Identification and Characteristics of Co-isolation of Multiple Nontuberculous Mycobacteria

OBJECTIVE: Although multiple nontuberculous mycobacteria (NTM) species can be isolated from the same patient, little has been reported on co-isolation. We clarified the trends and characteristics of the co-isolation of multiple NTM species. METHODS: To collect data on multiple NTM isolation, we first extracted all patients who visited our hospital from 2006 through 2015 with a diagnosis of NTM lung diseases other than Mycobacterium avium complex (MAC) and then reviewed their medical records to evaluate the co-isolation of multiple NTM species. RESULTS: Of 213 patients with non-MAC lung disease, the most common NTM species was M. gordonae (32%), followed by M. kansasii (20%) and M. abscessus (14%). Non-MAC NTM lung disease tended to be associated with middle age with a low body mass index and male predominance. Multiple NTM species were isolated from 55 (26%) of the 213 patients. The clinical characteristics associated with multiple NTM species isolation included female predominance, never smokers and the absence of cavity lesions in the lungs. The highest co-isolation rate was observed in patients with M. gordonae isolation (30%), followed by M. furtuitum isolation (26%) and M. abscessus isolation (20%). Only MAC was isolated when co-isolated with M. abscessus. Among M. szulgai, M. peregrinum and M. terrae isolation, no other NTM species were detected. CONCLUSION: Co-isolation of multiple NTM species was not uncommon, with 26% of patients with non-MAC NTM lung diseases showing co-isolation with multiple NTM species. Each NTM species had distinct characteristics in terms of co-isolation.