Cellular fatty acids as chemical markers for differentiation of Yersinia pestis and Yersinia pseudotuberculosis.

AIMS

Gas chromatography (GC) was utilized to investigate the cellular fatty acids (CFAs) composition of 141 Yersinia pestis isolates from different plague foci of China, and 20 Yersinia pseudotuberculosis strains as well.

METHODS AND RESULTS

The whole cell fatty acid methyl esters (FAMEs) were obtained by saponification, methylation and extraction followed with analysis using a standardized Microbial Identification System (MIS). Y. pestis and Y. pseudotuberculosis strains are quite similar in major CFA profiles, which include 16:0, 17:0 cyclo, 3-OH-14:0, 16:1 omega 7c and 18:1 omega 7c, accounting for more than 80% of the total CFAs.

CONCLUSIONS

Yersinia pestis could be easily differentiated from Y. pseudotuberculosis by plotting the ratios of some CFA pairs, i.e.,14:0/18:0 vs 18:1 omega 7c/18:0, 3-OH-14:0/18:0 vs 18:1 omega 7c/18:0, 16:1 omega 7c/18:0 vs 18:1 omega 7c/18:0, 12:0/18:0 vs 18:1 omega 7c/18:0 and 12:0 ALDE/18:0 vs 16:1 omega 7c/18:0 fatty acids.

SIGNIFICANCE AND IMPACT OF THE STUDY

In the present study, the normalized Sherlock MIS and Sherlock standard libraries were used to analyse the fatty acid composition of different strains of Y. pestis and Y. pseudotuberculosis. Meanwhile, ratios of certain CFA components were found to serve as chemical markers for differentiating the two closely related bacteria that are difficult to be differentiated by simply comparing CFA profiles based on other researches.