Urinary Tract Infections In Adults: Causes, Symptoms, Diagnosis, Treatment, Prevention

Urinary Tract Infections In Adults: Causes, Symptoms, Diagnosis, Treatment, Prevention

What is a Urinary Tract Infections In Adults?

Urinary tract infections are a serious health problem affecting millions of people each year.
Infections of the urinary tract are common--only respiratory infections occur more often. In 1997, urinary tract infections accounted for about 8.3 million doctor visits.* Women are especially prone to Urinary Tract Infections for reasons that are poorly understood. One woman in five develops a Urinary Tract Infections during her lifetime. Urinary Tract Infections in men are not so common, but they can be very serious when they do occur.

Urinary Tract Infections In Adults Causes, Symptoms, Diagnosis, Treatment, Prevention

The urinary system consists of the kidneys, ureters, bladder, and urethra. The key elements in the system are the kidneys, a pair of purplish-brown organs located below the ribs toward the middle of the back. The kidneys remove liquid waste from the blood in the form of urine, keep a stable balance of salts and other substances in the blood, and produce a hormone that aids the formation of red blood cells. Narrow tubes called ureters carry urine from the kidneys to the bladder, a triangle-shaped chamber in the lower abdomen. Urine is stored in the bladder and emptied through the urethra.

The average adult passes about a quart and a half of urine each day. The amount of urine varies, depending on the fluids and foods a person consumes. The volume formed at night is about half that formed in the daytime.

What Are the Causes of Urinary Tract Infections In Adults?

Normal urine is sterile. It contains fluids, salts, and waste products, but it is free of bacteria, viruses, and fungi. An infection occurs when microorganisms, usually bacteria from the digestive tract, cling to the opening of the urethra and begin to multiply. Most infections arise from one type of bacteria, Escherichia coli (E. coli), which normally lives in the colon.

In most cases, bacteria first begin growing in the urethra. An infection limited to the urethra is called urethritis. From there bacteria often move on to the bladder, causing a bladder infection (cystitis). If the infection is not treated promptly, bacteria may then go up the ureters to infect the kidneys (pyelonephritis).

Microorganisms called Chlamydia and Mycoplasma may also cause Urinary Tract Infections in both men and women, but these infections tend to remain limited to the urethra and reproductive system. Unlike E. coli, Chlamydia and Mycoplasma may be sexually transmitted, and infections require treatment of both partners.

The urinary system is structured in a way that helps ward off infection. The ureters and bladder normally prevent urine from backing up toward the kidneys, and the flow of urine from the bladder helps wash bacteria out of the body. In men, the prostate gland produces secretions that slow bacterial growth. In both sexes, immune defenses also prevent infection. Despite these safeguards, though, infections still occur.

How common are Urinary Tract Infections in adults?

Urinary tract infections are the second most common type of infection in the body, accounting for about 8.1 million visits to health care providers each year. Women are especially prone to Urinary Tract Infections for anatomical reasons. One factor is that a woman’s urethra is shorter, allowing bacteria quicker access to the bladder. Also, a woman’s urethral opening is near sources of bacteria from the anus and vagina. For women, the lifetime risk of having a Urinary Tract Infections is greater than 50 percent. Urinary Tract Infections in men are not as common as in women but can be serious when they occur.

Who is at risk for a Urinary Tract Infections In Adults?

Some people are more prone to getting a Urinary Tract Infections than others. Any abnormality of the urinary tract that obstructs the flow of urine (a kidney stone, for example) sets the stage for an infection. An enlarged prostate gland also can slow the flow of urine, thus raising the risk of infection.

A common source of infection is catheters, or tubes, placed in the bladder. A person who cannot void or who is unconscious or critically ill often needs a catheter that stays in place for a long time. Some people, especially the elderly or those with nervous system disorders who lose bladder control, may need a catheter for life. Bacteria on the catheter can infect the bladder, so hospital staff take special care to keep the catheter sterile and remove it as soon as possible.

People with diabetes have a higher risk of a Urinary Tract Infections because of changes in the immune system. Any disorder that suppresses the immune system raises the risk of a urinary infection.

