Skip to main content

Macrolide-resistant genes of Streptococcus pyogenes isolated from the upper respiratory tract by polymerase chain reaction

Abstract

The growing number of macrolide-resistant strains of Streptococcus pyogenes is an increasing problem worldwide. This study evaluated 300 clinical isolates obtained from the upper respiratory tract. Minimal inhibitory concentrations (MICs) of erythromycin (EM), azithromycin (AZM), and clindamycin (CLDM), serotypes, and macrolide resistance genes of mefA, ermB, and ermTR were determined. The genetic relationship of EM-resistant and susceptible strains were also analyzed by pulsed-field gel electrophoresis (PFGE). Twenty-nine (9.7%) EM-resistant S. pyogenes were identified. Of the 29 strains showing resistance to EM, 22 isolates (7.3%, MIC 3.13–12.5 µg/ml) expressed the mefA gene. The predominant serotypes among the mefA-positive isolates were T12, emm9 or T25, emm75-1. The two isolates (0.1%) that possessed the ermB gene were highly resistant to EM (MIC ≫ 100 µg/ml). The remaining five strains (1.6%) possessed the ermTR gene (MIC 3.13–100 µg/ml). Restriction fragment polymorphism analyzed by pulsed-field gel electrophoresis (PFGE) by SmaI and ApaI digestions showed several clones among the mefA-positive S. pyogenes. Our findings suggest that the mefA gene is the predominant mechanism for macrolide resistance and that this gene is horizontally transmitted among M phenotype strains of S. pyogenes. Consequently, macrolides would not be the first drug of choice for treatment of tonsillitis and other S. pyogenes-related diseases. Physicians and researchers need to take into consideration the macrolide resistance of some strains of S. pyogenes.

This is a preview of subscription content, access via your institution.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Noboru Yamanaka.

About this article

Cite this article

Billal, D., Hotomi, M., Yamauchi, K. et al. Macrolide-resistant genes of Streptococcus pyogenes isolated from the upper respiratory tract by polymerase chain reaction. J Infect Chemother 10, 115–120 (2004). https://doi.org/10.1007/s10156-004-0302-x

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10156-004-0302-x

Key words

  • Streptococcus pyogenes
  • Drug resistance
  • PCR
  • PFGE
  • Macrolide