The global emergence of plasmid-mediated colistin resistance (Col-R) conferred by mcr genes in gram-negative rods (GNRs) has jeopardized the last treatment option for multidrug-resistant bacterial infections in humans. This study aimed to assess the emergence of mcr gene-mediated Col-R in GNRs isolated from humans and animals in Pakistan. Animal and clinical specimens collected from various sources were prospectively analysed using standard microbiological procedures. Pathogens were identified using the API 20E and API 20NE systems (bioMerieux). Minimum inhibitory concentration (MIC) against colistin was determined using the MIC detection methods, and multiplex polymerase chain reaction (PCR) was used to amplify the mcr-1 to mcr-5 genes. We isolated 126 (88.1%) animal and 17 (11.9%) human Col-R phenotypes, among which there was a significant association (P < 0.01) of Escherichia coli and Proteus mirabilis with animals and of Acinetobacter baumannii with humans. Animal strains exhibited statistically significant (P < 0.05) resistance to co-trimoxazole, chloramphenicol, and moxifloxacin, and the human pathogens exhibited statistically significant (P < 0.05) antibiotic resistance to cephalosporins, carbapenems, and piperacillin-tazobactam. For Col-R strains, MIC50 values were > 6 µg/mL and > 12 µg/mL for human and animal isolates, respectively. mcr genes were detected in 110 (76.9%) bacterial strains, of which 108 (98.2%) were mcr-1 and 2 (1.8%) were mcr-2. The detection of a considerable number of mcr-1 and mcr-2 genes in animals is worrisome, as they are now being detected in clinical pathogens. The acquisition of mcr genes by colistin-susceptible bacteria could leave us in a post-antibiotic era.

中文翻译：

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人-动物界面上革兰氏阴性细菌质粒介导的mcr基因的出现

革兰氏阴性杆菌（GNR）中的mcr基因赋予的质粒介导的大肠菌素抗性（Col-R）的全球出现，危及了人类对多药耐药细菌感染的最后一种治疗选择。这项研究旨在评估由mcr基因介导的Col-R在分离自巴基斯坦人和动物的GNR中的出现。使用标准微生物程序对从各种来源收集的动物和临床标本进行前瞻性分析。使用API​​ 20E和API 20NE系统（bioMerieux）鉴定病原体。使用MIC检测方法确定针对大肠菌素的最小抑制浓度（MIC），并使用多重聚合酶链反应（PCR）扩增mcr-1至mcr-5基因。我们分离了126种（88.1％）动物和17种（11.9％）人类Col-R表型，其中大肠杆菌和奇异变形杆菌与动物之间存在显着关联（P <0.01），而鲍曼不动杆菌与人之间存在显着关联（P <0.01）。动物品系对协三唑，氯霉素和莫西沙星显示出统计学上的显着（P <0.05）耐药性，人类病原体对头孢菌素，碳青霉烯和哌拉西林-他唑巴坦显示出统计学上显着（P <0.05）的抗生素抗性。对于Col-R菌株，人和动物分离株的MIC50值分别> 6 µg / mL和> 12 µg / mL。在110（76.9％）个细菌菌株中检​​测到mcr基因，其中108（98.2％）个是mcr-1，2个（1.8％）是mcr-2。由于目前正在临床病原体中检测到它们，因此在动物中检测到大量的mcr-1和mcr-2基因令人担忧。