Chromatographic analysis of the Escherichia coli polysialic acid capsule

Susan M. Steenbergen, Eric R. Vimr

Research output: Chapter in Book/Report/Conference proceedingChapter


Polysialic acid capsules are the major virulence factors in Escherichia coli K1, K92, and groups B and C meningococci. The sialic acid monomers (2-keto-3-deoxy-5-acetamido-7,8,9- D - glycero - D - galacto -nonulosonic acids) comprising these homopolymeric polysaccharide chains can be selectively modified with 1,2- diamino-4,5-methylenedioxy-benzene to produce highly fluorescent quinoxalinone derivatives distinguished by their elution times during reverse phase chromatography. Here, we describe methods to release the constituent capsular polysialic acid monomers, and to detect and quantify them by sensitive fluorometry. There are relatively few 2-keto acids in bacteria, making it possible to rapidly analyze samples even without prior purification of capsular polysaccharides.

Original languageEnglish (US)
Title of host publicationMethods in Molecular Biology
Number of pages12
StatePublished - 2013

Publication series

NameMethods in Molecular Biology
ISSN (Print)10643745


  • Escherichia coli
  • Fluorometry
  • Polysialic acid capsules
  • Release of sialic acid monomers
  • Reverse phase chromatography
  • Virulence factors

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics


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