Absence of Bacterial Reservoirs in the Bladder Epithelium of Patients With Chronic Bacteriuria Due to Neurogenic Bladder

Abstract

Bacteriuria is common in patients with neurogenic bladder who are on clean intermittent catheterization for bladder emptying. In a longitudinal study patients carried 1 or 2 clones of Escherichia coli in the urine during months of surveillance. An explanation for persistent bacteriuria in this population could be that periurethral E. coli inoculated during clean intermittent catheterization would attach via type I adhesin, invade superficial bladder epithelial cells and establish reservoirs. Resurgence of bacteria from these reservoirs in bladder epithelium could later reenter the urine and establish a recurrent episode of bacteriuria. We investigated whether bacterial reservoirs were present in the superficial epithelium of patients with neurogenic bladder and chronic bacteriuria. Bladder biopsies were obtained from patients with neurogenic bladder and a history of chronic recurrent bacteriuria. Biopsies were fixed in Carnoy's solution to preserve the material overlying the luminal surface of the superficial bladder epithelium. Following fixation biopsies were stained with hematoxylin and eosin to detect intracellular bacterial reservoirs and with periodic acid-Schiff for exopolysaccharide of biofilm. Fluorescence in situ hybridization was done to visualize individual bacteria. No evidence of bacterial reservoirs was found in the superficial bladder epithelium of 9 patients with neurogenic bladder. On hematoxylin and eosin staining epithelium with an intact luminal surface had no intracellular bacterial pods. On periodic acid-Schiff staining no biofilm or collection of exopolysaccharide surrounding bacterial communities was found. No collections or individual bacteria were seen on fluorescence in situ hybridization stained sections examined at 1,000x magnification with oil immersion. Bacterial reservoirs do not appear to be an important source of bacteriuria in patients with chronic recurrent bacteriuria due to neurogenic bladder.