ABSTRACT
Background: In view of the diagnostic difficulties associated with sputum- negative pulmonary TB (PTB), we aimed at exploring if bronchoalveolar lavage (BAL) samples can be subjected to smear- microscopy and rapid mycobacterial culture (by Mycobacterial Growth Indicator Tube (MGIT) method) to achieve improved diagnosis of this condition. Methods: Patients presenting with clinico-radiological features suggestive of pulmonary tuberculosis and whose sputum smears were negative for acid- fast bacilli (AFB) or who could not expectorate sputum were prospectively enrolled in this study. BAL samples collected from them were subjected to smear- microscopy for AFB and micro-MGIT culture. BAL samples were also inoculated on Lowenstein- Jensen (LJ) slants. Results: A total of 105 patients (74 males) were recruited in the study, with a mean (±SD) age of 51 (± 15) years. The diagnosis of PTB was made in 52 patients on the basis of clinico- radiological presentation, with or without microbiological confirmation. Thirty- four patients (65.4 %) had microbiologically confirmed PTB. Of them, AFB were detected in 12 BAL samples, while culture- positivity was noted in 24 and 27 patients by the LJ and MGIT methods respectively. Intertest agreement between the LJ and MGIT methods was found to be significant (ê= 0.655; p= <0.001). However, the mean time to positivity was significantly lower for the MGIT method than for the LJ method (p= <0.001). Conclusion: Examination of BAL samples by smear- microscopy and micro-MGIT culture can, therefore, provide a rapid and definitive diagnosis of PTB in sputum- negative patients.
Subject(s)
Adolescent , Adult , Aged , Bronchoalveolar Lavage/analysis , Bronchoalveolar Lavage/microbiology , Bronchoscopy/methods , Culture Techniques , Humans , Middle Aged , Microbial Sensitivity Tests/instrumentation , Microbial Sensitivity Tests/methods , Microscopy/methods , Mycobacterium tuberculosis/growth & development , Sputum/microbiology , Tuberculosis, Pulmonary/diagnosis , Young AdultABSTRACT
The Cohas Amplicor Mycobacterium tuberculosis [CAMTB] assay was evaluated for routine detection and identification of Mycobacterium tuberculosis complex [MT-BC]. 80 sputum samples from 80 suspected patients were tested by AFB smear, Lowenstein -Jensen media culture and by CAMTB. 50 patients were sputum AFB smear negative and patients were subjected to bronchoscopy for bronchoalveolar lavage [BAL] samples which were tested by the same methods, and results were compared. The sensitivity, specificity, PPV and NPV of the CAMTB with sputum samples were 95%, 90%, 90 and 94% respectively