A rapid drug susceptibility test for Mycobacterium tuberculosis using the hybridization protection assay

The conventional drug susceptibility tests for Mycobacterium tuberculosis are time-consuming and the results are available only after 2-4 weeks. We have recently reported a new, simple and fast M. tuberculosis drug susceptibility test, using the hybridization protection assay (HPA), that allows the detection of isoniazid- or rifampicin-resistant strains of M. tuberculosis within 24 h of incubation. In the present study, the scope of application of our new test was extended to another two first-line antimycobacterial agents, namely ethambutol and streptomycin, and a quinolone antimicrobial agent, ciprofloxacin. The ethambutol-, streptomycin- and ciprofloxacin-resistance characteristics of M. tuberculosis were also delineated within 72 h of incubation with or without the drug. The results of our novel and rapid drug susceptibility test for M. tuberculosis were not only comparable to those determined by the conventional method, but became available within a few days of incubation. Our results also suggest that the drug susceptibility test using HPA might also be useful for detecting organisms resistant to antimicrobial agents other than antimycobacterials.