title: Isolation of non-tuberculous mycobacteria in children investigated for pulmonary tuberculosis.
abstract: OBJECTIVE
  To evaluate the frequency and clinical significance of non-tuberculous mycobacteria (NTM) isolates among children investigated for pulmonary tuberculosis in a rural South African community.
  
  
  METHODS
  Children were investigated for pulmonary tuberculosis as part of a tuberculosis vaccine surveillance program (2001-2005). The clinical features of children in whom NTM were isolated, from induced sputum or gastric lavage, were compared to those with culture-proven M. tuberculosis.
  
  
  RESULTS
  Mycobacterial culture demonstrated 114 NTM isolates from 109 of the 1,732 children investigated, a crude yield of 6% (95% CI 5-7). The comparative yield of positive NTM cultures from gastric lavage was 40% (95% CI 31-50), compared to 67% (95% CI 58-76) from induced sputum. 95% of children with NTM isolates were symptomatic. Two children were HIV-infected. By contrast, M. tuberculosis was isolated in 187 children, a crude yield of 11% (95% CI 9-12). Compared to those with culture-proven M. tuberculosis, children with NTM isolates were less likely to demonstrate acid-fast bacilli on direct smear microscopy (OR 0.19; 95% 0.0-0.76). Children with NTM were older (p<0.0001), and more likely to demonstrate constitutional symptoms (p = 0.001), including fever (p = 0.003) and loss of weight or failure to gain weight (p = 0.04), but less likely to demonstrate a strongly positive tuberculin skin test (p<0.0001) or radiological features consistent with pulmonary tuberculosis (p = 0.04).
  
  
  CONCLUSIONS
  NTM were isolated in 6% of all children investigated for pulmonary tuberculosis and in more than one third of those with a positive mycobacterial culture. NTM may complicate the diagnosis of PTB in regions that lack capacity for mycobacterial species identification. The association of NTM isolates with constitutional symptoms suggestive of host recognition requires further investigation.
authors.affiliation: South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, South Africa. mark@rmh.uct.ac.za
authors.forename: Mark
authors.initials: M
authors.lastname: Hatherill
authors.forename: Tony
authors.initials: T
authors.lastname: Hawkridge
authors.forename: Andrew
authors.initials: A
authors.lastname: Whitelaw
authors.forename: Michele
authors.initials: M
authors.lastname: Tameris
authors.forename: Hassan
authors.initials: H
authors.lastname: Mahomed
authors.forename: Sizulu
authors.initials: S
authors.lastname: Moyo
authors.forename: Willem
authors.initials: W
authors.lastname: Hanekom
authors.forename: Gregory
authors.initials: G
authors.lastname: Hussey
mesh_terms: D005751:Gastric Lavage; D006801:Humans; D007223:Infant; D009161:Mycobacterium / Q000302:isolation & purification; D009164:Mycobacterium Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology*; D011446:Prospective Studies; D012141:Respiratory Tract Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology*; D012424:Rural Population; D013019:South Africa / Q000453:epidemiology; D013183:Sputum / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000382:microbiology