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In vitro activity of josamycin against Streptococcus pyogenes isolated from patients with upper respiratory tract

M Auzou1, J Caillon2, C Poyart3

  • 1Service de microbiologie et CNR associé de la résistance aux antibiotiques, CHU de Caen, 14033 Caen, France.

Medecine Et Maladies Infectieuses
|June 10, 2015
PubMed
Abstract

Insights

Josamycin demonstrates high activity against Streptococcus pyogenes, with over 95% susceptibility observed in isolates from upper respiratory tract infections. This macrolide antibiotic can serve as an alternative treatment for pharyngitis.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Pharmacology

Background:

  • Streptococcus pyogenes is a common cause of upper respiratory tract infections.
  • Macrolide resistance in S. pyogenes is a growing concern.
  • Josamycin is a macrolide antibiotic with potential therapeutic applications.

Purpose of the Study:

  • To evaluate the in vitro activity of josamycin against clinical isolates of S. pyogenes.
  • To determine the prevalence of macrolide resistance mechanisms in these isolates.
  • To assess josamycin's potential as an alternative treatment for S. pyogenes infections.

Main Methods:

  • Broth microdilution method was used to determine Minimum Inhibitory Concentrations (MICs) for josamycin and other antibiotics.
  • Polymerase Chain Reaction (PCR) was employed to screen for key macrolide resistance genes (erm(B), erm(TR), mef(A)).
  • Susceptibility testing was performed on 193 S. pyogenes isolates from French patients.

Main Results:

  • Josamycin exhibited potent activity with MIC50 and MIC90 values of 0.12 and 0.25 mg/L, respectively.
  • The overall resistance rate to josamycin was low, estimated at 4.7%.
  • The erm(B) gene was identified as the primary mechanism of resistance in resistant isolates, while erm(TR) and mef(A) were associated with susceptibility.

Conclusions:

  • Josamycin demonstrated significant in vitro activity against the majority of S. pyogenes isolates.
  • The findings support the use of josamycin as a viable alternative therapeutic option for pharyngitis caused by S. pyogenes.
  • Understanding resistance mechanisms is crucial for guiding antibiotic selection.
Keywords:
Group A Streptococcus (GAS)Macrolide resistanceRésistance aux macrolidesS. pyogenesStreptocoque du groupe A (SGA)

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