HEALTH BURDEN OF GROUP B STREPTOCOCCI COLONIZATION IN THE OBSTETRIC POPULATION AT UNIVERSITY OF BENIN TEACHING HOSPITAL, BENIN CITY, NIGERIA
Background: Streptococcus agalactiae or Group B streptococci (GBS), are gram-positive cocci which may be beta-haemolytic; coagulase negative and catalase negative. GBS have been reported as the leading cause of early-onset neonatal sepsis in the industrializednations since the 1970’s. However, only recently has GBS been reported as an importantcause of neonatal sepsis in sub-Saharan Africa. Thirty to fifty per cent of cases of early- onset GBS sepsis develop in neonates born to mothers without clinical risk factors. Women with recto-vaginal colonization by GBS usually have no symptoms of disease. A culture is therefore required to detect the presence of the organism in the vagina or rectum. There are still opportunities for simple preventive measures affecting maternal and child health.
Aim: To estimate the burden of GBS disease in the obstetric and neonatal population at University of Benin Teaching Hospital (UBTH).
Methodology: A prospective cohort study. Swabs were taken from the parturient’s lower vagina and rectum. Four samples were also collected immediately after birth from theneonate’s throat; anterior nares; external ear canals; and base of the umbilical cord. Early- onset GBS neonatal sepsis was defined as confirmed isolation of GBS from blood and/or cerebro-spinal fluid cultures in neonates who presented with clinical features of sepsis. Specimens were selectively enriched in Lim broth before being sub-cultured to supplemented blood agar plates. Suspected bacterial colonies were subjected to biochemical tests and then Group B latex agglutination tests. Data was coded into an IBM SPSS spread sheet and analysed using IBM SPSS Statistics, version 22.0, Chicago, Illinois, U.S.A.
Results: Thirty percent of mother-infant pairs in this study were colonized with GBS. Two percent of colonized mothers developed postpartum endometritis. The early onset invasive neonatal GBS disease among study participants was 7.8% with an attack rate of 25.7% among GBS positive mother-infant pairs, a stillbirth incidence of 1.0% and a case fatality rate of 15.4%.
Conclusion: Maternal recto-vaginal colonization with GBS is prevalent (intrapartum) in the obstetric population delivering at UBTH. It increases the risk of maternal postpartum complications; neonatal colonization with GBS; GBS early-onset neonatal disease (sepsis); and perinatal mortality from GBS sepsis.
Recommendation: Antenatal mothers should receive health education on the significance of GBS screening. Maternal healthcare services should incorporate late antenatal screening (as a surrogate for intrapartum screening) for recto-vaginal colonization by GBS and selective intrapartum antibiotic prophylaxis.