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Can pulsed xenon ultraviolet light systems disinfect aerobic bacteria in the absence of manual disinfection?

  • Chetan Jinadatha
    Correspondence
    Address correspondence to Chetan Jinadatha, MD, MPH, 1901 S Veterans Dr, Temple, TX 76504.
    Affiliations
    Department of Medicine, Central Texas Veterans Healthcare System, Temple, TX

    Department of Medicine, College of Medicine, Texas A&M Health Science Center, Bryan, TX
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  • Frank C. Villamaria
    Affiliations
    Department of Medicine, Central Texas Veterans Healthcare System, Temple, TX

    Health Promotion & Community Health Science and Department of Epidemiology and Biostatistics, School of Public Health, Texas A&M University, College Station, TX
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  • Nagaraja Ganachari-Mallappa
    Affiliations
    Department of Medicine, Central Texas Veterans Healthcare System, Temple, TX
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  • Donna S. Brown
    Affiliations
    Department of Medicine, Central Texas Veterans Healthcare System, Temple, TX
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  • I-Chia Liao
    Affiliations
    Department of Medicine, Central Texas Veterans Healthcare System, Temple, TX

    Health Promotion & Community Health Science and Department of Epidemiology and Biostatistics, School of Public Health, Texas A&M University, College Station, TX
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  • Eileen M. Stock
    Affiliations
    Department of Medicine, College of Medicine, Texas A&M Health Science Center, Bryan, TX

    Department of Internal Medicine, Center for Applied Health Research, Temple, TX
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  • Laurel A. Copeland
    Affiliations
    Department of Medicine, Central Texas Veterans Healthcare System, Temple, TX

    Department of Medicine, College of Medicine, Texas A&M Health Science Center, Bryan, TX

    Health Promotion & Community Health Science and Department of Epidemiology and Biostatistics, School of Public Health, Texas A&M University, College Station, TX

    Department of Internal Medicine, Center for Applied Health Research, Temple, TX
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  • John E. Zeber
    Affiliations
    Department of Medicine, Central Texas Veterans Healthcare System, Temple, TX

    Department of Medicine, College of Medicine, Texas A&M Health Science Center, Bryan, TX

    Health Promotion & Community Health Science and Department of Epidemiology and Biostatistics, School of Public Health, Texas A&M University, College Station, TX

    Department of Internal Medicine, Center for Applied Health Research, Temple, TX
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Open AccessPublished:February 10, 2015DOI:https://doi.org/10.1016/j.ajic.2014.12.012

      Highlights

      • We sampled 38 hospital rooms for aerobic bacteria on surfaces.
      • Utilized PX-UV as a disinfectant tool without any manual cleaning.
      • Collected aerobic bacteria samples before and after PX-UV disinfection.
      • Found a significant decrease in aerobic bacteria counts after PX-UV usage.
      Whereas pulsed xenon-based ultraviolet light no-touch disinfection systems are being increasingly used for room disinfection after patient discharge with manual cleaning, their effectiveness in the absence of manual disinfection has not been previously evaluated. Our study indicates that pulsed xenon-based ultraviolet light systems effectively reduce aerobic bacteria in the absence of manual disinfection. These data are important for hospitals planning to adopt this technology as adjunct to routine manual disinfection.

