摘要

       抗生素抗性基因 (ARG) 的存在，包括在栖息于水生环境的大肠杆菌中表达 ESBL 和 AmpC-β-内酰胺酶的那些，是一个严重的健康问题。质粒，整合子，插入序列（IS），和转座子 - 的情况是由以下事实可以ARG游戏细菌物种之间容易地传递与移动遗传元件的帮助下进一步复杂化。因此，与相关联的ARG遗传环境和移动遗传元件的分析很重要，因为这些提供有关这些基因的流行病学的有用信息。在我们之前的研究中，我们报道了存在于穿越德里（印度）国家首都辖区的亚穆纳河的大肠杆菌菌株中存在各种 β-内酰胺抗性基因。在本研究中，我们已经分析了三个参数blaTEM-1的遗传环境那些大肠杆菌菌株的，blaCTX-M-15，和blaCMY -42。 1类整合及其基因盒的结构也进行了分析。插入序列是IS26 blaTEM-1的上游存在，ISEcp1是blaCTXM-15基因和orf477上游存在是本blaCTXM-15的下游。 ISEcp1也blaCMY上游存在-42和，BLC和菅基因是存在于该基因的下游区域。因此，围绕这些基因的总体遗传环境相似，从全局分离的大肠杆菌菌株的报道。转接合子的质粒 DNA 的接合测定、分离和分析表明 blaTEM-1、blaCTX-M-15、blaCMY -42 和 1 类整合子是质粒介导的，可能通过水平基因转移 (HGT) 在属之间传播。这可能导致在水生环境中细菌耐药基因传播。体现在本文的工作是在第一描述BLA和整合的从印度分离水生大肠杆菌遗传环境。

       The presence of antibiotic resistance genes (ARGs) including those expressing ESBLs and AmpC-β-lactamases in Escherichia coli inhabiting the aquatic environments is a serious health problem. The situation is further complicated by the fact that ARGs can be easily transferred among bacterial species with the help of mobile genetic elements – plasmids, integrons, insertion sequences (IS), and transposons. Therefore, the analysis of genetic environment and mobile genetic elements associated with ARGs is important as these provide useful information about the epidemiology of these genes. In our previous study, we had reported presence of various β-lactam resistance genes present in E. coli strains inhabiting the river Yamuna traversing the National Capital Territory of Delhi (India). In the present study, we have analyzed the genetic environment of three ARGs blaTEM-1, blaCTX-M-15, and blaCMY -42 of those E. coli strains. The structure of class 1 integrons and their gene cassettes was also analyzed. Insertion sequence IS26 was present upstream of blaTEM-1, ISEcp1 was present upstream of blaCTXM-15 gene and orf477 was present downstream of blaCTXM-15. ISEcp1 was also present upstream of blaCMY -42 and, blc and sugE genes were present in the downstream region of this gene. Thus, the overall genetic environment surrounding these genes was similar to that reported from E. coli strains isolated globally. Conjugation assays, isolation and analysis of plasmid DNA of the transconjugants indicated that blaTEM-1, blaCTX-M-15, blaCMY -42 and class 1 integron were plasmid-mediated and possibly transmit between genera through horizontal gene transfer (HGT). This might lead to dissemination of antimicrobial resistance genes in aquatic environment. The work embodied in this paper is the first describing the genetic environment of bla and integrons in aquatic E. coli isolated from India.

https://www.frontiersin.org/articles/10.3389/fmicb.2018.00382/full