Comparison of Yersinia pestis to other closely related Yersinia species using fatty acid profiles

Capillary gas chromatography with flame ionisation detection (GC–FID) was used to determine the cellular fatty acid (CFA) profiles of six Yersinia pestis strains. The profiles were then compared with the CFA profiles of other closely related Yersinia species including: Y. pseudotuberculosis, Y. enterocolitica, Y. intermedii, Y. kristensenii and Y. frederiksenii. For GC–FID analysis, whole cell fatty acid methyl esters (FAMEs) from cells cultured on brain–heart infusion (BHI) agar at 35 °C for 24 h were obtained by saponification, methylation and extraction into hexane/methyl tert-butyl ether. A data set for each Yersinia species was prepared using fatty acid profiles from five replicates prepared on different days. Major fatty acids of the 26 Yersinia strains evaluated in this study were straight-chain 12:0, 14:0, 15:0, 16:0 and unsaturated summed 16:1 ω7c/16:1 ω6c, 18:1 ω7c, and summed 14:0 3OH/16:1 iso, and 17:0 ω cyclo 7–8. The CFA profiles for Y. pestis and Y. pseudotuberculosis are similar, but there are several fatty acids, 16:1 ω5c, 16:0, 17:1 ω7c, 17:0 ω cyclo 7–8, 19:0 and summed 18:2 ω6c, 9c/18:0 ante, that differ significantly between these two species. Analysis of FAMEs from Yersinia strains grown on BHI agar by a rapid GC–FID method can provide a sensitive procedure for the identification of these organisms, and this analytical method provides a procedure for the differentiation of Y. pestis strains from closely related Yersinia species.