Pulsed dosing and extended daily dosing of oral vancomycin do not facilitate clearance of Clostridioides difficile colonization in mice.

Vancomycin taper and pulse regimens are commonly used to treat recurrent Clostridioides difficile infections, but the mechanism by which these regimens might reduce recurrences is unclear. Here, we used a mouse model to test the hypothesis that pulse dosing of vancomycin after a 10-day treatment course enhances clearance of C. difficile from the intestinal tract. Mice with C. difficile colonization received 10 days of once-daily oral vancomycin followed by 20 days of treatment with saline (controls), daily vancomycin, or pulse dosing of vancomycin every 2 or 3 days. Stool samples were collected to measure the concentration of C. difficile during and after treatment, vancomycin concentrations, and growth of vegetative C. difficile during every 3 days dosing. Pulse dosing of vancomycin was not effective in maintaining suppression of C. difficile (P > 0.05 in comparison to saline controls); growth of vegetative C. difficile occurred between pulse doses when vancomycin decreased to undetectable levels. Daily dosing of vancomycin suppressed C. difficile during treatment, but recurrent colonization occurred after treatment in more than 75% of mice, and by post-treatment day 14, there was no significant difference among the control, pulse dosing, and daily dosing groups (P > 0.05). These findings demonstrate that pulse dosing of vancomycin every 2 or 3 days does not facilitate the clearance of C. difficile spores in mice. Studies are needed to examine the impact of vancomycin taper and pulsed regimens in patients.

Efficacy of 23 commonly used liquid disinfectants against Candida auris isolates from the 4 major clades.

We tested the effectiveness of 23 disinfectants used in healthcare facilities against isolates from the 4 major clades of Candida auris. Sporicidal disinfectants were consistently effective, whereas quaternary-ammonium disinfectants had limited activity. Quaternary-ammonium-alcohol and hydrogen-peroxide-based disinfectants varied in effectiveness against C. auris.

Effectiveness of a novel 1-step cleaner and disinfectant against Candida auris.

A novel 1-step anionic surfactant disinfectant was effective against Candida auris isolates from the 4 major phylogenetic clades as well as methicillin-resistant Staphylococcus aureus (MRSA) and the enveloped virus bacteriophage Phi6. This anionic surfactant disinfectant may be a useful addition to the disinfectant products available for use against C. auris.

Efficacy of relatively low-cost ultraviolet-C light devices against Candida auris.

BACKGROUND: Ultraviolet-C (UV-C) light devices could be useful to reduce environmental contamination with Candida auris. However, variable susceptibility of C. auris strains to UV-C has been reported, and the high cost of many devices limits their use in resource-limited settings. OBJECTIVE: To evaluate the efficacy of relatively low-cost (<$15,000 purchase price) UV-C devices against C. auris strains from the 4 major phylogenetic clades. METHODS: A modification of the American Society for Testing and Materials (ASTM) standard quantitative disk carrier test method (ASTM E 2197) was used to examine and compare the effectiveness of UV-C devices against C. auris, methicillin-resistant Staphylococcus aureus (MRSA), and bacteriophage Phi6. Reductions of 3 log10 were considered effective. UV-C irradiance measurements and colorimetric indicators were used to assess UV-C output. RESULTS: Of 8 relatively low-cost UV-C devices, 6 met the criteria for effective decontamination of C. auris isolates from clades I and II, MRSA, and bacteriophage Phi6, including 3 room decontamination devices and 3 UV-C box devices. Candida auris isolates from clades III and IV were less susceptible to UV-C than clade I and II isolates; 1 relatively low-cost room decontamination device and 2 enclosed box devices met the criteria for effective decontamination of clade III and IV isolates. UV-C irradiance measurements and colorimetric indicator results were consistent with microorganism reductions. CONCLUSIONS: Some relatively low-cost UV-C light technologies are effective against C. auris, including isolates from clades III and IV with reduced UV-C susceptibility. Studies are needed to evaluate the effectiveness of UV-C devices in clinical settings.

Evaluation of a continuously active disinfectant for decontamination of portable medical equipment.

A single spray application of a continuously active disinfectant on portable equipment resulted in significant reductions in aerobic colony counts over 7 days and in recovery of Staphylococcus aureus and enterococci: 3 of 93 cultures (3%) versus 11 of 97 (11%) and 20 of 97 (21%) in quaternary ammonium disinfectant and untreated control groups, respectively.

Ultraviolet-C (UV-C) monitoring made simple: Colorimetric indicators to assess delivery of UV-C light by room decontamination devices.

OBJECTIVE: To evaluate the use of colorimetric indicators for monitoring ultraviolet-C (UV-C) light delivery to sites in patient rooms. METHODS: In laboratory testing, we examined the correlation between changes in color of 2 commercial colorimetric indicators and log10 reductions in methicillin-resistant Staphylococcus aureus (MRSA) and Clostridioides difficile spores with exposure to increasing doses of UV-C from a low-pressure mercury room decontamination device. In patient rooms, 1 of the colorimetric indicators was used to assess UV-C dose delivery to 27 sites in the room. RESULTS: In laboratory testing, the manufacturer's reference colors for MRSA and C. difficile reduction corresponded with doses of ∼10,000 and 46,000 µJ/cm2; these doses resulted in >3 log10 reductions in MRSA and C. difficile spores, respectively. In patient rooms, the colorimetric indicators demonstrated suboptimal delivery of UV-C dosing to shadowed areas, which was improved by providing cycles on each side of the patient bed rather than in a single position and altering device placement. Increasing duration of exposure increased the number of sites achieving adequate dosing to kill C. difficile spores. CONCLUSIONS: Commercial colorimetric indicators provide rapid and easy-to-interpret information on the UV-C dose delivered to sites in patient rooms. The indicators may be useful for training environmental services personnel and optimizing the effectiveness of UV-C room decontamination devices.

