Abstract

Background Group B Streptococcus (GBS) is a commensal bacterium of the digestive and genital tracts, that can occasionally cause maternal and neonatal disease. GBS is particularly a burden in low-resource settings, where infections with human immunodeficiency virus (HIV) are also highly prevalent. This study investigates the impact of HIV status on GBS colonization and antibody levels. Methods In Uganda, 90 non-pregnant women of childbearing age were followed for three months. Every two weeks, rectal and vaginal swabs were tested for GBS, and vaginal cups and blood collected for measurement of GBS capsular polysaccharides (CPS) IgG using standardised assays. Results 26/90 women were living with HIV. 51/90 women were GBS colonized at one or several visits. GBS colonization fluctuated in the rectal and vaginal sites. Most prevalent serotypes were Ia and III, with 33 individuals carrying different serotypes over time. Serum and vaginal CPS-IgG levels were stable over twelve weeks. In serum, for serotypes Ib to V, the geometric mean concentration (GMC) of CPS-IgG did not differ between HIV+ and HIV- participants. However, the GMC for serum CPS Ia IgG in the HIV+ group was 2.5 times lower than in the HIV- group (p=0.038). Vaginal CPS-IgG was measurable in 5/26 (19%) HIV+ participants, and 32/64 (50%) of HIV- participants. Conclusions Despite fluctuating GBS colonization, antibody levels remained stable over twelve weeks. The level of CPS Ia-specific IgG in serum was lower in women with HIV than without HIV. Vaginal CPS specific IgG was not measurable in 81% of individuals with HIV.