Escherichia albertii is an enteric bacterial species within the genus Escherichia. It is a newly emerging intestinal pathogen that has been associated with sporadic infections and human gastroenteritis outbreaks in different countries. Recently, a number of strains earlier identified as enteropathogenic and enterohemorrhagic E. coli have been shown to be E. albertii. In this work, we established O specific polysaccharide (OPS) structures and characterized O antigen gene clusters of representatives of all nine known E. albertii molecular types (potential O serotypes).
The OPSs of E. albertii O1-O9 were studied by sugar analysis, O-deacetylation, partial acid hydrolysis (for O5 and O8), selective solvolysis with CF₃SO₃H (O1) or CF₃CO₂H (O4 and O5), Smith degradation (O2 and O9), dephosphorylation with HF (O9), and 1D and 2D 1H and 13C NMR spectroscopy. As a result, the following new OPS structures of were elucidated:
The OPS structure of E. albertii O7 (erroneously named that time H. alvei) has been established earlier (R. Eserstam et al., Eur. J. Biochem. 269 (2002) 3289-3295). The OPSs of E. albertii O3 and O6 are identical to those of E. coli O181 and O3, respectively, except for the lack of O-acetylation in E. albertii O3. The OPS structures of both E. albertii O5 and O7 are related to those of E. coli O124 and O164, and that of E. albertii O8 is similar to the OPS of E. coli O128.
Functions of genes in the O-antigen gene clusters of the strains studied were tentatively assigned by comparison with sequences in available databases and found to be consistent with the OPS structures.
This work was supported by the Russian Science Foundation (project № 14-14-01042), the National Natural Science Foundation of China (81371762), and the Health and Family Planning Commission of Sichuan Province (150259).