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Capsular Serotyping of Streptococcus pneumoniae Using the Quellung Reaction
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Capsular Serotyping of Streptococcus pneumoniae Using the Quellung Reaction

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[Antibiotic sensitivity of Streptococcus pyogenes in pediatrics]

A Gené1, A González-Cuevas, T Juncosa

  • 1Servicio de Microbiología, Hospital Sant Joan de Déu, Barcelona.

Enfermedades Infecciosas Y Microbiologia Clinica
|October 9, 1998
PubMed

Insights

Pediatric Streptococcus pyogenes show high macrolide resistance, particularly in skin infections. Penicillin and clindamycin remain effective, but susceptibility testing is advised for macrolide treatments.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Pediatrics

Background:

  • Streptococcus pyogenes is a common pediatric pathogen.
  • Antibiotic resistance in S. pyogenes impacts treatment efficacy.
  • Understanding local resistance patterns is crucial for effective therapy.

Purpose of the Study:

  • To determine the current sensitivity of pediatric Streptococcus pyogenes strains to penicillin, clindamycin, clarithromycin, erythromycin, and azithromycin.
  • To assess macrolide resistance prevalence in pediatric S. pyogenes isolates.
  • To compare antibiotic susceptibility between pharyngeal and non-pharyngeal S. pyogenes strains.

Main Methods:

  • Collected 100 S. pyogenes strains (79 pharyngeal, 21 non-pharyngeal) between October 1996 and July 1997.
  • Determined Minimum Inhibitory Concentrations (MICs) using the E-test method.
  • Validated results by comparing with the Kirby-Bauer disk diffusion method.

Main Results:

  • All strains were sensitive to penicillin; one strain showed inducible resistance to clindamycin.
  • 19% of strains exhibited macrolide resistance (clarithromycin, erythromycin, azithromycin).
  • Higher resistance rates were observed in non-pharyngeal (28.5%) and cutaneous (4/6) samples compared to pharyngeal (16.5%) samples.

Conclusions:

  • A significant level of macrolide resistance in pediatric S. pyogenes, especially from cutaneous sources, was confirmed.
  • Penicillin and clindamycin demonstrated high susceptibility rates.
  • In vitro susceptibility testing is recommended for macrolide chemotherapy due to declining susceptibility rates.
Abstract

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