The cause of the infection is usually a type of bacteria. The most common place for a urinary tract infection is the bladder a condition called cystitis.
Bacteria usually gain access to the bladder by way of the urethra.
One thing which may promote a urinary tract infection is an abnormality in the urinary tract. If any part of the urinary tract is not properly formed at birth, the production or flow of urine can be slowed or stopped, allowing bacteria to infect the bladder. Urinary tract defects range in seriousness from those that rarely cause problems to those that can cause life-threatening problems. Most defects are treatable and many are corrected through surgery. Although urinary tract infections rarely happen in newborns or within the first year of life, infections that do happen usually develop in baby boys who have an abnormality present at birth.