Prediction of Fluoroquinolone Susceptibility Directly from Whole-Genome Sequence Data by Using Liquid Chromatography-Tandem Mass Spectrometry To Identify Mutant Genotypes

Antimicrob Agents Chemother. 2018 Feb 23;62(3):e01814-17. doi: 10.1128/AAC.01814-17. Print 2018 Mar.

Abstract

Fluoroquinolone resistance in Gram-negative bacteria is multifactorial, involving target site mutations, reductions in fluoroquinolone entry due to reduced porin production, increased fluoroquinolone efflux, enzymes that modify fluoroquinolones, and Qnr, a DNA mimic that protects the drug target from fluoroquinolone binding. Here we report a comprehensive analysis, using transformation and in vitro mutant selection, of the relative importance of each of these mechanisms for fluoroquinolone nonsusceptibility using Klebsiella pneumoniae as a model system. Our improved biological understanding was then used to generate 47 rules that can predict fluoroquinolone susceptibility in K. pneumoniae clinical isolates. Key to the success of this predictive process was the use of liquid chromatography-tandem mass spectrometry to measure the abundance of proteins in extracts of cultured bacteria, identifying which sequence variants seen in the whole-genome sequence data were functionally important in the context of fluoroquinolone susceptibility.

Keywords: Klebsiella pneumoniae; antibiotic resistance; susceptibility testing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Chromatography, Liquid / methods*
  • Fluoroquinolones / pharmacology*
  • Genotype
  • Klebsiella pneumoniae / drug effects
  • Klebsiella pneumoniae / genetics
  • Microbial Sensitivity Tests
  • Tandem Mass Spectrometry / methods*
  • Whole Genome Sequencing / methods*

Substances

  • Anti-Bacterial Agents
  • Fluoroquinolones