What details listed in the case study give clues to how this infection occurred?

Have a couple of questions regarding microbiology.The bacteria is Proteus vulgaris 1) Describe why the ability of this bacteria to use urea for energy is beneficial in a urinary tractinfection?Case Study:Alberta was furious. When she had gone to remove the last ice cream bar from the freezer, something looked amiss. It appeared someone had removed the bar from its wrapper and then replaced it. Close inspection showed what appeared to be lip prints on the chocolate coating. She confronted her roommate, who denied the accusations. Alberta was unconvinced, as there was a history of such events. To prove her point, Alberta took the ice cream bar to her microbiology lab in an attempt to culture any microbes from the chocolate coating. Surely this would be the smoking gun needed to prove her roommates guilt.2) What details listed in the case study give clues to how this infection occurred?