College of Veterinary Medicine, Gansu Agricultural University, Anning District, Lanzhou, Gansu Province, PR China; Key Laboratory of New Animal Drug Project of Gansu Province, Lanzhou, Gansu Province, PR China; Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture, Lanzhou, Gansu Province, PR China; Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, PR China.
Key Laboratory of New Animal Drug Project of Gansu Province, Lanzhou, Gansu Province, PR China; Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture, Lanzhou, Gansu Province, PR China; Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, PR China.
J Glob Antimicrob Resist. 2024 Sep;38:354-362. doi: 10.1016/j.jgar.2024.04.001. Epub 2024 May 23.
Colistin is known as the last resort antibiotic to treat the infections caused by multidrug resistant foodborne pathogens. The emergence and widespread dissemination of plasmid-mediated colistin resistance gene mcr-1 in the Escherichia coli (E. coli) incurs potential threat to public health. Here, we investigated the epidemiology, transmission dynamics, and genetic characterization of mcr-1 harbouring E. coli isolates from poultry originated in Hebei Province, China.
A total of 297 faecal samples were collected from the two large poultry farms in Hebei Province, China. The samples were processed for E. coli identification by matrix-assisted laser desorption ionization-time of flight mass spectrometry and 16S rDNA sequencing. Then, the mcr-1 gene harbouring E. coli strains were identified by polymerase chain reaction and subjected to antimicrobial susceptibility testing by broth microdilution assay. The genomic characterization of the isolates was done by whole genome sequencing using the various bioinformatics tools, and multi-locus sequence typing was done by sequence analysis of the seven housekeeping genes. The conjugation experiment was done to check the transferability of mcr-1 along with the plasmid stability testing.
A total of six mcr-1 E. coli isolates with minimum inhibitory concentration of 4 μg/mL were identified from 297 samples (2.02%). The mcr-1 harbouring E. coli were identified as multidrug resistant and belonged to ST101 (n = 4) and ST410 (n = 2). The genetic environment of mcr-1 presented its position on IncHI2 plasmid in 4 isolates and p0111 in 2 isolates, which is a rarely reported plasmid type for mcr-1. Moreover, both type of plasmids was transferable to recipient J53, and mcr-1 was flanked by 3 mobile elements ISApl1, Tn3, and IS26 forming a novel backbone Tn3-IS26-mcr-1- pap2-ISApl1 on the p0111 plasmid. The phylogenetic analysis shared a common lineage with mcr-1 harbouring isolates from the environment, humans, and animals, which indicate its horizontal spread among the diverse sources, species, and hosts.
This study recommends the one health approach for future surveillance across multiple sources and bacterial species to adopt relevant measures and reduce global resistance crises.
多黏菌素被认为是治疗食源性病原体引起的多重耐药感染的最后手段抗生素。黏菌素耐药基因 mcr-1 质粒介导的出现和广泛传播对公共卫生构成潜在威胁。本研究调查了来自中国河北省家禽源携带 mcr-1 的大肠杆菌（E. coli）的流行病学、传播动态和遗传特征。
本研究共采集了来自中国河北省两个大型家禽养殖场的 297 份粪便样本。通过基质辅助激光解吸电离飞行时间质谱和 16S rDNA 测序对样本进行大肠杆菌鉴定。然后，通过聚合酶链反应鉴定携带 mcr-1 基因的大肠杆菌菌株，并通过肉汤微量稀释法进行药敏试验。使用各种生物信息学工具对分离株进行基因组特征分析，并通过对 7 个看家基因序列分析进行多位点序列分型。通过接合实验检测 mcr-1 及其质粒的可转移性和稳定性。
从 297 份样本中（2.02%）共鉴定出 6 株 mcr-1 大肠杆菌，最低抑菌浓度为 4μg/ml。携带 mcr-1 的大肠杆菌被鉴定为多药耐药菌，属于 ST101（n=4）和 ST410（n=2）。mcr-1 的遗传环境在 4 株菌中位于 IncHI2 质粒上，在 2 株菌中位于 p0111 上，这是 mcr-1 罕见的报道质粒类型。此外，两种类型的质粒都可以转移到受体 J53 上，mcr-1 两侧由 3 个移动元件 ISApl1、Tn3 和 IS26 形成一个新的 Tn3-IS26-mcr-1-pap2-ISApl1 骨架。系统发育分析与环境、人类和动物携带 mcr-1 的分离株具有共同的进化枝，表明其在不同来源、物种和宿主之间水平传播。
本研究建议采用一种健康的方法对来自多个来源和细菌物种的细菌进行监测，以采取相关措施，减少全球耐药危机。
