title: Rapid diagnosis of pulmonary tuberculosis.
abstract: BACKGROUND
  World Health Organization had estimated 9.4 million tuberculosis cases on 2009, with 1.7 million of deaths as consequence of treatment and diagnosis failures. Improving diagnostic methods for the rapid and timely detection of tuberculosis patients is critical to control the disease. The aim of this study was evaluating the accuracy of the cord factor detection on the solid medium Middlebrook 7H11 thin layer agar compared to the Lowenstein Jensen medium for the rapid tuberculosis diagnosis.
  
  
  METHODS
  Patients with suspected tuberculosis were enrolled and their sputum samples were processed for direct smear and culture on Lowenstein Jensen and BACTEC MGIT 960, from which positive tubes were subcultured on Middlebrook 7H11 thin layer agar. Statistical analysis was performed comparing culture results from Lowenstein Jensen and the thin layer agar, and their corresponding average times for detecting Mycobacterium tuberculosis. The performance of cord factor detection was evaluated determining its sensitivity, specificity, positive and negative predictive value.
  
  
  RESULTS
  111 out of 260 patients were positive for M. tuberculosis by Lowenstein Jensen medium with an average time ± standard deviation for its detection of 22.3 ± 8.5 days. 115 patients were positive by the MGIT system identifying the cord factor by the Middlebrook 7H11 thin layer agar which average time ± standard deviation was 5.5 ± 2.6 days.
  
  
  CONCLUSIONS
  The cord factor detection by Middlebrook 7H11 thin layer agar allows early and accurate tuberculosis diagnosis during an average time of 5 days, making this rapid diagnosis particularly important in patients with negative sputum smear.
authors.affiliation: School of Health Sciences, Universidad Pontificia Bolivariana (UPB), Medellín, Colombia ; Bacteriology and Mycobacteriology Unit, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia.
authors.forename: José Mauricio Hernández
authors.initials: JM
authors.lastname: Sarmiento
authors.affiliation: Bacteriology and Mycobacteriology Unit, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia.
authors.forename: Natalia Builes
authors.initials: NB
authors.lastname: Restrepo
authors.affiliation: School of Health Sciences, Universidad Pontificia Bolivariana (UPB), Medellín, Colombia ; Bacteriology and Mycobacteriology Unit, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia.
authors.forename: Gloria Isabel
authors.initials: GI
authors.lastname: Mejía
authors.affiliation: Bacteriology and Mycobacteriology Unit, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia.
authors.forename: Elsa
authors.initials: E
authors.lastname: Zapata
authors.affiliation: Bacteriology and Mycobacteriology Unit, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia.
authors.forename: Mary Alejandra
authors.initials: MA
authors.lastname: Restrepo
authors.affiliation: School of Health Sciences, Universidad Pontificia Bolivariana (UPB), Medellín, Colombia ; Bacteriology and Mycobacteriology Unit, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia.
authors.forename: Jaime
authors.initials: J
authors.lastname: Robledo
mesh_terms: D001431:Bacteriological Techniques / Q000379:methods; D003311:Cord Factors / Q000032:analysis; D005188:False Negative Reactions; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification / Q000648:ultrastructure; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*
chemical_list: D003311:Cord Factors
keywords: Cord Factor; MGIT; Tuberculosis; thin layer agar