Urinary Tract Infections may occur in infants who are born with abnormalities of the urinary tract, which sometimes need to be corrected with surgery. Urinary Tract Infections are rarely seen in boys and young men. In women, though, the rate of Urinary Tract Infections gradually increases with age. Scientists are not sure why women have more urinary infections than men. One factor may be that a woman's urethra is short, allowing bacteria quick access to the bladder. Also, a woman's urethral opening is near sources of bacteria from the anus and vagina. For many women, sexual intercourse seems to trigger an infection, although the reasons for this linkage are unclear.

According to several studies, women who use a diaphragm are more likely to develop a Urinary Tract Infections than women who use other forms of birth control. Recently, researchers found that women whose partners use a condom with spermicidal foam also tend to have growth of E. coli bacteria in the vagina.

Recurrent Infections

Many women suffer from frequent Urinary Tract Infections. Nearly 20 percent of women who have a Urinary Tract Infections will have another, and 30 percent of those will have yet another. Of the last group, 80 percent will have recurrences.

Usually, the latest infection stems from a strain or type of bacteria that is different from the infection before it, indicating a separate infection. (Even when several Urinary Tract Infections in a row are due to E. coli, slight differences in the bacteria indicate distinct infections.)

Research funded by the National Institutes of Health (NIH) suggests that one factor behind recurrent Urinary Tract Infections may be the ability of bacteria to attach to cells lining the urinary tract. A recent NIH-funded study has also shown that women with recurrent Urinary Tract Infections tend to have certain blood types. Some scientists speculate that women with these blood types are more prone to Urinary Tract Infections because the cells lining the vagina and urethra may allow bacteria to attach more easily. Further research will show whether this association is sound and proves useful in identifying women at high risk for Urinary Tract Infections.

Infections in Pregnancy

Pregnant women seem no more prone to Urinary Tract Infections than other women. However, when a Urinary Tract Infections does occur, it is more likely to travel to the kidneys. According to some reports, about 2 to 4 percent of pregnant women develop a urinary infection. Scientists think that hormonal changes and shifts in the position of the urinary tract during pregnancy make it easier for bacteria to travel up the ureters to the kidneys. For this reason, many doctors recommend periodic testing of urine.

What Are the Symptoms of Urinary Tract Infections In Adults?

Not everyone with a Urinary Tract Infections has symptoms, but most people get at least some. These may include a frequent urge to urinate and a painful, burning feeling in the area of the bladder or urethra during urination. It is not unusual to feel bad all over—tired, shaky, washed out—and to feel pain even when not urinating. Often, women feel an uncomfortable pressure above the pubic bone, and some men experience a fullness in the rectum. It is common for a person with a urinary infection to complain that, despite the urge to urinate, only a small amount of urine is passed. The urine itself may look milky or cloudy, even reddish if blood is present. A fever may mean that the infection has reached the kidneys. Other symptoms of a kidney infection include pain in the back or side below the ribs, nausea, or vomiting.

How Is Urinary Tract Infections Diagnosed?

To find out whether you have a Urinary Tract Infections, your doctor will test a sample of urine for pus and bacteria. You will be asked to give a "clean catch" urine sample by washing the genital area and collecting a "midstream" sample of urine in a sterile container. (This method of collecting urine helps prevent bacteria around the genital area from getting into the sample and confusing the test results.) Usually, the sample is sent to a laboratory, although some doctors' offices are equipped to do the testing.

In the urinalysis test, the urine is examined for white and red blood cells and bacteria. Then the bacteria are grown in a culture and tested against different antibiotics to see which drug best destroys the bacteria. This last step is called a sensitivity test.

Some microbes, like Chlamydia and Mycoplasma, can be detected only with special bacterial cultures. A doctor suspects one of these infections when a person has symptoms of a Urinary Tract Infections and pus in the urine, but a standard culture fails to grow any bacteria.

