Group A Streptococcus Colonies From a Single Throat Swab Can Have Heterogeneous Antimicrobial Susceptibility Patterns

    loading  Checking for direct PDF access through Ovid

Abstract

This study describes for the first time heterogeneity of antibiotic resistance profiles among group A Streptococcus isolates originating from a single throat swab in patients with acute pharyngitis. For each throat swab, 10 group A Streptococcus colonies were randomly selected from the primary plate and subcultured to a secondary plate. These isolates were characterized by various phenotypic and genotypic methods. Our results demonstrated that differing antibiotic resistance profiles were present in 19% of pediatric patients with acute pharyngitis before antimicrobial treatment. This heterogeneity likely resulted from horizontal gene transfer among streptococcal isolates sharing the same genetic background. As only a minority of colonies displayed antibiotic resistance among these heterogeneous samples, a classical diagnostic antibiogram would have classified them in most instances as “susceptible,” although therapeutic failure could be caused by the proliferation of resistant strains after initiation of antibiotic treatment.

Related Topics

    loading  Loading Related Articles