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Quantification of Plasmid-Mediated Antibiotic Resistance in an Experimental Evolution Approach
12:32

Quantification of Plasmid-Mediated Antibiotic Resistance in an Experimental Evolution Approach

Published on: December 14, 2019

Plasmid-mediated quinolone resistance

Luis Martínez-Martínez1, María Eliecer Cano, José Manuel Rodríguez-Martínez

  • 1Service of Microbiology, University Hospital Marqués de Valdecilla, and Department of Molecular Biology, University of Cantabria, Santander, Spain. lmartinez@humv.es

Expert Review of Anti-Infective Therapy
|October 14, 2008
PubMed

Insights

Plasmid-mediated quinolone resistance genes, like qnrA1, protect bacterial enzymes from antibiotics. These genes, along with others conferring resistance through modification or efflux, are widespread in enterobacteria and promote further resistance development.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • The emergence of plasmid-mediated quinolone resistance (PMQR) genes, starting with qnrA1 in 1998, poses a significant challenge in combating bacterial infections.
  • These genes encode proteins that confer resistance by protecting bacterial type II topoisomerases from quinolone antibiotics.

Purpose of the Study:

  • To review the known plasmid-mediated quinolone resistance mechanisms.
  • To discuss the prevalence and implications of these resistance genes in Enterobacteriaceae.

Main Methods:

  • Literature review of identified plasmid-mediated quinolone resistance genes.
  • Analysis of reported mechanisms including target protection, drug modification, and active efflux.
  • Discussion of geographical distribution and prevalence challenges.

Main Results:

  • Several plasmid-mediated quinolone resistance genes (qnrA, qnrB, qnrS, qnrC) and related chromosomal homologs have been identified.
  • Additional mechanisms include quinolone modification by Aac(6)-Ib-cr and active efflux by QepA.
  • These genes are geographically widespread, particularly in Enterobacteriaceae, but their prevalence is underestimated due to detection difficulties.

Conclusions:

  • PMQR genes, despite conferring low-level resistance, play a crucial role in the selection and maintenance of higher-level resistance.
  • Understanding these mechanisms is vital for effective antimicrobial stewardship and the development of new therapeutic strategies.

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