Université de Caen Basse-Normandie, EA4655, CHU de Caen, Caen, France.
Appl Environ Microbiol. 2013 Apr;79(7):2428-34. doi: 10.1128/AEM.03586-12. Epub 2013 Feb 1.
To determine if hospital effluent input has an ecological impact on downstream aquatic environment, antibiotic resistance in Enterococcus spp. along a medical center-retirement home-wastewater treatment plant-river continuum in France was determined using a culture-based method. Data on antibiotic consumption among hospitalized and general populations and levels of water contamination by antibiotics were collected. All isolated enterococci were genotypically identified to the species level, tested for in vitro antibiotic susceptibility, and typed by multilocus sequence typing. The erm(B) and mef(A) (macrolide resistance) and tet(M) (tetracycline resistance) genes were detected by PCR. Along the continuum, from 89 to 98% of enterococci, according to the sampled site, were identified as Enterococcus faecium. All E. faecium isolates from hospital and retirement home effluents were multiply resistant to antibiotics, contained erm(B) and mef(A) genes, and belonged to hospital-adapted clonal complex 17 (CC17). Even though this species remained dominant in the downstream continuum, the relative proportion of CC17 isolates progressively decreased in favor of other subpopulations of E. faecium that were more diverse, less resistant to antibiotics, and devoid of the classical macrolide resistance genes and that belonged to various sequence types. Antibiotic concentrations in waters were far below the MICs for susceptible isolates. CC17 E. faecium was probably selected in the gastrointestinal tract of patients under the pressure of administered antibiotics and then excreted together with the resistance genes in waters to progressively decrease along the continuum.
为了确定医院污水排放是否对下游水生环境产生生态影响，研究人员采用基于培养的方法，检测了法国一个医疗中心-养老院-污水处理厂-河流连续体中肠球菌属的抗生素耐药性。收集了住院人群和普通人群的抗生素使用数据以及抗生素污染水平的数据。所有分离的肠球菌均进行了种水平的基因分型鉴定、体外抗生素药敏试验和多位点序列分型。通过 PCR 检测 erm(B)和 mef(A)（大环内酯类耐药）和 tet(M)（四环素耐药）基因。根据采样地点，连续体中 89%至 98%的肠球菌被鉴定为屎肠球菌。来自医院和养老院污水的所有屎肠球菌分离株均对多种抗生素具有耐药性，含有 erm(B)和 mef(A)基因，属于医院适应的克隆复合体 17（CC17）。尽管该物种在下游连续体中仍然占主导地位，但 CC17 分离株的相对比例逐渐减少，有利于其他多样性更高、抗生素耐药性更低、缺乏经典大环内酯类耐药基因且属于各种序列类型的屎肠球菌亚群。水中的抗生素浓度远低于敏感分离株的 MIC。CC17 屎肠球菌可能在接受抗生素治疗的患者的胃肠道中受到抗生素的选择压力，然后与耐药基因一起排泄到水中，并沿着连续体逐渐减少。
