Molecular epidemiology of group A streptococcus causing scarlet fever in northern Taiwan, 2001-2002

Area of Science:

• Microbiology
• Infectious Diseases
• Molecular Epidemiology

Background:

• Streptococcus pyogenes is a significant pathogen causing scarlet fever.
• Understanding the genetic diversity and antibiotic resistance of S. pyogenes is crucial for public health.
• Previous studies have highlighted the importance of M protein gene (emm) types in S. pyogenes epidemiology.

Purpose of the Study:

• To characterize the M protein gene (emm) types and genetic diversity of Streptococcus pyogenes isolates from scarlet fever patients in northern Taiwan.
• To determine the antimicrobial susceptibility profiles of these isolates, focusing on erythromycin resistance.
• To identify major clones associated with antibiotic resistance for public health relevance.

Main Methods:

• Analysis of 830 Streptococcus pyogenes isolates collected between 2001 and 2002.
• M protein gene (emm) sequence typing to determine genetic types.
• Pulsed-field gel electrophoresis (PFGE) for genetic fingerprinting.
• Antimicrobial susceptibility testing to assess resistance patterns.

Main Results:

• 21 emm types and 56 PFGE patterns were identified.
• The most prevalent emm types were emm1, emm4, emm12, emm6, stIL103, and emm22.
• Erythromycin resistance was detected in 24.6% of isolates, with emm4, emm12, emm1, emm22, and emm6 being major contributors.
• A decrease in erythromycin resistance was observed from 2001 to 2002, coinciding with a reduced prevalence of emm12 strains.
• Five major clones accounted for 72.1% of erythromycin-resistant isolates.

Conclusions:

• The study provides insights into the emm type distribution and genetic diversity of S. pyogenes in Taiwan.
• Erythromycin resistance is a significant concern, driven by specific emm types and clones.
• Findings are relevant for antimicrobial stewardship and potential vaccine development strategies against Streptococcus pyogenes.