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Characterization of Plasmid-Mediated Quinolone Resistance in Gram-Negative Bacterial Strains from Animals and Humans

Ping Li1, Dan Liu1, Xiuzhong Zhang1

  • 1Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, P.R. China.

Microbial Drug Resistance (Larchmont, N.Y.)
|April 23, 2019
PubMed

Insights

This study investigated plasmid-mediated quinolone resistance (PMQR) genes in common bacteria from China. High prevalence of PMQR genes, particularly in E. coli from livestock, highlights the need for monitoring antimicrobial resistance.

Area of Science:

  • Microbiology
  • Molecular Epidemiology
  • Antimicrobial Resistance

Background:

  • Plasmid-mediated quinolone resistance (PMQR) poses a significant threat to public health.
  • Understanding the prevalence and co-occurrence of PMQR genes in key bacterial species is crucial for effective control strategies.

Purpose of the Study:

  • To determine the molecular epidemiology of PMQR determinants in *Escherichia coli*, *Salmonella enterica*, *Klebsiella pneumoniae*, and *Proteus mirabilis* from various sources in China.
  • To investigate the co-harboring of PMQR genes with other resistance determinants using whole-genome sequencing (WGS).

Main Methods:

  • Collection and screening of 472 bacterial isolates for PMQR genes.
  • Whole-genome sequencing (WGS) of 49 PMQR-positive isolates to analyze co-occurrence of resistance genes.
  • Statistical analysis to compare prevalence and co-occurrence rates across different species and sources.

Main Results:

  • High rates of resistance to tetracycline (93.4%), nalidixic acid (81.5%), and norfloxacin (65.8%) were observed.
  • Predominant PMQRs identified were *aac(6')-Ib-cr* (28.6%) and *oqxAB* (21.4%).
  • PMQR prevalence was significantly higher in *E. coli* from livestock (pigs, poultry) compared to wild animals and dairy cattle.
  • 89.8% of PMQR-positive isolates co-harbored β-lactamase genes, with *bla*CTX-M being dominant.
  • Specific co-occurrence patterns of PMQR and other resistance genes (*oqxAB*, *qnrB*, *fosA*, *bla*DHA-1, *bla*SHV, *qnrD*, *bla*OXA-1, *mcr-1*) were observed in *K. pneumoniae*, *P. mirabilis*, and *E. coli*.

Conclusions:

  • The study reveals a significant prevalence of PMQR determinants in clinically relevant bacteria from China, particularly associated with livestock.
  • WGS analysis highlights extensive co-selection of PMQR with other critical resistance genes, including β-lactamases and colistin resistance (*mcr-1*).
  • Distinct patterns of PMQR gene distribution and co-occurrence in *E. coli*, *K. pneumoniae*, and *P. mirabilis* underscore the need for species-specific surveillance and intervention.
Keywords:
PMQRWGScoexistencegram-negative bacterial strainsmcr-1species preference

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