Poster Presentation Lancefield International Symposium for Streptococci and Streptococcal Diseases 2025

Molecular Epidemiology and Antimicrobial Resistance Profiles of Group A Streptococcus Isolates from Cape Town, South Africa:  Comparative analysis with High- and Low-Income countries (#110)

Kimona K Rampersadh 1 , Clinton C Moodley 2 , Standford S Kwenda 3 , Kélin KC Engel 1 , Mark ME Engel 4
  1. Department of Medicine, AFROStrep Research Initiative, Cape Heart Institute, University of Cape town, Cape Town, South Africa
  2. Division of Medical Microbiology, Department of Pathology, University of Cape Town, Cape Town , South Africa
  3. Sequencing Core Facility, National Institute for Communicable Diseases, National Health Laboratory Service, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa
  4. Cochrane South Africa, South African Medical Research Council, Cape Town, South Africa

 

Understanding the molecular epidemiology and antimicrobial resistance (AMR) of Group A Streptococcus (GAS), responsible for a diverse array of disease, is crucial for tracking its burden and informing vaccine development. This study on GAS data from South Africa, on a continent  where molecular data are severely lacking, investigated the relationships between emm types, virulence genes, and AMR profiles in GAS isolates from Cape Town, South Africa (SA).  We further conducted comparative analyses with data from high-income (HIC) and low-income (LIC) countries.

 

 

Whole-genome sequencing was performed on 108 GAS Cape Town isolates (40 invasive, 68 non-invasive) retrieved from the AFROStrep Biorepository. Results were compared with datasets from HICs (UK and USA) and LICs (Kenya, Fiji, and Brazil) with respect to phylogenetic analyses, emm typing, virulence gene profiling, and AMR characterization.

 

 

South African GAS isolates clustered primarily with HICs in terms of emm types and virulence genes. Virulence factors such as lmb, ska, and slo were prevalent across SA, HIC, and LICs, with notable variations in Fn-binding proteins like FbaA, more frequent in SA. Hyaluronic acid capsule genes were present in SA isolates but varied in LICs and HICs. AMR profiles showed higher tetM frequency in LICs, while mefA was observed in a SA isolate, indicating regional AMR gene distribution differences.

 

 

South African GAS isolates exhibited virulence profiles linked to emm types, clustering more with HIC isolates than LICs. These findings highlight the importance of regional differences in GAS surveillance to guide vaccine development and AMR strategies in LMICs.