title: Manual liquid culture on simple Middlebrook 7H9 or MGIT for the diagnosis of smear-negative pulmonary tuberculosis.
abstract: OBJECTIVE
  To compare the performance of liquid culture on simple Middlebrook 7H9 to the one of manual mycobacterial growth indicator tube (MGIT) and solid culture on Ogawa for the diagnosis of smear-negative tuberculosis (SN-TB) in a high-burden, resource-constrained setting.
  
  
  METHODS
  Sputum samples from patients with clinical suspicion of SN-PTB admitted to two-third-level hospitals in Lima between September 2005 and May 2008 were cultured in parallel on simple Middlebrook 7H9, manual MGIT and Ogawa. A case of SN-TB was defined as one with a positive culture in any medium.
  
  
  RESULTS
  Among samples from 542 patients, 151 (28%) cases of SN-TB were identified. The sensitivity of Middlebrook 7H9 (0.76, 95% CI 0.69-0.83) was not substantially different from that of MGIT (0.85, 95% CI 0.79-0.91). Ogawa had the lowest sensitivity (0.63, 95% CI 0.55-0.71). The median turnaround time was similar for both liquid media (18 days), and it was shorter than that of Ogawa (30 days).
  
  
  CONCLUSIONS
  Culture on simple Middlebrook 7H9 performs almost as well as MGIT, at a probably more affordable cost. Further studies on the cost-effectiveness of this overlooked technique should be performed.
authors.affiliation: Epidemiology & Disease Control Unit, Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: T
authors.initials: T
authors.lastname: Battaglioli
authors.forename: A
authors.initials: A
authors.lastname: Soto
authors.forename: J
authors.initials: J
authors.lastname: Agapito
authors.forename: V
authors.initials: V
authors.lastname: Acurio
authors.forename: P
authors.initials: P
authors.lastname: Van der Stuyft
mesh_terms: D000328:Adult; D001431:Bacteriological Techniques; D003470:Culture Media; D006295:Health Resources; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000254:growth & development*; D010568:Peru / Q000453:epidemiology; D011203:Poverty; D013183:Sputum / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology
chemical_list: D003470:Culture Media
keywords: M. tuberculosis; MGIT; Middlebrook 7H9; Mycobacterium tuberculosis; Ogawa; diagnosis; diagnostic; diagnóstico; mycobacterial growth indicator tube; smear-negative tuberculosis; tuberculose à frottis négatif; tuberculosis con baciloscopia negativa