[Isolated susceptibility of Streptococcus pyogenes to 3 macrolides]

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W Sakran1, R Raz, R Colodner

  • 1Infectious Disease Unit, HaEemek Medical Center, Afula.

Harefuah
|January 7, 1998
PubMed

Insights

Erythromycin is a top choice for penicillin-allergic patients with streptococcal pharyngitis. In Israel, macrolide antibiotics remain effective for treating S. pyogenes tonsillitis, showing low resistance rates.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Pharmacology

Context:

  • Streptococcal pharyngitis (S. pyogenes) treatment guidelines recommend erythromycin for penicillin-allergic patients.
  • Recent European studies indicate rising macrolide resistance in S. pyogenes isolates.
  • Evaluating current macrolide susceptibility in Israel is crucial for treatment recommendations.

Purpose:

  • To assess the minimum inhibitory concentration (MIC) of erythromycin, clarithromycin, and roxithromycin against S. pyogenes isolates in Israel.
  • To determine the prevalence of macrolide resistance in S. pyogenes causing tonsillitis in Israel.

Summary:

  • Erythromycin, clarithromycin, and roxithromycin MIC-50 values were 0.23, 0.13, and 0.47 mcg/ml, respectively.
  • MIC-90 values were 0.37, 0.23, and 0.78 mcg/ml for the respective macrolides.
  • Only 2.1% of S. pyogenes isolates exhibited resistance to all three macrolides tested.

Impact:

  • Macrolide antibiotics demonstrate low resistance rates in Israeli S. pyogenes isolates.
  • Empiric macrolide therapy is a viable and recommended option for S. pyogenes tonsillitis in penicillin-allergic individuals in Israel.
  • This study supports the continued use of macrolides for specific patient populations in Israel, contrasting with some international trends.

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