Strategies to Prevent Early and Late-Onset Group B Streptococcal Infection via Interventions in Pregnancy

Abstract

Group B Streptococcus is a Gram-positive bacterium that typically colonizes 10–30% of pregnant women, causing chorioamnionitis, preterm birth, and stillbirth, as well as neonatal sepsis and meningitis with early-onset disease (EOD) or late-onset disease (LOD) due to ascending infection or transmission during delivery. While there are some differences between EOD and LOD in terms of route of transmission, risk factors, and serotypes, the only preventive approach currently is maternal intrapartum antibiotic prophylaxis (IAP) which will not be able to fully address the burden of the disease since this has no impact on LOD. Probiotics and immunization in pregnancy may be more effective than IAP for both EOD and LOD. There is mixed evidence of probiotic effects on the prevention of GBS colonization, and the data from completed and ongoing clinical trials investigating different GBS vaccines are promising. Current vaccine candidates target bacterial proteins or the polysaccharide capsule and include trivalent, tetravalent, and hexavalent protein–polysaccharide conjugate vaccines. Some challenges in developing novel GBS vaccines include the lack of a correlate of protection, the potential for serotype switching, a need to understand interactions with other vaccines, and optimal timing of administration in pregnancy to maximize protection for both term and preterm infants.

Finnish paediatric study found a low incidence of bacterial meningitis from 2011 to 2018 but a substantial proportion of nosocomial meningitis

“…Maternal GBS prophylaxis with antibiotics has been reported to be efficient against early‐onset disease, but not against late‐onset disease 18 . Maternal GBS vaccines are urgently needed to prevent late‐onset GBS disease 5 . Neonatal nosocomial infections can, to some extent, be prevented by breastfeeding, probiotics and strict infection prevention programmes in neonatal units 19 .…”

“…18 Maternal GBS vaccines are urgently needed to prevent lateonset GBS disease. 5 Neonatal nosocomial infections can, to some extent, be prevented by breastfeeding, probiotics and strict infection prevention programmes in neonatal units. 19 The rapid initiation of antibiotic treatment for any suspicion of sepsis may prevent the infection developing into BM.…”

“…It decreased the incidence of N. meningitidis meningitis from 2.87 to 0.20 per 100 000 individuals between 1989–1993 and 2014–2019 2 . Neonatal BM is more difficult to prevent, because maternal intrapartum antibiotic prophylaxis does not protect children from late‐onset GBS disease 5 …”

“…2 Neonatal BM is more difficult to prevent, because maternal intrapartum antibiotic prophylaxis does not protect children from late-onset GBS disease. 5 Meningitis survivors risk neurological sequelae, such as hearing loss, cerebral palsy and mental retardation. 6 Although hearing loss can spontaneously improve, studies have reported that it was permanent in around 30% of pneumococcal meningitis survivors.…”

Immunization with Multiple Virulence Factors Provides Maternal and Neonatal Protection against Group B Streptococcus Serotypes

“…Streptococcus agalactiae , or group B streptococcus (GBS), is an encapsulated Gram-positive opportunistic pathogen that can be classified into 10 different serotypes (Ia, Ib, II–IX) based on the antigenic and structural properties of the capsular polysaccharide (CPS). GBS is found in the vagina or lower gastrointestinal tract of about 10–40% of women [ 1 ] and can cause chorioamnionitis, preterm birth, and stillbirth [ 2 , 3 ], as well as neonatal pneumonia, sepsis, and meningitis with early-onset disease (EOD) or late-onset disease (LOD) due to ascending infection or transmission during delivery [ 4 ]. GBS is also responsible for morbidity and mortality in gravidas, the elderly, and immunocompromised adults.…”