Streptococcus agalactiae

General:

Clinical: Pregnant women should be screened by culture of distal vaginal or anorectal swab(s) for Group B strep at 35~37wks; rapid direct detection still has low sensitivity.

• Normal:
• Abnormal: Group B strep are the leading infectious cause of neonatal morbidity & mortality in the U.S. Septicemia, pneumonia, and meningitis in neonates; septicemia, pneumonia, bone, skin, and soft-tissue in elderly/immunocompromised.

Resistance:

Morphology: Beta-hemolytic, Gram+ cocci in chains.

Growth characteristics: Group B beta-hemolytic strep. (the only Group B species), CAMP+, surface C protein. Strains are characterized by capsular polysaccharides (Ia, Ia/c, Ib/c, II, IIc, III to VIII). Serotypes Ia, III, and V are most common. Produce large buttery colonies with narrow zone of hemolysis at 24hrs; rare strains are non-hemolytic.

Common/important pathogens: