摘要

        可传播的质粒和整合子可能通过积累抗生素耐药基因（ARG）在水环境中的持续和传播发挥重要作用。从139株耐药大肠杆菌中提取质粒，经PCR扩增和DNA测序证实1、2类整合子（intI）、动员（mob）、磺胺甲恶唑耐药（sul）和甲氧苄啶耐药（dfr）基因。E、 此前，在阿肯色州西北部的污水处理厂废水和接受溪水的废水中已回收出大肠杆菌，分离出的大肠杆菌对1-6种抗生素产生了耐药性。几乎一半的分离株（47%）携带假定可传播的质粒，其中mobF12基因是最常检测到的动员基因。当每个分离物检测到两个或三个mob基因时，群体中的多药耐药（MDR）数量显著增加。1类和/或2类整合子普遍存在（46%），整合子的存在显著地使分离群体向更大的MDR数转移。与对各自抗生素的体外耐药相比，更多的菌株携带两个或三个sul基因（99.3%）的单一或共存，以及单个或组合多达五个dfr基因（89.3%）。这些发现不仅表明废水处理废水和河流环境在多重耐药大肠杆菌群体中ARG与可传播质粒和整合子的共同聚集中的作用，而且还表明分离物中sul和dfr抗性基因的密度可以作为移动MDR的生物标记将军。

         Transmissible plasmids and integrons may play important roles in the persistence and spread of antibiotic-resistant bacteria throughout aquatic environment by accumulating antibiotic resistance genes (ARG). Class 1 and class 2 integron (intI), mobilization (mob), sulfamethoxazole resistance (sul), and trimethoprim resistance (dfr) genes were PCR-amplified and confirmed through DNA sequencing following plasmid extraction from 139 antibiotic-resistant Escherichia coli. E. coli had previously been recovered from wastewater treatment plant effluent and receiving stream water in Northwest Arkansas and isolates had expressed resistance to one to six antibiotics. Almost half of the total isolates (47%) carried putatively transmissible plasmids with mob_F12 gene as the most frequently detected mobilization gene. When two or three mob genes were detected per isolate, there was a significant shift in the population toward larger multiple drug resistance (MDR) number. Class 1 and/or 2 integrons were prevalent (46%), and the presence of integron significantly shifted the isolate population toward larger MDR number. More isolates carried single or coexistence of two or three sul genes (99.3%), and single or a combination up to five dfr genes (89.3%) than had exhibited in vitro resistance to the respective antibiotics. These findings indicate not only the role of the wastewater treatment effluent and the stream environment in coaccumulation of ARG with transmissible plasmids and integrons in multiple antibiotic-resistant E. coli populations but also suggest that density of sul and dfr resistance genes within an isolate may serve as a biomarker for mobile MDR in general.

         https://www.liebertpub.com/doi/abs/10.1089/mdr.2016.0329?rfr_dat=cr_pub%3Dpubmed&url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&journalCode=mdr