Answer to CC #17

Case challenge #17 presented an 85-year-old Caucasian male with “bony protrusions” on his gums and the following histologic findings:

Casechallenge 17

Which of the following is the best initial treatment?

CC17 Voting

The correct answer is: IV Penicillin G

The image above reveals infection by a the filamentous, gram-positive, non-acid fast, anaerobic bacteria, ACTINOMYCES.


  • Subacute-to-chronic bacterial infection caused by filamentous gram positive, non-acid fast, anaerobic bacteria
  • Most common clinical forms of actinomycosis are cervicofacial, thoracic, and abdominal
  • Endemic world-wide
  • Thoracic actinomycosis accounts for 15-20% of cases. Aspiration of oropharyngeal secretions containing actinomycetes is the usual mechanism of infection.

Clinical Presentation

  • Cervicofacial, thoracic, abdominal, and CNS infections:
  • Often present with: dry or productive cough, blood streaked sputum, shortness of breath, fevers, weight loss, fatigue, anorexia


  • Direct identification and/or isolation of the organism from a clinical specimen
  • Sulfur granules


  • Preferred regimen: Pen G IV for 2-6 weeks, then amoxicillin PO for 6-12 months
  • Doxycycline, minocycline, tetracycline, clindamycin, erythromycin, and cephalosporins have been proven to be effective in case reports

Case Challenge 18, next week!