When an infection does not clear up with treatment and is traced to the same strain of bacteria, the doctor will order a test that makes images of the urinary tract. One of these tests is an intravenous pyelogram (IVP), which gives x-ray images of the bladder, kidneys, and ureters. An opaque dye visible on x-ray film is injected into a vein, and a series of x-rays is taken. The film shows an outline of the urinary tract, revealing even small changes in the structure of the tract.

If you have recurrent infections, your doctor also may recommend an ultrasound exam, which gives pictures from the echo patterns of soundwaves bounced back from internal organs. Another useful test is cystoscopy. A cystoscope is an instrument made of a hollow tube with several lenses and a light source, which allows the doctor to see inside the bladder from the urethra.

How Is Urinary Tract Infections In Adults Treated?

Urinary Tract Infections are treated with antibacterial drugs. The choice of drug and length of treatment depend on the patient's history and the urine tests that identify the offending bacteria. The sensitivity test is especially useful in helping the doctor select the most effective drug. The drugs most often used to treat routine, uncomplicated Urinary Tract Infections are trimethoprim (Trimpex), trimethoprim/sulfamethoxazole (Bactrim, Septra, Cotrim), amoxicillin (Amoxil, Trimox, Wymox), nitrofurantoin (Macrodantin, Furadantin), and ampicillin. A class of drugs called quinolones includes four drugs approved in recent years for treating Urinary Tract Infections. These drugs include ofloxacin (Floxin), norfloxacin (Noroxin), ciprofloxacin (Cipro), and trovafloxin (Trovan).

Often, Urinary Tract Infections can be cured with 1 or 2 days of treatment if the infection is not complicated by an obstruction or nervous system disorder. Still, many doctors ask their patients to take antibiotics for a week or two to ensure that the infection has been cured. Single-dose treatment is not recommended for some groups of patients, for example, those who have delayed treatment or have signs of a kidney infection, patients with diabetes or structural abnormalities, or men who have prostate infections. Longer treatment is also needed by patients with infections caused by Mycoplasma or Chlamydia, which are usually treated with tetracycline, trimethoprim/sulfamethoxazole (TMP/SMZ), or doxycycline. A followup urinalysis helps to confirm that the urinary tract is infection-free. It is important to take the full course of treatment because symptoms may disappear before the infection is fully cleared.

Severely ill patients with kidney infections may be hospitalized until they can take fluids and needed drugs on their own. Kidney infections generally require several weeks of antibiotic treatment. Researchers at the University of Washington found that 2-week therapy with TMP/SMZ was as effective as 6 weeks of treatment with the same drug in women with kidney infections that did not involve an obstruction or nervous system disorder. In such cases, kidney infections rarely lead to kidney damage or kidney failure unless they go untreated.

Various drugs are available to relieve the pain of Urinary Tract Infections. A heating pad may also help. Most doctors suggest that drinking plenty of water helps cleanse the urinary tract of bacteria. For the time being, it is best to avoid coffee, alcohol, and spicy foods. (And one of the best things a smoker can do for his or her bladder is to quit smoking. Smoking is the major known cause of bladder cancer.)

Recurrent Infections in Women

Women who have had three Urinary Tract Infections are likely to continue having them. Four out of five such women get another within 18 months of the last Urinary Tract Infections. Many women have them even more often. A woman who has frequent recurrences (three or more a year) should ask her doctor about one of the following treatment options:

  • Take low doses of an antibiotic such as TMP/SMZ or nitrofurantoin daily for 6 months or longer. (If taken at bedtime, the drug remains in the bladder longer and may be more effective.) NIH-supported research at the University of Washington has shown this therapy to be effective without causing serious side effects.
  • Take a single dose of an antibiotic after sexual intercourse.
  • Take a short course (1 or 2 days) of antibiotics when symptoms appear.
Dipsticks that change color when an infection is present are now available without prescription. The strips detect nitrite, which is formed when bacteria change nitrate in the urine to nitrite. The test can detect about 90 percent of Urinary Tract Infections when used with the first morning urine specimen and may be useful for women who have recurrent infections.

