Etiology
Pathogen
- Actinomyces are primarily anaerobic, gram-positive, non-acid fast, branching, rod-shaped bacteria.
 - Actinomyces bacteria, particularly Actinomyces israelii, are found in the normal oral flora.
 
Predisposing factors
- Cervicofacial actinomycosis (most frequent form of actinomycosis)
- Poor dental hygiene (e.g., dental caries)
 - Oral surgery (e.g., tooth extraction)
 - Maxillofacial trauma
 - Local tissue inflammation (e.g., tonsillitis, tumor)
 - Comorbidities (e.g., diabetes)
 
 - Abdominal and pelvic actinomycosis (See PID)
- Intestinal surgery
 - Foreign body ingestion
 - Tumor
 - Ascending infection from the uterus, associated with intra-uterine contraceptive devices
 
 - Thoracic actinomycosis
- History of aspiration
 - Recent oral infection
 
 
Clinical features
- Cervicofacial actinomycosis
- Slowly progressive mass in the neck and/or face; most commonly in the mandible region
 - Usually painless nodular lesions
 - Becomes indurated with purulent discharge that contains sulfur granules  from fistulae and draining sinus tracts.
- Sulfur granules refer to macroscopic grains – approx. 1 mm in diameter – of hard clumps of bacterial filaments, pus, debris, and hyaline. The granules appear yellow within pus, although despite the name they do not contain sulfur.
 
 
 - Thoracic actinomycosis
- Cough, chest pain
 - Possible hemoptysis with yellow granules
 
 
Tip
Definitive diagnosis is based on the identification of actinomycotic sulfur granules or bacteria.
Diagnostics
- Microscopy: direct visualization and staining of specimen → accumulations of radially protruding and branching Actinomyces (conglomerates with a “cauliflower-like” appearance) that are surrounded by numerous granulocytes

 

An aggregate of basophilic bacteria with radially branching filaments is visible at the center, which has a cauliflower-like appearance (yellow overlay).
The bacteria are surrounded by numerous granulocytes, resulting in a lesion with a rosette-like pattern (green overlay).
This is the typical histopathological appearance of a yellow “sulfur granule” caused by actinomycosis.
Treatment
Penicillin