title: Rapid and simple MTT method for rifampicin and isoniazid susceptibility testing of Mycobacterium tuberculosis.
abstract: The MTT method for rifampicin and isoniazid susceptibility testing of Mycobacterium tuberculosis was developed by using bacterial suspension prepared from colonies on solid media. The MTT tube assay in 1 ml Middlebrook 7H9 broth was completed within 4 days for rifampicin (RMP) and within 7 days for isoniazid (INH). When MTT assay results with 279 M. tuberculosis clinical isolates were compared with those of the conventional proportion method on Löwenstein-Jensen medium, high specificity and sensitivity values of 100% and 94.1%, respectively, for RMP susceptibility testing, and 99.5% and 89.2%, respectively, for INH susceptibility testing were obtained. The accuracy of the MTT method for RMP and INH was > 0.97 concordance with the proportion method. The MTT method is simple, inexpensive and rapid. The high level of agreement with the conventional proportion method suggests a potential to rapidly detect drug-resistant M. tuberculosis in developing countries, as only basic microbiological equipment is need.
authors.affiliation: Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkoknoi, Bangkok, Thailand. sisfm@mahidol.ac.th
authors.forename: S
authors.initials: S
authors.lastname: Foongladda
authors.forename: D
authors.initials: D
authors.lastname: Roengsanthia
authors.forename: W
authors.initials: W
authors.lastname: Arjrattanakool
authors.forename: C
authors.initials: C
authors.lastname: Chuchottaworn
authors.forename: A
authors.initials: A
authors.lastname: Chaiprasert
authors.forename: S G
authors.initials: SG
authors.lastname: Franzblau
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D006801:Humans; D066298:In Vitro Techniques; D007538:Isoniazid / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D011237:Predictive Value of Tests; D012293:Rifampin / Q000494:pharmacology*; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D000995:Antitubercular Agents; D007538:Isoniazid; D012293:Rifampin