Limbach Analytics GmbH, D-68229 Mannheim, Germany.
Division of Nosocomial Pathogens and Antibiotic Resistances, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, D-38855 Wernigerode, Germany.
Sci Total Environ. 2023 Sep 10;890:164179. doi: 10.1016/j.scitotenv.2023.164179. Epub 2023 May 16.
Carbapenemase-producing bacteria (CPB) such as Klebsiella pneumoniae and Escherichia coli are causing hospital outbreaks worldwide. An important transfer route into the aquatic environment is the urban water cycle. We aimed to determine the presence of CPB in hospital wastewater, wastewater treatment plants (WWTPs) and surface waters in a German metropolitan area and to characterise these bacteria by whole-genome comparisons. During two periods in 2020, 366 samples were collected and cultivated on chromogenic screening media. Bacterial colonies were selected for species identification and PCR-based carbapenemase gene screening. Genomes of all detected CPB were sequenced and analysed for resistance gene content, followed by multilocus sequence typing (MLST) and core genome MLST (cgMLST) for K. pneumoniae and E. coli isolates. Carbapenemase genes were detected in 243 isolates, most of which belonged to genera/species Citrobacter spp. (n = 70), Klebsiella spp. (n = 57), Enterobacter spp. (n = 52) and E. coli (n = 42). Genes encoding KPC-2 carbapenemase were detected in 124 of 243 isolates. K. pneumoniae produced mainly KPC-2 and OXA-232 whereas E. coli harboured various enzymes (KPC-2, VIM-1, OXA-48, NDM-5, KPC-2 + OXA-232, GES-5, GES-5 + VIM-1, IMP-8 + OXA-48). Eight and twelve sequence types (STs) were identified for K. pneumoniae and E. coli, respectively, forming different clusters. The detection of numerous CPB species in hospital wastewater, WWTPs and river water is of concern. Genome data highlight a hospital-specific presence of distinct carbapenemase-producing K. pneumoniae and E. coli strains belonging to "global epidemic clones" in wastewater samples representing local epidemiology. The various detected CPB species including E. coli ST635, which is not known to cause human infections, could serve as reservoirs/vectors for the spread of carbapenemase genes in the environment. Therefore, effective pretreatment of hospital wastewater prior to discharge into the municipal wastewater system may be required, although swimming lakes do not appear to be a relevant risk factor for CPB ingestion and infection.
产碳青霉烯酶细菌（CPB），如肺炎克雷伯菌和大肠杆菌，正在全球范围内引发医院疫情。一个重要的转移途径是城市水循环。我们旨在确定德国大都市地区医院废水、废水处理厂（WWTP）和地表水是否存在 CPB，并通过全基因组比较来描述这些细菌。在 2020 年的两个时期，采集了 366 个样本，并在显色筛选培养基上进行培养。选择细菌菌落进行种属鉴定和基于 PCR 的碳青霉烯酶基因筛选。所有检测到的 CPB 基因组均进行测序，并分析耐药基因含量，随后对肺炎克雷伯菌和大肠杆菌分离株进行多位点序列分型（MLST）和核心基因组 MLST（cgMLST）。在 243 个分离株中检测到碳青霉烯酶基因，其中大多数属于柠檬酸杆菌属（n=70）、肺炎克雷伯菌属（n=57）、肠杆菌属（n=52）和大肠杆菌属（n=42）。在 243 个分离株中，有 124 个检测到编码 KPC-2 碳青霉烯酶的基因。产碳青霉烯酶的肺炎克雷伯菌主要产生 KPC-2 和 OXA-232，而大肠杆菌则携带各种酶（KPC-2、VIM-1、OXA-48、NDM-5、KPC-2+OXA-232、GES-5、GES-5+VIM-1、IMP-8+OXA-48）。鉴定出肺炎克雷伯菌和大肠杆菌分别有 8 种和 12 种序列类型（ST），形成不同的簇。在医院废水、WWTP 和河水样本中检测到多种 CPB 物种令人担忧。基因组数据突出显示，在代表当地流行病学的废水样本中，存在特定于医院的、具有独特碳青霉烯酶的肺炎克雷伯菌和大肠杆菌菌株，属于“全球流行克隆”。包括尚未知是否引起人类感染的大肠杆菌 ST635 在内的各种检测到的 CPB 物种可能成为环境中碳青霉烯酶基因传播的储层/载体。因此，可能需要在将医院废水排放到城市污水系统之前对其进行有效预处理，尽管游泳湖泊似乎不是 CPB 摄入和感染的相关危险因素。
