Emergence of fluoroquinolone-resistant Stenotrophomonas maltophilia in blood isolates causing bacteremia: molecular epidemiology and microbiologic characteristics

Diagn Microbiol Infect Dis. 2016 Jun;85(2):210-2. doi: 10.1016/j.diagmicrobio.2016.02.020. Epub 2016 Feb 26.

Abstract

Among 127 Stenotrophomonas maltophilia isolates causing bacteremia, 41 (32.3%) were nonsusceptible to levofloxacin, in which four sequence types and 24 diverse allelic profiles were detected. The most prevalent ST was ST77 (n = 8, 19.5%), followed by ST28 (n = 3, 7.3%). Amino acid substitutions were found in the gyrB and parC genes of 10 and 1 isolates, respectively. No amino acid substitutions were identified in gyrA. Twenty-three (56.1%) isolates showed amino acid substitutions in the parE gene. These results suggest that quinolone resistance-determining regions of parE may not be the primary targets, but an important determining factor of high levels of fluoroquinolone resistance.

Keywords: Fluoroquinolone-resistance; QRDRs; Stenotrophomonas maltophilia.

MeSH terms

  • Amino Acid Substitution
  • Anti-Bacterial Agents / pharmacology*
  • Bacteremia / epidemiology
  • Bacteremia / microbiology*
  • Drug Resistance, Bacterial*
  • Fluoroquinolones / pharmacology*
  • Genes, Bacterial
  • Genotype
  • Gram-Negative Bacterial Infections / epidemiology
  • Gram-Negative Bacterial Infections / microbiology*
  • Humans
  • Molecular Epidemiology
  • Molecular Typing
  • Stenotrophomonas maltophilia / classification
  • Stenotrophomonas maltophilia / drug effects*
  • Stenotrophomonas maltophilia / genetics
  • Stenotrophomonas maltophilia / isolation & purification*

Substances

  • Anti-Bacterial Agents
  • Fluoroquinolones