[Experimental bladder stone production by human uropathogenic bacteria].

To investigate the formation of infection stones by 5 bacterial species isolated from patients with urinary calculi, such as Proteus mirabilis, Staphylococcus saprophyticus, Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli, a zinc disc was implanted and 10(6) bacteria were surgically inoculated at the same time into the bladder of male Wistar rats (10 rats per group). Urinary pH was measured on days 1, 3, 5 and 7. The rats were killed on day 7 and the bladder examined for the formation of infection stones. Infection stones were formed in all rats inoculated with P. mirabilis (mean stone weight 29.7 mg), and in 60% of those inoculated with S. saprophyticus (9.7 mg). Small bladder stones were formed in 30% of the rats inoculated with K. pneumoniae and 25% of those inoculated with P. aeruginosa. No bladder stones were formed in the rats inoculated with E. coli. Urinary pH was increased by P. mirabilis and S. saprophyticus but was unaffected by the other species. In conclusion, P. mirabilis and S. saprophyticus play a significant role in the formation of infection stones.