Twenty-nine strains of chromogenic mycobacteria belonging to the species Mycobacterium aurum (5 strains), M. duvalii (2), M. flavescens (1), M. gordonae (6), M. kansasii (3), M. obuense (1), M. parafortuitum (3), M. phlei (2), M. rhodesiae (1), M. vaccae (2) and Mycobacterium spp. (3) were studied for fatty acid composition and mycolic acid patterns by gas-liquid chromatography and thin-layer chromatography respectively. Fatty acids found ranged from those with 12-24 carbon atoms and were saturated and monounsaturated straight chain fatty acids, along with 10-methyl branched of 16, 17 and 18 (tuberculostearic acid) carbon atoms. Moreover, 2-methyl tetradecanoic acid was found in M. gordonae, M. kansasii and Mycobacterium spp. (2 strains), and 2,4-dimethyl tetradecanoic acid in M. kansasii and Mycobacterium spp. (2 strains). Nonadecenoic acid was found only in M. flavescens and tuberculostearic acid was not detected in M. gordonae. Three patterns of mycolic acids were obtained: the first, found in M. aurum, M. flavescens, M. phlei, M. rhodesiae and Mycobacterium spp. (1 strain), was characterized by the presence of several spots assigned to alpha-mycolates, keto-mycolates and wax-ester mycolates (omega-carboxy-mycolates and 2-eicosanol and related alcohols); the second, found in M. duvalii, M. obuense, M. parafortuitum and M. vaccae was similar to the first, but it contained an additional spot of alpha'-mycolates; the third pattern, found in M. gordonae, M. kansasii and Mycobacterium spp. (2 strains) contained three spots considered to be alpha-mycolates, methoxy-mycolates and keto-mycolates. The results obtained confirm previously reported data on the fatty and mycolic acid composition of the species studied.

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Cellular fatty acids of four rapid‐growing mycobacterial species (Mycobacterium chelonei, M. fortuitum, M. phlei, and M. smegmatis) were analysed by packed and capillary column gas chromatography after one, three, four, six, eight, and twelve days of incubation on Löwenstein‐Jensen and Sauton agar media. Variations in incubation time did not affect the chromatograms except in the case of twelve‐day incubated M. smegmatis. Mycobacteria cultivated on Sauton agar medium contained more tuberculostearic and less oleic acid compared with Löwenstein‐Jensen. For informative and reproducible analytical results, we recommend using a chemically defined culture medium and splitless injection on a capillary column capable of separating not only the methyl esters of the cellular fatty acids but also the diagnostically important secondary alcohols containing 18 and 20 carbon atoms.