Neonatal Group B Streptococcal Infections

1. Neonatal Group B Streptococcal Infections Perinatal CDC Prevention Guidelines Priscilla Joe, MD

2. The Disease • Leading cause of early-onset sepsis in US • Prior to intrapartum prophylaxis: 7,500 cases/year or 1.7/1000 live births • Reduced now to 1,200 cases/year or 0.34-0.37/1000 live births • Perinatal GBS disease burden • Neonatal illness/death, long-term disability • Maternal morbidity

3. Mother to Infant Transmission GBS colonized mother 50% 50% Non-colonized newborn Colonized newborn 98% 2% Early-onset sepsis, pneumonia, meningitis Asymptomatic

4. Colonization Rates • GBS Carriers • 10% - 30% of women • Higher in African Americans and nonsmokers • Clinical signs not predictive • Dynamic condition • Risk factor for early-onset disease: GBS colonization at delivery • Prenatal cultures late in pregnancy predict delivery status

5. Additional Risk Factors forEarly-Onset GBS Disease • Obstetric: prolonged rupture of membranes, preterm delivery, intrapartum fever • GBS bacteriuria • Previous infant with GBS disease • Demographic (African American, young age) • Immunologic (low antibody to GBS capsular polysaccharide)

6. Prevention of Perinatal GBS Disease • Intrapartum antibiotics • Highly effective at preventing early-onset disease in women at risk for transmission of GBS to their newborns • Challenge: How best to identify women at risk?

7. Rates of Early-Onset GBS Disease by Prenatal Colonization & Risk Factors Col: prenatal vag/rect culture RF: risk factors (gest. <37 wks, ROM >18 hr, fever > 37.5°C) Boyer & Gotoff, Antibiot Chemother 1985.

8. First U.S. Consensus Recommendations(CDC '96, ACOG '96, AAP '97) • Screening-based approach: • 35-37 wks culture, offer intrapartum antibiotic prophylaxis (IAP) to GBS carriers and to preterm unless neg. culture result available, or • Risk-based approach: • IAP to preterm, membrane rupture>18 hours, or intrapartum fever (T>38°C) Both strategies also give IAP to women with GBS bacteriuria, or previous infant with GBS disease

9. Why is screening more protective than the risk-based approach? • Broader coverage of at-risk population • Captures colonized women without obstetric risk factors (18% of all deliveries) • Antibiotic effectiveness in this cohort, based on birth survey data: 89% (64-97%) Schrag et al, NEJM 2002, 347:233-9

10. Intrapartum Prophylaxis: Indications • Previous infant with invasive GBS disease • GBS bacteriuria during current pregnancy • Positive GBS screening culture during current pregnancy (unless a planned c-section, in the absence of labor or amniotic membrane rupture) • Unknown GBS status AND any of the following: • Delivery at < 37 weeks’ gestation • Amniotic membrane rupture >18 hours • Intrapartum temperature >38.0°C

11. Intrapartum Prophylaxis NOT Indicated • Prior pregnancy with a positive GBS screening culture (unless culture positive ALSO during current pregnancy) • Planned c-section performed in the absence of labor or membrane rupture (regardless of maternal GBS culture status) • Negative vaginal and rectal GBS screening culture during the current pregnancy, regardless of intrapartum risk factors

12. Maternal Antibiotic Prophylaxis

13. Neonatal Management Algorithm

14. Neonatal Management Algorithm 1.Full diagnostic evaluation includes a blood culture, a complete blood count (CBC) including white blood cell differential and platelet counts, chest radiograph (if respiratory abnormalities are present), and lumbar puncture (if patient is stable enough to tolerate procedure and sepsis is suspected). 2. Antibiotic therapy should be directed toward the most common causes of neonatal sepsis, including intravenous ampicillin for GBS and coverage for other organisms (including Escherichia coli and other gram-negative pathogens) and should take into account local antibiotic resistance patterns. 3. Consultation with obstetric providers is important to determine the level of clinical suspicion for chorioamnionitis. Chorioamnionitis is diagnosed clinically and some of the signs are nonspecific. 4. Limited evaluation includes blood culture (at birth) and CBC with differential and platelets (at birth and/or at 6--12 hours of life). 5. If signs of sepsis develop, a full diagnostic evaluation should be conducted and antibiotic therapy initiated. 6. If ≥37 weeks' gestation, observation may occur at home after 24 hours if other discharge criteria have been met, access to medical care is readily available, and a person who is able to comply fully with instructions for home observation will be present. If any of these conditions is not met, the infant should be observed in the hospital for at least 48 hours and until discharge criteria are achieved. 7. Some experts recommend a CBC with differential and platelets at age 6--12 hours.

15. Early Onset Disease • Presentation within 1st 24 hrs, 0 - 6days • 75% of cases of GBS disease • Vertical transmission • Sepsis 25-40% • Pneumonia 35-55% • Meningitis 5-10% • Mortality 5%; higher in preterm infants • Due to opsonin deficiency, limited maternal antibody transfer, limited maternal capsular antibody

16. Late Onset Disease • 3-4 weeks after birth, range 7d-3mo • Term and preterm infants equally susceptible • Serotype III most common and predominant cause of meningitis • Bacteremia and meningitis • Osteomyelitis, septic arthritis, and cellulitis • Horizontal transmission (hospital, community, mother) • Incidence unchanged with intrapartum prophylaxis

17. Treatment of Asymptomatic Neonates • 24-48 hr observation period for infants with pretreated mothers • Routine use of antibiotics in infants whose mothers received adequate treatment is not indicated

18. Diagnosis • Blood, CSF, ETT cxs • CBC • CRP • CXR

19. Treatment of GBS Disease • Ampicillin and Gentamicin • 7-10 days for uncomplicated bacteremia • 14 days for uncomplicated meningitis • 21-28 days for meningitis complicated by abscesses, ventriculitis • 4-6 weeks for osteomyelitis or endocarditis

20. References • http://www.cdc.gov/groupbstrep/guidelines/guidelines.html