Risk factors for Group B Streptococcus colonisation and disease in Gambian women and their infants

K Le Doare,S Jarju,S Darboe,F Warburton,A Gorringe,P.T Heath,B Kampmann

doi:10.1016/j.jinf.2015.12.014

Abstract

SummaryObjectivesTo determine risk factors for GBS colonisation in Gambian mothers and in their infants from birth to day 60–89 of age.MethodsSwabs and breastmilk from mothers/infant pairs were collected and cultured on selective agar. Negative samples were analysed for GBS DNA via real-time PCR. Positive isolates were serotyped using multiplex PCR and gel-agarose electrophoresis.ResultsSeven hundred and fifty women/infant pairs were recruited. 253 women (33.7%) were GBS-colonised at delivery. The predominant serotypes were: V (55%), II (16%), III (10%), Ia (8%) and Ib (8%). 186 infants were colonised (24.8%) at birth, 181 (24.1%) at 6 days and 96 at day 60–89 (14%). Infants born before 34 weeks of gestation and to women with rectovaginal and breastmilk colonisation at delivery had increased odds of GBS colonisation at birth. Season of birth was associated with increased odds of persistent infant GBS colonisation (dry season vs. wet season AOR 2.9; 95% CI 1.6–5.2).ConclusionGBS colonisation is common in Gambian women at delivery and in their infants to day 60−89 and is dominated by serotype V. In addition to maternal colonisation, breastmilk and season of birth are important risk factors for infant GBS colonisation.

Highlights

Group B Streptococcus (GBS) is a leading cause of neonatal infection worldwide and transmission occurs mainly from mother to child during the peripartum period.[1]
Maternal colonisation is the leading risk factor for both early and late onset GBS disease,[1] yet in resource-poor countries little is known about maternal colonisation rates
Little is known about maternal or infant colonising serotypes in African countries but reports indicate that serotype (ST) V may be important as both a colonising and invasive disease serotype,[3,4] as it was in the USA in the 1990s

Summary

Introduction

Group B Streptococcus (GBS) is a leading cause of neonatal infection worldwide and transmission occurs mainly from mother to child during the peripartum period.[1] In the African setting, information on GBS disease prevalence remains sparse.[2] Under-identification and under-reporting of GBS cases and deaths appear likely, especially where it is difficult to access healthcare. The current leading candidate for maternal vaccination is a trivalent capsular polysaccharide protein conjugate vaccine containing ST Ia, Ib and III which is based on data on invasive disease serotypes in the USA, UK6 and South Africa.[3] Here, we report the results of a longitudinal prospective cohort study to investigate the prevalence of colonising and invasive disease serotypes of Gambian women and their infants from delivery to three months of age

Results

Discussion

Conclusion