Che Yongliang, Wu Renjie, Li Hongjie, Wang Longbai, Wu Xuemin, Chen Qiuyong, Chen Rujing, Zhou Lunjiang
Institute of Animal Husbandry and Veterinary Medicine, Fujian Academy of Agricultural Sciences, Fuzhou, China.
Fujian Animal Diseases Control Technology Development Center, Fuzhou, China.
Front Microbiol. 2023 May 16;14:1153740. doi: 10.3389/fmicb.2023.1153740. eCollection 2023.
This study aimed to characterize two novel variants, and , which originated from spp. that were isolated from diseased pigs in China. The spp. carrying novel variants were subjected to whole-genome sequencing (WGS) and phylogenetic analysis based on the 16S rRNA gene. The variants and were characterized using phylogenetic analysis, a comparison of genetic environments, and protein structure prediction. The WGS indicated that two novel variants were located in the chromosomes of three spp. with a genetic environment of -. In addition to the novel colistin resistance genes and , the three spp. contained other antimicrobial resistance genes, including , (O), , , and . A functional cloning assay indicated that either the or gene could confer resistance to colistin in DH5α and JM109. The nucleotide sequences of and presented 95.33 and 95.33% identities, respectively, to . The phylogenetic analysis showed that and were derived from spp. that belonged to subclades that were different from those of the variants ( to except ) originating from Enterobacteriaceae. The deduced amino acid sequences of MCR-1.35 (MCR-1.36) showed 96.67% (96.49%), 82.59% (82.04%), 84.07% (83.52%), 55.52% (55.17%), 59.75% (59.57%), and 61.88% (61.69%) identity to MCR-1.10, MCR-2.2, MCR-6.1, MCR-LIN, MCR-OSL, and MCR-POR, respectively, that originated from sp. Notably, protein structure alignment showed only a few changes in amino acid residues between MCR-1.1 and MCR-1.35, as well as between MCR-1.1 and MCR-1.36. In conclusion, this study identified spp. carrying two novel variants, and , conferring resistance to colistin, which were isolated from pig farms in China. In addition, -like variants were observed to be located in the chromosomes of some species of isolated from pig samples.
本研究旨在鉴定两个新的变体，即变体 和 ，它们源自从中国患病猪中分离出的 菌属。对携带新变体的 菌属进行了全基因组测序（WGS）以及基于16S rRNA基因的系统发育分析。利用系统发育分析、遗传环境比较和蛋白质结构预测对变体 和 进行了鉴定。全基因组测序表明，两个新的变体位于三个 菌属的染色体上，其遗传环境为-。除了新的黏菌素抗性基因 和 外，这三个 菌属还含有其他抗菌抗性基因，包括 、（O）、 、 、和 。功能克隆试验表明， 基因或 基因均可使DH5α和JM109对黏菌素产生抗性。 和 的核苷酸序列与 的同源性分别为95.33%和95.33%。系统发育分析表明， 和 源自 菌属，这些菌属所属的亚分支与源自肠杆菌科的 变体（ 至 ， 除外）不同。推导的MCR-1.35（MCR-1.36）氨基酸序列与源自 菌属的MCR-1.10、MCR-2.2、MCR-6.1、MCR-LIN、MCR-OSL和MCR-POR的同源性分别为96.67%（96.49%）、82.59%（82.04%）、84.07%（83.52%）、55.52%（55.17%）、59.75%（59.57%）和61.88%（61.69%）。值得注意 的是，蛋白质结构比对显示，MCR-1.1与MCR-1.35之间以及MCR-1.1与MCR-1.36之间的氨基酸残基仅有少数变化。总之，本研究鉴定出从中国猪场分离出的携带两个新的 变体（ 和 ）且对黏菌素具有抗性的 菌属。此外，在从猪样本中分离出的一些 菌属的染色体中观察到了类似 的变体。
