[Characterization of fatty acids and mycolic acid degradation products in mycobacterial species of major incidence in Argentina]

Abstract

The human immunodeficiency virus (HIV) epidemic has altered the epidemiological profile of tuberculosis in both industrialized and developing countries. Serious diseases caused by mycobacteria other that M. tuberculosis, mostly belonging to the M. avium-intracellulare complex (MAC), have become very common in association with severe immunosuppression. The increase in mycobacterial disease complexity has stimulated the development of more rapid and efficient methods of diagnosis. In the present study we characterized the cellular fatty acids and the mycolic acid cleavage product from most frequent mycobacteria species in Argentina using gas chromatography in order to develop a rapid technique for their identification. Fatty acids and mycolic acids extracted from saponified mycobacterial cells were examined as methyl esters by capillary has chromatography. The major constituent fatty acids in all species, with the exception of M. smegmatis, were octadecenoic (18:1) and hexadecanoic (16:1) acids. The fatty acids and mycolic acid cleavage product profiles from the studied species were quantitatively but not qualitatively different. Tuberculostearic acid was found in all species. Significantly different amounts of some fatty acids (p < 0.01) were observed among clinical isolates of M. tuberculosis, M. bovis and MAC. Traces of 2-eicosanol were detected in the M. tuberculosis H37Rv strain. Although a limited number of strains and species were tested, preliminary results indicate that this method could be used to characterize mycobacterial cultures.