Jennifer L. Cadnum

Evaluation of an automated ultraviolet radiation device for decontamination of Clostridium difficile and other healthcare-associated pathogens in hospital rooms

BackgroundEnvironmental surfaces play an important role in transmission of healthcare-associated pathogens. There is a need for new disinfection methods that are effective against Clostridium difficile spores, but also safe, rapid, and automated.MethodsThe Tru-D™ Rapid Room Disinfection device is a mobile, fully-automated room decontamination technology that utilizes ultraviolet-C irradiation to kill pathogens. We examined the efficacy of environmental disinfection using the Tru-D device in the laboratory and in rooms of hospitalized patients. Cultures for C. difficile, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) were collected from commonly touched surfaces before and after use of Tru-D.ResultsOn inoculated surfaces, application of Tru-D at a reflected dose of 22,000 μWs/cm2 for ~45 minutes consistently reduced recovery of C. difficile spores and MRSA by >2-3 log10 colony forming units (CFU)/cm2 and of VRE by >3-4 log10 CFU/cm2. Similar killing of MRSA and VRE was achieved in ~20 minutes at a reflected dose of 12,000 μWs/cm2, but killing of C. difficile spores was reduced. Disinfection of hospital rooms with Tru-D reduced the frequency of positive MRSA and VRE cultures by 93% and of C. difficile cultures by 80%. After routine hospital cleaning of the rooms of MRSA carriers, 18% of sites under the edges of bedside tables (i.e., a frequently touched site not easily amenable to manual application of disinfectant) were contaminated with MRSA, versus 0% after Tru-D (P < 0.001). The system required <5 minutes to set up and did not require continuous monitoring.ConclusionsThe Tru-D Rapid Room Disinfection device is a novel, automated, and efficient environmental disinfection technology that significantly reduces C. difficile, VRE and MRSA contamination on commonly touched hospital surfaces.

Contamination of Hands with Methicillin-Resistant Staphylococcus aureus after Contact with Environmental Surfaces and after Contact with the Skin of Colonized Patients

In a study of 40 methicillin-resistant Staphylococcus aureus (MRSA) carriers, hand contamination was equally likely after contact with commonly examined skin sites and commonly touched environmental surfaces in patient rooms (40% vs 45%). These findings suggest that contaminated surfaces may be an important source of MRSA transmission.

Contamination of Health Care Personnel During Removal of Personal Protective Equipment

IMPORTANCE Contamination of the skin and clothing of health care personnel during removal of personal protective equipment (PPE) contributes to dissemination of pathogens and places personnel at risk for infection. OBJECTIVES To determine the frequency and sites of contamination on the skin and clothing of personnel during PPE removal and to evaluate the effect of an intervention on the frequency of contamination. DESIGN, SETTING, AND PARTICIPANTS We conducted a point-prevalence study and quasi-experimental intervention from October 28, 2014, through March 31, 2015. Data analysis began November 17, 2014, and ended April 21, 2015. Participants included a convenience sample of health care personnel from 4 Northeast Ohio hospitals who conducted simulations of contaminated PPE removal using fluorescent lotion and a cohort of health care personnel from 7 study units in 1 medical center that participated in a quasi-experimental intervention that included education and practice in removal of contaminated PPE with immediate visual feedback based on fluorescent lotion contamination of skin and clothing. MAIN OUTCOMES AND MEASURES The primary outcomes were the frequency and sites of contamination on skin and clothing of personnel after removal of contaminated gloves or gowns at baseline vs after the intervention. A secondary end point focused on the correlation between contamination of skin with fluorescent lotion and bacteriophage MS2, a nonpathogenic, nonenveloped virus. RESULTS Of 435 glove and gown removal simulations, contamination of skin or clothing with fluorescent lotion occurred in 200 (46.0%), with a similar frequency of contamination among the 4 hospitals (range, 42.5%-50.3%). Contamination occurred more frequently during removal of contaminated gloves than gowns (52.9% vs 37.8%, P = .002) and when lapses in technique were observed vs not observed (70.3% vs 30.0%, P < .001). The intervention resulted in a reduction in skin and clothing contamination during glove and gown removal (60.0% before the intervention vs 18.9% after, P < .001) that was sustained after 1 and 3 months (12.0% at both time points, P < .001 compared with before the intervention). During simulations of contaminated glove removal, the frequency of skin contamination was similar with fluorescent lotion and bacteriophage MS2 (58.0% vs 52.0%, P = .45). CONCLUSIONS AND RELEVANCE Contamination of the skin and clothing of health care personnel occurs frequently during removal of contaminated gloves or gowns. Educational interventions that include practice with immediate visual feedback on skin and clothing contamination can significantly reduce the risk of contamination during removal of PPE.

