Cronobacter species were previously known as yellow pigmented Enterobacter cloacae, and Enterobacter sakazakii. According to current knowledge of taxonomy, Cronobacter consists of seven species: Cronobacter sakazakii, C. malonaticus, C. turicensis, C. muytjensii, C. dublinensis, C. universalis and C. condimenti [1]. Recognition of two new Cronobacter species: C. universalis and C. condimenti was based on phylogenetic analysis, using multilocus sequence analysis (MLSA). Another classification scheme is connected with the diversity of O-antigen polysaccharide structures. There already exists an O serotyping scheme for C. sakazakii based on antisera and antigen gene cluster RLFP [2]. Although chemical structures could help further define Cronobacter serotypes, the structural composition of only a few O-polysaccharides (OPS) has been determined. The main aim of this study was the structural investigation of O-polysaccharides isolated from three strains of Cronobacter turicensis (57, 564 and 566) belonging to the same sequence type 5. For this purpose lipopolysaccharide was isolated from the bacterial cells and hydrolysed. The OPS was purified using gel permeation chromatography (GPC). Component analysis was undertaken using classical chemical methods followed by GLC, and GLC-MS analysis. The obtained results together with (1)H and (13)C NMR spectroscopy experiments were used to determine O-polysaccharide repeating unit structure which was identical for all investigated strains:
1. Joseph S, Cetinkaya E, Drahovska H, Levican A, Figueras M, Forsythe SJ (2012) Intl J Syst Evol Microl 62: 1277–83.
2. Sun Y, Wang M, Wang Q, Cao B, He X, Li K, Feng L, Wang L (2012) Appl Environ Microbiol 78: 3966–74.
