title: Sputum induction is a safe procedure to use in prisoners and MGIT is the best culture method to diagnose tuberculosis in prisons: a cohort study.
abstract: OBJECTIVE
  To evaluate the concordance and safety of induced sputum (IS) and spontaneous sputum (SS), and estimate concordance and time to detection of M. tuberculosis between Lowenstein-Jensen (LJ), thin-layer agar (TLA), and the Mycobacteria Growth Indicator Tube system (MGIT).
  
  
  METHODS
  This was a cohort study. Prisoners with pulmonary tuberculosis (PTB) were followed for 2 years. At baseline and every follow-up visit, three sputum samples were taken on consecutive days (one IS and two SS) and adverse events occurring before, during, and 30 min after IS were registered. All sputum samples were stained with auramine and cultured in LJ, TLA (to test resistance), and MGIT.
  
  
  RESULTS
  Five hundred eighty-six IS and 532 SS were performed on 64 PTB patients. Breathlessness (1.6%), cough (1.2%), hemoptysis (0.3%), and cyanosis (0.2%) were the only complications. Concordance between IS and SS was 0.78 (95% confidence interval 0.69-0.87); 11 positive cultures from IS samples were negative in SS, and 11 positive cultures from SS samples were negative in IS. One hundred seventy-eight cultures were positive by any technique: MGIT 95%, LJ 73%, and TLA 57%. Time to detection of M. tuberculosis in LJ, TLA, and MGIT was 31, 18, and 11 days, respectively.
  
  
  CONCLUSIONS
  The IS procedure is safe in prisons. The MGIT system is better and faster than LJ and TLA in the diagnosis of M. tuberculosis.
authors.affiliation: Grupo Investigador de Problemas en Enfermedades Infecciosas, Facultad de Medicina, Calle 62 # 52-59, lab 630, Sede de Investigación Universitaria, Universidad de Antioquia, Medellín, Colombia. Electronic address: zulmaruedav@gmail.com.
authors.forename: Zulma Vanessa
authors.initials: ZV
authors.lastname: Rueda
authors.affiliation: Facultad de Medicina, Universidad Pontificia Bolivariana, Medellín, Colombia.
authors.forename: Lucelly
authors.initials: L
authors.lastname: López
authors.affiliation: Grupo Demografía y Salud, Facultad Nacional de Salud Pública, Universidad de Antioquia, Medellín, Colombia.
authors.forename: Diana
authors.initials: D
authors.lastname: Marín
authors.affiliation: Grupo Investigador de Problemas en Enfermedades Infecciosas, Facultad de Medicina, Calle 62 # 52-59, lab 630, Sede de Investigación Universitaria, Universidad de Antioquia, Medellín, Colombia.
authors.forename: Lázaro A
authors.initials: LA
authors.lastname: Vélez
authors.affiliation: Grupo de Epidemiología, Facultad Nacional de Salud Pública, Universidad de Antioquia, Medellín, Colombia.
authors.forename: María Patricia
authors.initials: MP
authors.lastname: Arbeláez
mesh_terms: D000362:Agar; D001431:Bacteriological Techniques; D001576:Benzophenoneidum; D015331:Cohort Studies; D004396:Coloring Agents; D003470:Culture Media; D003948:Diagnostic Techniques, Respiratory System / Q000009:adverse effects; D005260:Female; D006801:Humans; D008297:Male; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D011329:Prisoners; D011446:Prospective Studies; D013183:Sputum / Q000382:microbiology*; D013997:Time Factors; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*
chemical_list: D004396:Coloring Agents; D003470:Culture Media; D001576:Benzophenoneidum; D000362:Agar
keywords: Culture techniques; Diagnosis; Induced sputum; Prisons; Spontaneous sputum; Tuberculosis