Pulmonary infection caused by Mycobacterium gordonae in immunocompetent patient

We report a case of 67-year-old female immunocompetent patient admitted to our hospital because of hemoptysis. Computed tomography (CT) of the lung showed bronchiectasis in the right S5 and small nodules in the right S6 and left S5. The cultures of sputum and bronchial washing specimen repeatedly revealed acid-fast bacilli identified as Mycobacterium gordonae (M. gordonae) by DNA-DNA hybridization (DDH) method. Thus, she was diagnosed to be infected with M. gordonae. She was treated with isoniazid, rifampicin, ethambutol and streptomycin. After treatment, the cultures of sputum and bronchial washing specimen converted to negative, and the chest CT showed improvement of small nodules. M. gordonae is a nontuberculous mycobacterium of very low pathogenic potency. Recently there have been a few reports of infection by M. gordonae not only in immunocompromised patients but also in immunocompetent patients. These cases were considered to be sensitive to initial standard antimycobacterial therapy, therefore, it is important to examine for M. gordonae in cases suspected of nontuberculous mycobacterial infection.