Return to Urinary Tract Infections - Overview

Many women may associate E. coli bacteria with tainted hamburgers, but what some apparently don't know is that E. coli also happens to be the chief culprit of something that commonly affects them: urinary tract infections (UTIs).

Do you have a UTI?

Symptoms of a urinary tract infection include:

• Frequent urge to urinate.
• Painful, burning sensation in bladder or urethra during urination.
• Tired, washed out feeling.
• Milky or cloudy looking urine, even reddish if blood is present.

A national survey of more than 1,000 women ages 18 to 65 found nearly 90 percent had heard about the bacteria E. coli (Escherichia coli), yet only about half knew it could cause a UTI. More women thought using a hot tub was a cause of UTIs (48 percent) than E. coli (44 percent). The survey was sponsored by the Bayer Corporation.

Hot tubs rarely cause UTIs. However, experts say E. coli most definitely does. Although certain strains are deadly, most E. coli bacteria normally live harmlessly in the intestine. When the bacteria get into the normally sterile urinary tract, however, they grow and can cause an infection.

Experts blame E. coli for about 90 percent of UTIs, resulting in about 9.6 million doctor visits a year. And who makes most of those visits? Women.

Women prone to UTIs

"Most women have either had a UTI or know someone who has," says Susan Kalota, M.D., an Arizona urologist and president of the Society of Women in Urology.

About half of all American women experience cystitis (a bladder infection), at some point, according to Kalota, and bladder infections make up about 95 percent of all UTIs. The survey suggests the number of women experiencing UTIs could even be higher - about 60 percent - with about three-quarters having more than one in their lifetime.

The reason women are more prone to UTIs than men isn't fully understood, although some experts believe a woman's anatomy makes it easier for the E. coli bacteria to get swept up into the urinary tract.

Get the UTI facts

Kalota says women should learn the facts so they can get adequate treatment. The facts include:

1. Sexual intercourse can increase the risk of a UTI. Unlike a sexually transmitted disease, a bladder infection is not contagious. However, sexual intercourse can introduce bacteria into the bladder. (About 62 percent of women in the survey correctly perceived sexual activity as a cause of UTIs.)
2. Women who use a diaphragm or whose partners use a condom with a spermicidal foam tend to have a higher risk of UTIs. "Women should avoid douches, sprays, spermicides and vaginal deodorants because they are more likely to kill off the good bacteria and leave the bad bacteria," Kalota says.
3. Pregnant women seem more prone to UTIs than other women. Scientists think hormonal changes and shifts in the position of the urinary tract during pregnancy make it easier for bacteria to travel up to the ureters to the kidneys.
4. People with diabetes have a higher risk of a UTI because of changes in the immune system.
5. Bacteria on a catheter, or tube placed in the bladder, can cause an infection.
6. Incomplete bladder emptying and urinary tract obstructions (such as kidney stones) that prevent urine from flushing out bacteria are also risk factors for a UTI.
7. Coffee, carbonated drinks and alcohol do not cause cystitis.

Can you prevent a UTI?

Here are several steps you can take to help prevent a bladder infection:

• Urinating after intercourse. (Urine helps flush out bacteria.)
• Wiping from front to back can help prevent bacteria from traveling from the anus to the urethra.
• Wearing underwear with a cotton crotch.
• Seeking medical treatment if you experience incontinence (urine leakage).
• Drinking at least six to eight glasses of water a day.

Researchers have explored the use of cranberry juice to prevent bladder infections. Kalota says cranberry juice does work, although it's unclear why. "Most patients don't say, 'I drank a glass of cranberry juice.' They say, 'I drank a gallon of it.' So it might be the gallon, not the cranberry that is key," she says. It is already known, for instance, that drinking plenty of fluids can help reduce the risk of UTIs.

The type of antibiotic that your doctor prescribes for a UTI depends on your history and your urine test that identifies the strain and type of bacteria. Even though E. coli bacteria might be responsible for a woman having several UTIs in a row, there may be slight differences in the bacteria.

Often a UTI can be cured with one or two days of treatment. For infections of the bladder (called cystitis) the usual antibiotic treatment is for three days. Infections of the kidneys (called pyelonephritis) require a longer course of treatment, usually 10-14 days. Although antibiotics can be highly effective, as more doctors and patients are coming to understand, bacteria also can be quite good at resisting antibiotics.

In a study funded by the National Institutes of Health, researchers at Washington University School of Medicine in St. Louis learned the reason bladder infections are so tough to beat is that the E. coli can dodge antibiotics by invading the immune system cells that line the wall of the bladder.

"The bacteria have become smarter, and we're seeing more antibiotic resistance," says David Talan, M.D., professor of medicine at the University of California at Los Angeles School of Medicine and chairman of the Department of Emergency Medicine and faculty of the Division of Infectious Diseases at Olive View-UCLA Medical Center. Talan is one of the authors of a study in the Journal of the American Medical Association that showed that E. coli bacteria have become resistant to a standard antibiotic, trimethoprim/sulfamethoxazole (TMP/SMX) for treating UTIs.

The study, which was funded by Bayer, involved 255 women with an average age 25 who had acute uncomplicated pyelonephritis, a serious type of kidney infection. Researchers found nearly 18 percent of strains of E. coli were resistant to TMP/SMX, yet none was resistant to ciprofloxacin, which falls into a new class of drugs called quinolones. Bayer manufactures ciprofloxacin (Cipro®).

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External Sources The National Kidney and Urologic Diseases Information Clearinghouse The Journal of the American Medical Association

This article was reviewed and updated June 2007.