Related Experiment Video
Updated: Oct 3, 2026
In Vitro Assay of Bacterial Adhesion onto Mammalian Epithelial Cells
Published on: May 16, 2011
In vitro adhesion of uropathogenic Escherichia coli to human periurethral cells
Abstract:
The in vitro adhesion of three uropathogenic strains of Escherichia coli to epithelial cells from the periurethral area (area surrounding the urethral orifice) of women with and without a history of recurrent urinary tract infections was investigated. All strains showed a specific mannose-resistant hemagglutination restricted to human erythrocytes. Since only a few hundred periurethral cells were used in each test, gentle methods were required. Optimal results were obtained with bacteria grown for 16 h at 37 degrees C in nutrient broth without shaking. The binding of bacteria seemed to be irreversible under the conditions studied, since repeated washings of the epithelial cells after incubation did not decrease the number of adhering bacteria. Chloramphenicol was used to control the number of added bacteria in the incubation system. A difference in the adhesive capacity of periurethral cells of infection-prone and healthy individuals was most evident at concentrations of 2.5 x 10(9) bacteria/ml. Electron microscope studies indicated that pili mediated the adhesion. Adhesion was correlated with the mannose-resistant hemagglutination of human erythrocytes, indicating that the pili were not type 1 pili. Day-to-day variations in the adhesiveness of the bacteria were reduced by selecting well-adhering bacteria with the aid of in vitro passage on periurethral cells or human erythrocytes, and by exclusion of bacteria with low hemagglutination ability.
Insights
Uropathogenic Escherichia coli adhere to periurethral cells, increasing urinary tract infection risk. This adhesion, mediated by specific pili, is more pronounced in women prone to recurrent infections.
Area of Science:
- Microbiology
- Urology
- Infectious Diseases
Background:
- Recurrent urinary tract infections (UTIs) are common in women.
- Uropathogenic Escherichia coli (E. coli) are the primary cause of UTIs.
- Understanding bacterial adhesion mechanisms is crucial for UTI prevention.
Purpose of the Study:
- To investigate the in vitro adhesion of uropathogenic E. coli to human periurethral epithelial cells.
- To compare adhesion capacity in women with and without a history of recurrent UTIs.
- To identify bacterial factors mediating adhesion.
Main Methods:
- In vitro adhesion assays using periurethral cells and three uropathogenic E. coli strains.
- Mannose-resistant hemagglutination assay with human erythrocytes.
- Electron microscopy to visualize bacterial adhesion.
- Optimization of bacterial growth and incubation conditions.
Main Results:
- E. coli exhibited mannose-resistant hemagglutination specific to human erythrocytes.
- Bacterial adhesion to periurethral cells was largely irreversible.
- Adhesion was significantly higher with periurethral cells from infection-prone individuals.
- Electron microscopy confirmed pili-mediated adhesion, distinct from type 1 pili.
Conclusions:
- Specific pili mediate E. coli adhesion to human periurethral cells.
- Periurethral cell adhesiveness differs between women with and without recurrent UTIs.
- Mannose-resistant hemagglutination correlates with adhesive pili, suggesting a potential diagnostic marker.
Related Concept Videos
01:26Urinary Tract Infection I: Introduction
01:25Urinary Tract Infection II: Pathophysiology
01:28Microbiota of the Urogenital Tract