Test Details: The BACTEC MGIT 960 susceptibility test is based on growth of the Mycobacterium tuberculosis isolate in a drug-containing tube compared to a drug-free tube (Growth Control). The BACTEC MGIT 960 instrument continually monitors tubes for increasing fluorescence. Analysis of fluorescence in the drug-containing tube compared to the fluorescence of the growth control tube is made by the instrument to determine susceptibility results for SIRE and PZA at various concentrations. A result of susceptible or resistant is reported by the instrument.