Mucosal host responses to bacteriuria in colonic and ileal neobladders

Abstract

Objective: To study the local host response in patients with colonic and ileal neobladders, with or without bacteriuria.

Methods: Twenty-three patients with colonic neobladders and 19 with ileal neobladders were included. Eleven radical prostatectomy patients and seven healthy male volunteers were used as controls. Six urine samples were obtained from all patients and controls over a six-month period. The samples were cultured semiquantitatively, and the number of neutrophils and concentrations of the inflammatory mediators interleukin 6 and 8 (IL-6, IL-8) in the urine were determined.

Results: The prostatectomy patients and healthy volunteers had sterile urine, and concentrations of IL-6 and IL-8 were below the detection limit. Most (>70%) of the urine samples from patients with colonic and ileal neobladders showed anaerobic or aerobic bacterial growth, and uropathogens were identified in about 45% of the samples. The local host response was minimal or undetectable in the sterile urine samples. However, the host response was markedly induced by uropathogenic strains in the urine, but not by urinary carriage of nonpathogenic or anaerobic strains. IL-8, but not IL-6, was increased in colonic neobladders, which corresponds to the mucosal host responses in patients with intact lower urinary tracts and asymptomatic bacteriuria. In ileal neobladders, the IL-8 responses were higher, and levels of IL-6 were significantly increased.

Conclusion: Neobladders exhibit a significant local host response to colonization with bacterial uropathogens. This reaction is more pronounced and includes IL-6 activation in ileal neobladders than in colonic neobladders.