Prevalence and risk factors for Staphylococcus aureus colonisation among healthy individuals in low- and middle-income countries: A systematic review and meta-analysis.

BACKGROUND: Staphylococcus aureus is capable of asymptomatic colonisation, which can progress to opportunistic and potentially life-threatening infection. The data on S. aureus colonisation in low- and middle-income countries (LMIC) are limited. This systematic review and meta-analysis estimates the prevalence of S. aureus colonisation in asymptomatic individuals in LMIC, with secondary objectives of assessing antimicrobial resistance, colonisation risk factors, and the molecular epidemiology of colonising strains. METHODS: Articles published up to July 2023 were identified by searching four electronic databases. Studies that presented S. aureus colonisation prevalence in healthy individuals from a community setting in LMIC were included. Data extraction was performed independently by two reviewers with disagreement resolved through consensus. Studies were critically appraised using the Joanna Briggs Institute Prevalence tool. Random effects meta-analysis was conducted where appropriate. This study was registered in advance with PROSPERO (CRD42019147780). FINDINGS: A total of 16 610 citations were identified of which 138 studies (59 732 participants) met the eligibility criteria. The majority of studies had a low risk of bias. The pooled prevalence of S. aureus colonisation at nose and/or throat sites was 26·4% (95% CI 23·8 - 29·1%). The prevalence of methicillin-resistance in colonising S. aureus strains was 15·0% (95% CI: 11·8 to 18·6%), with a higher prevalence observed in Africa compared to Asia and South America (22·5% vs. 13·1% vs. 5·4% respectively). Panton-Valentine leukocidin genes were present in 26·4% (95% CI: 17·1% to 32·8%) of 2531 isolates. INTERPRETATION: While the prevalence of asymptomatic S. aureus colonisation in LMIC mirrors that found in high-income countries, there was a higher prevalence of antimicrobial resistance and other virulence factors. Variability in study methods and sparsity of data from many LMIC, underscore the need for a global approach to S. aureus surveillance. This will be critical for informing effective infection prevention strategies.