Antibacterial activity of the bladder mucosa.

Antibacterial activity of bladder mucosa is believed to be a host defense against infection. In this study we examined the antibacterial activity of the bladder mucosa without the effect of voiding. In addition we examined whether the property of adherence was advantageous for the organism in contact with the bladder mucosa. For this, three adhering and three nonadhering strains of E. coli were placed in contact with the bladder mucosa for 4 h in an in vivo rabbit model. E. coli grown in broth and applied to 32 bladders increased in titer by 1 log. E. coli grown in rabbit urine and applied to seven bladders increased in titer by 1.2 log. In contrast E. coli inoculated into control vials containing broth increased in titer by 2.3 log (P = 0.01). There was no significant difference in the titer between adhering and nonadhering strains of E. coli after 4 h of contact with the bladder mucosa. Bladder mucosa may have an inhibitory effect on bacterial growth (regardless of adherence characteristics) and with urine flow serves to prevent infection of the bladder urine.