A novel genotypic test for rapid detection of multidrug-resistant Mycobacterium tuberculosis isolates by a multiplex...

To develop and evaluate a novel genotypic test for rapid detection of rifampicin and isoniazid resistance of multidrug-resistant (MDR) Mycobacterium tuberculosis isolates by a multiplex probe array.

A multiplex probe array was designed for genotypic test to simultaneously screen the mutations of rpoB, katG, inhA and ahpC genes, associated with rifampin and isoniazid resistance in M. tuberculosis, with a probe detecting one of the recently confirmed genetic markers of isoniazid resistance ahpC-6 and -9 locus added. By using the genotypic test developed, 52 MDR isolates were identified, among which 46 isolates had mutations in rpoB (88.5%) and 45 at codon 315 of katG, regulatory region of inhA and oxyR-ahpC intergenic region (86.5%), whereas all 35 susceptible isolates identified showed a wild-type hybridization pattern. The sensitivity and specificity were 88.5% and 100% for rifampicin resistance, and 86.5% and 100% for isoniazid resistance, respectively.

A rapid and simultaneous detection of rifampicin and isoniazid resistance caused by the mutations of rpoB, katG, inhA and ahpC genes in M. tuberculosis isolates could be achieved by a multiplex probe array developed.

This genotypic test protocol has the potential to be developed on clinical application for the rapid detection of drug resistant M. tuberculosis isolates before an efficient chemotherapy is initiated.