Typing of macrolide resistant group A streptococci by random amplified polymorphic DNA analysis

Area of Science:

• Microbiology
• Genetics
• Epidemiology

Background:

• Macrolide resistance in Group A Streptococcus (GAS) is a growing concern, potentially driven by dominant resistant clones.
• Understanding the genetic diversity of macrolide-resistant GAS (MRGAS) is crucial for tracking resistance patterns.

Purpose of the Study:

• To investigate the genetic diversity of MRGAS isolated from pharyngitis patients in Serbia.
• To identify dominant clones responsible for macrolide resistance in Streptococcus pyogenes.

Main Methods:

• emm typing and random amplified polymorphic DNA (RAPD) analysis were used to study clonal relationships.
• 76 MRGAS isolates collected in Serbia during 2008 were analyzed.

Main Results:

• Seven distinct emm types were identified, with emm12, emm75, and emm77 being the most frequent (>90%).
• Despite 26 different RAPD patterns, two clones (emm12 and emm77) comprised 42% of the isolates.
• These two clones, emm12 and emm77, were found to be widely distributed.

Conclusions:

• The findings suggest a polyclonal spread of erythromycin-resistant Streptococcus pyogenes in Serbia.
• The predominance of specific clones (emm12, emm77) indicates their significant role in the dissemination of macrolide resistance.