title: Rapid and accurate detection of rifampin and isoniazid-resistant Mycobacterium tuberculosis using an oligonucleotide array.
abstract: To rapidly detect rifampin, isoniazid and multidrug resistance in Mycobacterium tuberculosis isolates, a new system (BluePoint MtbDR, Bio Concept Inc., Taichung, Taiwan) including an oligonucleotide array and an automatic reader was evaluated. The array simultaneously identifies M. tuberculosis and predominant mutations in the rpoB, katG and inhA upstream regulatory region (inhA-r) genes. The system was assessed with 324 clinical M. tuberculosis isolates, including 210 multidrug-resistant, 41 rifampin mono-resistant, 34 isoniazid mono-resistant and 39 fully susceptible isolates. The results were compared with those obtained using the GenoType MTBDRplus test, drug-resistant gene sequencing and conventional drug susceptibility testing. The detection limit of the array was 25 pg DNA. The array and the GenoType MTBDRplus test detected 179 (85.2%) and 182 (86.7%) multidrug-resistant M. tuberculosis strains, respectively. The sensitivities of the array for detecting rifampin and isoniazid resistance were 98.4% and 87.7%, respectively, whereas the sensitivities of the GenoType MTBDRplus test for detecting rifampin and isoniazid resistance were 98.8% and 88.9%, respectively. No significant difference was found between the tests with respect to their sensitivities to detect multidrug resistance (p 0.66), rifampin resistance (p 0.69) or isoniazid resistance (p 0.68). The discrepancies were mainly attributed to rare mutations in inhA-r, which were not included in the array. The array can directly reveal transmission-associated mutations, which are useful for epidemiological investigations. The turnaround time of the array test was 6-7 h. This study confirms the feasibility of using this system for rapid and accurate diagnosis of isoniazid and rifampin resistance in M. tuberculosis.
authors.affiliation: Reference Laboratory of Mycobacteriology, Research and Diagnostic Centre, Centres for Disease Control, Taipei, Taiwan.
authors.forename: W-L
authors.initials: WL
authors.lastname: Huang
authors.forename: Z-J
authors.initials: ZJ
authors.lastname: Hsu
authors.forename: T C
authors.initials: TC
authors.lastname: Chang
authors.forename: R
authors.initials: R
authors.lastname: Jou
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D002374:Catalase / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D006801:Humans; D007538:Isoniazid / Q000494:pharmacology; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000302:isolation & purification*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D010088:Oxidoreductases / Q000235:genetics; D012293:Rifampin / Q000494:pharmacology; D012680:Sensitivity and Specificity; D013997:Time Factors; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis* / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D001426:Bacterial Proteins; D010088:Oxidoreductases; D002374:Catalase; C480353:katG protein, Mycobacterium tuberculosis; C085257:InhA protein, Mycobacterium; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit; D007538:Isoniazid; D012293:Rifampin
keywords: Drug resistance; isoniazid; rapid diagnosis; rifampin; tuberculosis