Rapid and Ultrasensitive Approach for the Simultaneous Detection of Multilocus Mutations to Distinguish Rifampicin-Resistant Mycobacterium tuberculosis

The untested empirical medications exacerbated the development of multidrug-resistant Mycobacterium tuberculosis (MDR-TB). Here, we develop a rapid and specific method based on loop-mediated isothermal amplification and duplex-specific nuclease for distinguishing rifampicin-resistant M. tuberculosis. Three probes were designed for the codons 516, 526, and 531 on the RNA polymerase β-subunit (rpoB) gene. These three sites accounted for more than 90% of the total mutations of the ropB gene in the rifampicin-resistant strain. The approach can perform simultaneous and sensitive detection of three mutant sites with the actual detection limit as 10 aM of DNA and 62.5 cfu·mL-1 of bacteria in 67 min under isothermal conditions. Moreover, the positive mode of the approach for MDR-TB can not only deal with the randomness and diversity of mutations but also provide an easier way for medical staff to read the results. Therefore, it is a particularly valuable method to handle major and urgent MDR-TB diagnostics.