Actinomyces spp. 

  • Characteristics
    • Gram + rod in branching filaments
      • Forms long, branching filaments resembling fungi
      • Note: Nocardia is also a gram + filamentous rod
    • Produces yellow granules (“sulfur granules”)
      • Yellow bacterial aggregates bound together by proteins
      • Do not actually contain sulfur; named due to sulfur-like yellow color
    • Anaerobic
      • Contrast vs. Nocardia, which is aerobic
    • Does not stain acid-fast
      • Contrast vs. Nocardia, which stains acid-fast
  • Transmission
    • Infections usually follow dental work or oral trauma
      • Found in normal oral, reproductive, and GI flora
  • Presentation
    • Oral/facial abscesses
      • Presents as slow-growing firm abscesses in face/neck
      • Contrast vs. Nocardia, which usually presents with pulmonary infections 
    • Pelvic inflammatory disease
      • IUDs
  • Treatment
    • Penicillin
      • Tetracyclines may be used in patients with penicillin allergy
    • Surgical debridement