Ventral bladder hernia facilitates study of urinary tract infections in rats

Previous studies have demonstrated that after intravesical inoculation of Escherichia coli, rats drinking 5% glucose-water remained bacteriuric for up to 21 days while rats drinking tap water became abacteriuric within a few days. To facilitate accurate monitoring of bacteriuria, we created a ventral bladder hernia for percutaneous aspiration of urine. After intravesical inoculation with 10⁸E. coli, rats with ventral bladder hernias demonstrated clearance of bacteria at a rate comparable to that observed in rats with intrapelvic bladders (p<0.01). Of rats drinking tap water, 6 of 7 (85%) with intrapelvic bladders and 8 of 9 (89%) with ventral hernias had less than 10 colony forming units per ml of urine within 9 days of inoculation. Of rats drinking 5% glucose-water, 4 of 5 (80%) with intrapelvic bladders and 6 of 8 (75%) with ventral bladder hernias had >10⁵ colony forming units per ml of urine 9 days after inoculation. The results suggest that this technique does not alter the antibacterial response of control or polyuric rats to E. coli inoculated intravesically.