Structural and immunochemical relationship between the O-antegenic polysaccharides from the enteroaggregative Escherichia coli strain 396/C1 and Escherichia coli O126

• The structure of the O-antigen polysaccharide (PS) from the enteroaggregative Escherichia coli strain 396/C-1 has been determined. Sugar and methylation analyses together with 1H and 13C NMR spectroscopy were the main methods used. Inter-residue correlations were determined by 1H,1H-NOESY, 1H,13C-heteronuclear multiple-bond correlation and dipole–dipole cross-correlated relaxation experiments. The PS is composed of pentasaccharide repeating units with the following structure: Full-size image (2K) Analysis of NMR data reveals that on average the PS consists of 13 repeating units and indicates that the biological repeating unit contains an N-acetylglucosamine residue at its reducing end. This structure is different to that reported for the O-antigen polysaccharide from E. coli O126. Monospecific anti-E. coli O126 rabbit serum from The International Escherichia and Klebsiella Centre did not distinguish between the E. coli strain 396/C-1 and the E. coli O126 reference strain, neither in slide agglutination nor in an indirect enzyme immunoassay. Subsequent successful serotyping of the E. coli strain 396/C-1 showed it to be E. coli O126:K+:H27.

Ämnesord

NATURVETENSKAP  -- Kemi -- Organisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Organic Chemistry (hsv//eng)

Nyckelord

Escherichia coli; Enteroaggregative; Serology; Lipopolysaccharide; NMR

Organic chemistry

Organisk kemi

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