TOC  | ID  Urinary Tract Infections in Adults (Review)

TABLE 1 Urinary Tract Infections in Adults Category                Principal  pathogens    First-line-therapy                        Comments                      Acute uncomplicated cystitis •Escherichia coli •Staph.saprophyticus •Proteus mirabilis •Kleb. pneumoniae • TMP-SMX DS    (Bactrim, Septra) • Trimethoprim   • Ciprofloxacin (Cipro) • Three-day course is best • Quinolones may be used in areas of TMP-SMX resistance or in patients who cannot tolerate TMP-SMX Recurrent cystitis in young women As above • If the patient has more than three cystitis episodes per year, treat prophylactically with postcoital, patient- directed* or continuous daily therapy (see text) • Repeat therapy for seven to 10 days based on culture results and then use prophylactic therapy Acute cystitis in young men As above Same as for acute uncomplicated cystitis • Treat for seven to 10 days Acute uncomplicated pyelonephritis As above • If gram-negative organism, oral fluoroquinolone • If gram-positive organism, amoxicillin • If parenteral administration is required, ceftriaxone (Rocephin) or a fluoroquinolone • If Enterococcus species, add oral or IV amoxicillin • Switch from IV to oral administration when the patient is able to take medication by mouth; complete a 14-day course Complicated urinary tract infection • E. coli • K. pneumoniae • P. mirabilis • Enterococcus species • Pseudomonas aeruginosa • If gram-negative organism, oral fluoroquinolone • If Enterococcus species, ampicillin or amoxicillin with or without gentamicin (Garamycin) • Treat for 10 to 14 days Asymptomatic bacteriuria in pregnancy Same as for acute uncomplicated cystitis • Amoxicillin • Nitrofurantoin (Macrodantin) • Cephalexin (Keflex) • Avoid tetracyclines and fluoroquinolones • Treat for three to seven days Catheter-associated urinary tract infection • Depends on duration of catheterization • If gram-negative organism, a fluoroquinolone • If gram-positive organism, ampicillin or amoxicillin plus gentamicin • Remove catheter if possible, and treat for seven to 10 days • For patients with long-term catheters and symptoms, treat for five to seven days Information from Stamm WE, Hooton TM. Management of urinary tract infections in adults. N Engl J Med 1993;329:1328-34. Recurrent Cystitis in Young Women      Up to 20 percent of young women with acute cystitis develop recurrent UTIs. During these recurrent episodes, the causative organism should be identified by urine culture and then documented to help differentiate between relapse (infection with the same organism) and recurrence (infection with different organisms). Multiple infections caused by the same organism are, by definition, complicated UTIs and require longer courses of antibiotics and possibly further diagnostic tests (see the discussion of complicated UTIs). Fortunately, most recurrent UTIs in young women are uncomplicated infections caused by different organisms. These infections are generally not associated with underlying anatomic abnormalities and do not require further work-up of the genitourinary tract.5,11,18 Women who have more than three UTI recurrences documented by urine culture within one year can be managed using one of three preventive strategies3,19: Acute self-treatment with a three-day course of standard therapy. Postcoital prophylaxis with one-half of a trimethoprim-sulfamethoxazole double-strength tablet (40/200 mg) if the UTIs have been clearly related to intercourse. Continuous daily prophylaxis with one of these regimens for a period of six months: trimethoprim-sulfamethoxazole, one-half tablet per day (40/200 mg); nitrofurantoin, 50 to 100 mg per day; norfloxacin, 200 mg per day; cephalexin (Keflex), 250 mg per day; or trimethoprim, 100 mg per day. Each of these regimens has been shown to decrease the morbidity of recurrent UTIs without a concomitant increase in antibiotic resistance. Long-term studies have shown antibiotic prophylaxis to be effective for up to five years with trimethoprim, trimethoprim-sulfamethoxazole or nitrofurantoin, without the emergence of drug resistance.3,19 Unfortunately, antibiotic prophylaxis does not appear to alter the natural history of recurrences because 40 to 60 percent of these women reestablish their pattern or frequency of infections within six months of stopping prophylaxis.19 UTI in Men      Urinary tract infections most commonly occur in older men with prostatic disease, outlet obstruction or urinary tract instrumentation. These infections occasionally occur in young men who participate in anal sex (exposure to E. coli in the rectum), who are not circumcised (increased E. coli colonization of the glans and prepuce) or whose sexual partner is colonized with uropathogens.22 In men (unlike in women), a urine culture growing more than 1,000 CFU of a pathogen per mL of urine is the best sign of a urinary tract infection, with a sensitivity and specificity of 97 percent.23 Men with urinary tract infections should receive a minimum of seven days of antibiotic therapy (either trimethoprim-sulfamethoxazole or a fluoroquinolone). However, more extensive courses may be required in, for example, men with associated urinary tract infection and prostatitis. Consensus regarding the need for a urologic work-up in men with urinary tract infections is lacking. Among young men with acute cystitis who respond to seven days of treatment, diagnostic work-ups beyond cultures are generally unrewarding.24 Urologic evaluation should be performed routinely in adolescents and