Microbial bioburden of inpatient and outpatient areas beyond patient hospital rooms.

OBJECTIVE: To investigate the frequency of environmental contamination in hospital areas outside patient rooms and in outpatient healthcare facilities. DESIGN: Culture survey. SETTING: This study was conducted across 4 hospitals, 4 outpatient clinics, and 1 surgery center. METHODS: We conducted 3 point-prevalence culture surveys for methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, Clostridioides difficile, Candida spp, and gram-negative bacilli including Enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter baumanii, and Stenotrophomonas maltophilia in each facility. In hospitals, high-touch surfaces were sampled from radiology, physical therapy, and mobile equipment and in emergency departments, waiting rooms, clinics, and endoscopy facilities. In outpatient facilities, surfaces were sampled in exam rooms including patient and provider areas, patient bathrooms, and waiting rooms and from portable equipment. Fluorescent markers were placed on high-touch surfaces and removal was assessed 1 day later. RESULTS: In the hospitals, 110 (9.4%) of 1,195 sites were positive for 1 or more bacterial pathogens (range, 5.3%-13.7% for the 4 hospitals) and 70 (5.9%) were positive for Candida spp (range, 3.7%-5.9%). In outpatient facilities, 31 of 485 (6.4%) sites were positive for 1 or more bacterial pathogens (range, 2% to 14.4% for the 5 outpatient facilities) and 50 (10.3%) were positive for Candida spp (range, 3.9%-23.3%). Fluorescent markers had been removed from 33% of sites in hospitals (range, 28.4%-39.7%) and 46.3% of sites in outpatient clinics (range, 7.4%-82.8%). CONCLUSIONS: Surfaces in hospitals outside patient rooms and in outpatient facilities are frequently contaminated with healthcare-associated pathogens. Improvements in cleaning and disinfection practices are needed to reduce contamination.

Effectiveness and real-world materials compatibility of a novel hydrogen peroxide disinfectant cleaner.

A novel 4% hydrogen peroxide disinfectant was effective against methicillin-resistant Staphylococcus aureus (MRSA), Clostridioides difficile spores, carbapenem-resistant Escherichia coli, and 2 strains of Candida auris. In laboratory testing, a sodium hypochlorite disinfectant caused fading and loss of pliability of a hospital mattress, but the hydrogen peroxide disinfectant did not. These findings suggest that the hydrogen peroxide-based disinfectant may be a useful addition to the sporicidal disinfectant products available for use in healthcare settings.

Evaluation of 2 Ultraviolet-C Light Boxes for Decontamination of N95 Respirators.

BACKGROUND: Ultraviolet-C (UV-C) light devices are effective in reducing contamination on N95 filtering facepiece respirators. However, limited information is available on whether UV-C devices meet the Food and Drug Administration's (FDA) microbiological requirements for Emergency Use Authorization (EUA) for respirator bioburden reduction. METHODS: We tested the ability of 2 UV-C light boxes to achieve the 3-log10 microorganism reductions required for EUA for reuse by single users. Whole 3M 1860 or Moldex 1513 respirators were inoculated on the exterior facepiece, interior facepiece, and internal fibers with bacteriophage MS2 and/or 4 strains of bacteria and treated with UV-C cycles of 1 or 20 minutes. Colorimetric indicators were used to assess penetration of UV-C through the respirators. RESULTS: For 1 UV-C box, a 20-minute treatment achieved the required bioburden reduction for Moldex 1513 but not 3M 1860 respirators. For the second UV-C box, a 1-minute treatment achieved the required bioburden reduction in 4 bacterial strains for the Moldex 1513 respirator. Colorimetric indicators demonstrated penetration of UV-C through all layers of the Moldex 1513 respirator but not the 3M 1860 respirator. CONCLUSIONS: Our findings demonstrate that UV-C box technologies can achieve bioburden reductions required by the FDA for EUA for single users but highlight the potential for variable efficacy for different types of respirators.

Timing and route of contamination of hospitalized patient rooms with healthcare-associated pathogens.

OBJECTIVE: To investigate the timing and routes of contamination of the rooms of patients newly admitted to the hospital. DESIGN: Observational cohort study and simulations of pathogen transfer. SETTING: A Veterans' Affairs hospital. PARTICIPANTS: Patients newly admitted to the hospital with no known carriage of healthcare-associated pathogens. METHODS: Interactions between the participants and personnel or portable equipment were observed, and cultures of high-touch surfaces, floors, bedding, and patients' socks and skin were collected for up to 4 days. Cultures were processed for Clostridioides difficile, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant enterococci (VRE). Simulations were conducted with bacteriophage MS2 to assess plausibility of transfer from contaminated floors to high-touch surfaces and to assess the effectiveness of wearing slippers in reducing transfer. RESULTS: Environmental cultures became positive for at least 1 pathogen in 10 (59%) of the 17 rooms, with cultures positive for MRSA, C. difficile, and VRE in the rooms of 10 (59%), 2 (12%), and 2 (12%) participants, respectively. For all 14 instances of pathogen detection, the initial site of recovery was the floor followed in a subset of patients by detection on sock bottoms, bedding, and high-touch surfaces. In simulations, wearing slippers over hospital socks dramatically reduced transfer of bacteriophage MS2 from the floor to hands and to high-touch surfaces. CONCLUSIONS: Floors may be an underappreciated source of pathogen dissemination in healthcare facilities. Simple interventions such as having patients wear slippers could potentially reduce the risk for transfer of pathogens from floors to hands and high-touch surfaces.