Hi, Thanks for writing in. Proteus mirabilis are part of the human intestinal flora and can cause infection upon leaving this location. The most common infection involving Proteus mirabilis occurs when the bacteria moves to the urethra and urinary bladder and that might have happened with you. Urinary tract infections caused by Proteus mirabilis occur usually in patients under long-term catherization. The bacteria have been found to move and create encrustations on the urinary catheters. The encrustations cause the catheter to block and the bacteria multiply and colonize. Any catheterization during the hospital stay can be the cause of the infection. Rarely such a proteus mirabilis infection might occur even without catheterization.