Analysis of Fatty Acids in Yersinia pestis by Gas Chromatography

Abstract

Many methods can be used to identify medically important microorganisms. The traditional methods include characterizing phenotypic features and biochemical reactions that are usually mediated directly by enzyme activity. Immunodiagnostic and genetic marker techniques have higher sensitivity and specificity and save time. However, determining the cellular fatty acid (CFA) composition by gas chromatography (GC) could serve as an alternate method for identifying bacteria. Different from antigen detection and hybridization, this technique does not require a probe. The main requirement of a CFA analysis is proper instrumentation. With the technological development of advanced chromatographs and capillary columns, it is possible for GC to serve as a useful method for microbiology taxonomy. Improved microelectronics and computer-aided data interpretation have also promoted abundant applications of GC in clinical microbiology. Fatty acids are chemical components with high contents and stabilities, and they can be used to identify bacteria. Pioneering studies provided evidence suggesting that the analyzing CFAs by GC could be used successfully to identify and classify bacteria. CFA analysis is also used widely in the taxonomic study of aerobic endospore-forming bacilli. Various studies of the fatty acid compositions of Yersinia were conducted subsequently, which demonstrated that there were great differences in both the components and proportions of the fatty acids in Yersinia pestis, mainly because of the lack of a standardized GC Microbial Identification System (MIS). Consequently, the normalization of the bacterial fatty acid analysis method using GC is required for parallel comparisons of CFA results from different laboratories. Fortunately, the improvement of the Sherlock MIS and Sherlock standard libraries make this goal feasible.