Urinary Tract Infections: The Unappreciated Giant

Uncomplicated UTIs are usually due to microbial infections including fungi, viruses and bacteria. The most common bacterial infection is Escherichia coli (E. coli) which causes the vast majority of UTIs. Microbial infections affect women much more often than men.

Urethritis. Urethritis is an infection or inflammation of the lining of the urethra.

Cystitis. Cystitis, or bladder infection, is the most common UTI. It occurs in the lower urinary tract (the bladder and urethra) and nearly always in women. In most cases, the infection is brief and acute and only the surface of the bladder is infected. Deeper layers of the bladder may be harmed if the infection becomes persistent, or chronic, or if the urinary tract is structurally abnormal.

Pyelonephritis (Kidney Infection). Sometimes the infection spreads to the upper urinary tract (the ureters and kidneys). This is called pyelonephritis, or more commonly, a kidney infection.

Complicated UTIs, which occur in men and women of any age, are also caused by microorganisms but they tend to be more severe, more difficult to treat, and recurrent. Most often, they are the result of:

• Some anatomical or structural abnormality that impairs the ability of the urinary tract to clear out urine and therefore microorganisms.
• Catheter use in the hospital setting or chronic indwelling catheter usage in the outpatient setting.
• Bladder and kidney dysfunction, or kidney transplant (especially in the first 3 months after transplant).

Recurrences can occur in up to 50 60% of patients with a complicated UTI if the underlying structural or anatomical abnormalities are not corrected.

Recurrence is often categorized as either reinfection or relapse:

Reinfection. About 80% of recurring UTIs are reinfections. A reinfection occurs several weeks after antibiotic treatment has cleared up the initial episode and can be caused by the same microbial strain that caused the original episode or a different one. The infecting organism is usually introduced through fecal bacteria and moves up through the urinary tract.

Relapse. Relapse is the less common form of recurrent UTI. It is diagnosed when a UTI recurs within 2 weeks of treatment of the first episode and is due to treatment failure. Relapse usually occurs in kidney infection (pyelonephritis) or is associated with obstructions such as kidney stones, structural abnormalities or, in men, chronic prostatitis.

Most women who have had an uncomplicated UTI have occasional recurrences. About 25 - 50% of these women can expect another infection within a year of the previous one. Between 3 - 5% of women have ongoing, recurrent UTIs, which follow the resolution of a previous treated or untreated episode.

Many women suffer from frequent UTIs. About 20 percent of young women with a first UTI will have a recurrent infection. With each UTI, the risk that a woman will continue having recurrent UTIs increases. Some women have three or more UTIs a year. However, very few women will have frequent infections throughout their lives. More typically, a woman will have a period of 1 or 2 years with frequent infections, after which recurring infections cease.

Men are less likely than women to have a first UTI. But once a man has a UTI, he is likely to have another because microbes can hide deep inside prostate tissue. Anyone who has diabetes or a problem that makes it hard to urinate may have repeat infections.

Research funded by the National Institutes of Health (NIH) suggests that one factor behind recurrent UTIs may be the ability of bacteria to attach to cells lining the urinary tract. One NIH-funded study found that bacteria formed a protective film on the inner lining of the bladder in mice. If a similar process can be demonstrated in humans, the discovery may lead to new treatments to prevent recurrent UTIs. Another line of research has indicated that women who are nonsecretors of certain blood group antigens may be more prone to recurrent UTIs because the cells lining the vagina and urethra may allow bacteria to attach more easily. A nonsecretor is a person with an A, B, or AB blood type who does not secrete the normal antigens for that blood type in bodily fluids, such as fluids that line the bladder wall.

When a person has no symptoms of infection but significant numbers of bacteria have colonized the urinary tract, the condition is called asymptomatic UTI (also called asymptomatic bacteriuria). The condition is harmless in most people and rarely persists, although it does increase the risk for developing symptomatic UTIs.

Screening for asymptomatic bacteriuria is not necessary during most routine medical examinations, with the following exceptions:

• Pregnant women with asymptomatic bacteriuria have an increased risk of acute pyelonephritis in their second or third trimester. Therefore, they need screening and treatment for this condition. Guidelines recommend that pregnant women be screened for asymptomatic bacteriuria at 12 - 16 weeks gestation or at the first pre-natal visit, if later.
• People undergoing urologic surgery (such as prostate surgery in men). The presence of an infection during surgery can lead to serious consequences.

The bacteria that cause kidney infections (pyelonephritis) are generally the same bacteria that cause cystitis. There is some evidence, however, the E. coli strains in pyelonephritis are more virulent (able to spread and cause illness).

