Department of Civil Engineering, College of Engineering, University of Kentucky, USA.
Department of Civil Engineering, College of Engineering, University of Kentucky, USA.
Water Res. 2019 Jul 1;158:193-202. doi: 10.1016/j.watres.2019.04.035. Epub 2019 Apr 15.
Infections with Staphylococcus aureus are being spread through contact with the community environment, but the role of wastewater treatment plants in the transmission routes is not defined. This study investigated the prevalence, types, genetic elements, and potential for transmission of S. aureus by these engineered systems. Synchronized sampling events at two wastewater treatment plants were conducted with isolates of S. aureus obtained by a selective enrichment method using acriflavine that suppressed Staphylococcus epidermidis growth. DNA was extracted from a subset of the S. aureus isolates, checked by PCR to assure the absence of S. epidermidis, and sequenced to determine the multilocus sequence type, spa type, and carriage of the methicillin resistance and Panton-Valentine leukocidin genetic elements. Sequences were analyzed for single nucleotide polymorphism differences in pairwise comparison of isolates. There were two dominant S. aureus clonal complexes identified in the isolates, one commonly identified as hospital-related (CC5) and one community-related (CC8). Both types of isolates were found at both treatment facilities, even though only one facility had significant hospital sewage inputs. The presence of S. aureus persisted through treatment, with some isolates recovered from the final processes showing genetic diversity. The presence of the Panton-Valentine leukocidin genetic element was greater than the 1-5% expected from global reports. Our results suggest that treatment provides an opportunity for genetic shift, while the persistence and release of evolved strains of S. aureus may provide an environmentally relevant pathway to new hosts in the environment.
金黄色葡萄球菌感染是通过与社区环境接触传播的，但废水处理厂在传播途径中的作用尚未确定。本研究调查了这些工程系统中金黄色葡萄球菌的流行率、类型、遗传因子以及传播潜力。采用吖啶黄素选择性富集法对来自两个废水处理厂的金黄色葡萄球菌进行同步采样，该方法抑制了表皮葡萄球菌的生长。从金黄色葡萄球菌分离株中提取 DNA，通过 PCR 检查排除表皮葡萄球菌的存在，并进行测序以确定多位点序列型、spa 型以及耐甲氧西林和杀白细胞素基因的携带情况。对分离株的序列进行单核苷酸多态性差异的成对比较分析。从分离株中鉴定出两种主要的金黄色葡萄球菌克隆复合体，一种通常与医院相关（CC5），另一种与社区相关（CC8）。这两种类型的分离株都在两个处理设施中发现，尽管只有一个设施有大量的医院污水输入。金黄色葡萄球菌在处理过程中持续存在，从最终处理过程中回收的一些分离株显示出遗传多样性。杀白细胞素基因的存在大于全球报告中预期的 1-5%。我们的结果表明，处理为遗传转变提供了机会，而金黄色葡萄球菌进化株的持续存在和释放可能为环境中的新宿主提供了一条与环境相关的途径。
