Pulmonary mycobacteriosis caused by rifampicin-resistant Mycobacterium szulgai

We describe a rare case of pulmonary mycobacteriosis infected with rifampicin (RFP)-resistant Mycobacterium szulgai that was successfully eradicated with clarithromycin (CAM) treatment. An 80-year-old man was admitted to our hospital with a 4-week history of high fever, productive cough and malaise. Chest roentgenogram showed an infiltrative shadow in the left lower lung field. Isolated bacteria from sputum were acid-fast bacilli and identified as M. szulgai by the DNA-DNA hybridization method. Drug susceptibility tests showed resistance to RFP (MIC>100 microg/ml). Combined treatment with ethionamide, streptomycin and isoniazid based on the results of drug susceptibility tests resulted in clinical and radiologic improvement within two years. Additional treatment with CAM for another year resulted in complete eradication of the mycobacterium.