[A case of pulmonary actinomycosis, who expectorated sulfur granules, caused by Actinomyces odontolyticus and Actinomyces meyeri].

A 51-year-old man complaining of cough and bloody sputum, was admitted to our hospital because of antibiotic-resistant chronic pneumonia in the right upper lobe. Initially, bronchoscopic examination and sputum culture revealed no evidence of malignancy or any specific infection, either pathologically or microbiologically. However, pathological examination of a solid body expectorated with sputum revealed typical sulfur granules, indicating pulmonary actinomycosis. Two actinomyceses named Actinomyces odontolyticus and Actinomyces meyeri were detected later. Pulmonary infection caused by these types of actinomyceses is rare, and the diagnostic procedure seemed to be unusual.