title: Rapid detection of isoniazid and rifampin resistance mutations in Mycobacterium tuberculosis complex from cultures or smear-positive sputa by use of molecular beacons.
abstract: The slow-growing nature of Mycobacterium tuberculosis complex hinders the improvement of turnaround time for phenotypic drug susceptibility testing. We designed a set of molecular beacons for the detection of isoniazid and rifampin resistance mutations in M. tuberculosis complex organisms from cultures or from N-acetyl-l-cysteine-NaOH-treated, smear-positive specimens. The performance of the molecular beacons was characterized by studying a total of 196 clinical isolates (127 drug-resistant isolates and 69 drug-susceptible isolates). For detection of isoniazid resistance, the sensitivity and specificity of the assay were 82.7 and 100%, and the positive predictive value (PPV) and negative predictive value (NPV) at a resistance prevalence of 10% were 100 and 98.11%, respectively. For detection of rifampin resistance, the sensitivity and specificity of the assay were 97.5 and 100%, and the PPV and NPV at a resistance prevalence of 2.0% were 100 and 99.95%, respectively.
authors.affiliation: Microbial Diseases Laboratory, California Department of Health Services, Richmond, CA 94804, USA.
authors.forename: S-Y Grace
authors.initials: SY
authors.lastname: Lin
authors.forename: William
authors.initials: W
authors.lastname: Probert
authors.forename: Melanie
authors.initials: M
authors.lastname: Lo
authors.forename: Edward
authors.initials: E
authors.lastname: Desmond
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D001483:Base Sequence; D017931:DNA Primers; D024881:Drug Resistance, Bacterial; D006801:Humans; D007538:Isoniazid / Q000494:pharmacology*; D009154:Mutation / Q000235:genetics; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013048:Specimen Handling / Q000379:methods; D013183:Sputum / Q000382:microbiology*
chemical_list: D000995:Antitubercular Agents; D017931:DNA Primers; D007538:Isoniazid