Service d'Hygiène Hospitalière, UMR 6249 Chrono-environnement, Centre Hospitalier Régional Universitaire, Université de Franche-Comté, Besançon.
Département DISC, Institut FEMTO-ST, UMR 6174 CNRS, Université de Franche-Comté, Belfort, France.
Clin Infect Dis. 2014 Jun;58(12):1658-65. doi: 10.1093/cid/ciu190. Epub 2014 May 1.
The determinants of the spread of extended-spectrum β-lactamase-producing Escherichia coli (ESBLEC) in the community remain unclear. To evaluate its dissemination in the environment, we analyzed the ESBLEC population throughout an urban wastewater network.
Samples were collected weekly, over a 10-week period, from 11 sites throughout the wastewater network of Besançon city (France). Total E. coli and ESBLEC loads were determined for each sample. As a control, we analyzed 51 clinical ESBLEC isolates collected at our hospital. We genotyped both environmental and clinical ESBLEC by pulsed-field gel electrophoresis and multilocus sequence typing and identified their blaESBL genes by sequencing.
The E. coli load was higher in urban wastewater than in hospital wastewater (7.5 × 10(5) vs 3.5 × 10(5) CFU/mL, respectively). ESBLEC was recovered from almost all the environmental samples and accounted for 0.3% of total E. coli in the untreated water upstream from the wastewater treatment plant (WWTP). The ESBLEC load was higher in hospital wastewater than in community wastewater (27 × 10(3) vs 0.8 × 10(3) CFU/mL, respectively). Treatment by the WWTP eliminated 98% and 94% of total E. coli and ESBLEC, respectively. The genotyping revealed considerable diversity within both environmental and clinical ESBLEC and the overrepresentation of some clonal complexes. Most of the sequence types displayed by the clinical isolates were also found in the environment. CTX-M enzymes were the most common enzymes whatever the origin of the isolates.
The treatment at the WWTP led to the relative enrichment of ESBLEC. We estimated that >600 billion of ESBLEC are released into the river Doubs daily and the sludge produced by the WWTP, used as fertilizer, contains 2.6 × 10(5) ESBLEC per gram.
社区中产超广谱β-内酰胺酶肠杆菌（ESBLEC）传播的决定因素仍不清楚。为了评估其在环境中的传播，我们分析了贝桑松市废水网络中的 ESBLEC 种群。
在 10 周的时间内，每周从贝桑松市废水网络的 11 个地点采集样本。确定每个样本的总大肠杆菌和 ESBLEC 负荷。作为对照，我们分析了我院采集的 51 株临床 ESBLEC 分离株。我们通过脉冲场凝胶电泳和多位点序列分型对环境和临床 ESBLEC 进行基因分型，并通过测序鉴定其 blaESBL 基因。
城市废水中的大肠杆菌负荷高于医院废水中的负荷（分别为 7.5×10(5)和 3.5×10(5)CFU/mL）。从几乎所有环境样本中都回收了 ESBLEC，并且在废水处理厂（WWTP）上游未经处理的水中占总大肠杆菌的 0.3%。医院废水中的 ESBLEC 负荷高于社区废水中的负荷（分别为 27×10(3)和 0.8×10(3)CFU/mL）。WWTP 的处理分别消除了 98%和 94%的总大肠杆菌和 ESBLEC。基因分型显示，无论是环境还是临床 ESBLEC，都存在相当大的多样性，并且某些克隆复合体的代表性过高。临床分离株所表现出的大多数序列类型也存在于环境中。CTX-M 酶无论分离株的来源如何，都是最常见的酶。
WWTP 的处理导致 ESBLEC 的相对富集。我们估计，每天有超过 6000 亿的 ESBLEC 被释放到多尔多涅河中，WWTP 产生的污泥用作肥料，每克含有 2.6×10(5)ESBLEC。
