Prevention of neonatal infection
The only reliable way to prevent EOD currently is intrapartum antibiotic prophylaxis (IAP), that is to say administration of antibiotics during delivery. It has been proved that intravenous penicillin or ampicillin administered for at least 4 hours before delivery to GBS colonized women is very effective at preventing vertical transmission of GBS from mother to baby and EOD. Intravenous penicillin remains the agent of choice for IAP, with intravenous ampicillin as an acceptable alternative. For penicillin allergic women, the laboratory requisitions for ordering antepartum GBS screening cultures should indicate clearly the presence of penicillin allergy.Cefazolin, clindamycin, and vancomycin are used to prevent EOD in infants born to penicillin-allergic mothers. Intravenous vancomycin is recommended for IAP in women colonized with a clindamycin-resistant Group B Streptococcus strain and a severe penicillin allergy.There are two ways to identify female candidates to receive intrapartum antibiotic prophylaxis: a risk-based approach or a culture-based screening approach. The culture-based screening approach identifies candidates to receive IAP using lower vaginal and rectal cultures obtained between 36 and 37 weeks gestation (32–34 weeks of gestation for women with twins) and IAP is administered to all GBS colonized women.
These factors include onset of labor before 37 weeks of gestation (premature birth), prolonged rupture of membranes (≥18h before delivery), intra-partum fever (>38 °C,  >100.4 °F), amniotic infections (chorioamnionitis), young maternal age, and low levels of GBS anticapsular polysaccharide antibodies in the mother. Nevertheless, most babies who develop EOD are born to GBS colonized mothers without any additional risk factor. A previous sibling with EOD is also an important risk factor for development of the infection in subsequent deliveries, probably reflecting a lack of GBS polysaccharides protective antibodies in the mother. Heavy GBS vaginal colonization is also associated with a higher risk for EOD. Overall, the case–fatality rates from EOD have declined, from 50% observed in studies from the 1970s to 2 to 10% in recent years, mainly as a consequence of improvements in therapy and management. Fatal neonatal infections by GBS are more frequent among premature infants.GBS LOD affects infants from 7 days to 3 months of age and is more likely to cause bacteremia or meningitis. LOD can be acquired from the mother or from environmental sources. Hearing loss and mental impairment can be a long-term sequela of GBS meningitis. In contrast with EOD, the incidence of LOD has remained unchanged at 0.26 per 1000 live births in the US. S. agalactiae neonatal meningitis does not present with the hallmark sign of adult meningitis, a stiff neck; rather, it presents with nonspecific symptoms, such as fever, vomiting and irritability, and can consequently lead to a late diagnosis.