Complicated UTIs that are related to underlying physical or structural abnormalities of the urinary tract are apt to be caused by a wider range of bacteria. E. coli is still the most common bacteria, but others include Klebsiella, P. mirabilis, and Citrobacter.

Other bacteria associated with complicated or severe infection include Pseudomonas aeruginosa, Enterobacter, and Serratia species gram-positive organisms (including Enterococcus species).

Fungal organisms, such as Candida species can cause complicated UTIs. Candida albicans causes the "yeast infections" that also occur in the mouth, digestive tract, and vagina.

Recurring infections are often caused by different bacteria than those that caused a previous or first infection.

Structure of the Female Urinary Tract. In general, the higher risk in women is mostly due to the shortness of the female urethra which is 1.5 inches compared to 8 inches in men. This anatomical difference allows microbes quicker access to the bladder. Also, a womans urethral opening is near sources of microbes from the anus and vagina. For women, the lifetime risk of having a UTI is greater than 50 percent.

Sexual Behavior. Sexually active women tend to have more UTIs than do women who are not sexually active. Sexual activity can move microbes from the bowel or vaginal cavity to the urethral opening. If these microbes have special characteristics that allow them to live in the urinary tract, it is harder for the body to remove them quickly enough to prevent infection. Following sexual intercourse, most women have a significant number of bacteria in their urine, but the body normally clears them within 24 hours. Nearly 80% of all UTIs in premenopausal women occur within 24 hours of intercourse. UTIs are very rare in celibate women. However, UTIs are not sexually transmitted infections. In general, the physical act of intercourse itself produces the conditions that increase susceptibility to developing a UTI.

Types of Contraceptives. Women who use diaphragms for birth control tend to develop UTIs. The spring-rim of the diaphragm can bruise the area near the bladder making it susceptible to bacteria. Using a diaphragm may slow urinary flow and allow bacteria to multiply. In some women, spermicidal foam or gel used with diaphragms, as well as, spermicidal condoms, may irritate the skin, increasing the risk of bacteria invading surrounding tissues. Most spermicides contain nonoxynol-9, a chemical that is associated with increased UTI risk. Condom use is also associated with increased risk of UTIs, possibly because of the increased trauma that occurs to the vagina during sexual activity.

Pregnancy. In pregnant women, the presence of asymptomatic bacteriuria is associated with increased risk of kidney infection, which can cause early labor and other serious pregnancy complications. For this reason, pregnant women should be screened and treated for asymptomatic bacteriuria. Pregnant women are more susceptible to kidney infections because as the uterus enlarges it compresses the ureters and bladder. This causes urine to back up into the kidneys, increasing the risk of bacterial infection.

Menopause. The risk for UTIs, both symptomatic and asymptomatic, is highest in women after menopause. This is primarily due to the decrease in estrogen, which thins the walls of the urinary tract and reduces its ability to resist bacteria. Estrogen loss can also reduce certain immune factors in the vagina that help block E. coli from adhering to vaginal cells. For some women, topical estrogen therapy helps restore healthy bacteria and reduce the risk of recurrent UTIs. Oral hormone replacement therapy is not helpful in the prevention of UTIs.

Other age-related urinary conditions, such as urinary incontinence, can increase the risk for recurrent UTIs.

Allergies. Women who have skin allergies to ingredients in soaps, vaginal creams, bubble baths, or other chemicals that are used in the genital area are at increased risk for developing UTIs. In such cases, the allergies may cause small injuries that can introduce bacteria.

Antibiotic Use. Antibiotics often eliminate lactobacilli, the protective bacteria, along with harmful bacteria. This can cause an overgrowth of E. coli in the vagina.

Prostate Problems. Men become more susceptible to UTIs after age 50, when they begin to develop prostate problems. Benign prostatic hyperplasia (BPH), enlargement of the prostate gland, can result in obstruction in the urinary tract and increase the risk for infection. In men, recurrent UTIs are also associated with prostatitis, an infection of the prostate gland. Although only about 20% of UTIs occur in men, these infections can cause more serious problems than they do in women. Men with UTIs are far more likely to require hospitalization than women.

Diabetes. Diabetes puts women at significantly higher risk for asymptomatic bacteriuria. The longer a woman has diabetes, the higher the risk. Control of blood sugar does not affect this condition. The risk for UTI complications, and fungal-related UTIs, is also higher in people with diabetes.

