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Identification and characterization of a uroepithelial cell adhesin from a uropathogenic isolate of Proteus mirabilis
Abstract:
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.
Insights
Researchers identified a key bacterial protein, the uroepithelial cell adhesin, responsible for Proteus mirabilis adhering to urinary tract cells. This finding is crucial for understanding urinary tract infections (UTIs) and developing targeted treatments.
Area of Science:
- Microbiology
- Infectious Diseases
- Urology
Background:
- Proteus mirabilis frequently causes urinary tract infections (UTIs), especially in specific patient populations.
- Bacterial adherence to uroepithelial cells is a critical factor in UTI pathogenesis.
- Most Proteus strains exhibit adherence to shed uroepithelial cells, suggesting a specific adhesin.
Purpose of the Study:
- To identify the specific adherence factor of Proteus mirabilis responsible for binding to uroepithelial cells.
- To characterize the identified adherence factor and its role in virulence.
Main Methods:
- Outer membrane material from radiolabeled Proteus mirabilis was sheared and incubated with uroepithelial cells.
- Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to analyze binding components.
- Purification of the adherence factor involved heat shock and Sepharose CL-4B gel filtration.
- Electron microscopy was employed to visualize the purified adhesin structure.
Main Results:
- A major adherence element, a protein of approximately 17,500 molecular weight, was identified and provisionally named uroepithelial cell adhesin.
- The purified adhesin was observed to form long, flexible rods under electron microscopy.
- Limited N-terminal amino acid sequence homology was found between the adhesin subunit and K99 fimbriae of Escherichia coli.
Conclusions:
- The identified uroepithelial cell adhesin is a significant virulence factor for Proteus mirabilis in UTIs.
- This adhesin mediates the binding of Proteus mirabilis to uroepithelial cells.
- The structural and sequence characteristics suggest a novel fimbrial-like adhesin.