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Emergence of plasmid-mediated resistance to quinolones in Enterobacteriaceae

Patrice Nordmann1, Laurent Poirel

  • 1Service de Bactériologie-Virologie, Hôpital de Bicêtre, Assistance Publique/Hôpitaux de Paris, Faculté de Médecine Paris-Sud, Université Paris Sud, 78 rue du Général Leclerc, 94275, K.-Bicêtre, France. nordmann.patrice@bct.ap-hop-paris.fr

The Journal of Antimicrobial Chemotherapy
|July 16, 2005
PubMed

Insights

Plasmid-encoded Qnr determinants contribute to quinolone resistance in bacteria, protecting DNA from quinolone binding. Environmental bacteria like Shewanella algae may act as reservoirs for these emerging antibiotic resistance genes.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Environmental Science

Background:

  • Quinolone resistance in Enterobacteriaceae primarily arises from chromosomal mutations.
  • Plasmid-encoded Qnr determinants represent an alternative mechanism for quinolone resistance.
  • Qnr proteins shield bacterial DNA from quinolone interaction, reducing drug efficacy.

Purpose of the Study:

  • To investigate the role of plasmid-mediated Qnr determinants in bacterial quinolone resistance.
  • To explore the prevalence and genetic context of qnrA genes.
  • To identify potential environmental reservoirs for Qnr determinants.

Main Methods:

  • Literature review of identified Qnr protein types (QnrA-like, QnrB, QnrS).
  • Analysis of genetic environments, including association with integrons and beta-lactamases.
  • Investigation of the environmental origin of QnrA determinants in Shewanella algae.

Main Results:

  • Qnr determinants are found worldwide, with high prevalence in Asian isolates.
  • qnrA genes are frequently embedded within sul1-type integrons.
  • The environmental species Shewanella algae has been identified as a source of QnrA determinants.

Conclusions:

  • The environment serves as a reservoir for emerging antibiotic resistance threats like Qnr determinants.
  • Understanding the environmental origin and transfer mechanisms of qnrA genes is crucial.
  • Preventing the spread of this novel antibiotic resistance mechanism is a public health priority.

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