Streptococcus agalactiae

Categorization
Cell Wall: Gram Positive Shape: Cocci
Biochemistry: Catalase Negative Metabolism: Microaerophilic
Streptococcal subclassification: Group B, beta-hemolytic
Virulence Factors
  • Antiphagocytic capsule
Clinical Consequences
  • Overview
    • S. agalactiae, more popularly known as "Group B Streptococcus (GBS)", primarily affects neonates who acquire the infection as they pass through the birth canal during delivery i.e. (Mother-to-Child Transmission). The organism is a part of the normal vaginal flora in a third of women. FYI: All women are now screened for GBS colonization in their rectovaginal mucosa during the third trimester and if positive are treated with antibiotics immediately prior to delivery, an intervention that has been shown to reduce rates of neonatal sepsis.
  • Possible Pathologies
    • Neonatal Sepsis is the pathology of most concern and can become rapidly fatal if not treated promptly
    • Neonatal Meningitis is less common compared to sepsis but can also occur
    • Neonatal Pneumonia is also possible and can potentially result in Neonatal Respiratory Distress Syndrome
Treatment
  • Empirical treatment of neonatal sepsis must also cover E. coli and Listeria in addition to GBS and thus typically involves ampicillin and gentamicin.