The urethra is a channel from which the urine is discharged from the body. Urinary tract infection (UTI) is an infection cause by the bacteria E.coli. Women are more likely than men to get this infection because they have short urethra than men, which allows the bacteria to enter the bladder and cause infection. Also, affects kidneys and ureters. Cystitis is an infection of the bladder lower urinary tract caused by the bacteria that travels up to the urethra to the bladder. Pyelonephritis is an infection of kidneys and ureters.