[Fatty acid composition of Leptospira lipids as a taxonomic criterion].

The fatty-acid composition of microbial cells in 17 pathogenic and saprophytic Leptospira strains, comprising 14 serovars and 10 serogroups, has been studied. The strains under investigation have proved to fall into 3 groups differing by this characteristic. The group of saprophytic strains is characterized by a comparatively high level of myristic acid and, consequently, by the ratio of saturated and unsaturated fatty acids with 14 carbon atoms approaching 1:1; besides, it is also characterized by a lower, in comparison with the pathogenic Leptospira strains belonging to the serogroups Icterohaemorrhagiae, Canicola, Ballum has a higher level of unsaturated fatty acids. The second group of pathogenic Leptospira strains including the serogroups Grippotyphosa, Hebdomadis, Pomona, Tarassovi, Pyrogenes, Australia has been found to occupy an intermediate position between the first group of pathogenic Leptospira strains and the group of saprophytic ones. As the difference in the content of myristic acid in pathogenic and saprophytic Leptospira strains is a stable characteristic, it can be used for the differentiation of these strains. The present investigation has revealed that the distribution of the main fatty acids in Leptospira phospholipids is similar to their distribution in Leptospira neutral lipids with the exception of unsaturated fatty acid with 14 carbon atoms, occurring mainly in phospholipids.