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Plasmid Dynamics of mcr-1-Positive Salmonella spp. in a General Hospital in China

Authors :
Jianzhong Fan
Linghong Zhang
Jintao He
Maoying Zhao
Belinda Loh
Sebastian Leptihn
Yunsong Yu
Xiaoting Hua
Source :
Frontiers in Microbiology, Vol 11 (2020)
Publication Year :
2020
Publisher :
Frontiers Media S.A., 2020.

Abstract

Salmonella is an important food pathogen that can cause severe gastroenteritis with more than 600,000 deaths globally every year. Colistin (COL), a last-resort antibiotic, is ineffective in bacteria that carry a functional mcr-1 gene, which is often spread by conjugative plasmids. Our work aimed to understand the prevalence of the mcr-1 gene in clinical isolates of Salmonella, as the frequency of occurrence of the mcr-1 gene is increasing globally. Therefore, we analyzed 689 clinical strains, that were isolated between 2009 and late 2018. The mcr-1 gene was found in six strains, which we analyzed in detail by whole genome sequencing and antibiotic susceptibility testing, while we also provide the clinical information on the patients suffering from an infection. The genomic analysis revealed that five strains had plasmid-encoded mcr-1 gene located in four IncHI2 plasmids and one IncI2 plasmid, while one strain had the chromosomal mcr-1 gene originated from plasmid. Surprisingly, in two strains the mcr-1 genes were inactive due to disruption by insertion sequences (ISs): ISApl1 and ISVsa5. A detailed analysis of the plasmids revealed a multitude of ISs, most commonly IS26. The IS contained genes that meditate broad resistance toward most antibiotics underlining their importance of the mobile elements, also with respect to the spread of the mcr-1 gene. Our study revealed potential reservoirs for the transmission of COL resistance and offers insights into the evolution of the mcr-1 gene in Salmonella.

Details

Language :
English
ISSN :
1664302X
Volume :
11
Database :
Directory of Open Access Journals
Journal :
Frontiers in Microbiology
Publication Type :
Academic Journal
Accession number :
edsdoj.ba92bd48ad3a45d98772f9897a8a0074
Document Type :
article
Full Text :
https://doi.org/10.3389/fmicb.2020.604710