Prevalence of Shigella species and antimicrobial resistance patterns in Africa: systematic review and meta-analysis

Background: Shigellosis continues to pose a significant public health problem in Africa; however, there is a lack of comprehensive knowledge regarding its prevalence, serogroup distribution, and antimicrobial resistance profiles. Therefore, the objective of this systematic review and meta-analysis was to determine the overall prevalence of Shigella, the distribution of species, and the patterns of antimicrobial resistance across Africa. Methods: Following PRISMA guidelines, a systematic search strategy was conducted using the PubMed, Web of Science and Scopus databases from January 31, 2024 to February 10, 2024. The study quality was assessed using the Joanna Briggs Institute checklist, and data were analyzed using the R statistical language and the R package ‘meta’. The random effects model was employed to estimate the pooled prevalence, while heterogeneity was assessed using the I² statistic and prediction interval. Results: A total of 116 studies from 29 African countries were included in this meta-analysis, involving the examination of 99,510 samples. The overall pooled estimate of Shigella prevalence was determined to be 5.9% (95% CI: 4.9 – 7.0%). Regional prevalence showed prevalences of Southern Africa (6.9 [95% CI: 3.0 – 12.2%]), Northern Africa (6.7% [95% CI: 4.1 – 9.8%]), Eastern Africa (6.2% [95% CI: 4.9 – 7.6%]), Central Africa (4.5% [95% CI: 2.6 – 6.8%]) and Western Africa (4.0% [95% CI: 2.5 – 5.9%]). Shigella prevalence was found to be higher in children (6.6%, 95% CI: 3.2 – 11.1%) than in adults (3.6%, 95% CI: 1.6 – 6.3%). The most prevalent species was S. flexneri (53.6%, 95% CI: 46.1%—61.0%), followed by S. sonnei (11.5%, 95% CI: 7.7%—15.7%), S. dysenteriae (10.1%, 95% CI: 6.2 – 14.5%) and S. boydii (7.7%, 95% CI: 4.7 – 11.1%). Among the currently recommended first-line antibiotics, ciprofloxacin and ceftriaxone showed resistance prevalences of 10.0% (95% CI: 4.5%—16.9%) and 8.5% (95% CI: 2.4—16.9%) respectively. Conclusion: This review highlights the burden of shigellosis in Africa. S. flexneri remains the most prevalent species associated with shigellosis cases with S. sonnei being the second most dominant. The antimicrobial resistance patterns observed in the study suggest local antimicrobial patterns in choosing antibiotics for the treatment of Shigellosis. Recommendation: There is the need to explore alternative treatments for shigellosis with particular focus on vaccine development. There is also the need for more genomic epidemiology studies exploring the dissemination and risk of drug-resistant S. sonnei clones in Africa.