Actinomycosis

Actinomycosis

Essentials of Diagnosis

History of recent dental infection or abdominal trauma

Chronic pneumonia or indolent intra-abdominal or cervicofacial abscess

Sinus tract formation

General Considerations

Anaerobic, gram-positive, branching filamentous bacteria

Anaerobic organisms are not easily identified in regular culture. When biopsy or drainage samples from the infection site are exposed to room air, the anaerobic organisms die. Thus, the culture finding will be negative. Anaerobic organisms are usually identified by pathology/morphology finding of the biopsy samples.

Normal flora of the mouth and tonsillar crypts

Lesions may develop in the gastrointestinal tract or lungs following ingestion or aspiration of the organism from its endogenous source in the mouth

Because actinmycete is a normal flora of the mouth and tonsillar crypts, the most frequent infection site of actinomycyte is cervical and facial region. People with peri0d0ntal diseases, whose sliva has higher concentration of actinomycte, are predisposed to pulmonary actinomycosis.

Infection typically follows extraction of a tooth or other trauma

Symptoms and Signs in Pulmonary Infections

Fever, cough, sputum production

Night sweats, weight loss

Pleuritic pain

Multiple sinuses may extend through the chest wall to the heart or abdomen

Differential Diagnosis

Lung cancer

Tuberculous lymphadenitis (scrofula)

Other cause of cervical lymphadenopathy

Nocardiosis

Crohn's disease

Pelvic inflammatory disease from another cause

Treatment

Penicillin G (drug of the choice) 10 to 20 million units IV for 4–6 weeks followed by penecillin V, 500 mg PO four times daily for 4-6 months

Ampicillin 12 g/d IV for 4–6 weeks followed by amoxicillin 500 mg PO three times a day for 4-6 months, are alternatives

Actinomyocte may form abcesses, sinuses, and/or fistulas where antibiotics have poor penetration. Therefore, higher concentration of antibiotics are required. IV route to administer antibiotics I & D and antibiotics administration should be done simultaneously if any abcesses, sinuses, and/or fistulas are found. If medical managements failed, consider surgical excision.

Sulfonamides such as sulfamethoxazole may be an alternative regimen at a total daily dosage of 2–4 g

When to Admit
All patients with thoracic or abdominal actinomycosis

Patients with cervicofacial actinomycosis if the diagnosis is in question, to control symptoms, or initiate IV antibiotics

Sudhakar SS et al: Short-term treatment of actinomycosis: two cases and a review. Clin Infect Dis 2004;38:444.