Streptococcal, Group A Infections

Key Features

• Arthritis, pneumonia, empyema, endocarditis, and necrotizing fasciitis are relatively uncommon infections that may be caused by group A streptococci

• Toxic shock-like syndrome also occurs

Clinical Findings

• Arthritis generally occurs in association with cellulitis

• Pneumonia and empyema often are characterized by

  • Extensive tissue destruction

  • Aggressive, rapidly progressive clinical course associated with significant morbidity and mortality

• Endocarditis (rare)

• Any streptococcal infection, especially necrotizing fasciitis, can be associated with streptococcal toxic shock syndrome

• Streptococcal toxic shock syndrome

  • Characterized by

    • Invasion of skin or soft tissues

    • Acute respiratory distress syndrome

    • Kidney failure

  • Persons who are very young, older adults, and those with underlying medical conditions are at particularly high risk for invasive disease

  • Bacteremia occurs in most cases

  • Skin rash and desquamation may not be present

  • Mortality rates can be up to 80%

Diagnosis

• Culture of affected site or blood

Treatment

• Arthritis

  • Penicillin G aqueous, 2 million units intravenously every 4 hours (or cefazolin or vancomycin)

  • Frequent percutaneous needle aspiration to remove joint effusions

  • Open surgical drainage may be necessary in many cases

  • Treatment duration is usually 2–4 weeks

• Pneumonia/empyema

  • Penicillin G aqueous, 4 million units intravenously every 4 hours

  • Chest tube drainage for treatment of the empyema

  • Vancomycin is an acceptable substitute in penicillin-allergic patients

  • Duration of therapy is guided by clinical improvement, with a minimum of 5 days for pneumonia

  • Adequate drainage is key for the management of empyema, and serial imaging is usually necessary to assess for resolution

• Endocarditis

  • Penicillin G aqueous, 4 million units intravenously every 4 hours for 4–6 weeks

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

• Necrotizing fasciitis: early, extensive debridement is essential for survival (see Necrotizing Fasciitis)

• Streptococcal toxic shock syndrome

  • Penicillin G aqueous, 4 million units intravenously every 4 hours, plus clindamycin, 900 mg intravenously every 8 hours, especially in the presence of shock

  • Intravenous immune globulin can be added: 0.5 g/kg once daily for 5–6 days or a single dose of 2 g/kg with a repeat dose at 48 hours if the patient remains unstable