Actinomyces infection

Actinomycosis can affect any organ and characteristically manifests as:
• Cervicofacial disease (most common site):

1.Occurs in the setting of poor dental hygiene, recent dental surgery, or minor oral trauma
2.Painful soft tissue swelling commonly seen at the angle of the mandible
3.Fever, chills, and weight loss
4.Trismus
5.Soft tissue facial infection with sinus tract or fistula formation

• Thoracic disease:

1.Can involve the lungs, pleura, mediastinum, or chest wall.
2.Presumed secondary to aspiration of Actinomyces organisms in patients with poor oral hygiene.
3.Fever, cough, weight loss, and pleuritic chest pains are common symptoms.
4.Signs of pneumonia or pleural effusion may be present.
5.With extension beyond the lungs to mediastinal structures and the chest wall, signs and symptoms of pericarditis, empyema, chest wall sinus drainage, and tracheoesophageal fistula can all occur ( Fig. 1–12 ).

1.Occurs most commonly after appendectomy, perforated bowel, diverticulitis, or surgery to the gastrointestinal tract.

2.Lesions develop most commonly in the ileocecal valve, causing abdominal pain, fever, weight loss, and a palpable mass.

3.Extension may occur to the liver, causing jaundice and abscess formation.

4.Sinus tracts to the abdominal wall can occur.

1.Commonly occurs by extension from abdominal disease of the ileocecal valve to the right adnexa (80% of cases).
2.Endometritis.

• Actinomycosis is most commonly caused by Actinomyces israelii. Other causes are A. naeslundii, A. odontolyticus, A. viscosus, A. meyeri, and A. gerencseriae.
• Actinomyces are gram-positive, non-spore-forming, anaerobic or microaerophilic rods.
• Actinomycosis infections are polymicrobial, usually associated with Streptococcous, Bacteroides, Eikenella corrodens, Enterococcus, and Fusobacterium.
• Infects individuals only after entry into disrupted mucosa or tissue injury.

Isolating the bacteria in the proper clinical setting makes the diagnosis of actinomycosis.

Nocardiosis, botryomycosis, chromomycosis, intestinal tuberculosis, ameboma, Crohn’s disease, colon cancer, and other causes of acute, subacute, or chronic infections of the lung, abdomen, hepatic, GI, GU, musculoskeletal, and CNS system.

The workup includes obtaining specimens either by aspirating abscesses, excising sinus tracts, or tissue biopsies.

• Isolating “sulfur granules” from tissue specimens or draining sinuses confirm the diagnosis of actinomycosis.

1.Sulfur granules are nests of Actinomyces species. Sulfur granules may be macroscopic or microscopic

2.Sulfur granules are crushed and stained for identification of Actinomcyes organisms and may take up to 3 wk to grow in culture media.

• Imaging studies are useful adjunctive tests in localizing the site and spread of infection.

1.Chest x-ray examination
2.CT scan of the head, chest, abdomen, and pelvic areas is useful

• Incision and drainage of abscesses
• Excision of sinus tract

• Penicillin 10 to 20 million units per day in 4 divided doses for 4 to 6 wk.
• In penicillin-allergic patients, erythromycin, tetracycline, clindamycin, or cephalosporins (depending on the type of penicillin allergy) are reasonable alternatives.
• Chloramphenicol 50 to 60 mg/kg/day has been used for CNS actinomycosis.

• Following 4 to 6 wk IV penicillin, oral penicillin V 500 mg PO qid for 6 to 12 mo.
• Treatment of associated microorganisms is not needed.

• Clinical actinomycosis, if not treated, spreads to contiguous tissues and structures ignoring tissue planes. Hematogenous spread, although possible, is rare.
• Actinomycosis is very sensitive to antibiotics but requires chronic long-term treatment to prevent relapse.

If the diagnosis of actinomycosis is suspected, consultation with an infectious disease specialist is suggested. General surgical consultation for excision of sinus tracts and abscess incision and drainage is recommended.

• There is no person-to-person transmission of Actinomyces.
• Isolation of the organism in an asymptomatic individual does not mean the person has actinomycosis. Active symptoms must be present to make the diagnosis.
• Pelvic actinomycosis has been associated with use of an intrauterine device (IUD).
• Actinomycosis can also involve the CNS, causing multiple brain abscesses.

Russo TA: Agents of actinomycosis. In Mandell, Douglas, and Bennett’s principles and practice of infectious diseases, ed 5, New York, 2000, Churchill Livingstone.

Smego RA, Foglia G: Actinomycosis, Clin Infect Dis 26:1255, 1998.