      Key Words

      Aerobic bacterial colony (ABC) counts on hospital high-touch surfaces indicate the level of microbiologic contamination.
      • Dancer S.
      How do we assess hospital cleaning? A proposal for microbiological standards for surface hygiene in hospitals.
      ABC counts have been used in studies to assess the effectiveness of mercury-based ultraviolet (Hg-UV) and pulsed xenon-based ultraviolet (PX-UV) no-touch disinfection devices (NTD).
      • Anderson D.J.
      • Gergen M.F.
      • Smathers E.
      • Sexton D.J.
      • Chen L.F.
      • Weber D.J.
      • et al.
      Decontamination of targeted pathogens from patient rooms using an automated ultraviolet-C-emitting device.
      • Stibich M.
      • Stachowiak J.
      • Tanner B.
      • Berkheiser M.
      • Moore L.
      • Raad I.
      • et al.
      Evaluation of a pulsed-xenon ultraviolet room disinfection device for impact on hospital operations and microbial reduction.
      • Rutala W.A.
      • Gergen M.F.
      • Weber D.J.
      Room decontamination with UV radiation.
      Although a room could be disinfected manually without using NTD, the reverse is not accepted practice.
      • Anderson D.J.
      • Gergen M.F.
      • Smathers E.
      • Sexton D.J.
      • Chen L.F.
      • Weber D.J.
      • et al.
      Decontamination of targeted pathogens from patient rooms using an automated ultraviolet-C-emitting device.
      • Jinadatha C.
      • Quezada R.
      • Huber T.W.
      • Williams J.B.
      • Zeber J.E.
      • Copeland L.A.
      Evaluation of a pulsed-xenon ultraviolet room disinfection device for impact on contamination levels of methicillin-resistant Staphylococcus aureus.
      But there may be occasions where surfaces are not thoroughly disinfected due to human error or significant contamination.
      • Carling P.
      Evaluating the thoroughness of environmental cleaning in hospitals.
      There is evidence to suggest the effectiveness of Hg-UV disinfection on ABC counts in the absence of any manual cleaning, but, such data is lacking for PX-UV disinfection devices.
      • Anderson D.J.
      • Gergen M.F.
      • Smathers E.
      • Sexton D.J.
      • Chen L.F.
      • Weber D.J.
      • et al.
      Decontamination of targeted pathogens from patient rooms using an automated ultraviolet-C-emitting device.
      • Rutala W.A.
      • Gergen M.F.
      • Weber D.J.
      Room decontamination with UV radiation.
      Hence, we devised a study to evaluate the effectiveness of PX-UV disinfection on ABC counts in the absence of any manual disinfection.

      Materials and methods

      To determine if the PX-UV disinfection system can effectively reduce ABC without prior manual disinfection, a prospective pre–post study design was developed. The study site was a single Veterans Affairs facility located in Temple, Texas. A convenience sample of 38 recently vacated rooms (n = 38) that had not yet undergone any manual disinfection and had been occupied for a minimum of 48 hours were identified and before and after PX-UV surface samples were collected. The description of the device and the methodology used for disinfection was similar to those described in Jinadatha et al
      • Jinadatha C.
      • Quezada R.
      • Huber T.W.
      • Williams J.B.
      • Zeber J.E.
      • Copeland L.A.
      Evaluation of a pulsed-xenon ultraviolet room disinfection device for impact on contamination levels of methicillin-resistant Staphylococcus aureus.
      except there was no manual disinfection before PX-UV use. Five high-touch surfaces within each room were sampled before and after PX-UV disinfection. The surfaces included 3 in the patient room (ie, call button, bedrail, and tray table) and 2 in the bathroom (ie, handrail and toilet). Therefore, a total of 190 samples before and after PX-UV disinfection were obtained across 38 rooms.
      Tryptic soy agar supplemented with lecithin and polysorbate 80 Rodac contact plates (Hardy Diagnostics, Santa Maria, Calif) were used for sampling of surfaces. If gross visible soiling was observed, such as food particles or spilt condiments, the area adjacent was sampled by press plate technique. Roll plate method was used for nonflat surfaces such as bedrails and handrails. Once the baseline samples were taken the PX-UV was used to disinfect the room and then post-PX-UV samples were collected in areas adjacent to the samples taken before disinfection.
      The plates were then incubated for 48 hours at 37°C. After incubation the colonies were counted and recorded. The mean and the median aerobic bacteria CFU/25 cm2 and 95% confidence intervals (CIs) were calculated for each surface type. An upper limit of 200 CFU was used for ABC counts exceeding this value. The effectiveness of PX-UV on the concentration of aerobic bacteria was assessed employing a Wilcoxon signed-rank test for all 190 pre–post samples in 38 rooms, as well as by surface location. A type 1 error of α = 0.05 was assumed. Data were analyzed using SAS version 9.2 (SAS Institute Inc, Cary, NC).

