Differentiation of Enterobacter sakazakii from closely related Enterobacter and Citrobacter species using fatty acid profiles

Paul Whittaker, Christine E. Keys, Eric Wayne Brown, Frederick S. Fry

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Capillary gas chromatography with flame ionization detection (GC-FID) was used to determine the cellular fatty acid (CFA) profiles of 134 Enterobacter sakazakii strains, and these were compared to the CFA profiles of other closely related Enterobacter and Citrobacter species. For GC-FID analysis, whole cell fatty acid methyl esters (FAMEs) from cells cultured on brain heart infusion (BHI) agar at 37°C for 24 h were obtained by saponification, methylation, and extraction into hexane/methyl tert-butyl ether. A database for E. sakazakii was prepared using fatty acid profiles from the 134 strains. Major fatty acids of E. sakazakii strains evaluated in this study were straight-chain 12:0, 14:0, and 16:0, unsaturated 18:1 ω7c, and 17:0 ωcyclo 7-8. Principal component analysis (PCA) based on CFA profiles for E. sakazakii strains shows separation of E. sakazakii subgroups A and B. The CFA profiles for E. sakazakii and Enterobacter cloacae show that there are several fatty acids, 14:0, 17:0 ωcyclo 7-8, 18:1 ω7c, and summed 16:1 ω6c/16:1 ω7c, that differ significantly between these two species. A PCA model based on CFA profiles for E. sakazakii strains clearly shows separation of E. sakazakii from closely related Enterobacter and Citrobacter species. Analysis of FAMEs from E. sakazakii strains grown on BHI agar by a rapid GC-FID method can provide a sensitive procedure for the identification of this organism, and this analytical method provides a confirmatory procedure for the differentiation of E. sakazakii strains from closely related Enterobacter and Citrobacter species.

Original languageEnglish (US)
Pages (from-to)4617-4623
Number of pages7
JournalJournal of agricultural and food chemistry
Volume55
Issue number11
DOIs
StatePublished - May 30 2007

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Agricultural and Biological Sciences(all)

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