Prevalence of group B Streptococcus colonisation and antimicrobial susceptibility pattern among pregnant women attending a tertiary health facility in Ogun State, Southwest Nigeria

Background: Genital colonisation by group B Streptococcus (GBS) in pregnant women in their third trimester has been shown to be a known risk factor for morbidity and mortality among newborns. Aim: The aim of the study was to determine the prevalence of GBS colonisation among pregnant women in Abeokuta, its associated sociodemographic factors, and the neonatal outcome among exposed babies. Design: Longitudinal cohort study. Setting: Department of Obstetrics and Gynaecology, Federal Medical Centre, Abeokuta, Ogun State. Methodology: One hundred sixty pregnant women presenting for routine antenatal care between 35 and 41 weeks were recruited consecutively. Swabs were taken from the vagina and then the rectum using a single swab. The samples were processed at the hospital's Medical Microbiology Laboratory using standard microbiological methods. Babies whose mothers were positive had their bodies swabbed and the samples sent for GBS isolates. They were also screened for early-onset neonatal sepsis with C-reactive protein. Results: Prevalence of GBS vaginal colonisation was 4.3%. There was no significant association between GBS colonisation status and age, level of education, or occupation; however, women of parity ≤1 had significantly higher prevalence of GBS colonisation than those of parity ≥2. There was no incidence of GBS infection observed in the babies. The GBS isolates were 100% sensitive to cefuroxime and 83.3% resistant to ampicillin. Conclusion: The prevalence of GBS is low in our environment. The organisms were highly sensitive to cefuroxime, erythromycin, and ceftriaxone. Routine screening of all pregnant women may be unnecessary. However, women at risk of GBS who present in labour without a recent GBS screening should be offered intrapartum prophylactic cefuroxime.