Bladder Infection (Cystitis) What Is It? A bladder infection,
also called cystitis, is caused by an abnormal growth of
bacteria inside the bladder, the balloon-like organ that stores
urine. Bladder infections are one of the most common bacterial
infections to affect humans, with up to one-third of all females
having at least one infection at some point in their lives.
Bladder infections are classified as either simple or
complicated. Simple bladder infections affect only healthy women
with normal urinary systems. Bladder infections are rare in men
who are otherwise healthy, so men are included in the
complicated category with members of both sexes who have
abnormal urinary systems. - Simple bladder infections. Simple
bladder infections develop when bacteria migrate into the
bladder. Because of the structure of the female urinary system,
women are far more likely than men to get these infections. In
women, the opening to the urethra (where urine comes out) is
close to the rectum. Therefore, bacteria can migrat