Bladder Infection (Cystitis)

1. Take the UTI Quiz
2. Urinary Tract Infection (UTI) Slideshow Pictures
3. Urinary Incontinence in Women Slideshow Pictures

Medical Author:

Siamak T. Nabili, MD, MPH

Siamak T. Nabili, MD, MPH

Dr. Nabili received his undergraduate degree from the University of California, San Diego (UCSD), majoring in chemistry and biochemistry. He then completed his graduate degree at the University of California, Los Angeles (UCLA). His graduate training included a specialized fellowship in public health where his research focused on environmental health and health-care delivery and management.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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Bladder infection is an infection of the bladder. Bladder infection is also called cystitis and is a type of urinary tract infection (UTI). The urinary tract is naturally sterile and when microbes invade it, an infection may result.

The bladder is a part of the urinary tract system. It serves as storage for urine before it is excreted from the body. Urine is produced by the kidney and it travels through ureters (one from the right kidney and one from the left) to pass into the bladder. The urine can then be eliminated from the body when bladder is full. The bladder contracts to empty its contents outside through the urethra (the connection between the bladder and outside of the body). Urethra length traverses the length of the penis in males, thus it is longer than the urethra in females.

Similar to other fluids in the body, urine is normally sterile. Presence of bacteria in the urine may lead to bladder infection and other forms of urinary tract infection.

The most common way bacteria gain access to the urinary system from outside is through the urethra (the drainage from the bladder to outside of the body).

• Bacteria can travel from the rectum or the vagina towards the urethra to enter the bladder causing bladder infection or cystitis.
• Sometimes bacteria may enter the bladder via the urethra from nearby skin.
• In general, women are more susceptible to bladder infections due to their shorter length of urethra.

In terms of specific bacteria, E. coli. (Escherichia coli) is by far the most common organism responsible for bladder infection or cystitis. Staph organisms (from skin) and other gut bacteria (Proteus, Klebsiella, Enterococcus) are other bacteria that can cause cystitis and other forms of urinary infections.

Rarely, bladder infection can be caused by a fungus. Candida is the most common fungus to cause bladder infection. This can occur in patients with untreated kidney stones with recurrent infections or in individuals whose immune system is compromised.