USE OF GAS-CHROMATOGRAPHIC FATTY-ACID AND MYCOLIC ACID CLEAVAGE PRODUCT DETERMINATION TO DIFFERENTIATE AMONG MYCOBACTERIUM-GENAVENSE, MYCOBACTERIUM-FORTUITUM, MYCOBACTERIUM-SIMIAE, AND MYCOBACTERIUM-TUBERCULOSIS

Three Mycobacterium genavense strains and three American Type Culture Collection reference strains each of Mycobacterium fortuitum, Mycobact erium simiae, and Mycobacterium tuberculosis were subcultured onto Myc obacteria 7H11 agar (Difco Laboratories, Detroit, Mich.) supplemented with mycobactin J (Allied Laboratories, Fayette, Mo.). After 4 weeks o f incubation at 37 degrees C in 10% CO2, the cultures were analyzed by gas-liquid chromatography (GLC) for their fatty acids and mycolic aci d cleavage products. M. fortuitum was clearly differentiated from M. g enavense by the presence of the specific marker 2-methyloctadecenoic a cid in M. fortuitum and by the ratio of tetracosanoic acid to hexacosa noic acid. This ratio was <1 for M. genavense and >3 for M. fortuitum. M. fortuitum also contained docosanoic acid, which was not detected i n M. genavense. M. genavense, M. simiae, and M. tuberculosis, which ha ve similar GLC profiles, were also differentiated from each other by t he presence of either cis-10-hexadecenoic acid or cis-11-hexadecenoic acid and by tetradecanoic acid content.