Epidemiology of Group B Streptococcus: Maternal Colonization and Infant Disease in Kampala, Uganda
Kyohere M., Davies HG., Karampatsas K., Cantrell L., Musoke P., Nakimuli A., Tusubira V., Nsimire JS., Jamrozy D., Khan UB., Bentley SD., Spiller OB., Farley C., Hall T., Daniel O., Beach S., Andrews N., Schrag SJ., Cutland CL., Gorringe A., Leung S., Taylor S., Heath PT., Cose S., Baker C., Voysey M., Le Doare K., Sekikubo M., Djennad A., Nyamaizi A., Ssali A., Amone A., Wamawobe A., Nanyunja C., Najuka C., Komugisha C., Sseremba C., Nakibuuka L., Kibirige D., Shelley DR., Portal EAR., Duckworth E., Karafillakis E., O'Hara G., Matovu G., Seeley J., Peacock J., Cowie K., Hookham L., Cochet M., Sewegaba M., Owor M., Etti M., Musooko M., Atuhaire P., Nalubega P., Ravji P., Katungye R., Namugumya R., Parks R., Azuba R., Kipyeko S., Old T., Mutabazi T., Chalker V.
Abstract Background Child survival rates have improved globally, but neonatal mortality due to infections, such as group B Streptococcus (GBS), remains a significant concern. The global burden of GBS-related morbidity and mortality is substantial. However, data from low and middle-income countries is lacking. Vaccination during pregnancy could be a feasible strategy to address GBS-related disease burden. Methods We assessed maternal rectovaginal GBS colonization and neonatal disease rates in a prospective cohort of 6062 women-infant pairs. Surveillance for invasive infant disease occurred in parallel at two Kampala hospital sites. In a nested case-control study, we identified infants <90 days of age with invasive GBS disease (iGBS) (n=24) and healthy infants born to mothers colonized with GBS (n=72). We measured serotype-specific anti-capsular immunoglobulin G in cord blood/infant sera using a validated multiplex Luminex assay. Results We found a high incidence of iGBS (1.0 per 1,000 live births) within the first 90 days of life across the surveillance sites, associated with a high case fatality rate (18.2%). Maternal GBS colonization prevalence was consistent with other studies in the region (14.7%; 95% confidence interval 13.7-15.6%). IgG geometric mean concentrations were lower in cases than controls for serotypes Ia (0.005 vs 0.12 µg/mL; p=0.05), III (0.011 vs 0.036 µg/mL; p=0.07) and in an aggregate analysis of all serotypes, (0.014 vs 0.05 µg/mL; p=0.02). Conclusions We found that GBS is an important cause of neonatal and young infant disease in Uganda and confirmed that maternally derived antibodies were lower in early-onset GBS cases than in healthy exposed controls.