Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Urinary Tract Infection In Adults ?
    ### Response:
    Most UTIs are caused by bacteria that live in the bowel. The bacterium Escherichia coli (E. coli) causes the vast majority of UTIs. Microbes called Chlamydia and Mycoplasma can infect the urethra and reproductive system but not the bladder. Chlamydia and Mycoplasma infections may be sexually transmitted and require treatment of sexual partners.
    