The Clinical and Molecular Epidemiology of Streptococcus Agalactiae Colonisation on the Kenyan Coast

Sub-Saharan Africa (sSA) has the highest regional rates of perinatal mortality worldwide. Group B Streptococcus (GBS) has been identified as a leading cause of early onset neonatal sepsis (EOS, in <7 days of life) in sSA. In other regions, maternal carriage is associated with early onset neonatal sepsis, but in addition, other adverse perinatal outcomes (stillbirths, early neonatal death, low birth weight and prematurity). Robust data on maternal GBS carriage in sSA and its burden on adverse perinatal outcomes are lacking, with important consequences for public health interventions.

Through investigation of maternal carriage and perinatal outcomes at three different sites: rural, semi-rural and urban, this study will provide a comprehensive description of the burden of GBS in coastal Kenya, informing public health policy and driving forward interventions. Risk factors for maternal colonisation and invasive neonatal disease will be assessed, including through retrospective immunological investigation of cord blood in neonates subsequently identified as having invasive GBS disease or other adverse perinatal outcomes, compared to those without.

GBS isolates from maternal colonisation will be typed (sero-typing and molecular analysis), and these isolates will be compared to existing archived neonatal isolates from investigation of neonatal sepsis in KDH (Kilifi District Hospital). This is important so that we know the prevalent sub-types causing neonatal disease in Kenya, those which are carried by mothers, and therefore whether maternal GBS carriage correlates with a high risk of perinatal disease. GBS vaccines in development are type-specific and this will inform their use in sSA.

Stillbirths will also be investigated, in individual cases, through additional detailed microbiological and other laboratory investigations to make an assessment of the contribution of GBS to stillbirths in Kenya.