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Establishment and Characterization of UTI and CAUTI in a Mouse Model
Published on: June 23, 2015
Aggregative adherence of uropathogenic Proteus mirabilis to cultured epithelial cells
Sérgio P D Rocha1, Waldir P Elias, Aurora M Cianciarullo
1Departamento de Microbiologia, Universidade Estadual de Londrina, Paraná, Brazil, and Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil.
Abstract:
Proteus mirabilis is an important cause of urinary tract infection (UTI) in patients with complicated urinary tracts. Thirty-five strains of P. mirabilis isolated from UTI were examined for the adherence capacity to epithelial cells. All isolates displayed the aggregative adherence (AA) to HEp-2 cells, a phenotype similarly presented in LLC-MK(2) cells. Biofilm formation on polystyrene was also observed in all strains. The mannose-resistant Proteus-like fimbriae (MR/P), Type I fimbriae and AAF/I, II and III fimbriae of enteroaggregative Escherichia coli were searched by the presence of their respective adhesin-encoding genes. Only the MR/P fimbrial subunits encoding genes mrpA and mrpH were detected in all isolates, as well as MR/P expression. A mutation in mrpA demonstrated that MR/P is involved in aggregative adherence to HEp-2 cells, as well as in biofilm formation. However, these phenotypes are multifactorial, because the mrpA mutation reduced but did not abolish both phenotypes. The present results reinforce the importance of MR/P as a virulence factor in P. mirabilis due to its association with AA and biofilm formation, which is an important step for the establishment of UTI in catheterized patients.
Insights
Proteus mirabilis strains causing urinary tract infections (UTIs) exhibit aggregative adherence and biofilm formation. Mannose-resistant Proteus-like (MR/P) fimbriae are key virulence factors in these processes.
Area of Science:
- Microbiology
- Infectious Diseases
- Bacterial Pathogenesis
Background:
- Proteus mirabilis is a significant pathogen causing complicated urinary tract infections (UTIs).
- Understanding bacterial adherence and biofilm formation is crucial for managing UTIs, especially in catheterized patients.
Purpose of the Study:
- To investigate the adherence capacity and biofilm formation of P. mirabilis strains isolated from UTIs.
- To identify the role of mannose-resistant Proteus-like (MR/P) fimbriae in these virulence phenotypes.
Main Methods:
- Examined adherence of 35 P. mirabilis UTI isolates to HEp-2 cells.
- Assessed biofilm formation on polystyrene surfaces.
- Screened for adhesin-encoding genes, focusing on MR/P genes (mrpA, mrpH).
- Created an mrpA mutant to evaluate its impact on adherence and biofilm formation.
Main Results:
- All P. mirabilis isolates showed aggregative adherence (AA) to HEp-2 cells and formed biofilms.
- Only MR/P fimbrial genes (mrpA, mrpH) and MR/P expression were detected in all isolates.
- An mrpA mutation reduced but did not eliminate AA and biofilm formation, indicating multifactorial involvement.
Conclusions:
- MR/P fimbriae are important virulence factors for P. mirabilis in UTIs.
- MR/P contributes to aggregative adherence and biofilm formation, critical for infection establishment in catheterized patients.
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