Poster Presentation Lancefield International Symposium for Streptococci and Streptococcal Diseases 2025

A systematic review of asymptomatic colonisation with Group A Streptococcus in low and middle income countries (#15)

Hermaleigh Townsley 1 2 , Thomas Locke 1 2 , Alexander J Keeley 1 2 3 , Nicholas Laundy 4 , Christopher Keil 5 , Jean Hamilton 6 , Abdullah Pandor 6 , Thomas Darton 1 2 , Thushan de Silva 1 2 3
  1. The Florey Institute of Infection, The University of Sheffield, Sheffield, UK
  2. Division of Clinical Medicine, School of Medicine and Population Health, University of Sheffield, Sheffield, UK
  3. Vaccines and Immunity Theme, MRC Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, The Gambia
  4. The Royal Hobart Hospital and University of Tasmania, Hobart, Tasmania, Australia
  5. Department of Medical Microbiology, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
  6. Sheffield Centre for Health and Related Research (SCHARR), School of Medicine and Population Health, University of Sheffield, Sheffield, UK

Background: Group A Streptococcus (GAS) remains a significant global health problem, with distinct epidemiology and disproportionate disease burden in low- and middle-income countries (LMIC). Asymptomatic GAS colonisation contributes to disease transmission (1) and may be immunogenic (2,3). This systematic review aimed to estimate GAS colonisation prevalence in LMIC and influencing factors.

Methods: Studies reporting GAS colonisation in asymptomatic individuals in LMIC community settings were included. Articles published up to 2024 were identified by search of four online databases. Data extraction was performed independently by two reviewers and confirmed by consensus. Meta-analysis with a random effects model was performed to estimate prevalence of GAS colonisation overall and stratified by predefined variables. Univariate meta-regression assessed effects of different factors on colonisation.

Results: 50 studies were included with 40,713 participants (75.9% in Asia, 21.8% in Africa). 49 studies reported pharyngeal colonisation in children only, while one study reported skin colonisation in children and adults. Pooled prevalence of pharyngeal GAS colonisation was 7.2% (95% CI 5.5-9.1%), compared to skin colonisation of 1.95% (0.01 – 3.2%). Prevalence was highest in South America (15%) and lowest in Southern/Eastern Asia (5.8%). Sex and publication year did not significantly affect prevalence. All isolates were susceptible to penicillin, with 35.4% (82% in Asia, 17% in Africa) clarithromycin-resistant.

Conclusion: This study highlights heterogeneity of GAS colonisation rates and resistance patterns across LMICs, underscoring the need for targeted prevention strategies. Findings also emphasise the importance of improved surveillance and further research on skin colonisation, an understudied source of streptococcal disease.

  1. Armitage EP, de Crombrugghe G, Keeley AJ, Senghore E, Camara FE, Jammeh M, et al. Streptococcus pyogenes carriage and infection within households in The Gambia: a longitudinal cohort study. Lancet Microbe. 2024;5(7):679–88.
  2. Salie MT, Muhamed B, Engel K, Rampersadh K, Daniels R, Mhlanti L, et al. Serum Immune Responses to Group A Streptococcal Antigens following Pharyngeal Acquisitions among Children in Cape Town, South Africa. mSphere. 2023 Jun 22;8(3):e0011323.
  3. Keeley AJ, Groves D, Armitage EP, Senghore E, Jagne YJ, Sallah HJ, et al. Streptococcus pyogenes Colonization in Children Aged 24–59 Months in the Gambia: Impact of Live Attenuated Influenza Vaccine and Associated Serological Responses. J Infect Dis. 2023 Oct 1;228(7):957–65.