Antibacterial activity of bladder mucosa is believed to be a host defe
nse against infection. In this study we examined the antibacterial act
ivity of the bladder mucosa without the effect of voiding. In addition
we examined whether the property of adherence was advantageous for th
e organism in contact with the bladder mucosa. For this, three adherin
g 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. co
li grown in rabbit urine and applied to seven bladders increased in ti
ter by 1.2 log. In contrast E. coli inoculated into control vials cont
aining broth increased in titer by 2.3 log (P = 0.01). There was no si
gnificant difference in the titer between adhering and nonadhering str
ains of E. coli after 4 h of contact with the bladder mucosa. Bladder
mucosa may have an inhibitory effect on bacterial growth (regardless o
f adherence characteristics) and with urine flow serves to prevent inf
ection of the bladder urine.