title: The diagnostic utility of line probe assays for multidrug-resistant tuberculosis.
abstract: Owing to the burden of multidrug-resistant tuberculosis, molecular techniques have been approved by the WHO for the rapid diagnosis of the same. The objectives of this prospective, diagnostic study, conducted at Christian Medical College, a tertiary care center in South India, were to compare the performance of line probe assay (GenoTypeMTBDRplus) with culture, as well as the Xpert MTB/Rif assay on sputum samples. Ninety-one consecutive suspects of multidrug-resistant pulmonary tuberculosis patients from January 2013 to June 2013 were enrolled in this study and the results of line probe assay compared to culture and Xpert MTB/Rif. Compared to culture, the assay demonstrated a sensitivity and specificity of 81.5% (95%CI 67.4-91.1%) and 87.5% (95%CI 71-96.5%) for the detection of tuberculosis, with sensitivity and specificity of 100% (95%CI 85.2-100%) and 93.8% (95%CI 69.8-99.8%), respectively, for rifampicin resistance. For isoniazid resistance, sensitivity and specificity were 89.3% (95%CI 71.8-97.7%) and 100% (95%CI 71.5-100%), respectively. Compared to Xpert MTB/Rif assay, the assay showed a sensitivity of 80% (95%CI 68.2-88.9%) and specificity of 100% (95%CI 85.8-100%) for the detection of tuberculosis a sensitivity of 94.3% (95%CI 80.8-99.3%) and specificity of 94.1% (95%CI 71.3-99.9%) for rifampicin resistance was attained. This assay performed well on smear positive samples, but poorly on smear negative and scanty samples, and can serve as a rapid diagnostic tool, particularly in isoniazid monoresistant cases of tuberculosis, which are not diagnosed by Xpert MTB/Rif.
authors: a Department of Microbiology , Christian Medical College and Hospital , Vellore , India.
authors: Marilyn M
authors: MM
authors: Ninan
authors: b Department of Biostatistics , Christian Medical College and Hospital , Vellore , India.
authors: Mahasampath
authors: M
authors: Gowri
authors: c Department of Pulmonary Medicine , Christian Medical College and Hospital , Vellore , India.
authors: D J
authors: DJ
authors: Christopher
authors: d Department of Infectious Diseases , Christian Medical College and Hospital , Vellore , India.
authors: Priscilla
authors: P
authors: Rupali
authors: a Department of Microbiology , Christian Medical College and Hospital , Vellore , India.
authors: Joy S
authors: JS
authors: Michael
mesh_terms: D000328:Adult; D015342:DNA Probes / Q000235:genetics*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005260:Female; D006801:Humans; D007194:India; D008297:Male; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D011446:Prospective Studies; D015203:Reproducibility of Results; D012293:Rifampin / Q000494:pharmacology; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D062606:Tertiary Care Centers; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis* / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000382:microbiology; D055815:Young Adult
chemical_list: D015342:DNA Probes; D012293:Rifampin
keywords: Diagnostics; Drug resistance; Tuberculosis