Group B Streptococcus

1
Group B Streptococcus

• Streptococcus agalactiae

2
GBS Epidemiology

• Colonizes the genital tract risk groups include
• Infants Colonization during delivery may
  results in invasive disease
• Pregnant and post-partum women
• Non-pregnant adults
• Elderly
• Individuals with chronic underlying disease

3
Burden of Invasive GBS Disease, 1989-1990,
AtlantaNEJM, 1993 3281807
4
Age Distribution of GBS in Infants and Neonates
Clin Microbiol Rev, 1998 11497.
5
Incidence of Invasive GBS Disease with Age,
1989-1990, AtlantaNEJM, 1993 3281807
6
Risk Factors for Early Onset Group B
Streptococcal DiseaseBMJ, 2002 325308
Risk Factor Adjusted Odds Ratio (95 CI)
Group B Streptococcus isolated during pregnancy 1.9 (0.03 to 142.7)
Gestation lt 37 weeks 12.1 (2.7 to 53.8)
Prolonged rupture of membranes gt 18 hours 4.8 (0.98 to 23.1)
Rupture of membranes before onset of labour 3.6 (0.7 to 17.6)
Intrapartum fever 10.0 (1.7 to 60.7)
7
1996 Recommendations (CDC)MMWR, 1996 45(No.
RR-7)

• Prenatal GBS screening at 35-37 weeks
• Offer penicillin intrapartum if
• GBS ()
• Culture not done and risk factors present
• Previous infant had IGBS disease
• Mother had GBS bacteriuria, this pregnancy
• Delivery occurred at lt 37 weeks gestation

• Risk factor screening
• Offer penicillin intrapartum if
• Previous infant had IGBS disease
• Mother had GBS bacteriuria, this pregnancy
• Delivery occurred at lt 37 weeks gestation
• Duration of ruptured membranes gt 18 hours
• Intrapartum temperature gt 100.4F

8
Reduction in IGBS Disease Emerg Infect Dis,
2001 792
9
Population-based Comparison of Strategies to
Prevent Early-Onset GBSNEJM, 2002 347233
10
2002 Recommendations (CDC)MMWR, 2002 51(No.
RR-11)

• Universal screening of all women at 35-37 weeks
  gestation
• Prophylax
• Previous infant with IGBS
• GBS bacteriuria this pregnancy
• Positive GBS screen this pregnancy unless
• C-section planned in the absence of labor or
  rupture of membranes
• Unknown GBS status AND delivery at lt 37 weeks,
  rupture of membranes gt 18 hours, or intrapartum
  temperature gt 100.4 F

11
VaccineArch Dis Child, 2003 88375-8

• Phase I trial completed
• Women at 32-34 weeks
• Serum antibody and cord blood antibody
• Elevated after immunization
• Promoted killing of GBS in vitro
• May protect against both late and early onset
  disease
• Barriers
• Pharmaceutical leadership / liability issues

12
GBS Clinical Presentation

• Neonates
• Sepsis, meningitis, pneumonia, cellulitis,
  osteomyelitis, septic arthritis
• Pregnant and post-partum women
• Mild UTI, sepsis less commonly osteomyelitis,
  endocarditis, meningitis
• Non-pregnant adults
• Bacteremia, skin or soft tissue infections gt
  pneumonia gt urosepsis gt endocarditis gt
  peritonitis gt meningitis gt empyema

13
IGBS Case Definition (draft)

• Clinical description
• Invasive group B streptococcal infections may
  manifest as any of several clinical syndromes,
  including pneumonia, deep soft-tissue infection,
  meningitis, peritonitis, osteomyelitis, septic
  arthritis, postpartum sepsis (i.e., puerperal
  fever), neonatal sepsis, and nonfocal bacteremia.

14
IGBS Case Definition (draft)

• Laboratory criteria for diagnosis
• Isolation of group B Streptococcus (Streptococcus
  agalactiae) by culture from a normally sterile
  site (e.g., blood or cerebrospinal fluid, or,
  less commonly, joint, pleural, or pericardial
  fluid)
• Case classification
• Confirmed a case that is laboratory confirmed

15
Public Health Action

• Case ascertainment
• Case investigation
• Fill out yellow card and CDC meningitis form
• Follow up early onset disease (onset lt 7 days of
  age) to determine if mother was
  cultured/prophylaxed.

16
GBS - Summary

• Important pathogen of
• Newborns
• Pregnant and post-partum women
• Non-pregnant adults with underlying disease
• Vaccine in development
• Investigation
• Demographics, site of infection, source of
  isolate (establish baseline incidence before
  vaccine licensure)
• Follow-up of early-onset disease