Bacterial biofilm formation on the bladder epithelium of spinal cord injured patients. II. Toxic outcome on cell viability.

As a follow up to our first study of 10 spinal cord injured patients, a further 8 patients were investigated over 2 months for biofilm formation on their bladder epithelial cells and for evidence that these uropathogens damage the host bladder. All the patients were found to be colonized with uropathogens, regardless of whether or not they were receiving antibiotics. Using vital staining, it was discovered that there was a significant reduction (33%) in bladder cell viability in the presence of bacterial biofilms compared to controls. This was not associated with cell turnover rates. In vitro tests showed a similar reduction in cell viability when uropathogens were incubated with bladder cells. In addition, white cell counts were significantly elevated in the patients' urine, indicative of an infectious and/or inflamed state. There was no difference between symptomatic and asymptomatic patients in their mean bacterial adhesion counts. Patients were just as likely to be symptomatic as asymptomatic when on antibiotics. In summary, the presence of virulent organisms in the bladder does adversely affect the host, even when the patient has insignificant signs and symptoms of infection, thereby raising concerns over the decision not to treat the patient. Unless specific antibiotics are used which eradicate adherent biofilms from the bladder, the treatment of symptomatic patients will only impact upon the signs and symptoms in some patients, and not alter their susceptibility to reinfection.