文献类型： 外文期刊

作者： Che, Yongliang ¹ ; Wu, Renjie ¹ ; Li, Hongjie ¹ ; Wang, Longbai ¹ ; Wu, Xuemin ¹ ; Chen, Qiuyong ¹ ; Chen, Rujing ¹ ; Zhou, Lunjiang ¹ ;

作者机构： 1.Fujian Acad Agr Sci, Inst Anim Husb & Vet Med, Fuzhou, Peoples R China

2.Fujian Anim Dis Control Technol Dev Ctr, Fuzhou, Peoples R China

关键词： pig; Moraxella; mcr-1 variant; colistin; resistance; mcr-1; 35; 36

期刊名称：FRONTIERS IN MICROBIOLOGY （ 影响因子：5.2； 五年影响因子：6.2 ）

ISSN：

年卷期： 2023 年 14 卷

页码：

收录情况： SCI

摘要： This study aimed to characterize two novel mcr-1 variants, mcr-1.35 and mcr-1.36, which originated from Moraxella spp. that were isolated from diseased pigs in China. The Moraxella spp. carrying novel mcr-1 variants were subjected to whole-genome sequencing (WGS) and phylogenetic analysis based on the 16S rRNA gene. The mcr-1 variants mcr-1.35 and mcr-1.36 were characterized using phylogenetic analysis, a comparison of genetic environments, and protein structure prediction. The WGS indicated that two novel mcr-1 variants were located in the chromosomes of three Moraxella spp. with a genetic environment of mcr-1-pap2. In addition to the novel colistin resistance genes mcr-1.35 and mcr-1.36, the three Moraxella spp. contained other antimicrobial resistance genes, including aac(3)-IId, tet(O), sul2, floR, and bla(ROB-3). A functional cloning assay indicated that either the mcr-1.35 or mcr-1.36 gene could confer resistance to colistin in Escherichia coli DH5 alpha and JM109. The nucleotide sequences of mcr-1.35 and mcr-1.36 presented 95.33 and 95.33% identities, respectively, to mcr-1.1. The phylogenetic analysis showed that mcr-1.35 and mcr-1.36 were derived from Moraxella spp. that belonged to subclades that were different from those of the mcr-1 variants (mcr-1.1 to mcr-1.34 except mcr-1.10) 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 Moraxella 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 Moraxella spp. carrying two novel mcr-1 variants, mcr-1.35 and mcr-1.36, conferring resistance to colistin, which were isolated from pig farms in China. In addition, mcr-like variants were observed to be located in the chromosomes of some species of Moraxella isolated from pig samples.