Structural studies of O-polysaccharide isolated from Cronobacter sakazakii Sequence Type 12 from a case of neonatal necrotizing enterocolitis.

The O-polysaccharide (OPS) of Cronobacter sakazakii NTU 696 (Sequence Type 12) from a case of neonatal necrotizing enterocolitis was isolated from the polysaccharide fraction obtained after lipopolysaccharide (LPS) hydrolysis. Purified OPS was analyzed by NMR spectroscopy ((1)H, COSY, TOCSY, NOESY, HSQC, HSQC-TOCSY and HMBC experiments) and chemical methods. Obtained monosaccharide derivatives analyzed by gas chromatography and gas chromatography-mass spectrometry allowed the identification of six sugar components. Performed experiments enabled to establish a structure of the OPS repeating unit of C. sakazakii NTU 696, as: [structure: see text].

The structure of O-polysaccharide isolated from Cronobacter universalis NCTC 9529T.

The O-polysaccharide (OPS) was isolated from Cronobacter universalis NCTC 9529(T), a new species in the genus Cronobacter, which was created by the reclassification of the species Enterobacter sakazakii. Purified polysaccharide was analyzed by NMR spectroscopy ((1)H, COSY, TOCSY, ROESY, HSQC, and HSQC-TOCSY) and chemical methods. The monosaccharide derivatives were analyzed by gas chromatography and gas chromatography-mass spectrometry. These experiments enabled the type and number of monosaccharides in the repeating unit of OPS, their positions of linkages, and absolute configuration to be determined. Together the chemical analysis established a structure of the OPS of C. universalis NCTC 9529(T). [structure: see text]. OPS isolated from C. universalis was structurally characterized for the first time.

Chemical structure of the O-polysaccharides isolated from Cronobacter turicensis sequence type 5 strains 57, 564, and 566.

The Cronobacter spp. are Gram-negative bacterial pathogens that can cause infections in all age groups, and have a high mortality rate in neonates due to necrotizing enterocolitis and meningitis. Recent genotyping studies have revealed a strong clonal lineage in the genus, but this has not been compared with physiological traits. The O-polysaccharides (OPS) were isolated from three C. turicensis sequence type 5 strains (57, 564, and 566) and structurally characterized using (1)H and (13)C NMR spectroscopy, including two-dimensional DQF-COSY, TOCSY, ROESY, and HSQC analysis. Further compositional determination was undertaken using classical chemical methods followed by GLC, and GLC-MS analysis. The repeating unit of the isolated O-polysaccharides consists of GlcNAc, Rha, Glc, and had the structure shown below and therefore complemented the sequence type. [structure: see text].

Chemical structure of the O-polysaccharide isolated from Pectobacterium atrosepticum SCRI 1039.

The lipopolysaccharide (LPS) of the bacterium Pectobacterium atrosepticum SCRI 1039 was hydrolyzed and the products were separated. A study of the obtained O-polysaccharide by means of chemical methods, GLC, GLC-MS, and NMR spectroscopy allowed us to identify a branched polymer with a pentasaccharide repeating unit of the structure shown below, in which the fucose residue was partially O-acetylated at C-2, C-3 or C-4.

Chemical structure of wall teichoic acid isolated from Enterococcus faecium strain U0317.

Wall teichoic acid (WTA) was isolated from Enterococcus faecium strain U0317 and structurally characterized using (1)H, (13)C, and (31)P NMR spectroscopy, including two-dimensional COSY, TOCSY, ROESY, HMQC, and HMBC experiments. Further compositional determination was undertaken using classical chemical methods and HF treatment followed by GLC and GLC-MS analyses. The repeating unit of WTA consisted of two residues of 2-acetamido-2-deoxy-D-galactose, glycerol (Gro), and phosphate, and has the structure shown below: [See formula in text].