Kidney Problems. Nearly any kidney disorder, including kidney stones, increases the risk for complicated UTIs.
Neurogenic Bladder. A number of brain and nerve disorders can affect the nerves of the bladder and cause problems with the ability to empty the bladder and control urine leakage. Multiple sclerosis, stroke, spinal cord injury, and diabetic neuropathy are common examples.

Sickle-Cell Anemia. Patients with sickle-cell anemia are particularly susceptible to kidney damage from their disease, and UTIs put them at even greater risk.

Immune System Problems. People with immunocompromised systems, such as those who have HIV/AIDS or who are undergoing treatment for cancer, are at increased risk for all types of infections, including UTIs and pyelonephritis.

Urinary Tract Abnormalities. Some people have structural abnormalities of the urinary tract that cause urine to stagnate or flow upwards into the upper urinary tract. A prolapsed bladder (cystocele) can result in incomplete urination so that urine collects in the bladder creating a breeding ground for bacteria. Tiny pockets called diverticula sometimes develop inside the urethral wall and can collect urine and debris, further increasing the risk for infection.

Elderly Adults. All older adults who are immobilized, catheterized or dehydrated are at increased risk for UTIs. Nursing home residents especially those who are incontinent are at very high risk.

Hospitalizations. About 40% of all infections that develop in patients while in the hospital are in the urinary tract. The organisms that cause infections in hospitals (called nosocomial infections) are often different from those that commonly cause UTIs. They are also more likely to be resistant to standard antibiotics. Hospitalized patients at highest risk for such infections are those with in-dwelling urinary catheters, patients undergoing urinary procedures, long-stay elderly men, and patients with severe medical conditions.

Catheters. About 80% of UTIs in the hospital are due to catheters. The longer any urinary catheter is in place, the higher the risk for growth of bacteria and an infection. In most cases of catheter-induced UTIs, there are no symptoms. Because of the risk for wider infection, however, anyone requiring a catheter should be screened for infection. Catheters should be used only when necessary and should be removed as soon as possible.

Nursing Homes. All older adults who are immobilized, catheterized or dehydrated are at increased risk for UTIs. Nursing home residents, particularly those who are incontinent, are at very high risk. Symptoms of UTIs in patients and nursing home residents are often subtle.

Symptoms of lower UTIs in adults do not always cause signs and symptoms, but when they do they may include:

• A frequent, intense urge to urinate which may recur immediately after the bladder is emptied.
• A painful burning sensation in the bladder (cystitis) or urethra (urethritis) when urinating.
• The amount of urine voided may be very small.
• Discomfort or pressure in the lower abdomen. The abdomen can feel bloated.
• Pain in the pelvic area or back.
• The urine often has a strong smell, looks cloudy, or contains blood. This is a sign of pyuria, or a high white blood cell count in the urine, and is a very reliable indicator of UTIs.
• Occasionally, fever develops which is not attributable to any other cause. Normally, UTIs do not cause fever if they are in the bladder. A fever may mean the infection has reached the kidneys or has penetrated the prostate.

Symptoms of Severe Infection in the Kidney (Pyelonephritis) tend to affect the whole body and be more severe than those of cystitis (inflammation of the bladder). These symptoms may include:

• Symptoms of lower UTIs that persist longer than a week. Sometimes lower UTI symptoms may be the only signs of kidney infection. People at highest risk for such "silent" upper UTIs include patients with diabetes, impaired immune systems, or a history of relapsing or recurring UTIs.
• An increased need to urinate at night.
• Chills and persistent fever typically lasting more than 2 days and are not attributable to any other cause.
• Pain in the flank (pain that runs along the back at about waist level).
• Vomiting and nausea.

The classic lower UTI symptoms of pain, frequency, or urgency and upper UTI symptoms of flank pain, chills, and tenderness may be absent or altered in older patients. Older women and men are more likely to be tired, shaky, and weak and have muscle aches. Other symptoms of a kidney infection include pain in the back or side below the ribs.

Symptoms of UTIs that may occur in seniors but not in younger adults may include mental changes or confusion, nausea or vomiting, abdominal pain, or cough and shortness of breath. Concomitant illness may further confuse the picture and make diagnosis difficult.

UTIs may be overlooked or mistaken for other conditions in older adults.

Urinalysis (UA). A urinalysis is an evaluation of various components of a urine sample. It involves looking at the urine color and clarity, using a special dipstick to do different chemical testing, and possibly inspecting some of the urine underneath a microscope. A urinalysis usually provides enough information for a PCP to start treatment.

