title: Direct detection of Mycobacterium tuberculosis in clinical specimens using single-tube biotinylated nested polymerase chain reaction-enzyme linked immunoassay (PCR-ELISA).
abstract: A biotinylated single-tube nested polymerase chain reaction (PCR) assay with microwell hybridization assay (bPCR-ELISA) was developed for detection of Mycobacterium tuberculosis in clinical specimens. A total of 659 specimens (601 respiratory specimens and 58 nonrespiratory specimens) were collected for evaluation using three DNA amplification techniques: newly designed bPCR-ELISA, in-house single-tube nested PCR for IS6110 gene sequence (nPCR), and commercial automated assays, the Cobas Amplicor System from Roche Diagnostic Systems (aPCR). Sixty-four (9.7%) specimens were culture-positive for M. tuberculosis. Eleven (1.7%) specimens culture-positive for nontuberculosis mycobacteria were negative by all three PCR assays. The resolved performance of bPCR-ELISA, nPCR, and aPCR was found at sensitivities of 97%, 94%, and 97%, respectively. All three PCR assays exhibited a 100% specificity. In evaluation of bPCR-ELISA, a clear distinction between PCR-positive and PCR-negative specimens when an OD405 value of 0.6 was chosen as cut-off. With serial dilutions of M. tuberculosis H37Rv DNA, the detection limit of bPCR-ELISA was found to be 0.75 cfu per reaction at OD405 value of 0.6. Our developed bPCR-ELISA provides a highly sensitive and low-costing molecular diagnosis suitable for developing countries with high prevalence of tuberculosis.
authors.affiliation: Department of Microbiology, The University of Hong Kong, University Pathology Building, Queen Mary Hospital, Hong Kong, China.
authors.forename: W C
authors.initials: WC
authors.lastname: Yam
authors.forename: V C C
authors.initials: VC
authors.lastname: Cheng
authors.forename: W T
authors.initials: WT
authors.lastname: Hui
authors.forename: L N
authors.initials: LN
authors.lastname: Wang
authors.forename: W H
authors.initials: WH
authors.lastname: Seto
authors.forename: K Y
authors.initials: KY
authors.lastname: Yuen
mesh_terms: D001431:Bacteriological Techniques; D001710:Biotin / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis / Q000382:microbiology*
chemical_list: D001710:Biotin