Doctors suggest some additional steps that a woman can take on her own to avoid an infection:

  • Drink plenty of water every day.
  • Urinate when you feel the need; don't resist the urge to urinate.
  • Wipe from front to back to prevent bacteria around the anus from entering the vagina or urethra.
  • Take showers instead of tub baths.
  • Cleanse the genital area before sexual intercourse.
  • Avoid using feminine hygiene sprays and scented douches, which may irritate the urethra.
  • Some doctors suggest drinking cranberry juice.

Infections in Pregnancy

A pregnant woman who develops a Urinary Tract Infections should be treated promptly to avoid premature delivery of her baby and other risks such as high blood pressure. Some antibiotics are not safe to take during pregnancy. In selecting the best treatments, doctors consider various factors such as the drug's effectiveness, the stage of pregnancy, the mother's health, and potential effects on the fetus.

Complicated Infections

Curing infections that stem from a urinary obstruction or nervous system disorder depends on finding and correcting the underlying problem, sometimes with surgery. If the root cause goes untreated, this group of patients is at risk of kidney damage. Also, such infections tend to arise from a wider range of bacteria, and sometimes from more than one type of bacteria at a time.

Infections in Men

Urinary Tract Infections in men usually stem from an obstruction--for example, a urinary stone or enlarged prostate--or from a medical procedure involving a catheter. The first step is to identify the infecting organism and the drugs to which it is sensitive. Usually, doctors recommend lengthier therapy in men than in women, in part to prevent infections of the prostate gland.

Prostate infections (chronic bacterial prostatitis) are harder to cure because antibiotics are unable to penetrate infected prostate tissue effectively. For this reason, men with prostatitis often need long-term treatment with a carefully selected antibiotic. Urinary Tract Infections in older men are frequently associated with acute bacterial prostatitis, which can be fatal if not treated immediately.

Is There a Vaccine To Prevent Recurrent Urinary Tract Infections?

In the future, scientists may develop a vaccine that can prevent Urinary Tract Infections from coming back. Researchers in different studies have found that children and women who tend to get Urinary Tract Infections repeatedly are likely to lack proteins called immunoglobulins, which fight infection. Children and women who do not get Urinary Tract Infections are more likely to have normal levels of immunoglobulins in their genital and urinary tracts.

Early tests indicate that a vaccine helps patients build up their own natural infection-fighting powers. The dead bacteria in the vaccine do not spread like an infection; instead, they prompt the body to produce antibodies that can later fight against live organisms. Researchers are testing injection and oral vaccines to see which works best. Another method being considered for women is to apply the vaccine directly as a suppository in the vagina.

Preventing a Urinary Tract Infections In Adults 

Not all urinary tract infections can be prevented, but there are some steps you can take to reduce your risk of developing an infection.

Cranberry juice and capsules

Drinking cranberry juice may help to prevent Urinary Tract Infections. If you have had recurring Urinary Tract Infections, higher-strength cranberry capsules are recommended. These are available from most pharmacists.

Don't drink cranberry juice or take cranberry capsules if you are taking warfarin (a medicine that is used to prevent blood clots).

Treat constipation promptly

Constipation (where it is difficult to defecate, or poo) can increase your chances of developing Urinary Tract Infections.

Recommended treatments for constipation include:
  • increasing the amount of fibre in your diet (20g to 30g of fibre a day)
  • using a mild laxative on a short-term basis
  • drinking plenty of fluids
See your GP if your symptoms don't improve after 14 days. Children should see their GP if their symptoms have not improved after seven days.

Diaphragms and condoms

If you're a woman, using a diaphragm for contraception can increase the risk of getting Urinary Tract Infections. This is because the diaphragm may press on your bladder and prevent it from emptying completely when you urinate.

If you use a diaphragm and have recurring Urinary Tract Infections, you might want to consider changing to another method of contraception. There are 15 different methods of contraception to choose from.

If you get recurring Urinary Tract Infections and you use condoms, try using condoms that don’t have a spermicidal lubricant on them - it will say whether it does on the packet. Spermicidal lubricant can cause irritation and make it more likely that you’ll get Urinary Tract Infections. There are lots of condoms that have non-spermicidal lubricant, so use these instead.

