[A case of pyothorax caused by Mycobacterium avium].

A 74-year-old woman was admitted to our hospital in December, 2003 because of anorexia and weight loss lasting from August, 2003. Chest CT scan showed empyema with a niveau in the right lung and infiltrative and nodular shadows in the left lung. Acid-fast bacilli were detected in pleural effusion. Polymerase chain reaction (PCR) test was negative for Mycobacterium tuberculosis (M. tuberculosis) but positive for Mycobacterium avium (M. avium). PCR test for M. avium was also positive in bronchial lavage fluid, and many colonies of M. avium complex ( MAC) were cultured from pleural effusion. After we administered 4 drugs including RFP, EB, SM, and CAM, cultured colonies of M. avium decreased, the inflammatory reaction improved, and infiltrates in the left upper lobe has disappeared. These improvements confirmed the diagnosis of empyema caused by M. avium. Since nontuberculous mycobacteria induced empyema has rarely been reported, the clinical features of this disease should further be examined.