According to Paul Perito MD a urinary tract infection may involve the urethra, bladder, ureters and kidneys and generally affects men of advanced age.
There are two basic types of urinary tract infection–lower tract and upper tract. Lower tract infections, says Paul Perito MD, include infection of the urethra and bladder. Usually these types of infections are caused by intestinal bacterium which enters through the urethra. Paul Perito MD also notes that certain microorganisms, such as chlamydia and gonorrhea, may be spread through sexual contact.