Urine Culture (UC). If necessary, the PCP may order a urine culture, which involves incubating and growing the bacteria contained in the urine. A urine culture can help identify the specific microorganism causing the infection, and determine which type of antibiotics to use for treatment. A urine culture may be ordered if the urinalysis does not show signs of infection but the PCP still suspects a UTI is causing the symptoms. It may also be ordered if the PCP suspects complications from the infection.

Urine Clean-Catch Sample. To obtain an untainted urine sample, PCPs usually request a so-called midstream, or clean-catch, urine sample. To ensure the best possible collection of the urine sample, the patient must be directed to:

• first wash their hands thoroughly, and then wash the penis or vulva and surrounding area four times, with front-to-back strokes, using a new soapy sponge each time.
• begin urinating into the toilet and stop after a few ounces of urine have been voided.
• position the container to catch the middle portion of the urine stream. Ideally, this urine will contain only the microorganisms and other evidence of the UTI.
• finish urinating into the toilet.
• securely screw the container cap in place without touching the inside of the rim and, if directed, write their name on the outside of the container.

The sample is generally given to the PCP or sent to the laboratory for analysis.

Collection with a Catheter. Some patients especially the elderly, immobilized or confused cannot provide a urine sample. In such cases, a catheter may be inserted into the bladder to collect urine. This is the best method for providing a contaminant-free sample.

If the UTI does not respond to treatment, the PCP may order other tests to determine what is causing the symptoms. Imaging tests can help identify:

• Serious and recurrent cases of pyelonephritis
• Structural abnormalities
• Obstruction or abscess

Kidney and Bladder Ultrasound. Ultrasound is a noninvasive imaging test that uses a device, called a transducer that bounces safe, painless sound waves off organs to create an image of their structure. The procedure is performed in a PCPs office, outpatient center, or hospital by a specially trained technician. The images are interpreted by a radiologist. Anesthesia is not needed. The images can be used to screen for hydronephrosis (obstructions of the flow of urine), kidney stones that predispose to infection, and kidney abscesses. In men, ultrasound can detect enlargement or abscesses of the prostate and is an accurate method for detecting incomplete emptying of the bladder, a common cause of UTIs in men over age 50. However, this test cannot reveal all important urinary abnormalities or measure how well the kidneys work.

Special Types of X-Rays. Special x-rays can be used to screen for structural abnormalities, urethral narrowing, or incomplete emptying of the bladder, which can cause stagnation of urine and predispose to infection. Due to the possible risks to the fetus, x-rays are not performed on pregnant women.

• Voiding cystourethrogram is an image of the bladder and urethra taken while the bladder is full and during urination, also called voiding. As the patient lies on the x-ray table, a PCP inserts the tip of a thin, flexible tube called a catheter through the urethra into the bladder. The bladder and urethra are filled with contrast medium to make the structures clearly visible on the x-ray images. The x-rays are taken from various angles while the bladder is full of the contrast medium. The catheter is then removed and x-ray images are taken during urination. The procedure is performed in a PCPs office, outpatient center, or hospital by an x-ray technician. The technician is supervised by a radiologist while the images are taken. The radiologist then interprets the images. Anesthesia is not needed, but light sedation may be used for some patients. This test can show abnormalities of the inside of the urethra and bladder. The test can also determine whether the flow of urine is normal when the bladder empties.
• An intravenous pyelogram (IVP) is an x-ray of the kidney. For a pyelogram, the contrast medium is injected into a vein and eliminated by the kidneys. In both cases, the dye passes through the urinary tract and reveals any obstructions or abnormalities on x-ray images.
• Computed Tomography (CT) scan may be used to check for kidney stones or other obstructions. CT scans use a combination of x-rays and computer technology to create three-dimensional (3-D) images. A CT scan may include the injection of contrast medium. CT scans require the patient to lie on a table that slides into a tunnel-shaped device where the x-rays are taken. The procedure is performed in an outpatient center or hospital by an x-ray technician, and the images are interpreted by a radiologist. Anesthesia is not needed. CT scans can provide clearer, more detailed images to help the PCP understand the problem.

Magnetic Resonance Imaging (MRI). MRI machines use radio waves and magnets to produce detailed pictures of the bodys internal organs and soft tissues without using x-rays. An MRI may include an injection of contrast medium. With most MRI machines, the patient lies on a table that slides into a tunnel-shaped device that may be open ended or closed at one end. Some newer machines are designed to allow the patient to lie in a more open space. The procedure is performed in an outpatient center or hospital by a specially trained technician, and the images are interpreted by a radiologist. Anesthesia is not needed though light sedation may be used for patients with a fear of confined spaces. Like CT scans, MRIs can provide clearer, more detailed images.

