Streptococcus pyogenes emm Type 3.93 Emergence, the Netherlands and England

Area of Science:

• Microbiology
• Infectious Diseases
• Genomics

Background:

• Global increase in invasive group A Streptococcus (iGAS) infections observed post-COVID-19 restrictions, with M1_UK dominating.
• Seasonal decline in iGAS incidence during summer 2023 preceded a new strain's emergence.

Purpose of the Study:

• To investigate the rapid expansion of a previously rare emm type 3.93 of iGAS.
• To characterize the clinical associations and genomic features of the emm3.93 strain.
• To highlight the importance of molecular surveillance in public health.

Main Methods:

• Analysis of iGAS incidence data from England and the Netherlands.
• Genomic analysis of historic and contemporary emm3.93 isolates using long-read sequencing.

Main Results:

• A rapid, simultaneous expansion of emm3.93 was observed starting November 2023.
• emm3.93 became a significant cause of iGAS in children (6-17 years), associated with increased risk of pneumonia, pleural empyema, and meningitis.
• No increased mortality risk was associated with emm3.93 compared to other iGAS types.
• Genomic analysis revealed 3 new clades of emm3.93 with potentially advantageous configurations.

Conclusions:

• Molecular surveillance, including advanced sequencing techniques, is crucial for identifying emerging infectious disease threats.
• The emm3.93 strain represents a significant public health concern due to its rapid spread and association with severe pediatric iGAS infections.