infectious diseases
Actinomycosis
Diagnosis of Actinomycosis
Microscopy Culture Actinomycosis is suspected clinically and confirmed by identification ofA. israeliior otherActinomycesspecies using microscopy and culture of sputum (ideally obtained endoscopically), pus, or a biopsy specimen. Imaging tests (eg, chest x-ray, abdominal or thoracic CT) are often done depending on findings. In pus or tissue, the microorganism appears as the distinctive sulfur granules or as tangled masses of branched and unbranched wavy bacterial filaments, pus cells, and debris, surrounded by an outer zone of radiating, club-shaped, hyaline, and refractive filaments that take hematoxylin-eosin stain in tissue but are positive on Gram stain. The laboratory must be notified that actinomycosis is suspected because special procedures are required to isolate and identify these organisms. Lesions in any location may simulate malignant growths. Lung lesions must be distinguished from those of TB and cancer. Most abdominal lesions occur in the ileocecal region and are difficult to diagnose, except during laparotomy or when draining sinuses appear in the abdominal wall. 