Identification and characterization of a uroepithelial cell adhesin from a uropathogenic isolate of Proteus mirabilis.

Proteus mirabilis is a frequent cause of urinary tract infections in rehabilitation hospitals and among persons with structural abnormalities of the urinary tract. Adherence to uroepithelial tissues may be an important virulence determinant in these infections because most Proteus strains adhere to desquamated uroepithelial cells. To identify the adherence factor responsible for this phenomenon, we sheared outer membrane material from 35SO4-radiolabeled bacteria and allowed it to bind to uroepithelial cells. Following sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the major adherence element was a protein with an apparent molecular weight of 17,500 and was provisionally designated as the uroepithelial cell adhesin. This adhesin was purified by heat shock and gel filtration on Sepharose CL-4B. After purification, the adhesin was seen assembled as long, flexible rods by electron microscopy. The N-terminal amino acid sequence of the subunit had limited homology with that of the K99 fimbriae of Escherichia coli.