Tracing the recent evolution of Group A Streptococcus M1 serotype

Area of Science:

• Microbiology
• Genomics
• Epidemiology

Background:

• Global surges in scarlet fever and invasive Group A Streptococcus (GAS) infections observed in the 21st century.
• Emergence of the toxigenic M1_UK GAS lineage, characterized by increased SpeA superantigen expression and 27 single nucleotide polymorphisms (SNPs).
• M1_UK has become the dominant GAS emm1 lineage in Europe, Australia, and Canada, signifying a major shift in molecular epidemiology.

Purpose of the Study:

• To review the recent evolution of the GAS emm1 lineage.
• To emphasize the genomic and molecular drivers behind GAS diversification.
• To highlight the need for continued surveillance and research into GAS pathogens.

Main Methods:

• Review of recent genomic and molecular studies on GAS emm1 lineage evolution.
• Analysis of epidemiological data on scarlet fever and invasive GAS infections.
• Comparative analysis of emerging emm1 variants in different global regions.

Main Results:

• The M1_UK lineage, with enhanced SpeA expression and specific SNPs, has rapidly expanded globally.
• Distinct emm1 variants have emerged in China and Denmark but have not yet achieved widespread global expansion.
• Ongoing diversification of the GAS emm1 lineage is evident, with varying expansion patterns.

Conclusions:

• The M1_UK lineage represents a significant evolutionary development in GAS, impacting global public health.
• Understanding the genomic and molecular drivers of GAS diversification is crucial for effective control strategies.
• Continued global surveillance and research are essential to monitor and combat the evolving threat of GAS infections.