Abstract

Rapid diagnosis of multidrug- resistant Mycobacterium tuberculosis (MDR-TB) plays a role in guiding standardized treatment regimen. Traditional drug susceptibility (DST) testing takes about six to eight weeks. Therefore, the aim of the present study is to characterize the mutations in rpoB and katG genes from the sputum specimens of MDR-TB by using polymerase chain reaction (PCR)-direct sequencing analysis and to diagnose the MDR-TB as soon as earlier. The sensitivity and specificity of this molecular DST would be assessed further. Rpob and katG genes were detected directly from the clinical sputum specimens of inpatients with MDR-TB by PCR-direct sequencing. The sensitivity, specificity of rpoB and katG gene for 48 specimens was as follows: 95.8, 100% and 93.75, 97.9%, respectively. Our study demonstrated that PCR-direct sequencing analysis was a rapid, sensitive and specific molecular approach for the mutation detection of rpoBand katG genes that are associated with multidrug-resistance clinical sputum specimens within 48 h of receipt, which is more rapid than drug susceptibility testing after the bacillus culture.

Key words: Multidrug-resistant Mycobacterium tuberculosis, polymerase chain reaction (PCR)-direct sequencing, genetic mutation, diagnosis, rpoB, katG.