Pulmonary non-tuberculous mycobacteria in a general respiratory population

The prevalence of non-tuberculous mycobacterium (NTM) appears to be increasing. Much of the experience in the literature about this emerging organism comes from specialised units or populations such as cystic fibrosis patients. We, therefore, aim to evaluate the experience in a general respiratory population of dealing with patients with positive culture of NTM. We did a retrospective review of medical notes of general respiratory patients from whom NTM were isolated from January 2007 to July 2012. Cystic fibrosis patients were excluded. We reviewed 37 patients' (19 males, 18 females) medical records. A total of 73 positive cultures were reviewed. 28 isolates were from sputum samples alone, 34 isolates were from bronchoalveolar lavage alone and 11 isolates were from a combination of sputum and bronchoalveor lavage (11 isolates), We found that Mycobacterium avium was the most frequently isolated Mycobacterium in our laboratory with 22 (60%) patients had Mycobacterium avium in their pulmonary cultures. Interestingly, Mycobacterium gordonae and mycobacterium intracellulare were the second commonest mycobacterium (4, 11%) cultured. We noted 2 (5%), cases of Mycobacterium szulgai, 2 (5%) cases of Mycobacterium chelonae and 2 (5%) cases of Mycobacterium abscessus. There was 1(3%) case of Mycobacterium malmoense. There is prevalence of NTM in male COPD patients (7, 89%) and femal bronchiectasis (10, 77%) patients. Of our 8 COPD patients, 6 (75%) were on inhaled corticosteroids while 2 (25%) were not. 9 (24%) patients were smokers, 11 (30%) were ex-smokers, 14 (38%) were non-smokers and the smoking status of the remaining 3 (8%) was unknown. Of the 37 patients, only 6 (16%) received treatment. However, 2 patients stopped their treatment due to treatment toxicity. We concluded that the isolation of NTM is not uncommon. Defining NTM disease is difficult and deciding which patient to be treated needs careful evaluation as treatment can potentially be very toxic.