Kitagawa Hiroki, Tadera Kayoko, Hara Toshinori, Kashiyama Seiya, Mori Minako, Ohge Hiroki
Project Research Center for Nosocomial Infectious Diseases, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan; Department of Surgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan.
Project Research Center for Nosocomial Infectious Diseases, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan; Section of Clinical Laboratory, Department of Clinical Support, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan.
Infect Dis Health. 2020 Aug;25(3):181-185. doi: 10.1016/j.idh.2020.03.001. Epub 2020 Apr 11.
Contamination of healthcare environments by multidrug-resistant organisms (MDRO) and Clostridioides difficile is a risk for healthcare-associated infections. The efficacy of pulsed xenon ultraviolet (PX-UV) disinfection in healthcare environments has been described previously. However, there are few reports about PX-UV disinfection in Japan. The aim of this study was to investigate in vitro the efficacy of PX-UV disinfection of MDRO and C. difficile spores commonly isolated in Japanese hospitals.
We investigated reductions in microbial counts after exposure to PX-UV of the following clinically-isolated organisms on seeding agar plates: methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium, carbapenemase-producing Klebsiella pneumoniae, extended spectrum β-lactamase-producing Escherichia coli, multidrug resistant Acinetobacter baumannii, and C. difficile spores. We also visually assessed the attenuation of disinfection by shielding of MRSA and carbapenemase-producing K. pneumoniae from PX-UV exposure.
PX-UV disinfection for 5 min induced >5-log colony-forming units (CFU)/cm growth inhibition of all the MDRO. PX-UV disinfection for 15 min induced >3-log CFU/cm growth inhibition of C. difficile spores. Where a plate was shielded from PX-UV exposure the bacteria showed confluent growth, but no colonies were observed on unshielded (exposed) parts of the plates.
This study shows the efficacy of PX-UV disinfection against clinical MDROs. C. difficile spores were more resistant to PX-UV disinfection than vegetative bacteria. Further evaluation of the efficacy of PX-UV disinfection in reducing the contamination of real-world surfaces and the incidence of healthcare-associated infections is needed.
耐多药微生物（MDRO）和艰难梭菌对医疗环境的污染是医疗相关感染的一个风险因素。此前已有关于脉冲氙气紫外线（PX-UV）消毒在医疗环境中效果的描述。然而，在日本关于PX-UV消毒的报道较少。本研究的目的是在体外研究PX-UV对日本医院中常见分离出的MDRO和艰难梭菌孢子的消毒效果。
我们研究了接种在琼脂平板上的以下临床分离菌暴露于PX-UV后微生物数量的减少情况：耐甲氧西林金黄色葡萄球菌（MRSA）、耐万古霉素粪肠球菌、产碳青霉烯酶肺炎克雷伯菌、产超广谱β-内酰胺酶大肠杆菌、多重耐药鲍曼不动杆菌以及艰难梭菌孢子。我们还通过遮挡MRSA和产碳青霉烯酶肺炎克雷伯菌使其不暴露于PX-UV，直观评估消毒效果的减弱情况。
PX-UV消毒5分钟可使所有MDRO的菌落形成单位（CFU）/厘米生长抑制>5个对数级。PX-UV消毒15分钟可使艰难梭菌孢子的CFU/厘米生长抑制>3个对数级。在平板被遮挡使其不暴露于PX-UV的地方，细菌呈融合生长，但在平板未遮挡（暴露）的部分未观察到菌落。
本研究表明PX-UV对临床MDRO具有消毒效果。艰难梭菌孢子比营养细菌对PX-UV消毒更具抗性。需要进一步评估PX-UV消毒在减少实际环境表面污染和医疗相关感染发生率方面的效果。
