Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.
Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.
J Glob Antimicrob Resist. 2022 Jun;29:281-288. doi: 10.1016/j.jgar.2022.03.020. Epub 2022 Mar 28.
Hospital-associated infections with vancomycin-resistant Enterococcus faecium (VREfm) have increased dramatically in Denmark. A cornerstone in infection control is effective cleaning and disinfection. This study investigated the survival and resuscitation/growth of clinical isolates of E. faecium exposed to the chlorine-releasing disinfectant, sodium dichloroisocyanurate plus detergent (NaDCC Plus).
To assess biocide efficacy, we modified a method developed to characterise the dose-time-response of bacteria to antibiotics. E. faecium isolates (n = 59) were screened in 96-well plates containing 50-1400 ppm free available chlorine. Bacteria were exposed for 10 min, after which the biocide was inactivated with a neutralizer. Cells were collected by centrifugation, new broth added, and after 20-22 h, viability was recorded as growth/no growth. For a subset of strains the impact of shorter biocide exposure times were examined, as was the influence of longer incubation times.
E. faecium survived exposure to relatively high concentrations of NaDCC Plus, average 415 ppm of free available chlorine (SD ± 78 ppm), compared to recommended in-use concentration (1000 ppm). "Outbreak" clones did not prove more tolerant to NaDCC Plus compared to other VREfm clones, hospital-associated vancomycin-susceptible E. faecium (VSEfm) or community-associated VSEfm. Shorter exposure time and extended incubation time in broth both significantly increased the concentration needed to eradicate E. faecium, with some isolates surviving higher concentrations than the recommended in-use concentration.
Our results indicate that if an exposure time of 10 min is not achieved, the efficacy of the disinfectant will not be sufficient.
丹麦肠球菌医院相关性感染（VREfm）急剧增加。感染控制的基石是有效清洁和消毒。本研究调查了临床分离的屎肠球菌暴露于含氯消毒剂二氯异氰尿酸钠加清洁剂（NaDCC Plus）后的存活和复苏/生长情况。
为了评估杀生物剂的功效，我们修改了一种方法，用于描述细菌对抗生素的剂量-时间反应。在含有 50-1400 ppm 游离有效氯的 96 孔板中筛选屎肠球菌分离株（n=59）。细菌暴露 10 分钟后，用中和剂灭活杀生物剂。通过离心收集细胞，添加新的肉汤，20-22 小时后记录存活/不存活情况。对一部分菌株检查了较短的杀生物剂暴露时间的影响，以及较长的孵育时间的影响。
与推荐的使用浓度（1000 ppm）相比，屎肠球菌相对较高浓度的 NaDCC Plus 暴露后存活，平均游离有效氯浓度为 415 ppm（SD ± 78 ppm）。“暴发”克隆并没有比其他 VREfm 克隆、医院相关的万古霉素敏感屎肠球菌（VSEfm）或社区相关的 VSEfm 对 NaDCC Plus 更耐受。较短的暴露时间和延长的肉汤孵育时间都显著增加了消除屎肠球菌所需的浓度，一些分离株存活的浓度高于推荐的使用浓度。
我们的结果表明，如果不能达到 10 分钟的暴露时间，消毒剂的功效将不足。
