Hultman Jenni, Tamminen Manu, Pärnänen Katariina, Cairns Johannes, Karkman Antti, Virta Marko
Department of Microbiology, University of Helsinki, Viikinkaari 9, 00014 University of Helsinki, Finland.
Department of Biology, University of Turku, University Hill, 20014 University of Turku, Finland.
FEMS Microbiol Ecol. 2018 Apr 1;94(4). doi: 10.1093/femsec/fiy038.
Wastewater treatment plants (WWTPs) collect wastewater from various sources for a multi-step treatment process. By mixing a large variety of bacteria and promoting their proximity, WWTPs constitute potential hotspots for the emergence of antibiotic resistant bacteria. Concerns have been expressed regarding the potential of WWTPs to spread antibiotic resistance genes (ARGs) from environmental reservoirs to human pathogens. We utilized epicPCR (Emulsion, Paired Isolation and Concatenation PCR) to detect the bacterial hosts of ARGs in two WWTPs. We identified the host distribution of four resistance-associated genes (tetM, int1, qacEΔ1and blaOXA-58) in influent and effluent. The bacterial hosts of these resistance genes varied between the WWTP influent and effluent, with a generally decreasing host range in the effluent. Through 16S rRNA gene sequencing, it was determined that the resistance gene carrying bacteria include both abundant and rare taxa. Our results suggest that the studied WWTPs mostly succeed in decreasing the host range of the resistance genes during the treatment process. Still, there were instances where effluent contained resistance genes in bacterial groups not carrying these genes in the influent. By permitting exhaustive profiling of resistance-associated gene hosts in WWTP bacterial communities, the application of epicPCR provides a new level of precision to our resistance gene risk estimates.
污水处理厂（WWTPs）从各种来源收集废水，进行多步骤处理。通过混合多种细菌并促使它们相互靠近，污水处理厂成为了抗生素耐药菌出现的潜在热点。人们对污水处理厂将抗生素抗性基因（ARGs）从环境库传播到人类病原体的可能性表示担忧。我们利用乳液、配对分离和串联PCR（epicPCR）来检测两个污水处理厂中ARGs的细菌宿主。我们确定了进水和出水中四个抗性相关基因（tetM、int1、qacEΔ1和blaOXA - 58）的宿主分布。这些抗性基因的细菌宿主在污水处理厂进水和出水之间有所不同，出水中的宿主范围总体上呈下降趋势。通过16S rRNA基因测序确定，携带抗性基因的细菌包括丰富和罕见的分类群。我们的结果表明，所研究的污水处理厂在处理过程中大多成功地缩小了抗性基因的宿主范围。然而，仍有一些情况是，出水中含有抗性基因的细菌群体在进水中并不携带这些基因。通过对污水处理厂细菌群落中抗性相关基因宿主进行详尽分析，epicPCR的应用为我们的抗性基因风险评估提供了新的精确水平。
