Streptococcal, Non-Group A Infections

Key Features

• Non-group A hemolytic streptococci (eg, groups B, C, and G) produce a spectrum of disease similar to that of group A β-hemolytic streptococci

• Viridans streptococci are part of the normal oral flora but may produce focal pyogenic infection

Clinical Findings

• Group B streptococci

  • An important cause of sepsis, bacteremia, and meningitis in the neonate

  • Antepartum screening vaginal cultures are recommended to identify carrier mothers

  • May cause septic abortion, endometritis, or peripartum infections in women and, less commonly, cellulitis, bacteremia, and endocarditis in adults

• Group D streptococci

  • Include Streptococcus bovis and the enterococci

  • S bovis is a cause of endocarditis in association with colorectal cancer or cirrhosis

• Viridans streptococci

  • Nonhemolytic or α-hemolytic (ie, producing a green zone of hemolysis on blood agar)

  • Leading cause of native valve endocarditis

Diagnosis

• Culture of affected site or blood

Treatment

• Non-group A hemolytic streptococci (eg, groups B, C, and G

  • Give penicillin G aqueous, 4 million units every 4 hours intravenously

  • Vancomycin, 1 g intravenously every 12 hours, is recommended for persons allergic to penicillin

• Group B streptococci

  • Addition of low-dose gentamicin, 1 mg/kg every 8 hours is recommended by some experts because of in vitro synergism

  • Peripartum antimicrobial prophylaxis is recommended

• Viridans streptococci

  • Give penicillin with or without addition of gentamicin

  • Alternatives are cephalosporin and vancomycin

• S bovis infection treated like viridans streptococci