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The dynamic Alp landscape of Streptococcus dysgalactiae
Camilla Olaisen1,2, Alba Kaci3, Christina Gabrielsen Ås1,2,4
1Department of Medical Microbiology, St. Olavs Hospital, Trondheim, Norway.
Frontiers in Cellular and Infection Microbiology
|April 27, 2026
Summary
Alpha-like proteins (Alps) are common in Streptococcus dysgalactiae, with five new genes identified. These virulence factors show significant genetic diversity and are found on mobile elements, suggesting cross-species exchange.
Area of Science:
- Microbiology
- Genomics
- Pathogen Research
Background:
- Streptococcus dysgalactiae is a significant human and animal pathogen.
- Alpha-like proteins (Alps) are key adhesins and virulence factors in streptococci.
- The diversity and prevalence of Alps in S. dysgalactiae are poorly understood.
Purpose of the Study:
- To investigate the presence and diversity of alpha-like protein (alp) genes in Streptococcus dysgalactiae.
- To characterize the genetic heterogeneity and distribution of alp genes across global strains.
Main Methods:
- Screened 1,243 S. dysgalactiae genomes from diverse geographic origins.
- Utilized long-read sequencing for detailed analysis of alp gene tandem repeat regions in a subset of strains.
Main Results:
- Identified five novel alp genes (dysalp2-5, alp1-3 hybrid).
- Observed extensive genetic heterogeneity in alp genes due to mosaicism and repeat variations.
- Detected alp genes in 18% of human and 10-15% of animal strains, with geographic variations.
Conclusions:
- Alpha-like proteins are common and genetically diverse in S. dysgalactiae.
- Findings enhance understanding of Alp diversity and evolutionary mechanisms.
- Identified mobile genetic elements carrying alp genes, indicating potential for cross-species exchange.
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