Radionuclide scan is an imaging technique that relies on the detection of small amounts of radiation after injection of radioactive chemicals. Because the dose of the radioactive chemicals is small, the risk of causing damage to cells is low. Special cameras and computers are used to create images of the radioactive chemicals as they pass through the kidneys. Radionuclide scans are performed in a PCPs office, outpatient center, or hospital by a specially trained technician, and the images are interpreted by a radiologist. Anesthesia is not needed. Radioactive chemicals injected into the blood can provide information about kidney function. Radioactive chemicals can also be put into the fluids used to fill the bladder and urethra for x-ray, MRI, and CT imaging.

Cystoscopy is used to detect structural abnormalities, interstitial cystitis, or masses that might not show up on x-rays during an IVP. The patient is given a light anesthetic, and the bladder is filled with water. The procedure uses a cystoscope, a flexible, tube-like instrument that the urologist inserts through the urethra into the bladder. Cystoscopy is performed by an urologist in his/her office, outpatient facility, or hospital with local anesthesia. However, in some cases, sedation and regional or general anesthesia are needed.

Urodynamics. Urodynamic testing is a procedure that looks at how well the bladder, sphincters, and urethra are storing and releasing urine. Most of these tests are performed in an urologists office by an urologist, physician assistant, or nurse practitioner. Some procedures may require light sedation to keep a patient calm. Most urodynamic tests focus on the bladders ability to hold urine and empty steadily and completely. Urodynamic tests can also show whether the bladder is having abnormal contractions that cause leakage. A PCP may order these tests if there is evidence that the patient has some kind of nerve damage.

Blood Cultures. If symptoms are severe, the PCP will order blood cultures to determine if the infection is in the bloodstream and threatening other parts of the body.

About half of women with symptoms of a UTI actually have some other condition, such as irritation of the urethra, vaginitis, interstitial cystitis, or sexually transmitted diseases (STDs). Some of these problems may also accompany or lead to UTIs.

Vaginitis. Vaginitis is a common vaginal infection that can be caused by a fungus (candidiasis) or bacteria. Occasionally, the infection causes frequent urination, mimicking cystitis. The typical symptoms of vaginitis are itching and an abnormal vaginal discharge.

Sexually Transmitted Diseases. Women with painful urination whose urine does not exhibit signs of bacterial growth in culture may have a sexually transmitted disease. The most common microorganism is Chlamydia trachomatis. Other STDs that may be responsible include gonorrhea and genital herpes.

Interstitial Cystitis. Interstitial cystitis (IC) is an inflammation of the bladder wall that occurs almost predominantly in women. The average age of patients with IC is 40 years old, but 25% of cases occur in women under age 30. Symptoms are very similar to cystitis, but no bacteria are present. Pain during sex is a very common complaint in these patients, and stress may intensify symptoms.

Kidney Stones. The pain of kidney stones along with blood in the urine can resemble the symptoms of pyelonephritis. There are no bacteria present in the urine with kidney stones, however.

Thinning Urethral and Vaginal Walls. After menopause, the vaginal and urethral walls become dry and fragile; causing pain and irritation that can mimic a UTI.

Prostate Conditions in Men. Prostate conditions, including prostatitis (inflammation of the prostate) and benign prostatic hyperplasia, can cause symptoms similar to urinary tract infections.

UTIs in low-risk women can often be successfully treated over the phone. In such cases, a PCP provides the patients with a 3-day antibiotic regimen without requiring an office urine test. This course is recommended only for women at low risk for recurrent infection, who do not have symptoms (such as vaginitis) suggesting other problems.

Antibiotic Regimen. Oral antibiotic treatment cures 94% of uncomplicated UTIs, although the rate of recurrence remains high. The following antibiotics are commonly used for uncomplicated UTIs:

• Beta-Lactams. The beta-lactam antibiotics share common chemical features and include penicillins, cephalosporins, and some newer similar drugs.
  
  Penicillins (Amoxicillin). Until recent years, the standard treatment for a UTI was 10 days of amoxicillin, a penicillin antibiotic, but it is now ineffective against E. coli bacteria in up to 25% of cases. A combination of amoxicillin-clavulanate (Augmentin) is sometimes given for drug-resistant infections. Amoxicillin or Augmentin may be useful for UTIs caused by Gram-positive organisms, including Enterococcus species and S. saprophyticus.
  