      Results

      The overall mean ABC count across all 190 samples before PX-UV disinfection was 73.6 (95% CI, 63.8-83.4) (Table 1). The surface with greatest ABC count was the call button, with a mean of 88.5 (95% CI, 66.7-110.3), followed by the bedrail, with a mean 84.0 (95% CI, 61.6-106.4). The tray table had the lowest mean ABC count before PX-UV disinfection, with 54.5 (95% CI, 34.5-74.5). After disinfection, the call button had the greatest mean ABC count reduction of 72.4 (median reduction of 66.0; P < .01). All high-touch surfaces experienced a significant reduction in ABC count. Overall, before PX-UV disinfection, 187 (98.4%) of the surfaces were contaminated with aerobic bacteria; this was reduced to 169 (88.9%) surfaces after disinfection, leading to 18 (9.6%) contaminated surfaces now becoming free of aerobic bacteria after PX-UV disinfection. Levels of ABC were reduced from 74 ± 10 to no more than 20 ± 3 colonies overall, with the highest residual counts on bathroom surfaces. When the results from Table 1 were compared with ABC count reduction after standard manual disinfection without use of PX-UV disinfection, the results were similar (data not shown).
      Table 1Mean aerobic bacterial colony (ABC) counts from high-touch surfaces before and after application of pulsed xenon-based ultraviolet light (PX-UV) disinfection systems in the absence of manual cleaning
      LocationNo. of samplesABC before PX-UVABC after PX-UVABC reductionP value
      Wilcoxon signed-rank tests were employed, assuming a significance level of α = 0.05.
      Call button3888.5 ± 68.7

      76 (5, 200) (21-122)
      16.1 ± 33.0

      4 (0, 161) (1-12)
      72.4 ± 64.8

      66 (–52, 199) (19-108)
      <.01
      Bedrail3884.0 ± 70.3

      42 (7, 200) (32-125)
      13.0 ± 17.2

      5.5 (0, 70) (2-18)
      71.0 ± 66.6

      35 (–6, 200) (20-112)
      <.01
      Tray table3854.5 ± 62.9

      23 (1, 200) (12-67)
      13.3 ± 17.0

      7.5 (0, 79) (1-22)
      41.2 ± 61.8

      15.5 (–24, 200) (8-45)
      <.01
      Bathroom handrail3860.7 ± 56.3

      35 (0, 200) (16-95)
      16.1 ± 32.9

      6.5 (0, 200) (3-16)
      44.6 ± 62.1

      30.5 (–171, 194) (9-79)
      <.01
      Toilet seat3880.2 ± 81.0

      46 (0, 200) (11-200)
      40.6 ± 59.3

      13 (0, 200) (2-45)
      39.6 ± 69.7

      14 (–70, 199) (1-61)
      <.01
      Overall19073.6 ± 69.0

      47 (0, 200) (19-113)
      19.8 ± 36.6

      6 (0, 200) (2-20)
      53.8 ± 66.1

      28.5 (–171, 200) (10-90)
      <.01
      NOTE. Values are presented as mean ± SD (top values) and median (minimum, maximum; interquartile range) (bottom values).
      Wilcoxon signed-rank tests were employed, assuming a significance level of α = 0.05.

