Group B Streptococcus in African pregnancies: A systematic review and meta-analysis of its maternal rectovaginal colonization, vertical transmission, serotype distribution, and antimicrobial resistance

OBJECTIVES: We conducted a systematic review and meta-analysis to estimate maternal Group B Streptococcus (GBS) colonization, vertical transmission, serotype distribution, and antimicrobial resistance (AMR) burden of GBS in African pregnant women and newborn infants. METHODS: Literature searches were performed on CINAHL, EMBASE, Cochrane Library, Google Scholar, ProQuest, PsycINFO, MEDLINE/PubMed, WHO IRIS, Scopus, Web of Science, African Journals Online, and University repositories. Heterogeneity was evaluated using Cochrane's chi-square test and the I² statistics, and potential publication bias was assessed using Egger's regression intercept. RESULTS: A total of 116 studies from 29 African countries (n = 53,770 participants) were included. The pooled prevalence of maternal rectovaginal GBS colonization was 18% (95% confidence interval [CI]: 16%-20%). The pooled proportion of vertical transmission was 47% (95% CI: 39%-55%). Among maternal isolates, serotypes V (27%; 95% CI: 23%-32%), Ia (24%; 95% CI: 19%-29%), III (23%; 95% CI: 19%-26%), and II (19%; 95% CI: 13%-25%) were most frequently detected. Among neonatal isolates, serotypes V (31%; 95% CI: 22%-41%), Ia (26%; 95% CI: 17%-35%), III (23%; 95% CI: 15%-31%), and II (15%; 95% CI: 12%-19%) were identified. AMR was high for tetracycline (87%; 95% CI: 85%-88%) and cotrimoxazole (75%; 95% CI: 72%-78%), and low for β-lactams, including ampicillin (10%; 95% CI: 9%-12%) and penicillin (9%; 95% CI: 8%-11%). CONCLUSION: The prevalence of maternal GBS rectovaginal colonization and vertical transmission in Africa is high and comparable to global estimates, but there were marked regional variations. The predominance of serotypes V, Ia, and III supports their inclusion in multivalent vaccine formulations. Widespread resistance to tetracycline and cotrimoxazole and moderate macrolide resistance highlight the need for antimicrobial stewardship and ongoing surveillance.