Rapid and simple MTT method for rifampicin and isoniazid susceptibility testing of Mycobacterium tuberculosis.
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.
Foongladda
S
S
Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkoknoi, Bangkok, Thailand. sisfm@mahidol.ac.th
Roengsanthia
D
D
Arjrattanakool
W
W
Chuchottaworn
C
C
Chaiprasert
A
A
Franzblau
S G
SG
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
D000995:Antitubercular Agents; D007538:Isoniazid; D012293:Rifampin