodbury MG, Houghton PE. Effect of ultrviolet light C on bcteril coloniztion in chronic wounds. Ostomy Wound Mnge 2005;51: Owens MU, Del DR, Shoemker MO, et l. High-dose ultrviolet C light inctivtes spores of Bcillus subtilis vr. niger nd Bcillus nthrcis Sterne on non-reflective surfces. Appl Biosfety 2005;10: Jindth C, Quezd R, Huber TW, Willims JB, Zeber JE, Copelnd LA. Evlution of pulsed-xenon ultrviolet room disinfection device for impct on contmintion levels of methicillinresistnt Stphylococcus ureus. BMC Infect Dis 2014;14: Levin J, Riley LS, Prrish C, English D, Ahn S. The effect of portble pulsed xenon ultrviolet light fter terminl clening on hospitl-ssocited Clostridium difficile infection in community hospitl. Am J Infect Control 2013;41: Otki M, Okud A, Tjim K, Iwski T, Kinoshit S, Ohgki S. Inctivtion differences of microorgnisms by low pressure UV nd pulsed xenon lmps. Wter Sci Technol 2003; 47: Stibich M, Stchowik J, Tnner B, et l. Evlution of pulsedxenon ultrviolet room disinfection device for impct on hospitl opertions nd microbil reduction. Infect Control Hosp Epidemiol 2011;32: Umezw K, Asi S, Inokuchi S, Miychi H. A comprtive study of the bctericidl ctivity nd dily disinfection housekeeping surfces by new portble pulsed UV rdition device. Curr Microbiol 2012;64: Nerndzic MM, Cdnum JL, Pultz MJ, Donskey CJ. Evlution of n utomted ultrviolet rdition device for decontmintion of Clostridium difficile nd other helthcre-ssocited pthogens in hospitl rooms. BMC Infect Dis 2010;10: Sorg JA, Sonenshein AL. Bile slts nd glycine s cogerminnts for Clostridium difficile spores. J Bcteriol 2008;190(7): Nerndzic MM, Donskey CJ. Effective nd reduced-cost modified selective medium for isoltion of Clostridium difficile. J Clin Microbiol 2009;47(2): Ntionl Committee for Clinicl Lbortory Stndrds. Methods for dilution ntimicrobil susceptibility tests for bcteri tht grow erobiclly; pproved stndrd, M7. Wyne, PA: Clinicl nd Lbortory Institute, Nerndzic MM, Cdnum JL, Eckrt KE, Donskey CJ. Evlution of hnd-held fr-ultrviolet rdition device for decontmintion of Clostridium difficile nd other helthcre-ssocited pthogens. BMC Infect Dis 2012;12: Nerndzic MM, Fisher CW, Donskey CJ. Sorting through the welth of options: Comprtive evlution of 2 ultrviolet disinfection systems. PLOS ONE, 9:e Zhng A, Nerndzic MM, Kundrpu S, Donskey CJ. Does orgnic mteril on hospitl surfces reduce the effectiveness of hypochlorite nd UV rdition for disinfection of Clostridium difficile? Infect Control Hosp Epidemiol 2013;34: Brbut F, Menuet D, Verchten M, Girou E. Comprison of the efficcy of hydrogen peroxide dry-mist disinfection system nd sodium hypochlorite solution for reduction of Clostridium difficile spores. Infect Control Hosp Epidemiol 2009;30: Boyce JM, Hvill NL, Otter JA, et l. Impct of hydrogen peroxide vpor room decontmintion on Clostridium difficile environmentl contmintion nd trnsmission in helthcre setting. Infect Control Hosp Epidemiol 2008;29: Hs JP, Menz J, Dusz S, Monteclvo MA. Implementtion nd impct of ultrviolet environmentl disinfection in n cute cre setting. Am J Infect Control 2014;42: