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A Murine Model of Group B Streptococcus Vaginal Colonization
10:19

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Published on: November 16, 2016

Distribution of emm type and antibiotic susceptibility of group A streptococci causing invasive and noninvasive

Takeaki Wajima1, Somay Y Murayama1, Katsuhiko Sunaoshi1

  • 1Laboratory of Molecular Epidemiology for Infectious Agents, Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan.

Journal of Medical Microbiology
|October 18, 2008
PubMed

Insights

Macrolide resistance in Streptococcus pyogenes (GAS) reached 16.2%, with specific resistance genes identified. Intermediate levofloxacin resistance was observed in 17.4% of strains, linked to genetic mutations.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Antimicrobial Resistance

Background:

  • Streptococcus pyogenes (group A Streptococcus or GAS) is a significant human pathogen.
  • Understanding antibiotic resistance patterns is crucial for effective treatment of GAS infections.

Purpose of the Study:

  • To determine the prevalence of macrolide and levofloxacin resistance in Streptococcus pyogenes strains in Japan.
  • To genetically characterize macrolide-resistant and levofloxacin-intermediately resistant GAS strains.

Main Methods:

  • Collection of 482 GAS strains from 45 Japanese medical institutions (2003-2006).
  • Classification of strains by infection type: invasive, acute otitis media, abscess, and pharyngotonsillitis.
  • Genetic characterization including emm typing and identification of resistance genes (erm(A), erm(B), mef(A)).
  • Determination of minimum inhibitory concentrations (MICs) for macrolides and levofloxacin.

Main Results:

  • Macrolide resistance was found in 16.2% of strains, with erm(A), erm(B), and mef(A) genes present in 2.5%, 6.2%, and 7.5% respectively.
  • emm1 was the predominant type in invasive infections and acute otitis media.
  • Intermediate levofloxacin resistance (MIC 2-4 µg/mL) was observed in 17.4% of strains, associated with ParC amino acid substitutions.
  • Macrolide resistance was more frequent in certain emm types.

Conclusions:

  • Macrolide resistance is a significant concern in Streptococcus pyogenes infections in Japan.
  • Specific emm types are associated with both invasive disease and macrolide resistance.
  • Intermediate levofloxacin resistance, linked to ParC mutations, warrants monitoring.

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