[Adhesive properties of bacteria isolated from patients with urinary tract infection to the urinary bladder]

Clinically isolated Staphylococcus epidermidis KK3-75, Enterococcus faecalis SMU-14, and Escherichia coli TF6-27 were subjected to test for bladder lodgments.

Experimental cystitis on mice was investigated pathologically by light, confocal laser, and electron microscope after intravesical injection of cell suspensions of the strains. Bacterial affinities with bladder mucosal proteins and with extracellular components were detected by Western blot analysis.

Pathological findings of experimental cystitis revealed prominent infiltration of neutrophils except for those that were challenged with Enterococcus faecalis SMU-14. Capsule-like structures were demonstrated for the other two strains. Each strain showed histological tropism within the tissue sections, which correlated with the capability to bind the respective extracellular matrix components tested. Type I collagen bound only to cellular extracts of Enterococcus faecalis SMU-14 and Escherichia coli TF6-27, whereas fibronectin and type IV collagen bound only to those of Staphylococcus epidermidis KK3-75 and Enterococcus faecalis SMU-14. Bladder mucosal proteins had a variety of ability to bind cell surface proteins of each strain. Bacterial cell surface binding of all except for two of the bladder mucosal proteins detected was inhibited by extracellular matrix components.

These experimental results suggest that the bacterial affinity of the bladder restricted by strain specific cell surface properties may be important for explanation in the difference of occurrence and progression of urinary tract infections caused by each strain.