Proteus mirabilis facilitates the formation of kidney stones because the organism produces a potent urease. Proteus: Causes 1-2% of cases of UTI in healthy women. 5% of cases of hospital-acquired UTI. High prevalence of stones is due to bacterial production of urease (Hydrolyzes urea -ammonia - alkalization of the urine-precipitation of struvite and carbonate-apatite crystals- development of calculi). Option 1: Destruction of blood vessels in the kidney is seen in HUS (Haemolytic uremic syndrome) caused by Enteroheamorrhagic Escherichia coli (EHEC). Option 2: Swarming is the propey of Proteus but not associated with stone formation. Option 3: Proteus is lactose non fermenter ie. does not ferment lactose (sugar).