Bacterial adherence in a rat bladder augmentation model: ileocystoplasty versus colocystoplasty

PURPOSE: Various intestinal segments are used to reconstruct the urinary tract. For unclear reasons asymptomatic chronic bacteriuria is common in patients treated with reconstruction. We compared bacterial adherence in ileum, colon and bladder in rats with ileal and colonic bladder augmentation. MATERIALS AND METHODS: Bladder augmentation using ileum or colon was performed in 8-week-old rats. After 3 months urinary pH was measured and urine was cultured. Urovirulence factors of Escherichia coli aspirated from the augmented bladders were detected by polymerase chain reaction. In rats with negative urine culture after augmentation experimental cystitis was induced by the transurethral inoculation of E. coli C5, with type I pili and aerobactin or E. coli C92 with type I pili, P fimbriae and aerobactin at a concentration of 10(5) colony forming units per 0.3 ml. After 14 days we counted the colony forming units per cm.(2) of bladder and cm.(2) of intestinal augmentation tissue. RESULTS: When cultures were negative, mean urinary pH plus or minus standard deviation for ileocystoplasty (7.35 +/- 0.33) was significantly higher than that for colocystoplasty (6.80 +/- 0.45) or in controls (6.67 +/- 0.30). Bacterial colonization occurred in 60 of 96 ileocystoplasties (62.5%) and 36 of 68 colocystoplasties (52.9%). All 32 E. coli strains aspirated from ileocystoplasties had type I pili. In colocystoplasties 14 strains had type I pili, 4 had P fimbriae and type I pili, and 1 had no virulence factor. In experimental cystitis in the ileal patch and bladder there were 10(3.2) to 10(6.2) (log mean 4.9) and 10(1.1) to 10(5.1) (log mean 3.5) colony forming units of E. coli C5, respectively. In the colonic patch and bladder there were 10(2.2) to 10(6.2) (log mean 3.9) and 10(2.1) to 10(5.1) (log mean 3.7) colony forming units of E. coli C5, respectively. In the ileal patch and bladder versus the colonic patch and bladder there were 10(3.2) to 10(6.2) (log mean 5.0) and 10(3.1) to 10(6.1) (log mean 4.5) versus 10(3.2) to 10(6.2) (log mean 4.3) and 10(2.1) to 10(6.1) (log mean 3.8) colony forming units of E. coli C92, respectively. E. coli C5 adhered to more ileum than bladder, while bacterial adherence did not differ for colon and bladder. Adherence of E. coli C92 did not differ significantly in bladder and implanted ileum or colon. CONCLUSIONS: The colonic segment offers more resistance to E. coli than the ileal segment in urinary diversion.