      Discussion

      Surface contamination has been shown to play a significant role in the acquisition of hospital-acquired infections.
      • Weber D.J.
      • Anderson D.
      • Rutala W.A.
      The role of the surface environment in healthcare-associated infections.
      • Huang S.S.
      • Datta R.
      • Platt R.
      Risk of acquiring antibiotic-resistant bacteria from prior room occupants.
      In fact, Huang et al
      • Huang S.S.
      • Datta R.
      • Platt R.
      Risk of acquiring antibiotic-resistant bacteria from prior room occupants.
      showed a 40% increased odds of transmission for methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci if the room's previous occupant was positive for either antibiotic-resistant bacteria. The current standard for disinfection in most hospitals is manual cleaning by Environmental Management Services staff with disinfectants.
      • Carling P.
      • Parry M.
      • Von Beheren S.
      Group HEHS
      Identifying opportunities to enhance environmental cleaning in 23 acute care hospitals.
      These methods are inconsistent and often inadequate in decreasing environmental bioburden.
      • Jinadatha C.
      • Quezada R.
      • Huber T.W.
      • Williams J.B.
      • Zeber J.E.
      • Copeland L.A.
      Evaluation of a pulsed-xenon ultraviolet room disinfection device for impact on contamination levels of methicillin-resistant Staphylococcus aureus.
      • Carling P.
      • Von Beheren S.
      • Kim P.
      • Woods C.
      Intensive care unit environmental cleaning: an evaluation in sixteen hospitals using a novel assessment tool.
      Newer NTD technologies have the potential to supplement manual disinfection to provide enhanced disinfection.
      • Anderson D.J.
      • Gergen M.F.
      • Smathers E.
      • Sexton D.J.
      • Chen L.F.
      • Weber D.J.
      • et al.
      Decontamination of targeted pathogens from patient rooms using an automated ultraviolet-C-emitting device.
      • Stibich M.
      • Stachowiak J.
      • Tanner B.
      • Berkheiser M.
      • Moore L.
      • Raad I.
      • et al.
      Evaluation of a pulsed-xenon ultraviolet room disinfection device for impact on hospital operations and microbial reduction.
      • Rutala W.A.
      • Gergen M.F.
      • Weber D.J.
      Room decontamination with UV radiation.
      • Jinadatha C.
      • Quezada R.
      • Huber T.W.
      • Williams J.B.
      • Zeber J.E.
      • Copeland L.A.
      Evaluation of a pulsed-xenon ultraviolet room disinfection device for impact on contamination levels of methicillin-resistant Staphylococcus aureus.
      Anderson et al
      • Anderson D.J.
      • Gergen M.F.
      • Smathers E.
      • Sexton D.J.
      • Chen L.F.
      • Weber D.J.
      • et al.
      Decontamination of targeted pathogens from patient rooms using an automated ultraviolet-C-emitting device.
      showed that Hg-UV is effective at decreasing the ABC counts in hospital settings even in the absence of manual disinfection. However, until now research has been lacking for PX-UV disinfection systems. Our study results indicate that PX-UV disinfection reduces aerobic bacteria in the absence of manual disinfection. Our results were similar to the reduction of ABC counts seen in other studies that used a mercury-based no-touch UV disinfection device.
      • Anderson D.J.
      • Gergen M.F.
      • Smathers E.
      • Sexton D.J.
      • Chen L.F.
      • Weber D.J.
      • et al.
      Decontamination of targeted pathogens from patient rooms using an automated ultraviolet-C-emitting device.
      • Rutala W.A.
      • Gergen M.F.
      • Weber D.J.
      Room decontamination with UV radiation.
      In our previous study, we evaluated a properly truncated aesthetic cleaning protocol supplemented by PX-UV disinfection in vacated hospital rooms.
      • Jinadatha C.
      • Quezada R.
      • Huber T.W.
      • Williams J.B.
      • Zeber J.E.
      • Copeland L.A.
      Evaluation of a pulsed-xenon ultraviolet room disinfection device for impact on contamination levels of methicillin-resistant Staphylococcus aureus.
      But we were not able to delineate if PX-UV was effective on surfaces where Environmental Management Services personnel did not apply a chemical disinfectant, which is part of standard cleaning protocol. It is highly unlikely that the UV light devices are going to be used alone without manual precleaning, for aesthetic reasons. Although our study is not intended to advocate abandoning manual disinfection practices altogether, it provides insight into what happens if a surface is missed by Environmental Management Services personnel during manual disinfection when PX-UV is subsequently deployed. Our study had several limitations, including no evaluation of organism-specific reduction. This study was conducted in a Veterans Affairs hospital setting and may not be generalizable to community hospitals. Although the sample size was small, it represents a larger cohort than other previously reported studies.
      • Stibich M.
      • Stachowiak J.
      • Tanner B.
      • Berkheiser M.
      • Moore L.
      • Raad I.
      • et al.
      Evaluation of a pulsed-xenon ultraviolet room disinfection device for impact on hospital operations and microbial reduction.
      • Jinadatha C.
      • Quezada R.
      • Huber T.W.
      • Williams J.B.
      • Zeber J.E.
      • Copeland L.A.
      Evaluation of a pulsed-xenon ultraviolet room disinfection device for impact on contamination levels of methicillin-resistant Staphylococcus aureus.

