title: Bronchoscopy in suspected pulmonary TB with negative induced-sputum smear and MTD(®) Gen-probe testing.
abstract: BACKGROUND
  In our institution, patients with suspected pulmonary TB undergo multiple induced-sputum sampling for microscopy, culture and nucleic acid amplification (NAA) with the MTD(®) Gen-probe assay. Those with negative induced-sputum results still suspected with TB are then referred for bronchoscopy. We sought to determine the diagnostic yield of bronchoscopy in these patients with negative initial induced-sputum results both via smear and NAA testing.
  
  
  METHODS
  We identified 30 consecutive cases of suspected pulmonary TB between 2001 and 2007, who had undergone a diagnostic bronchoscopy after negative results on induced-sputum smears and the MTD(®) Gen-probe on at least 2 samples.
  
  
  RESULTS
  The cohort (M = 20 & F = 10) had a median age of 37 (range 16-85 yrs); were predominantly foreign born (27/30); HIV-negative (29/30) individuals with strongly positive TST's (mean 18 + 5 mm). Induced-sputum cultures were negative for M-TB in all patients after a full 60-day incubation period. BAL was culture positive for M-TB in 3/30 cases (10%) with 2 strains being pan-sensitive and the third being INH resistant. BAL microscopy with acid-fast smear (n = 30) and BAL Gen-probe (n = 23) were negative in all cases. A third of the patients (9/27, 33%) with negative bronchoscopy results were treated for culture negative TB. Treatment for latent TB was initiated in 5/27 (18%) individuals whereas 13/27 (48%) received no further treatment.
  
  
  CONCLUSIONS
  Bronchoscopy provided diagnostic confirmation of pulmonary TB in 10% of subjects at least 2 negative induced-sputum samples by smear microscopy and NAA testing.
authors.affiliation: Division of Pulmonology and Critical Care Medicine, Mayo Clinic College of Medicine, Gonda 18S, 200 First Street SW, Rochester, MN 55905, USA. iyer.vivek@mayo.edu
authors.forename: Vivek N
authors.initials: VN
authors.lastname: Iyer
authors.forename: A Y
authors.initials: AY
authors.lastname: Joshi
authors.forename: T G
authors.initials: TG
authors.lastname: Boyce
authors.forename: M W
authors.initials: MW
authors.lastname: Brutinel
authors.forename: M C
authors.initials: MC
authors.lastname: Scalcini
authors.forename: J W
authors.initials: JW
authors.lastname: Wilson
authors.forename: Kevin
authors.initials: K
authors.lastname: McCoy
authors.forename: T R
authors.initials: TR
authors.lastname: Aksamit
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001999:Bronchoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000235:genetics*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D012189:Retrospective Studies; D013183:Sputum / Q000378:metabolism / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000382:microbiology / Q000473:pathology; D055815:Young Adult