Defining the Vulnerable Period for Re-Establishment of Clostridium difficile Colonization after Treatment of C. difficile Infection with Oral Vancomycin or Metronidazole

Background Clostridium difficile is an anaerobic, spore-forming bacterium that is the most common cause of healthcare-associated diarrhea in developed countries. A significant proportion of patients receiving oral vancomycin or metronidazole for treatment of Clostridium difficile infection (CDI) develop recurrences. However, the period of vulnerability to re-establishment of colonization by C. difficile after therapy is not well defined. Principal Findings In a prospective study of CDI patients, we demonstrated that most vancomycin-treated patients maintained inhibitory concentrations of vancomycin in stool for 4 to 5 days after therapy, whereas metronidazole was only detectable during therapy. From the time of elimination of the antibiotics to 14 to 21 days after therapy, a majority of stool suspensions supported growth of C. difficile and deep 16S rRNA sequencing demonstrated persistent marked alteration of the indigenous microbiota. By 21 to 28 days after completion of CDI treatment, a majority of stool suspensions inhibited growth of C. difficile and there was evidence of some recovery of the microbiota. Conclusions These data demonstrate that there is a vulnerable period for re-establishment of C. difficile colonization after CDI treatment that begins within a few days after discontinuation of treatment and extends for about 3 weeks in most patients.

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

OBJECTIVE To determine the effectiveness of a pulsed xenon ultraviolet (PX-UV) disinfection device for reduction in recovery of healthcare-associated pathogens. SETTING Two acute-care hospitals. METHODS We examined the effectiveness of PX-UV for killing of Clostridium difficile spores, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) on glass carriers and evaluated the impact of pathogen concentration, distance from the device, organic load, and shading from the direct field of radiation on killing efficacy. We compared the effectiveness of PX-UV and ultraviolet-C (UV-C) irradiation, each delivered for 10 minutes at 4 feet. In hospital rooms, the frequency of native pathogen contamination on high-touch surfaces was assessed before and after 10 minutes of PX-UV irradiation. RESULTS On carriers, irradiation delivered for 10 minutes at 4 feet from the PX-UV device reduced recovery of C. difficile spores, MRSA, and VRE by 0.55±0.34, 1.85±0.49, and 0.6±0.25 log10 colony-forming units (CFU)/cm2, respectively. Increasing distance from the PX-UV device dramatically reduced killing efficacy, whereas pathogen concentration, organic load, and shading did not. Continuous UV-C achieved significantly greater log10CFU reductions than PX-UV irradiation on glass carriers. On frequently touched surfaces, PX-UV significantly reduced the frequency of positive C. difficile, VRE, and MRSA culture results. CONCLUSIONS The PX-UV device reduced recovery of MRSA, C. difficile, and VRE on glass carriers and on frequently touched surfaces in hospital rooms with a 10-minute UV exposure time. PX-UV was not more effective than continuous UV-C in reducing pathogen recovery on glass slides, suggesting that both forms of UV have some effectiveness at relatively short exposure times.

Skin and Environmental Contamination with Methicillin-Resistant Staphylococcus aureus among Carriers Identified Clinically Versus through Active Surveillance

In a prospective study involving 115 patients with methicillin-resistant Staphylococcus aureus nares carriage, we found that skin and environmental contamination with methicillin-resistant S. aureus was as likely among individuals whose S. aureus carriage was identified only through active surveillance as it was among those individuals whose S. aureus carriage was identified clinically, which suggests that strategies to limit transmission must address colonized patients, as well as infected patients.

Evaluation of a hand-held far-ultraviolet radiation device for decontamination of Clostridium difficile and other healthcare-associated pathogens

BackgroundEnvironmental surfaces play an important role in transmission of healthcare-associated pathogens. There is a need for new disinfection methods that are effective against Clostridium difficile spores, but also safe and rapid. The Sterilray™ Disinfection Wand device is a hand-held room decontamination technology that utilizes far-ultraviolet radiation (185-230 nm) to kill pathogens.MethodsWe examined the efficacy of disinfection using the Sterilray device in the laboratory, in rooms of hospitalized patients, and on surfaces outside of patient rooms (i.e. keyboards and portable medical equipment). Cultures for C. difficile, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) were collected from commonly-touched surfaces before and after use of the Sterilray device.ResultsOn inoculated surfaces in the laboratory, application of the Sterilray device at a radiant dose of 100 mJ/cm2 for ~ 5 seconds consistently reduced recovery of C. difficile spores by 4.4 CFU log10, MRSA by 5.4 log10CFU and of VRE by 6.9 log10CFU. A >3 log10 reduction of MRSA and VRE was achieved in ~2 seconds at a lower radiant dose, but killing of C. difficile spores was significantly reduced. On keyboards and portable medical equipment that were inoculated with C. difficile spores, application of the Sterilray device at a radiant dose of 100 mJ/cm2 for ~ 5 seconds reduced contamination by 3.2 log10CFU. However, the presence of organic material reduced the lethal effect of the far-UV radiation. In hospital rooms that were not pre-cleaned, disinfection with the Sterilray device significantly reduced the frequency of positive C. difficile and MRSA cultures (P =0.007).ConclusionsThe Sterilray™ Disinfection Wand is a novel environmental disinfection technology that rapidly kills C. difficile spores and other healthcare-associated pathogens on surfaces. However, the presence of organic matter reduces the efficacy of far-UV radiation, possibly explaining the more modest results observed on surfaces in hospital rooms that were not pre-cleaned.

