Challenges in reducing group B Streptococcus disease in African settings

Abstract

Group B Streptococcus (GBS) is a leading cause of neonatal sepsis and meningitis in high-income settings and is associated with high rates of neonatal mortality and morbidity. There is now increasing evidence to suggest that there is a high GBS disease burden in resource-limited countries, and it is therefore critically important to identify suitable and practical preventive strategies. In Europe and North America, intrapartum antibiotic prophylaxis (IAP) has led to a dramatic reduction of early-onset GBS disease. However, the methods for identifying pregnant women who should receive IAP and how to reduce late-onset GBS disease are not without controversy and are challenging for most sub-Saharan African countries. GBS vaccines are approaching phase III trials but are still under development. This review aims to explore the current evidence related to strategies for reducing invasive GBS disease in an African setting, the development of a GBS vaccine and whether preventative measures against GBS disease can be practically implemented.

Perinatal Group B Streptococcal Infections: Virulence Factors, Immunity, and Prevention Strategies

“…Thus, GBS surveillance programs would need to remain vigilant even after a vaccine becomes widely used. There are also significant challenges in resource-limited settings to consider prior to implementation (Reviewed in [132]). Regardless, it is clear that a vaccine would be the most effective means of reducing the global GBS burden of disease [133].…”

Pan-GWAS of Streptococcus agalactiae highlights lineage-specific genes associated with virulence and niche adaptation

“…Since the 1970s, GBS has been reported as one of the leading causes of neonatal mortality and morbidity in the US [Dermer, et al, 2004] but it is increasingly recognised that the burden is greatest in low-to-middle income countries. In sub-Saharan Africa, for example, where up to 30 percent of women carry GBS asymptomatically, the incidence of invasive GBS disease in neonates has been reported to be up to 2.1 per 1000 livebirths, with case fatality rates ranging from 13 to 46 percent [Dagnew, et al, 2012;Heyderman, et al, 2016;Nishihara et al, 2017].…”

“…In neonates, early-onset disease (EOD) in the first week of life typically presents as pneumonia or sepsis [Edmond et al, 2012, Nishihara et al, 2017. Late-onset disease (LOD) develops from 7 days to 3 months after birth and is frequently characterised by meningitis leading to chronic neurological damage, seizures, blindness and cognitive impairment in those that survive [Berardi et al, 2013;Nishihara et al, 2017]. The gastrointestinal tract is the reservoir for GBS and is the most likely source for maternal vaginal colonisation [Meyn et al, 2004].…”

“…The gastrointestinal tract is the reservoir for GBS and is the most likely source for maternal vaginal colonisation [Meyn et al, 2004]. This may lead to GBS transmission before or during birth, potentially leading to early onset disease in the infant [Nishihara et al, 2017]. The route for late onset colonisation and disease is less clear: while vertical transmission is still possible, environmental transmission and acquisition are considered more common [Rajagopal et al, 2009].…”

Within-Host Diversity and Vertical Transmission of Group B Streptococcus Among Mother-infant Dyads in The Gambia

“…A recent global estimate reported that, in 2015, GBS caused 90,000 deaths in infants aged younger than three months of age [1]; Africa accounted for 54% of estimated cases and 65% of all foetal/infant deaths. Maternal colonisation of GBS is an important source of infection in new-borns-up to 70% of infants born to colonised mothers are likely to be colonised themselves [2]. However, the microbial population genetics of mother-infant transmission of GBS remains poorly understood.…”