Isolation of multiple nontuberculous mycobacteria species in the same patients.

BACKGROUND: During the observation of many patients with nontuberculous mycobacteria (NTM) infections, we have often isolated different NTM species in the same patient. In this study we elucidated the patterns of multiple NTM species isolation.

METHODS: The analysis included all patients from whom more than one species of mycobacteria were cultured from a respiratory specimen at Seoul National University Hospital, a tertiary referral hospital in South Korea, between January 2002 and December 2008. The demographic characteristics and clinical and radiographic findings were reviewed retrospectively.

RESULTS: Multiple NTM species were isolated from 37 patients. Four patients with Mycobacterium gordonae, Mycobacterium terrae, or Mycobacterium lentiflavum were excluded due to the possibility of contamination. Transition to another NTM species was observed in 23 patients (69.7%), while alternating isolation of two or three NTM species was seen in nine patients. Two species were isolated simultaneously from different sputum samples collected from one patient on the same day.

CONCLUSIONS: Different NTM species were isolated from the same patients.