Rapid and low-cost colorimetric method using 2,3,5-triphenyltetrazolium chloride for detection of multidrug-resistant Mycobacterium tuberculosis Mohammadzadeh, Alireza and Farnia, Parisa and Ghazvini, Kiarash and Behdani, Mahdi and Rashed, Tahereh and Ghanaat, Javad,, 55, 1657-1659 (2006), doi = https://doi.org/10.1099/jmm.0.46442-0, publicationName = Microbiology Society, issn = 0022-2615, abstract= A rapid and inexpensive method for the detection of drug resistance in Mycobacterium tuberculosis is essential for the effective control of tuberculosis. The aim of this study was to evaluate a colorimetric method using 2,3,5-triphenyltetrazolium chloride (TTC) for antibiotic susceptibility testing of M. tuberculosis isolates. Eleven multidrug-resistant (MDR) isolates of M. tuberculosis and 12 isolates which were susceptible to rifampicin (RIF) and isoniazid (INH) were used. The test was performed with a critical concentration of 0.2 μg ml−1 for INH and 2.0 μg ml−1 for RIF in 7H9GC broth with 0.625 μg TTC ml−1. Each isolate was inoculated under these conditions and inspected daily for colour changes; the results were obtained after a mean of 4.9 days. The sensitivity and specificity of this method were 100 % and 92 %, respectively, for both antibiotics. Considering the speed, technical ease and cost-effectiveness of this method, the TTC assay is a good alternative method for drug susceptibility testing of M. tuberculosis isolates., language=, type=