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Molecular epidemiology, antimicrobial susceptibility, and characterization of fluoroquinolone non-susceptible

Kazuaki Tatara1, Kenji Gotoh1, Kiyohito Okumiya2

  • 1Department of Infection Control and Prevention, Kurume University School of Medicine, Kurume, Japan; Department of Pediatrics and Child Health, Kurume University School of Medicine, Kurume, Japan.

Journal of Infection and Chemotherapy : Official Journal of the Japan Society of Chemotherapy
|November 5, 2019
PubMed

Insights

Fluoroquinolone resistance in Streptococcus pyogenes (GAS) is increasing in Japan. This study found diverse fluoroquinolone-non-susceptible GAS strains in children with pharyngotonsillitis, highlighting the need for ongoing monitoring.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Antimicrobial Resistance

Background:

  • Streptococcus pyogenes (Group A streptococci) infections are common, with penicillin as the primary treatment.
  • Macrolide and fluoroquinolone resistance in GAS is a growing global concern.
  • Alternative antibiotic therapies are needed for patients with allergies or resistant strains.

Purpose of the Study:

  • To investigate the characteristics of fluoroquinolone-non-susceptible GAS strains.
  • To determine the prevalence and features of these resistant strains in children with pharyngotonsillitis in Japan.
  • To assess the potential impact of fluoroquinolone usage on GAS antimicrobial susceptibility.

Main Methods:

  • Analysis of 298 GAS strains isolated from children in Fukuoka, Japan (2011-2013).
  • Determination of minimum inhibitory concentration (MIC) to tosufloxacin (≥1 μg/ml defined non-susceptibility).
  • Investigation of T-serotype, emm typing, Multilocus Sequence Typing (MLST), and Pulsed-Field Gel Electrophoresis (PFGE).

Main Results:

  • 33 (11.1%) of the GAS strains exhibited fluoroquinolone non-susceptibility.
  • Six T-serotypes and nine emm/MLST patterns were identified among resistant strains.
  • Predominant combinations included emm6/ST382 (42.4%) and emm89/ST101 (15.2%).
  • PFGE revealed 10 distinct pulsotypes, indicating diverse origins of resistant strains.

Conclusions:

  • Fluoroquinolone-non-susceptible GAS strains in Japan are genetically diverse.
  • Fluoroquinolone drug usage may negatively impact GAS antimicrobial susceptibility.
  • Continuous monitoring of quinolone-non-susceptible GAS is essential.
Keywords:
Fluoroquinolone non-susceptibleMLSTPFGES. pyogenesemm typing

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