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Published on: March 2, 2020

Fluoroquinolone resistance in Streptococcus pneumoniae from a university hospital, Thailand

Somporn Srifuengfung1, Chanwit Tribuddharat, Kulkanya Chokephaibulkit

  • 1Department of Microbiology, Faculty of Medicine Siriraj Hopital, Mahidol University, Bangkok, Thailand.

Journal of the Medical Association of Thailand = Chotmaihet Thangphaet
|February 8, 2011
PubMed

Insights

Fluoroquinolone resistance in Streptococcus pneumoniae (S. pneumoniae) is linked to specific gene mutations. This study identified these resistance mechanisms in Thai S. pneumoniae isolates for the first time.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • Fluoroquinolone resistance in Streptococcus pneumoniae (S. pneumoniae) is primarily associated with mutations in DNA gyrase (gyrA, gyrB) and topoisomerase IV (parC, parE) genes.
  • In 2008, a Bangkok hospital reported 6.5% of S. pneumoniae isolates were resistant to ofloxacin.

Purpose of the Study:

  • To investigate the molecular mechanisms of fluoroquinolone resistance in S. pneumoniae isolates from Thailand.
  • To identify specific mutations in gyrA and parC genes associated with resistance.

Main Methods:

  • Polymerase Chain Reaction (PCR) and DNA sequencing were employed.
  • Analysis focused on quinolone-resistance-determining regions of gyrA and parC genes.

Main Results:

  • Four ofloxacin- and ciprofloxacin-resistant S. pneumoniae isolates (MIC > 32 µg/ml) were analyzed.
  • Mutations identified include Ser81Phe, Glu85Gly, Glu85Lys in gyrA and Ser79Tyr in parC.
  • Three isolates harbored mutations in both gyrA and parC genes. Serotype 6B and non-vaccine serotypes were observed.

Conclusions:

  • This study provides the first report on the genetic mechanisms of fluoroquinolone resistance in S. pneumoniae in Thailand.
  • Specific gyrA and parC mutations are key determinants of fluoroquinolone resistance in these isolates.

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