Mycolic acid index susceptibility method for Mycobacterium tuberculosis.
A rapid drug susceptibility test to measure the susceptibility of Mycobacterium tuberculosis to isoniazid (INH) and rifampin (RIF) using clinical isolates and a newly defined mycolic acid index (MAI) was evaluated. A total of 200 clinical isolates of M. tuberculosis were tested for susceptibility or resistance to INH and RIF by the MAI susceptibility and indirect-proportion methods. Overall, there was agreement between the two methods for 398 (99.5%) of the 400 total tests. Specifically, the sensitivity of the MAI susceptibility method for INH and RIF was 97.6 and 100%, respectively. The specificity and positive predictive value were 100% for both drugs, and the negative predictive value for INH and RIF was 98.3 and 100%, respectively. In conclusion, the MAI susceptibility method described here can be used for rapid drug susceptibility testing of M. tuberculosis clinical isolates within 5 days after clinical isolates are incubated in the presence or absence of an antituberculosis drug.
Viader-Salvadó
J M
JM
Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, México. jviader@ccr.dsi.uanl.mx
Garza-González
E
E
Valdez-Leal
R
R
del Bosque-Moncayo
M A
MA
Tijerina-Menchaca
R
R
Guerrero-Olazarán
M
M
D000995:Antitubercular Agents / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D006801:Humans; D007538:Isoniazid / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests / Q000379:methods / Q000592:standards; D009169:Mycobacterium tuberculosis / Q000737:chemistry* / Q000187:drug effects*; D009171:Mycolic Acids / Q000032:analysis*; D011237:Predictive Value of Tests; D012293:Rifampin / Q000494:pharmacology*; D012680:Sensitivity and Specificity; D013997:Time Factors; D014397:Tuberculosis, Pulmonary / Q000382:microbiology
D000995:Antitubercular Agents; D009171:Mycolic Acids; D007538:Isoniazid; D012293:Rifampin