Streptococcus Bovis

• Overview
  • Group D Streptococcus (now reclassified as Streptococcus gallolyticus)
  • Gram-positive cocci in chains
  • Key association: Colorectal cancer (CRC) and colonic polyps
• Clinical Significance
  • Causes subacute bacterial endocarditis (similar to S. viridans)
  • Bacteremia/sepsis, especially in elderly
  • Strong association with GI malignancy (up to 25-80% of cases)
• Pathophysiology
  • Normal gut flora
  • Translocation across damaged colonic mucosa (from polyps/tumors) → bacteremia
  • Adheres to damaged heart valves → endocarditis
• Clinical Features
  • Endocarditis: fever, new murmur, embolic phenomena
  • Often indolent presentation (subacute)
  • May present with signs of underlying CRC (anemia, weight loss, change in bowel habits)
• Diagnostics
  • Blood cultures: Gram-positive cocci in chains
  • Echocardiography (TEE preferred): vegetations on heart valves
  • Mandatory colonoscopy when S. bovis bacteremia/endocarditis is identified (to screen for CRC)
• Treatment
  • Endocarditis: IV Penicillin G or Ceftriaxone (4-6 weeks)
  • Add Gentamicin for synergy in severe cases
  • Treat underlying colonic pathology if identified
• Key Associations/Buzzwords
  • S. bovis bacteremia = Get a colonoscopy
  • Subacute endocarditis in elderly patient → think colon cancer screening
  • Group D Streptococcus (PYR negative, unlike Enterococcus)