摘要

       污水处理厂（WWTP）在传播抗生素耐药性方面起着关键作用，分析其耐药基因（ARGs）和耐药菌的丰度是评价污水处理厂（WWTP）增殖风险的必要条件。由于很少有研究调查抗生素耐药性的季节性变化，本研究旨在确定德国某污水处理厂β-内酰胺酶和mcr基因的丰度，并对季节性耐药菌株进行表型分析。在一年的时间内收集废水、污泥和废水样本，并使用定量实时PCR进行分析。分离出耐药菌株，用VITEK 2进行鉴定和药敏试验。结果表明，与污泥和污水相比，废水中几乎所有被调查的ARGs的发生率都显著提高。废水中的ARG丰度与温度呈负相关，暖、冷季的ARG丰度存在显著差异，显示出季节效应。测定了产超广谱β-内酰胺酶（ESBL）的多重耐药阴沟肠杆菌和大肠杆菌中mcr-1和碳青霉烯酶基因的共现性。据我们所知，这是首次在产ESBL大肠杆菌中检测到mcr-1、blaVIM和blaOXA-48。尽管废水处理降低了ARGs和抗性菌株的丰度，但由于废水中仍存在碳青霉烯酶、CTX-M和mcr-1基因携带菌株，可能会向河流中传播。

        Wastewater treatment plants (WWTP) play a key role in the dissemination of antibiotic resistance and analyzing the abundance of antibiotic resistance genes (ARGs) and resistant bacteria is necessary to evaluate the risk of proliferation caused by WWTPs. Since few studies investigated the seasonal variation of antibiotic resistance, this study aimed to determine the abundance of beta-lactamase and mcr genes and to characterize phenotypic resistant strains in a WWTP in Germany over the seasons. Wastewater, sewage sludge and effluent samples were collected over a one year period and analyzed using quantitative real-time PCR. Resistant strains were isolated, followed by identification and antibiotic susceptibility testing using VITEK 2. The results show a significantly higher occurrence of nearly all investigated ARGs in the wastewater compared to sewage sludge and effluent. ARG abundance and temperature showed a negative correlation in wastewater and significant differences between ARG abundance during warmer and colder seasons were determined, indicating a seasonal effect. Co-occurrence of mcr-1 and carbapenemase genes in a multi-drug resistant Enterobacter cloacae and Escherichia coli producing extended-spectrum beta-lactamase (ESBL) was determined. To the best of our knowledge, this is the first detection of mcr-1, bla_VIM and bla_OXA-48 in an ESBL-producing E. coli. Although wastewater treatment reduced the abundance of ARGs and resistant strains, a dissemination into the river might be possible because carbapenemase-, CTX-M- and mcr-1-gene harboring strains were still present in the effluent.

        https://linkinghub.elsevier.com/retrieve/pii/S0048-9697(20)30007-3