N-nitrosamine formation in urinary-tract infections.

Urine samples from 31 patients with urinary-tract infections and from 31 controls were analysed for volatile nitrosamines, N-nitrosamino acids, total N-nitroso compounds as a group, and nitrite/nitrate. The concentration of N-nitrosodimethylamine was significantly elevated in urines infected with Escherichia coli, Proteus mirabilis and Klebsiella pneumoniae. The levels of nitrite, N-nitrosoproline and total N-nitroso compounds, when expressed as the amount per mol creatinine, were also significantly increased in patients with bacteriuria. Several bacterial strains were capable of catalysing nitrosation of morpholine at neutral pH. These results suggest that N-nitroso compounds can be formed in vivo in the infected bladder, which could explain the association between urinary-tract infections and increased risk for bladder cancer.