Bladder infections in teens and adults are caused by bacterial growth inside the urinary bladder. For people with decreased immune resistance, fungi can cause bladder infections too.
A bladder infection is a form of urinary tract infection (UTI). This may be from infections in any area in the urinary tract, for instance, the bladder, kidneys, ureters, or urethra.
Microorganisms that enter through the urethra and move into the bladder cause bladder infections. Usually, the body removes microorganisms by flushing them out in urine.
Microorganisms can attach to the walls of the bladder and grow quickly. This overwhelms the body’s ability to destroy them, causing a bladder infection.