  Cephalosporins. Antibiotics known as cephalosporins are also alternatives for infections that do not respond to standard treatments or for special populations. They are often classed as first, second, or third generation. Cephalosporins used for treatment of UTIs include cephalexin (Keflex), cefadroxil (Duricef) cefuroxime (Ceftin), loracarbef (Lorabid), and cefixime (Suprax, among others).
  
  Other Beta-Lactam Drugs. Other beta-lactam antibiotics have been developed. For example, pivmecillinam (a form of mecillinam), is commonly used in Europe for UTIs.
   
• Trimethoprim-Sulfamethoxazole (TMP-SMX)
  
  The standard regimen is a 3-day course of the combination drug trimethoprim-sulfamethoxazole, commonly called TMP-SMX (such as Bactrim, Cotrim, or Septra). A 1-day course is somewhat less effective but poses a lower risk for side effects. A single dose of TMP-SMX is sometimes prescribed in mild cases, but cure rates are generally lower than with 3-day regimens. Longer courses (7 - 10 days) work no better than the 3-day course and have a higher rate of side effects. TMP-SMX combines an antibiotic with a sulfa drug.
  
  TMP-SMX should not be used in patients whose infections occurred after dental work or in patients allergic to sulfa drugs. Allergies to sulfa are common and may be serious. Trimethoprim (such as Proloprim or Trimpex) is sometimes used alone in those allergic to sulfa drugs. TMP-SMX can interfere with the effectiveness of oral contraceptives. High rates of bacterial resistance to TMP-SMX exist in many parts of the United States.
   
• Fluoroquinolones (Quinolones)
  
  Fluoroquinolone antibiotics, also called quinolones, have usually been a second choice. However, in geographic areas that have a high resistance to TMP-SMX, quinolones are now the first-line treatment for UTIs. Examples of quinolones include ofloxacin (Floxacin), ciprofloxacin (Cipro), norfloxacin (Noroxin), and levofloxacin (Levaquin). Ciprofloxacin (Cipro) is the quinolone antibiotic most commonly prescribed. Quinolones are usually given over a 3-day period and have severe side effects. Pregnant women should not take these drugs.
   
• Tetracyclines
  
  Tetracyclines include doxycycline, tetracycline, and minocycline. Treatment with tetracycline or doxycycline may be used for infections that are caused by Mycoplasma or Chlamydia. Tetracyclines have unique side effects among antibiotics, including skin reactions to sunlight, possible burning in the throat, and tooth discoloration. They cannot be taken by pregnant women.
   
• Aminoglycosides
  
  Aminoglycosides (gentamicin, tobramycin, amikacin) are given by injection for very serious bacterial infections. They can be given only in combination with other antibiotics. Gentamicin is the most commonly used aminoglycoside for severe UTIs. They can have very serious side effects, including damage to hearing, sense of balance, and the kidneys.
   
• Nitrofurantoin
  
  Nitrofurantoin (Furadantin, Macrodantin) is an antibiotic that is used specifically for UTIs as an alternative to TMP-SMX or a quinolone. Unlike many of the other drugs, however, it is usually taken for 7 - 10 days, even in cases of simple cystitis. It is not useful for treating kidney infections. Nitrofurantoin frequently causes stomach upset and interacts with many drugs. Other chronic or serious medical conditions may also affect its use. It should not be used in pregnant women within 1 - 2 weeks of delivery, in nursing mothers, or in those with kidney disease.
   
• Fosfomycin
  
  The antibiotic fosfomycin (Monurol) may be prescribed as a 1-dose treatment for women who are pregnant. Fosfomycin (Monurol) is less effective for treating UTIs than TMP-SMX or nitrurantoin but may be used during pregnancy or for other select patients. Resistance rates to this drug are very low.
   
• Doripenem
  
  Doripenem (Doribax) is a new carbapenem antibiotic, which was approved in 2007 for the treatment of complicated UTIs. It is given by injection.

After a week of antibiotic treatment, most patients are free of infection. If the symptoms do not clear up within the first few days of therapy, PCPs generally suggest that women discontinue their antibiotic and provide a urine sample for culturing in order to identify the specific organism causing the condition.

Although antibiotics can cure most UTIs, severe symptoms can persist for several days until treatment effectively eliminates the bacteria. A number of options are available for relieving symptoms until the antibiotics take effect. 

