[Antibiotic sensitivity of Streptococcus pyogenes in pediatrics]

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.