Non-tuberculous slow-growing mycobacterial pulmonary infections in non-HIV-infected patients in south London.

BACKGROUND

UK data on slow-growing non-tuberculous mycobacterial (NTM) pulmonary infections are sparse and there is little consensus on optimal treatment regimens.

METHODS

This was a retrospective study of NTM pulmonary infections in a London teaching hospital. Inclusion criteria were culture of slow-growing mycobacteria between 2000 and 2007, age > 18 y, HIV-negative, and meeting American Thoracic Society criteria.

RESULTS

Fifty-seven patients were included; 68% were males and the median age was 61 y. Predisposing factors were smoking (70%), alcohol abuse (28%), and chronic obstructive pulmonary disease (37%). Cavitation (56%) and infiltrates (42%) were common radiological findings. The predominant organism was Mycobacterium kansasii (70%). Ninety-three percent of patients with M. kansasii, 63% with Mycobacterium avium intracellulare, 60% with Mycobacterium malmoense, and 25% with Mycobacterium xenopi had clinical disease. Of the 57 patients, 37 were treated and had follow-up data available. Most patients received 3 drugs: rifampicin, ethambutol, and clarithromycin or ciprofloxacin for at least 9 months. Thirty percent experienced drug side effects. M. kansasii treatment had a 100% cure and 10% relapse rate, but 15% died.

CONCLUSIONS

M. kansasii was the most common NTM and its isolation was predictive of clinical disease. Compared with other studies, treatment with 3 agents had a similar rate of cure and did not appear to reduce the relapse rate of disease, but did increase the risk of side effects.