• Phenazopyridine. Phenazopyridine (such as Pyridium, Uristat, Barodium, Eridium, and AZO Standard) relieves pain and burning caused by the infection. Patients should not take this medication for more than 2 days. Side effects include headache and stomach distress. The medication turns urine a red or orange color, which can stain fabric and be difficult to remove. Rarely, it can cause serious side effects, including shortness of breath, a bluish skin, a sudden reduction in urine output, shortness of breath, and confusion. In such cases, patients should immediately call their PCP.   
• Antispasm Drugs. Methenamine (such as Atrosept, Prosed, and Urised) or flavoxate (Urispas) reduce bladder spasms, which may occur with some UTIs. These medications can have severe side effects, however, that the patient should discuss with their PCP.

A relapsing infection caused by treatment failure usually occurs within 3 weeks in about 10% of women. Relapse is treated similarly to a first infection, but the antibiotics are usually continued for 7 - 14 days. Relapsing infections may be due to structural abnormalities, abscesses, or other problems that may require surgery, and such conditions should be ruled out.

Women who have two or more symptomatic UTIs within 6 months or three or more over the course of a year may need preventive antibiotics. A woman's own perception of discomfort can generally guide her decisions on whether or not to use preventive antibiotics. All women should use lifestyle measures to prevent recurrences.

Intermittent Self Treatment. Many, if not most, women with recurrent UTIs can effectively self-treat without going to a PCP. In general, this requires the following steps:

• As soon as the patient develops symptoms, she takes the antibiotic. Infections that occur less than twice a year are usually treated as if they were an initial attack, with single-dose or 3-day antibiotic regimens.   
• In some cases, she also performs a clean-catch urine test before starting antibiotics and sends it to the PCP for culturing to confirm the infection.

A woman should consult her PCP under the following circumstances:

• If symptoms have not gone away within 48 hours
• If there is a change in symptoms
• If the patient suspects that she is pregnant
• If the patient has more than four infections a year

Women who are not good candidates for self-treatment are those with impaired immune systems, previous kidney infections, structural abnormalities of the urinary tract, or a history of infection with antibiotic-resistant bacteria.

Postcoital Antibiotics. If recurrent infections are clearly related to sexual activity and episodes recur more than two times within a 6-month period, a single preventive dose taken immediately after intercourse is effective. Antibiotics for such cases include TMP-SMX, nitrofurantoin, cephalexin, or a fluoroquinolone (such as ciprofloxacin). Fluoroquinolones are not appropriate during pregnancy.

Continuous Preventive Antibiotics (Prophylaxis). Continuous preventive (prophylactic) antibiotics are an option for some women who do not respond to other measures. With this approach, low-dose antibiotics are taken continuously for 6 months or longer.

Patients with uncomplicated kidney infections (pyelonephritis) may be treated at home with oral antibiotics. Patients with moderate-to-severe acute kidney infection and those with severe symptoms or other complications may need to be hospitalized. In such cases, antibiotics are usually given intravenously for several days. Chronic pyelonephritis may require long-term antibiotic treatment.

Treating Pregnant Women. Pregnant women seem no more prone to UTIs than other women. However, when a UTI does occur in a pregnant woman, it is more likely to travel to the kidneys. According to some reports, about 4 to 5 percent of pregnant women develop a UTI. Scientists think that hormonal changes and shifts in the position of the urinary tract during pregnancy make it easier for microbes to travel up the ureters to the kidneys and cause infection. For this reason, PCPs routinely screen pregnant women for microbes in the urine during the first 3 months of pregnancy.

The antibiotics used during pregnancy include amoxicillin, ampicillin, nitrofurantoin, and cephalosporin. Fosfomycin (Monurol) is not as effective as others but may be used during pregnancy. Pregnant women should not take fluoroquinolones or tetracyclines.

Pregnant women with asymptomatic bacteriuria (evidence of infection but no symptoms) have a 30% risk for acute pyelonephritis in their second or third trimester. They need screening and treatment for this condition. In such cases, they should be treated with a short course of antibiotics (3 - 5 days). For an uncomplicated UTI, pregnant women may need longer-term antibiotics (7 - 10 days).

Catheter-induced UTIs are very common, and preventive measures are extremely important. Catheters should not be used unless absolutely necessary and they should be removed as soon as possible. Reducing the risk for infections during long-term catheter use, however, remains problematic.

Intermittent Use of Urinary Catheters. If a urinary catheter is required for long periods, it is best to use it intermittently if possible (as opposed to an indwelling catheter). Some PCPs recommend replacing an indwelling urinary catheter every 2 weeks to reduce the risk of infection and irrigating the bladder with antibiotics between replacements.

