Clonal spread of mcr-1 in PMQR-carrying ST34 Salmonella isolates from animals in China.
Clonal spread of mcr-1 in PMQR-carrying ST34 Salmonella isolates from animals in China.
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DOI：
10.1038/srep38511
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发表时间：
2016-12-05
影响因子：
4.6
通讯作者：
Sun J
中科院分区：
文献类型：
--
作者：
Li XP;Fang LX;Song JQ;Xia J;Huo W;Fang JT;Liao XP;Liu YH;Feng Y;Sun J
肠杆菌科细菌中质粒介导的粘菌素耐药基因mcr-1自在我国首次发现以来，其广泛的地理分布引起了人们的极大关注。本研究中，共有22株肠道沙门氏菌对粘菌素耐药，而只有5株属于ST 34肠道沙门氏菌血清型鼠伤寒沙门氏菌。鼠伤寒沙门氏菌）为mcr-1阳性。其中4株的PFGE分型基本相同，但寄主种类和地理分布不同。所有mcr-1阳性的S.鼠伤寒沙门氏菌表现出多重耐药表型，除粘菌素外，还包括氨苄青霉素、链霉素、庆大霉素、氟苯尼考、萘啶酸、四环素、甲氧苄啶-磺胺甲氧。oqxAB和aac（6′）-Ib-cr基因分别在4株（80.0%）和5株（100%）中单独或联合存在。在4种遗传相关菌株中，mcr-1基因位于可转移的IncI 2质粒上。在另一株菌株中，mcr-1位于约190 kb IncHI 2质粒上。总之，我们报告了5例mcr-1阳性的S。鼠伤寒/ST 34分离株。IncI 2型质粒的克隆扩增和水平传播均参与了中国食品动物源肠道沙门氏菌mcr-1基因的传播。非常需要监测mcr-1基因的潜在传播。
Since initial identification in China, the widespread geographical occurrence of plasmid-mediated colistin resistance gene mcr-1 in Enterobacteriaceae has been of great concern. In this study, a total of 22 Salmonella enterica were resistant to colistin, while only five isolates which belonged to ST34 Salmonella enterica serovar Typhimurium (S. Typhimurium) were mcr-1 positive. Four of them shared nearly identical PFGE type, although they were from different host species and diverse geographical locations. All the mcr-1-positive S. Typhimurium exhibited multi-resistant phenotypes including ampicillin, streptomycin, gentamicin, florfenicol, nalidixic acid, tetracycline, trimethoprim-sulfamethox, in addition to colistin. The oqxAB and aac(6′)-Ib-cr genes were present alone or in combination in four (80.0%) and five (100%) isolates, respectively. The mcr-1 gene was located on a transferable IncI2 plasmid in the four genetically related strains. In the other one strain, mcr-1 was located on an approximately 190 kb IncHI2 plasmid. In conclusion, we report five mcr-1-positive S. Typhimurium/ST34 isolates. Both clonal expansion and horizontal transmission of IncI2-type plasmids were involved in the spread of the mcr-1 gene in Salmonella enterica from food-producing animals in China. There is a great need to monitor the potential dissemination of the mcr-1 gene.