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Chemical characterization and serological properties of a unique O-polysaccharide of the Proteus mirabilis Sm 99 clinical strain – Identification of a new, O81, serotype

Zabłotni, Agnieszka, Arbatsky, Nikolay P., Drzewiecka, Dominika, Shashkov, Alexander S., Knirel, Yuriy A.
International journal of biological macromolecules 2018
O-antigens, Proteus mirabilis, Western blotting, bacteria, enzyme-linked immunosorbent assay, glucuronic acid, nuclear magnetic resonance spectroscopy, patients, serotypes, urine, women, Poland
The current serological classification scheme of the medically important bacteria from the genus Proteus consists of 80 O serogroups, the last four of which (O77–O80) were created from clinical strains from Łódź, Poland. There are more serologically unique strains isolated from patient that do not fit into the existing scheme, such as Proteus mirabilis strain Sm 99 isolated from urine of a 74-year-old woman in Łódź. Serological investigation involving ELISA and Western blotting failed to classify the Proteus mirabilis strain Sm 99 into any of the 80 Proteus O serogroups. Sugar analysis along with two-dimensional NMR spectroscopy showed that the O-polysaccharide is composed of branched pentasaccharide repeating units containing one residue each of d-Glc, d-GlcNAc, d-GalNAc, d-glucuronic acid, and 4-[(R)-3-hydroxybutanoylamino]-4,6-dideoxy-d-glucose. The chemical and serological data show that the O antigen of P. mirabilis Sm 99 is unique among the known Proteus O antigens. Based on this finding, it is proposed to extend the current serological classification scheme of Proteus by adding a new serogroup, O81, which at present consists of P. mirabilis strain Sm 99 only.