[Three cases of Mycobacterium avium lung disease in an iron foundry].

We report three cases of M. avium lung disease, all occurring in the same iron foundry over a 5-year period. Case 1: A 38-year-old man was admitted to our hospital because of abnormal chest x-ray shadows observed during a routine checkup. M. avium complex was isolated from the sputum and a CT scan showed multiple nodular shadows with cavities. Case 2: A 63-year-old man presented with dyspnea. Chest CT showed nodular shadows in both upper lobes. M. avium complex was isolated from his sputum. Case 3: A 62-year-old man was hospitalized for treatment of diabetes mellitus. A nodular cavitary shadow* OK?* in the right upper lobe was observed in the radiograph. CT scanning demonstrated a nodular shadow with thick pleural indentation. M. avium was isolated from the sputum and gastric juices. There were similarities in the radiographic findings in all cases: nodular shadows with cavities in the upper lung fields. These findings differed from those in another M. avium infection in the lung which occurred in a middle-aged woman. We suspected inhalation of an aerosol contaminated by M. avium complex. There have hitherto been no reports of group infections in healthy persons. We suspected the same environmental source for the infection.