Laboratoire Génétique Moléculaire, Génomique et Microbiologie, UMR7156, CNRS-Université de Strasbourg, Strasbourg, France.
Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France.
Environ Sci Pollut Res Int. 2018 Jan;25(2):1470-1483. doi: 10.1007/s11356-017-0535-8. Epub 2017 Oct 31.
Several studies have suggested the existence of a close relationship between antibiotic-resistant phenotypes and resistance to other toxic compounds such as heavy metals, which involve co-resistance or cross-resistance mechanisms. A metagenomic library was previously constructed in Escherichia coli with DNA extracted from the bacterial community inhabiting an acid mine drainage (AMD) site highly contaminated with heavy metals. Here, we conducted a search for genes involved in antibiotic resistance using this previously constructed library. In particular, resistance to antibiotics was observed among five clones carrying four different loci originating from CARN5 and CARN2, two genomes reconstructed from the metagenomic data. Among the three CARN2 loci, two carry genes homologous to those previously proposed to be involved in antibiotic resistance. The third CARN2 locus carries a gene encoding a membrane transporter with an unknown function and was found to confer bacterial resistance to rifampicin, gentamycin, and kanamycin. The genome of Thiomonas delicata DSM 16361 and Thiomonas sp. X19 were sequenced in this study. Homologs of genes carried on these three CARN2 loci were found in these genomes, two of these loci were found in genomic islands. Together, these findings confirm that AMD environments contaminated with several toxic metals also constitute habitats for bacteria that function as reservoirs for antibiotic resistance genes.
已有多项研究表明，抗生素耐药表型与其他有毒化合物（如重金属）的耐药性之间存在密切关系，这涉及共耐药或交叉耐药机制。先前曾用从富含重金属的酸性矿山排水（AMD）地点栖息的细菌群落中提取的 DNA 在大肠杆菌中构建了一个宏基因组文库。在这里，我们使用这个先前构建的文库来搜索与抗生素耐药性相关的基因。特别地，在携带四个来自 CARN5 和 CARN2 的不同基因座的五个克隆中观察到了抗生素耐药性，这两个基因座是从宏基因组数据重建的两个基因组。在三个 CARN2 基因座中，有两个携带与先前提出的与抗生素耐药性相关的基因同源的基因。第三个 CARN2 基因座携带一个编码具有未知功能的膜转运蛋白的基因，被发现赋予细菌对利福平、庆大霉素和卡那霉素的耐药性。本研究还对 Thiomonas delicata DSM 16361 和 Thiomonas sp. X19 的基因组进行了测序。在这些基因组中发现了携带这三个 CARN2 基因座的基因的同源物，其中两个基因座位于基因组岛上。这些发现共同证实，富含多种有毒金属的 AMD 环境也是作为抗生素耐药基因库的细菌的栖息地。
