Clinical Background
Group B Streptococcus (GBS) is one of the major causes of maternal or neonatal severe infections and sepsis.
Epidemiology
- Incidence
- 2/100 live births for neonatal infections
- 45.5/1000 live birth risk of neonatal GBS infection if mother has one of the risk factors mentioned below
- Transmission - vertical from mother to neonate in 75% of neonatal cases
Organism
- Streptococcus Group B are gram-positive cocci that aggregate in clusters or chains
- Also known as Streptococcus agalactiae
Risk Factors
- Maternal - preterm delivery, prolonged rupture of membranes, intrapartum fever, prior infant with GBS infection
Clinical Presentation
- Neonatal infection
- Early onset (first week of life) - respiratory distress, lethargy and hypotension
- Late onset (1 week - 3 months) - meningitis is the most frequent manifestation
- Infection is associated with impaired psychomotor development
- Adult infection
- Majority are related to pregnancy and parturition
- Most common presentation is fever with signs and symptoms of chorioamnionitis or endometritis
- Other presentations outside of pregnancy include cellulitis, urinary tract infection, pneumonia and endocarditis
Treatment
- Intrapartum antibiotic therapy reduces attack rate in mother and neonate
See Also
Diagnosis
Diagnosis
- Laboratory testing
- Screening is routinely performed at 35-37 weeks
- Culture is gold standard test when PCR is not available
- Rapid diagnostic tests may be limited by false-negative results in patients not heavily colonized
Tests generally appear in the order most useful for common clinical situations
| Test name: Streptococcus Group B by PCR
|
| ARUP #: 0060705 |
| Methodology: Polymerase Chain Reaction
|
| Use: Screen pregnant women at 35-37 weeks |
| Limitations: Low rate of colonization |
| Follow-up: If negative and high suspicion for GBS, perform culture |
References
Guidelines
ACOG Practice Bulletin No. 80: premature rupture of membranes. Clinical management guidelines for obstetrician-gynecologists. Obstet Gynecol.
2007;
109(
4):
1007-1019.
General References
Benitz WE, Gould JB, Druzin ML. Risk factors for early-onset group B streptococcal sepsis: estimation of odds ratios by critical literature review. Pediatrics.
1999;
103(
6):
e77-.
Hanley J. Neonatal infection: group B streptococcus. Clin Evid.
2006;
(
15):
476-479.
Honest H, Sharma S, Khan KS. Rapid tests for group B Streptococcus colonization in laboring women: a systematic review. Pediatrics.
2006;
117(
4):
1055-1066.
Pettersson K. Perinatal infection with Group B streptococci. Semin Fetal Neonatal Med.
2007;
12(
3):
193-197.
Winn HN. Group B streptococcus infection in pregnancy. Clin Perinatol.
2007;
34(
3):
387-392.
Early-onset and late-onset neonatal group B streptococcal disease--United States, 1996-2004. MMWR Morb Mortal Wkly Rep.
2005;
54(
47):
1205-1208.
Medical Reviewers
Carney, Heather, M.D. Assistant Medical Director, Transfusion Services at ARUP Laboratories; Pathology, University of Utah
Petti, Cathy A., M.D. Medical Director, Infectious Diseases at ARUP Laboratories; Assistant Professor, Pathology and Medicine, University of Utah
Comprehensive Review: March 2008
Last Update: July 2008
