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Phylogenetic analysis of chromosomally determined qnr and related proteins

George A Jacoby1, David C Hooper

  • 1Lahey Clinic, Burlington, Massachusetts, USA. george.a.jacoby@lahey.org

Antimicrobial Agents and Chemotherapy
|January 16, 2013
PubMed

Insights

Quinolone resistance (qnr) genes, initially found on plasmids, are widespread in bacterial genomes. Their original function remains unknown, despite their prevalence in diverse bacterial species.

Area of Science:

  • Microbiology
  • Genomics
  • Antibiotic Resistance

Background:

  • Quinolone resistance (qnr) genes were first identified on plasmids.
  • These genes confer reduced susceptibility to quinolone antibiotics.
  • Homologs of qnr genes are found across a wide range of bacterial species.

Purpose of the Study:

  • To investigate the distribution and potential evolutionary origins of qnr genes and related mfpA genes.
  • To highlight the broad presence of these genes in bacterial genomes beyond their initial plasmid-borne discovery.

Main Methods:

  • Bioinformatic analysis of bacterial genome sequences.
  • Comparative genomics to identify qnr and mfpA gene homologs.

Main Results:

  • qnr gene homologs are present in at least 92 species of Gram-negative, Gram-positive, and anaerobic bacteria.
  • The mfpA gene, encoding a related pentapeptide repeat protein, is found in at least 19 Mycobacterium species and 10 other Actinobacteria species.
  • These genes are widely distributed across diverse bacterial phyla.

Conclusions:

  • The widespread distribution of qnr and mfpA genes suggests ancient origins and important, yet unknown, native functions.
  • Understanding the native roles of these genes is crucial for comprehending their evolution and contribution to antibiotic resistance.

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