Influence of culture medium and incubation time on the fatty acid compositions of some rapid-growing mycobacteria as analysed by packed and capillary column gas chromatography.

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.