GBS

Key Factors
  • Streptococcus agalactiae or group B streptococcus (GBS) is a leading cause of serious neonatal infections including septicaemia, pneumonia and less frequently meningitis, and urinary tract infections, chorioamnionitis, endometritis and bacteremia in women.
  • GBS is an opportunistic commensal constituting a part of the intestinal and vaginal physiologic flora in almost 25% of healthy adult women.
  • Maternal colonization is the principal route of GBS transmission. GBS is a pathobiont that converts from the asymptomatic mucosal carriage state to a major bacterial pathogen causing severe invasive infections.
  • At present, as many as 10 serotypes (Ia, Ib, and II–IX) are recognized.
  • As per 2017 WHO estimates, almost 21.7 million pregnant women carry GBS in all regions of the world; ranging from 11% in eastern Asia to 35% in the Caribbean.
  • The top five countries by numbers of pregnant women colonised were: India (2,466,500), China (1,934,900), Nigeria (1,060,000), United States of America (942,800) and Indonesia (799,100).

Fig: SEM of GBS. Bar marker 5 µm.

Ref:
1. Maisey et al. Recent advances in understanding the molecular basis of group B Streptococcus virulence. Expert Rev Mol Med.
2. Epidemiology of Group B Streptococcus in developing countries. Vaccine 31S (2013) D43– D451.
3. Wikipedia

GBS CHALLENGE TILL DATE : DISEASE BURDEN, WHO ESTIMATES 2017
  • 21.7 million pregnant women carry GBS, in all regions of the world; ranging from 11% in eastern Asia to 35% in the Caribbean. A maternal vaccine (which is 80% effective and can reach 90% of the women) could potentially prevent 231,000 infant and maternal GBS cases.
  • The top five countries by numbers of pregnant women colonized were : India (2,466,500), China (1,934,900), Nigeria (1,060,000), United States of America(942,800) and Indonesia (799,100).
  • Out of 410,000 GBS cases every year, there will be 147,000 still births and infant deaths globally. Africa has the highest burden, with 54% of estimated cases and 65% of still births and infant deaths.
  • An estimated one in five pregnant women around the world carry Group B Streptococcus (GBS).
  • Maternal immunization is the most promising and effective counter measure against GBS infection.
  • Considering the severe systemic infections caused by GBS during pregnancy and the postpartum period, maternal vaccination with GBS vaccine, in the late second or early third trimester, is likely to be effective at preventing GBS disease in the mother as well as the infant.
  • A maternal vaccine (which is 80% effective and can reach 90% of the women) could potentially prevent 231,000 infant and maternal GBS cases.