Rapid Detection of Tuberculosis Resistant to Isoniazid and Rifampicin by Real-Time PCR and Melting Curve Analysis

Abstract

Tuberculosis (TB) is a chronic disease and drug resistant tuberculosis is considered a serious public health treat. The treatment of multi-drug resistant tuberculosis (MDR-TB) in which M. tuberculosis poses resistance to at least isoniazid and rifampicin, major anti-tuberculosis drugs is difficult and time consum-ing. Drug-susceptibility testing (DST) for Mycobacterium tuberculosis (MTB) is important for the effec-tive treatment of tuberculosis (TB). This study assessed the real-time PCR method for rapid detection of drug-resistant tuberculosis (DR-TB). The assay was able to detect MTB resistant to isoniazid (INH) and rifampicin (RMP) simultaneously based on the analysis of DNA mutations. A total of 148 MTB clinical isolates having the results of DST, a standard method based on culture, were selected and subjected to real-time PCR analysis. A comparison of real-time PCR results and DST data showed a concordance, 54 of 54 (100%) in susceptible strains, 43 of 50 (86%) for INH resistance, 5 of 6 for RMP resistance and 34 of 38 isolates (89%) for multidrug-resistant TB (MDR-TB). Comparison of detection results by real-time PCR and DST, 12 samples showed discrepancy results. Further analysis revealed concordance with se-quencing analysis in 11 of 12 samples. In conclusion, the method is rapid and suits for routine use in rapid detection of drug resistant TB. The detection result provides useful information in the initiation of TB treatment.