      Conclusions

      Our study suggests that PX-UV effectively reduces ABC counts in the absence of manual disinfection. These data are important for hospitals that plan to adapt this technology as adjunct to routine manual disinfection and alleviate any fears that adapting this technology may actually harm patients because Environmental Management Services personnel may miss surfaces.

      Acknowledgments

      The authors thank Kimberly Sikes, Robin Keene, and Deana Hamson for collecting samples; Elicia Greene and the entire Infection Prevention and Control Department; Allen Lassiter and the Environmental Management Services team; and the nursing service personnel for their help in coordinating study activities.

      References

        • Dancer S.
        How do we assess hospital cleaning? A proposal for microbiological standards for surface hygiene in hospitals.
        J Hosp Infect. 2004; 56: 10-15
        • Anderson D.J.
        • Gergen M.F.
        • Smathers E.
        • Sexton D.J.
        • Chen L.F.
        • Weber D.J.
        • et al.
        Decontamination of targeted pathogens from patient rooms using an automated ultraviolet-C-emitting device.
        Infect Control Hosp Epidemiol. 2013; 34: 466-471
        • Stibich M.
        • Stachowiak J.
        • Tanner B.
        • Berkheiser M.
        • Moore L.
        • Raad I.
        • et al.
        Evaluation of a pulsed-xenon ultraviolet room disinfection device for impact on hospital operations and microbial reduction.
        Infect Control Hosp Epidemiol. 2011; 32: 286-288
        • Rutala W.A.
        • Gergen M.F.
        • Weber D.J.
        Room decontamination with UV radiation.
        Infect Control Hosp Epidemiol. 2010; 31: 1025-1029
        • Jinadatha C.
        • Quezada R.
        • Huber T.W.
        • Williams J.B.
        • Zeber J.E.
        • Copeland L.A.
        Evaluation of a pulsed-xenon ultraviolet room disinfection device for impact on contamination levels of methicillin-resistant Staphylococcus aureus.
        BMC Infect Dis. 2014; 14: 1-7
        • Carling P.
        Evaluating the thoroughness of environmental cleaning in hospitals.
        J Hosp Infect. 2008; 68: 273-274
        • Weber D.J.
        • Anderson D.
        • Rutala W.A.
        The role of the surface environment in healthcare-associated infections.
        Curr Opin Infect Dis. 2013; 26: 338-344
        • Huang S.S.
        • Datta R.
        • Platt R.
        Risk of acquiring antibiotic-resistant bacteria from prior room occupants.
        Arch Intern Med. 2006; 166: 1945-1951
        • Carling P.
        • Parry M.
        • Von Beheren S.
        • Group HEHS
        Identifying opportunities to enhance environmental cleaning in 23 acute care hospitals.
        Infect Control Hosp Epidemiol. 2008; 29: 1-7
        • Carling P.
        • Von Beheren S.
        • Kim P.
        • Woods C.
        Intensive care unit environmental cleaning: an evaluation in sixteen hospitals using a novel assessment tool.
        J Hosp Infect. 2008; 68: 39-44