摘要

       耐抗生素肠杆菌科和非乳糖发酵革兰氏阴性菌是医院感染的主要原因。滥用抗生素助长了耐药细菌和导致抗生素耐药性 (ARG) 基因的全球传播。有证据表明 ARG 在非临床环境中无处不在，尤其是那些受人为活动影响的环境。然而，对抗生素使用有严格规定的国家的环境中 ARGs 的出现和主要来源尚未得到充分探索。本研究的目的是评估从医院到废水处理厂 (WWTP) 以及瑞典中部下游水生环境的定向连接地点的可培养革兰氏阴性细菌的 ARG 库。使用 qPCR 从选择性培养的大肠菌群和革兰氏阴性菌群中分离的基因组 DNA 中检测到 ARG。结果表明，医院废水是 blaIMP-1、blaIMP-2 和 blaOXA-23 等几种 B 类 β-内酰胺酶基因的蓄水池，但在下游位置未观察到这些基因中的大部分。此外，在下游河水中检测到 blaOXA-48、blaCTX-M-8 和 blaSFC-1、blaV IM-1 和 blaV IM-13 等 β-内酰胺酶基因，但在污水处理厂中未检测到。结果表明，污水处理厂和医院废水是大多数 ARG 的蓄水池，并有助于相关自然环境中 ARG 的多样性。然而，这项研究表明，其他因素也可能对自然环境中 ARGs 的流行和多样性的影响很小。

       Antibiotic-resistant Enterobacteriaceae and non-lactose fermenting Gram-negative bacteria are a major cause of nosocomial infections. Antibiotic misuse has fueled the worldwide spread of resistant bacteria and the genes responsible for antibiotic resistance (ARGs). There is evidence that ARGs are ubiquitous in non-clinical environments, especially those affected by anthropogenic activity. However, the emergence and primary sources of ARGs in the environment of countries with strict regulations for antibiotics usage are not fully explored. The aim of the present study was to evaluate the repertoire of ARGs of culturable Gram-negative bacteria from directionally connected sites from the hospital to the wastewater treatment plant (WWTP), and downstream aquatic environments in central Sweden. The ARGs were detected from genomic DNA isolated from a population of selectively cultured coliform and Gram-negative bacteria using qPCR. The results show that hospital wastewater was a reservoir of several class B β-lactamase genes such as blaIMP-1, blaIMP-2, and blaOXA-23, however, most of these genes were not observed in downstream locations. Moreover, β-lactamase genes such as blaOXA-48, blaCTX-M-8, and blaSFC-1, blaV IM-1, and blaV IM-13 were detected in downstream river water but not in the WWTP. The results indicate that the WWTP and hospital wastewaters were reservoirs of most ARGs and contribute to the diversity of ARGs in associated natural environments. However, this study suggests that other factors may also have minor contributions to the prevalence and diversity of ARGs in natural environments.

https://www.frontiersin.org/articles/10.3389/fmicb.2019.00688/full