men with pyelonephritis or recurrent infections.11,25 When bacterial prostatitis is the source of a urinary tract infection, eradication usually requires antibiotic therapy for six to 12 weeks and in rare instances even longer. Catheter-Associated UTI (CAUTI)      Between 10 and 20 percent of patients who are hospitalized receive an indwelling Foley catheter. Once this catheter is in place, the risk of bacteriuria is approximately 5 percent per day. With long-term catheterization, bacteriuria is inevitable. Catheter-associated urinary tract infections account for 40 percent of all nosocomial infections and are the most common source of gram-negative bacteremia in hospitalized patients. The diagnosis of catheter-associated urinary tract infection can be made when the urine culture shows 100 or more CFU per mL of urine from a catheterized patient. The microbiology of catheter-associated urinary tract infections includes E. coli and Proteus, Enterococcus, Pseudomonas, Enterobacter, Serratia and Candida species. The bacterial distribution reflects the nosocomial origin of the infections because so many of the uropathogens are acquired exogenously via manipulation of the catheter and drainage device. Bacteriuria is often polymicrobic, especially in patients with long-term indwelling urinary catheters. Symptomatic bacteriuria in a patient with an indwelling Foley catheter should be treated with antibiotics that cover potential nosocomial uropathogens. Patients with mild to moderate infections may be treated with one of the oral quinolones, usually for 10 to 14 days. Parenteral antibiotic therapy may be necessary in patients with severe infections or patients who are unable to tolerate oral medications. The recommended duration of therapy for severe infections is 14 to 21 days. Treatment is not recommended for catheterized patients who have asymptomatic bacteriuria, with the following exceptions: patients who are immunosuppressed after organ transplantation, patients at risk for bacterial endocarditis and patients who are about to undergo urinary tract instrumentation.26 Bacteriuria is almost inevitable with long-term catheterization, and prevention strategies have largely been unsuccessful. In such patients, catheters should be changed periodically to prevent the formation of concretions and obstruction that can lead to infection. Prophylactic systemic antibiotics have been shown to delay the onset of bacteriuria in catheterized patients, but this strategy may lead to increased bacterial resistance.26 Prophylactic antibiotic therapy has been successful in reducing the frequency of bacteriuria only in patients who can be weaned from indwelling catheters to intermittent catheterization. [Whereas CAUTls are a major reservoir of antibiotic-resistant organisms in the hospital, they are rarely symptomatic and infrequently cause bloodstream infection.   Symptoms referable to the urinary tract, fever, or peripheral leukocytosis have little predictive value for the diagnosis of CAUTI. Arch Intern Med. March 13, 2000;160:678-682 ] Asymptomatic Bacteriuria         Asymptomatic bacteriuria is defined as the presence of more than 100,000 CFU per mL of voided urine in persons with no symptoms of urinary tract infection. The largest patient population at risk for asymptomatic bacteriuria is the elderly. Up to 40 percent of elderly men and women may have bacteriuria without symptoms. Although early studies noted an association between bacteriuria and excess mortality, more recent studies have failed to demonstrate any such link.27 In fact, aggressively screening elderly persons for asymptomatic bacteriuria and subsequent treatment of the infection has not been found to reduce either infectious complications or mortality. Consequently, this approach currently is not recommended. Three groups of patients with asymptomatic bacteriuria have been shown to benefit from treatment: (1) pregnant women, (2) patients with renal transplants and (3) patients who are about to undergo genitourinary tract procedures. Pregnant women with asymptomatic bacteriuria should be treated with a three- to seven-day course of antibiotics, and the urine should subsequently be cultured to ensure cure and the avoidance of relapse.29 Although amoxicillin is frequently suggested as the agent of choice, E. coli is now commonly resistant to ampicillin, amoxicillin and cephalexin. Thus, treatment should be based on the results of susceptibility tests. Nitrofurantoin or trimethoprim-sulfamethoxazole may also be used; however, caution should be exercised in the third trimester because the sulfonamides compete with bilirubin binding in the newborn. Most pregnant women with pyelonephritis should be hospitalized. Initially, these patients should receive intravenous antibiotic therapy. They should complete a 14-day course of acute antibiotic therapy followed by nightly suppressive therapy until delivery. Recent studies have shown that selected pregnant women with pyelonephritis can be treated with either outpatient intramuscularly administered ceftriaxone (Rocephin) or orally administered cephalexin.28 Ceftriaxone, a third-generation parenterally administered cephalosporin, is a suitable agent for inpatient treatment. Tetracyclines and fluoroquinolones should be avoided in pregnancy.       Does Cranberry Juice Have Antibacterial Activity? (JAMA April 5, 2000 ;283)  -  Yee-Lean Lee; John Owens; Lauri Thrupp; Thomas C. Cesario (UC, Irvine) These preliminary data suggest that concentrated cranberry juice has some antibacterial activity. 2008