Other useful advice

The following advice may be useful in helping you to keep your bladder and urethra free from bacteria:
  • go to the toilet as soon as you feel the need to urinate, rather than holding it in
  • wipe from front to back after going to the toilet
  • practise good hygiene by washing your genitals every day, and before having sex
  • empty your bladder after having sex

Eating, Diet, and Nutrition for Urinary Tract Infections In Adults

Drinking lots of fluid can help flush bacteria from the system. Water is best. Most people should try for six to eight, 8-ounce glasses a day. A person who has kidney failure should not drink this much fluid. A health care provider should be consulted to learn how much fluid is healthy.

Urination Habits

A person should urinate often and when the urge arises. Bacteria can grow when urine stays in the bladder too long. Women and men should urinate shortly after sex to flush away bacteria that might have entered the urethra during sex. Drinking a glass of water will also help flush bacteria away.

After using the toilet, women should wipe from front to back. This step is most important after a bowel movement to keep bacteria from getting into the urethra.


Cotton underwear and loose-fitting clothes should be worn, so air can keep the area around the urethra dry. Tight-fitting jeans and nylon underwear should be avoided because they can trap moisture and help bacteria grow.

Birth Control

For women, using a diaphragm or spermicide for birth control can lead to Urinary Tract Infections by increasing bacteria growth. A woman who has trouble with Urinary Tract Infections should try switching to a new form of birth control. Unlubricated condoms or spermicidal condoms increase irritation, which may help bacteria grow. Switching to lubricated condoms without spermicide or using a nonspermicidal lubricant may help prevent Urinary Tract Infections.

What can be expected after treatment for urinary tract infections?

Simple Urinary Tract Infections routinely improve with the three days of oral antibiotics and you do not need a urine culture to prove that it is gone. If you have a complicated Urinary Tract Infections, however, you should have a urine culture to show that the Urinary Tract Infections is gone. If your symptoms continue even with medication, then you may need a longer course of medications, a different drug or different delivery method (for example, if you are taking medication by mouth, then you may need it intravenously).

Will Urinary Tract Infections cause damage to the kidneys?

If the Urinary Tract Infections is treated early, then there will probably be no lasting influence on your urinary tract. Recurrent or unrecognized Urinary Tract Infections could cause damage if not remedied expeditiously.

What if I am pregnant?

If you are pregnant and have symptoms of Urinary Tract Infections, then you should contact your doctor immediately. Urinary Tract Infections during pregnancy can put both mother and baby at risk if not addressed quickly and properly.

If Urinary Tract Infections are recurring, can I get over them?

If you are having recurrent Urinary Tract Infections (three or more per year), then you should see your doctor for possible further testing like a urinalysis. You may also need an ultrasound or CT scan to look for any abnormalities of the urinary tract. If you continue to have Urinary Tract Infections, you may benefit from a longer course of low-dose antibiotics or by taking an antibiotic after sexual intercourse. There are also methods of self-testing that your urologist may help coordinate with you to institute both diagnosis and treatment of Urinary Tract Infections at home.

Points to Remember

Most urinary tract infections arise from one type of bacteria, Escherichia coli (E. coli), which normally lives in the bowel.

Symptoms of Urinary Tract Infections in adults may include the following:

  • a frequent and intense urge to urinate
  • a painful, burning feeling in the bladder or urethra during urination
  • feeling tired, shaky, and weak
  • muscle aches
  • abdominal pain
  • only small amounts of urine passed, despite a strong urge to urinate
  • cloudy, dark, or bloody urine or urine that has a foul smell
  • pain in the back or side below the ribs
  • nausea and vomiting

Fever may indicate a kidney or prostate infection.

Because bacteria can be found in the urine of healthy individuals, Urinary Tract Infections is diagnosed based both on symptoms and a laboratory test.

Urinary Tract Infections are treated with bacteria-fighting medications called antibiotics or antimicrobials.