Mycobacterium simiae is a nontuberculous mycobacterium that does not commonly cause clinical disease. We describe a case of M. simiae pulmonary infection in a patient with common variable immunodeficiency (CVID).

Our patient is a 74-year-old female with a history of bronchiectasis and Mycobacterium avium complex (MAC) pulmonary infection that prompted an immunodeficiency evaluation. After about one year of MAC therapy, the patient was diagnosed with CVID. Prior to starting IVIG, the patient presented with hemoptysis, increased cough and new airspace disease on chest CT. Bronchoalveolar lavage and five sputum cultures were positive for M. simiae sensitive to clarithromycin, sulfamethaxazole and gatifloxacin. The patient was started on these antibiotics and IVIG therapy was initiated one month later. The patient improved clinically over the next 6 months on this therapy.

M. simiae is an environmental organism whose role in clinical disease remains to be established. Most reports of isolation, usually unrelated to clinical disease, have occurred in a small group of specific locations including Texas, Arizona, Israel and Guadelupe. Published cases of clinical pulmonary disease usually involved patients with chronic lung disease, namely bronchiectasis or prior mycobacterial disease, while reports of disseminated disease most often occurred in HIV infected individuals. It is likely that the bronchiectasis related to CVID in this patient contributed to her development of clinical M. simiae pulmonary infection.

To our knowledge, this is the first case of Mycobacterium simiae infection in a patient with common variable immunodeficiency.