Use of Gas Chromatographic Fatty Acid and Mycolic Acid Cleavage Product Determination To Differentiate among Mycobacterium genavense , Mycobacterium fortuitum , Mycobacterium simiae , and Mycobacterium tuberculosis

Abstract

ABSTRACT Three Mycobacterium genavense strains and three American Type Culture Collection reference strains each of Mycobacterium fortuitum , Mycobacterium simiae , and Mycobacterium tuberculosis were subcultured onto Mycobacteria 7H11 agar (Difco Laboratories, Detroit, Mich.) supplemented with mycobactin J (Allied Laboratories, Fayette, Mo.). After 4 weeks of incubation at 37°C in 10% CO 2 , the cultures were analyzed by gas-liquid chromatography (GLC) for their fatty acids and mycolic acid cleavage products. M. fortuitum was clearly differentiated from M. genavense by the presence of the specific marker 2-methyloctadecenoic acid in M. fortuitum and by the ratio of tetracosanoic acid to hexacosanoic acid. This ratio was <1 for M. genavense and >3 for M. fortuitum. M. fortuitum also contained docosanoic acid, which was not detected in M. genavense. M. genavense , M. simiae , and M. tuberculosis , which have similar GLC profiles, were also differentiated from each other by the presence of either cis -10-hexadecenoic acid or cis -11-hexadecenoic acid and by tetradecanoic acid content.