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Non-tuberculous mycobacteria in patients with bronchiectasis
  1. M Wickremasinghe,
  2. L J Ozerovitch,
  3. G Davies,
  4. T Wodehouse,
  5. M V Chadwick,
  6. S Abdallah,
  7. P Shah,
  8. R Wilson
  1. Host Defence Unit, Royal Brompton Hospital, London, UK
  1. Correspondence to:
    Dr R Wilson
    Host Defence Unit, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK;r.wilsonrbh.nthames.nhs.uk

Abstract

Background: Non-tuberculous mycobacteria (NTM) are ubiquitous environmental organisms. Patients with pre-existing lung damage are susceptible to NTM, but their prevalence in bronchiectasis is unknown. Distinguishing between lung colonisation and disease can be difficult.

Methods: A prospective study of 100 patients with bronchiectasis was undertaken to evaluate the prevalence of NTM in sputum, and a retrospective analysis of clinical, microbiological, lung function and radiology data of our clinic patients with NTM sputum isolates over 11 years was performed.

Results: The prevalence of NTM in this population of patients with bronchiectasis was 2%. Patients in the retrospective study were divided into three groups: bronchiectasis + multiple NTM isolates (n = 25), bronchiectasis + single isolates (n = 23), and non-bronchiectasis + multiple isolates (n = 22). Mycobacterium avium complex (MAC) species predominated in patients with bronchiectasis compared with non-bronchiectasis lung disease (72% v 9%, p<0.0001). Single isolates were also frequently MAC (45.5%). Multiple isolates in bronchiectasis were more often smear positive on first sample than single isolates (p<0.0001). NTM were identified on routine screening samples or because of suggestive radiology. No particular bronchiectasis aetiology was associated with an NTM. Pseudomonas aeruginosa and Staphylococcus aureus were frequently co-cultured. Six (25%) of multiple NTM patients had cavities of which five were due to MAC. Half the patients with multiple isolates were treated, mostly due to progressive radiology.

Conclusions: NTM are uncommon in non-cystic fibrosis bronchiectasis. Routine screening identifies otherwise unsuspected patients. MAC is the most frequent NTM isolated.

  • AFB, acid fast bacilli
  • FEV1, forced expiratory flow in 1 second
  • MAC, Mycobacterium avium complex
  • MEF50, maximum expiratory flow with 50% of vital capacity remaining in lung
  • NTM, non-tuberculous mycobacteria
  • RV, residual volume
  • Tlco, carbon monoxide transfer factor
  • non-tuberculous mycobacteria
  • bronchiectasis
  • Mycobacterium avium complex
  • lung function

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Footnotes

  • Published Online First 14 October 2005

  • Competing interests: none declared.

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