摘要
      移动粘菌素耐药性（mcr）基因在全球的出现和传播对公众健康构成了重大威胁，因为粘菌素仍然是耐多药感染的最后一线治疗选择之一。2018年至2020年间，在爱尔兰采集了环境样本（157份水和157份废水）。使用Brilliance ESBL、Brilliance CRE、mSuperCARBA和含有环丙沙星圆盘的McConkey琼脂评估所收集的样品是否存在抗微生物耐药性细菌。在培养之前，对所有水和综合人工湿地进水和出水样品进行过滤，并在缓冲蛋白胨水中富集，而废水样品则直接培养。收集的分离物通过MALDI-TOF进行鉴定，测试对包括粘菌素在内的16种抗菌药物的易感性，随后进行全基因组测序。总体而言，从六个样本（淡水（n=2）、医疗机构废水（n=2个）、污水处理厂进水（n=1个）和综合人工湿地进水（养猪场废物）（n=1））中回收了八种mcr阳性肠杆菌（一种mcr-8和七种mcr-9）。虽然mcr-8阳性的肺炎克雷伯菌对粘菌素表现出耐药性，但所有7种携带肠杆菌的mcr-9仍然易感。所有分离株都表现出多药耐药性，通过全基因组测序分析，发现其携带多种抗微生物耐药性基因，即30±4.1（10–61），包括碳青霉烯酶、blaOXA-48（n=2）和blaNDM-1（n=1），其中三个分离株携带这些基因。mcr基因位于IncHI2、IncFIIK和IncI1样质粒上。这项研究的发现突出了环境中mcr基因的潜在来源和库，并说明需要进一步研究，以更好地了解环境在抗微生物耐药性的持久性和传播中所起的作用。
Abstract
The emergence and dissemination of mobile colistin resistance (mcr) genes across the globe poses a significant threat to public health, as colistin remains one of the last line treatment options for multi-drug resistant infections. Environmental samples (157 water and 157 wastewater) were collected in Ireland between 2018 and 2020. Samples collected were assessed for the presence of antimicrobial resistant bacteria using Brilliance ESBL, Brilliance CRE, mSuperCARBA and McConkey agar containing a ciprofloxacin disc. All water and integrated constructed wetland influent and effluent samples were filtered and enriched in buffered peptone water prior to culture, while wastewater samples were cultured directly. Isolates collected were identified via MALDI-TOF, were tested for susceptibility to 16 antimicrobials, including colistin, and subsequently underwent whole genome sequencing. Overall, eight mcr positive Enterobacterales (one mcr-8 and seven mcr-9) were recovered from six samples (freshwater (n = 2), healthcare facility wastewater (n = 2), wastewater treatment plant influent (n = 1) and integrated constructed wetland influent (piggery farm waste) (n = 1)). While the mcr-8 positive K. pneumoniae displayed resistance to colistin, all seven mcr-9 harbouring Enterobacterales remained susceptible. All isolates demonstrated multi-drug resistance and through whole genome sequencing analysis, were found to harbour a wide variety of antimicrobial resistance genes i.e., 30 ± 4.1 (10–61), including the carbapenemases, blaOXA-48 (n = 2) and blaNDM-1 (n = 1), which were harboured by three of the isolates. The mcr genes were located on IncHI2, IncFIIK and IncI1-like plasmids. The findings of this study highlight potential sources and reservoirs of mcr genes in the environment and illustrate the need for further research to gain a better understanding of the role the environment plays in the persistence and dissemination of antimicrobial resistance.

https://www.sciencedirect.com/science/article/pii/S0048969723012652