- Often missed, particularly when it mimics malignancy
- Both fine-needle aspiration and biopsy are being used successfully to obtain clinical material for diagnosis, as are CT- and ultrasound-guided aspirations or biopsies
- The diagnosis is most commonly made by microscopic identification of sulfur granules
- occasionally these granules, if sought, can be grossly identified from draining sinus tracts or other purulent material
- Microbiologic identification of actinomycetes is possible in only a minority of cases and is often precluded by prior antimicrobial therapy. Therefore, for optimal yield, the avoidance of even a single dose of antibiotics is mandatory.
- Primary isolation usually requires 5 to 7 days but may take as long as 2 to 4 weeks
- Immunofluorescence testing for A. israelii, A. naeslundii, and P. propionicum (available through the Centers for Disease Control and Prevention in Atlanta) has become a useful diagnostic alternative
- Because these organisms are components of the normal oral and genital-tract flora, their identification in sputum, bronchial washings, and cervicovaginal secretions is of little significance in the absence of sulfur granules
- Actinomyces can be detected in urine by means of appropriate staining and culture.