Dissection of Highly Prevalent <i>qnrS1</i>-Carrying IncX Plasmid Types in Commensal <i>Escherichia coli</i> from German Food and Livestock
Plasmids are mobile genetic elements, contributing to the spread of resistance determinants by horizontal gene transfer. Plasmid-mediated quinolone resistances (PMQRs) are important determinants able to decrease the antimicrobial susceptibility of bacteria against fluoroquinolones and quinolones. Th...
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| Main Authors: | , , , , , |
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| Format: | Book |
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MDPI AG,
2021-10-01T00:00:00Z.
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| Summary: | Plasmids are mobile genetic elements, contributing to the spread of resistance determinants by horizontal gene transfer. Plasmid-mediated quinolone resistances (PMQRs) are important determinants able to decrease the antimicrobial susceptibility of bacteria against fluoroquinolones and quinolones. The PMQR gene <i>qnrS1</i>, especially, is broadly present in the livestock and food sector. Thus, it is of interest to understand the characteristics of plasmids able to carry and disseminate this determinant and therewith contribute to the resistance development against this class of high-priority, critically important antimicrobials. Therefore, we investigated all commensal <i>Escherichia</i> (<i>E</i>.) <i>coli</i> isolates, with reduced susceptibility to quinolones, recovered during the annual zoonosis monitoring 2017 in the pork and beef production chain in Germany (n = 2799). Through short-read whole-genome sequencing and bioinformatics analysis, the composition of the plasmids and factors involved in their occurrence were determined. We analysed the presence and structures of predominant plasmids carrying the PMQR <i>qnrS1</i>. This gene was most frequently located on IncX plasmids. Although the <i>E. coli</i> harbouring these IncX plasmids were highly diverse in their sequence types as well as their phenotypic resistance profiles, the IncX plasmids-carrying the <i>qnrS1</i> gene were rather conserved. Thus, we only detected three distinct IncX plasmids carrying <i>qnrS1</i> in the investigated isolates. The IncX plasmids were assigned either to IncX1 or to IncX3. All <i>qnrS1</i>-carrying IncX plasmids further harboured a β-lactamase gene (<i>bla</i>). In addition, all investigated IncX plasmids were transmissible. Overall, we found highly heterogenic <i>E. coli</i> harbouring conserved IncX plasmids as vehicles for the most prevalent <i>qnr</i> gene <i>qnrS1</i>. These IncX plasmids may play an important role in the dissemination of those two resistance determinants and their presence, transfer and co-selection properties require a deeper understanding for a thorough risk assessment. |
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| Item Description: | 10.3390/antibiotics10101236 2079-6382 |