Daily Hygiene. A typical indwelling urinary catheter is one that has been preconnected and sealed and uses a drainage bag system. To prevent infection, some of the following tips may be helpful:

• Drink plenty of fluids, including 3 glasses of cranberry juice a day.
• The catheter tubing should be free of any knots or kinks.
• Clean the catheter and the area around the urethra with soap and water daily and after each bowel movement. Women should be sure to clean their perineum front to back.
• Wash hands before touching the catheter or surrounding area.
• Never disconnect the catheter from the drainage bag without careful instructions from a health professional on strict methods for preventing infection.
• Keep the drainage bag off the floor.
• Stabilize the bag against the leg using tape or some other system.

Antibiotics for Catheter-Induced Infections. Patients using catheters who develop UTIs with symptoms should be treated for each episode with antibiotics and the catheter should be removed, if possible, or changed. A major problem in treating catheter-related UTIs is that the organisms involved are constantly changing. Because there are likely to be multiple species of microorganisms, PCPs generally recommend an antibiotic that is effective against a wide variety of microorganisms.

Although high bacterial counts in the urine (bacteriuria) occur in most catheterized patients, administering antibiotics to prevent a UTI is rarely recommended. Many catheterized patients do not develop symptomatic UTIs even with high bacterial counts. If bacteriuria occurs without symptoms, antibiotic therapy has little benefit if the catheter is to remain in place for a long period.

• Cranberry juice, cranberries, blueberries, and lignonberry, a European relative of the cranberry, are three fruits that may have protective properties against UTIs. These fruits contain compounds called tannins (or proanthocyanadins). Tannins may prevent E. coli bacteria from adhering to cells in the urinary tract, thereby inhibiting infection. Cranberry juice is the best-studied home remedy for UTIs. There is some indication, though it has not been proven, that cranberry juice may have infection-fighting properties and thus drinking it daily may help to prevent UTIs. Studies have shown the greatest effect in women who have frequent UTIs. Studies involving children and older adults have shown mixed results. It is not clear how much or how often a patient would have to drink it to have an effect. If a patient enjoys drinking cranberry juice and thinks it helps prevent UITs, there is little harm in continuing to drink it but calorie intake needs to be monitored. For most patients, drinking cranberry juice is safe but some report an upset stomach or diarrhea. A patient should not drink cranberry juice if they are taking warfarin (Coumadin) because this may lead to bleeding. It is not clear what the optimum dosage is for cranberries, or whether it is best to use juice or tablet form. Some research recommends drinking at least 1- 2 cups of cranberry juice daily or taking at least 300 - 400 mg in tablet form twice daily.
• Probiotics and Lactobacilli are beneficial microorganisms that may protect against infections in the genital and urinary tracts. The best-known probiotics are the lactobacilli strains, such as acidophilus, which is found in yogurt and other fermented milk products (kefir), as well as in dietary supplement capsules. The probiotics bifidobacteria and GG lactobacilli may also be helpful. Other probiotics include the lactobacilli rhamnosus, casel, planetarium, bulgaricus, and salivarius and also Enterococcus faecium and Streptococcus thermophilus. Not all studies show a benefit for probiotics in preventing UTIs. More research is needed.

Perineal Care and Hygiene. The following are some good hygiene tips:

• After using the toilet, women should wipe their perineum from front to back which may help reduce the chances of introducing microorganisms into the vagina and urethra. Females are especially vulnerable to this, because the vagina and urethra are in close proximity to the rectum which increases the chance of dragging E. coli bacteria from the rectal area to the vagina and urethra.
• Wear sanitary napkins instead of tampons which some PCPs believe encourage the development of UTIs. Sanitary napkins and tampons, in any case, should be changed after urinating or defecating.
• Take showers rather than baths.

Avoid Potentially Irritating Feminine Products. Avoid bath oils, feminine hygiene sprays, douches, and powders in the genital area which can irritate the urethra. As a general rule, do not use any product containing perfumes or other possible allergens near the genital area. Douching is never recommended as it may irritate the vagina and urethra and increase the risk of sexually transmitted diseases.

Sexual Precautions. The following recommendations may reduce the risks of developing a UTI from sexual activity:

• Avoid sex with multiple partners. This can cause many health problems, including sexually transmitted diseases and UTIs.
• Keep the genital and anal areas clean before and after sex. Both men and women should urinate before and after intercourse to empty the bladder and cleanse the urethra of microorganisms.

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

Clothing. Cotton-crotch underwear and loose-fitting clothes should be worn and changed at least once a day 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 microbes grow. Mild detergents are best for washing underwear.

Urinate often. A person should urinate often and when the urge arises. Microorganisms can grow when urine stays in the bladder too long.