Immunochemical properties of Proteus penneri lipopolysaccharides--one of the major Proteus sp. virulence factors.

Proteus penneri, like the other seven species from the genus, are Gram-negative, peritrichously flagellated rods capable of swarming growth on humid solid media. These bacteria are human opportunistic pathogens involved in many infections but they mainly affect the urinary tract of hospitalized, long-term catheterized patients. P. penneri rods produce a lot of virulence factors, among which the lipopolysaccharide seems to be the most interesting due to its structural and serological diversity. From the three LPS regions of P. penneri strains only the core region and O-specific polysaccharide (OPS) were structurally and serologically examined. P. penneri LPS core region is characterized by a common inner part representing the III glycoform and a diverse distal part (12 different structures). The P. penneri O-antigens contain sugar and non-sugar compounds and some of them rarely occur in nature. In both P. penneri LPS regions putative epitopes have been pointed out. Serospecificity of OPS allowed classifying many P. penneri isolates to different Proteus sp. O-serogroups, among which 12 contain P. penneri strains only.