i am assuming you are a female since most utis are in females. most of the time the e. coli that causes a uti is usually from you. e. coli is the most common pathogen that causes a uti and those germs live in your colon. logistically the rectal opening and vaginal/urethral opening is a close neighbor. it doesn't take much for those colon germs to make it to the urethra. improper wiping sexual intercourse etc.
how do you get an e coli based uti infection