title: Diagnostic performance of automated liquid culture and molecular line probe assay in smear-negative pulmonary tuberculosis.
abstract: The diagnosis of smear-negative pulmonary tuberculosis (PTB) is particularly challenging, and automated liquid culture and molecular line probe assays (LPA) may prove particularly useful. The objective of our study was to evaluate the diagnostic potential of automated liquid culture (ALC) technology and commercial LPA in sputum smear-negative PTB suspects. Spot sputum samples were collected from 145 chest-symptomatic smear-negative patients and subjected to ALC, direct drug susceptibility test (DST) testing and LPA, as per manufacturers' instructions. A diagnostic yield of 26.2% was observed among sputum smear-negative TB suspects with 47.4% of the culture isolates being either INH- and/or rifampicin-resistant. Complete agreement was observed between the results of ALC assay and LPA except for two isolates which demonstrated sensitivity to INH and rifampicin at direct DST but were rifampicin-resistant in LPA. Two novel mutations were also detected among the multidrug isolates by LPA. In view of the diagnostic challenges associated with the diagnosis of TB in sputum smear-negative patients, our study demonstrates the applicability of ALC and LPA in establishing diagnostic evidence of TB.
authors: 1 Associate Professor, Department of Microbiology, Himalayan Institute of Medical Sciences, Dehradun, India.
authors: Aarti
authors: A
authors: Kotwal
authors: 2 Professor, Department of Microbiology, Himalayan Institute of Medical Sciences, Dehradun, India.
authors: Debasis
authors: D
authors: Biswas
authors: 3 Professor, Department of Radiodiagnosis, Himalayan Institute of Medical Sciences, Dehradun, India.
authors: Shailendra
authors: S
authors: Raghuvanshi
authors: 4 Professor, Department of Pulmonary Medicine, Himalayan Institute of Medical Sciences, Dehradun, India.
authors: Girish
authors: G
authors: Sindhwani
authors: 1 Associate Professor, Department of Microbiology, Himalayan Institute of Medical Sciences, Dehradun, India.
authors: Barnali
authors: B
authors: Kakati
authors: 5 Postgraduate Student, Department of Microbiology, Himalayan Institute of Medical Sciences, Dehradun, India.
authors: Shweta
authors: S
authors: Sharma
mesh_terms: D000328:Adult; D001431:Bacteriological Techniques / Q000379:methods*; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology; D018432:Drug Resistance, Multiple / Q000235:genetics; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015336:Molecular Probe Techniques; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000302:isolation & purification*; D010994:Pleura / Q000382:microbiology; D012293:Rifampin / Q000627:therapeutic use; D013183:Sputum / Q000382:microbiology; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D012293:Rifampin
keywords: Smear-negative pulmonary tuberculosis; automated liquid culture; line probe assay; multi-drug resistance