This slant is recommended for cultivation of Mycobacterium tuberculosis and for resistance testing. Lowenstein Jensen Medium Base w/o Starch is recommended for drug resistance testing of Mycobacteria by WHO. Penicillin and nalidixic acid (FD053) along with malachite green prevents growth of the majority of contaminants . RNA (in FD053) acts as stimulant and helps to increase the isolation rate of Mycobacteria. Rifampicin (20 µg/ml) is the antibiotic used for resistance testing.