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Abstract Background Environmental surface decontamination is a crucial tool to prevent the spread of infections in hospitals. However, manual cleaning and disinfection may be insufficient to eliminate pathogens from contaminated surfaces. Ultraviolet-C (UV-C) irradiation deploying autonomous disinfection devices, i.e. robots, are increasingly advertised to complement standard decontamination procedures with concurrent reduction of time and workload. Although the principle of UV-C based disinfection is proven, little is known about the operational details of UV-C disinfection delivered by robots. To explore the impact of a UV-C disinfection robot in the clinical setting, we investigated its usability and the effectiveness as an add-on to standard environmental cleaning and disinfection. Additionally, its effect on Candida auris, a yeast pathogen resistant to antifungals and disinfectants, was studied. Methods After setting the parameters “surface distance” and “exposure time” for each area as given by the manufacturer, the robot moved autonomously and emitted UV-C irradiation in the waiting areas of two hospital outpatient clinics after routine cleaning and/or disinfection. To quantify the efficacy of the robotic UV-C disinfection, we obtained cultures from defined sampling sites in these areas at baseline, after manual cleaning/disinfection and after the use of the robot. Four different C. auris strains at two concentrations and either in a lag or in a stationary growth phase were placed in these areas and exposed to UV-C disinfection as well. Results The UV-C irradiation significantly reduced the microbial growth on the surfaces after manual cleaning and disinfection. C. auris growth in the lag phase was inhibited by the UV-C irradiation but not in the presence of the rim shadows. The effects on C. auris in the stationary phase were differential, but overall C. auris strains were not effectively killed by the standard UV-C disinfection cycle. Regarding usability, the robot’s interface was not intuitive, requiring advanced technical knowledge or intensive training prior to its use. Additionally, the robot required interventions by the technical operator during the disinfection process, e.g. stopping due to unforeseen minor dislocation of items during the clinical service or due to moving individuals, making it a delicate high-tech device but not yet ready for the autonomous use in the clinical routine. Conclusions Presently, the UV-C robot tested in this study is not ready to be integrated in the environmental cleaning and disinfection procedures in our hospital. The single standard disinfection UV-C irradiation cycle is not sufficient to inactivate pathogens with augmented environmental resilience, e.g. C. auris, particularly when microbial loads are high.

Background: Carbapenemase-producing enterobacteriaceae (CPE) are a major threat for severely ill patients. However, only limited data on the epidemiology and on evidence-based infection prevention and control measures are available. The aim of this study was to investigate the epidemiology of patients with CPE, characterizing the CPE isolates by their resistance mechanisms and genetic similarity, to explore risk factors for their acquisition, and to evaluate the effectiveness of the current CPE infection control measures., Methods: A retrospective case-control study was performed using data from 2011 to 2016 in a 1800-bed academic hospital in Central Europe, where risk-based screening at patients´ admission is performed. Carbapenem resistance mechanisms of all carbapenem resistant enterobacteriaceae from patients admitted during this period were investigated. Clinical data of the CPE-positive patients were analysed and compared to a matched control group (case-control ratio of 1:3). We performed univariate and multivariate statistical analysis to identify risk factors for CPE acquisition., Results: Of 621,623 admitted patients in the study period, 75 patients with carriage of carbapenem resistant enterobacteriaceae were included (0.12/1000 admittances). Carbapenemase-encoding genes were detected in 77.3% (58/75) of patients with carbapenem-resistant enterobacteriaceae. The enzyme bla OXA-48 was found in 34.5% (20/58), bla KPC in 29.3% (17/58), bla NDM enzymes in 20.7% (12/58) and bla VIM in 8.6% (5/58) of the isolates. The overall mortality among CPE patients was 25.9% (15/58) and attributable mortality of CPE was 53.3% (8/15). Multivariate analysis revealed four risk factors to be independent predictors of CPE carriage: the length of hospital admission > 20 days (AOR: 4.9, 95% CI: 1.4-15.5; P  <  0.001), hospital admission within the previous year (AOR: 22.3, 95% CI: 3.9-88.4; P <  0.001), exposure to a healthcare facility in a country with high or unknown carbapenem-resistant enterobacteriaceae prevalence 3 months before admission (AOR: 11.8, 95% CI: 2.2-63.2; P  <  0.01) and the use of antibiotics longer than 10 days (AOR: 5.2, 95% CI: 1.4-35.9; P  <  0.05). The current risk-based screening strategy at hospital admission could not identify 37 (63.8%) of the 58 CPE-positive patients. Epidemiological investigation and genotyping revealed that no outbreaks due to CPE occurred during this period., Conclusion: Overall, the CPE carriage rate in patients was very low, the attributable mortality, however, is alarming (53%). Bla OXA-48 and bla KPC were the main cause of carbapenem resistance in enterobacteriaceae. Although the strict application of standard infection control measures was effective for prevention of outbreaks in this setting, an enlarged risk based targeted screening strategy has to be implemented., Competing Interests: Competing interestsThe authors declare that they have no competing interests., (© The Author(s). 2020.)