Occurrence of Skin and Environmental Contamination with Methicillin-Resistant Staphylococcus aureus before Results of Polymerase Chain Reaction at Hospital Admission Become Available

BACKGROUND Active surveillance to detect patients colonized with methicillin-resistant Staphylococcus aureus (MRSA) is increasingly practiced in healthcare settings. However, inpatients may already become sources of transmission before appropriate precautions are implemented. OBJECTIVE To examine the frequency of MRSA contamination of commonly touched skin and environmental surfaces before patient carriage status became known. METHODS We conducted a 6-week prospective study of patients who were identified by use of polymerase chain reaction (PCR) at hospital admission as having nasal MRSA colonization. Skin and environmental contamination was assessed within hours of completion of PCR screening. RESULTS There were 116 patients identified by PCR screening as having nasal MRSA colonization during the period from mid-April to May 2008, of whom 83 (72%) were enrolled in our study. Overall, MRSA was detected on the skin of 38 (51%) of 74 patients and in the environment of 37 (45%) of 83 patients. Of 83 environmental culture samples, 63 (76%) were obtained within 7 hours after PCR results became available, and 73 (88%) were obtained before wards were notified of PCR results. Of the 83 MRSA-colonized patients, 15 (18%) had contaminated their environment 25 hours after admission, and 29 (35%) had contaminated their environment 33 hours after admission. Thirty-two (39%) of the 83 patients had roommates, 13 (41%) of whom contaminated their environment. The median interval from admission to PCR result was 20 hours, and the median interval from PCR result to notification was 23 hours. An increased quantity of MRSA cultured from a nasal sample was significantly associated with contamination. CONCLUSIONS Before any contact precautions can be implemented, newly identified MRSA carriers frequently have contaminated their environment with MRSA and have contamination of commonly examined skin sites. In hospitals that perform active surveillance, strategies are needed to minimize delays in screening or to preemptively identify patients at high risk for disseminating MRSA.

Outpatient Healthcare Settings and Transmission of Clostridium difficile

Background Recent reports suggest that community-associated Clostridium difficile infection (CDI) (i.e., no healthcare facility admission within 90 days) may be increasing in frequency. We hypothesized that outpatient clinics could be an important source for acquisition of community-associated CDI. Methods We performed a 6-month prospective study of CDI patients to determine frequency of and risk factors for skin and environmental shedding during outpatient visits and to derive a prediction rule for positive cultures. We performed a point–prevalence culture survey to assess the frequency of C. difficile contamination in outpatient settings and evaluated the frequency of prior outpatient visits in patients with community-associated CDI. Results Of 67 CDI patients studied, 54 (81%) had 1 or more outpatient visits within 12 weeks after diagnosis. Of 44 patients cultured during outpatient visits, 14 (32%) had skin contamination and 12 (27%) contaminated environmental surfaces. Decreased mobility, fecal incontinence, and treatment with non-CDI antibiotics were associated with positive cultures, whereas vancomycin taper therapy was protective. In patients not on CDI therapy, a prediction rule including incontinence or decreased mobility was 90% sensitive and 79% specific for detection of spore shedding. Of 84 clinic and emergency department rooms cultured, 12 (14%) had 1 or more contaminated environmental sites. For 33 community-associated CDI cases, 31 (94%) had an outpatient visit during the 12 weeks prior to onset of diarrhea. Conclusions Patients with recent CDI present a significant risk for transmission of spores during outpatient visits. The outpatient setting may be an underappreciated source of community-associated CDI cases.

Effectiveness of disinfectants against candida auris and other candida species

Contaminated surfaces are a suspected source for dissemination of the globally emerging pathogen Candida auris. In laboratory testing, sporicidal and improved hydrogen peroxide disinfectants were highly effective against C. auris, C. glabrata, and C. albicans. The widely used quaternary ammonium disinfectants exhibited relatively poor activity against all of the Candida species. Infect Control Hosp Epidemiol 2017;38:1240-1243.