Urinary Tract Infection

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Contents 1 More Specific Terms 2 Introduction 3 Etiology 4 Epidemiology 5 Pathology 6 Clinical-manifestations 7 Laboratory 8 Radiology 9 Differential-diagnosis 10 Management 11 More General Terms 12 Additional Terms 13 References

More Specific Terms

• catheter-associated urinary tract infection
• cystitis
• pyelonephritis
• recurrent urinary tract infection
• urethritis
• urosepsis

Introduction

• An infection in the urinary tract caused by the invasion of pathogenic micro-organisms, which proceed to establish themselves, multiply, & produce various symptoms in their host.

Etiology

• colonic bacteria ascend through the urethra
• short length & positioning of urethra makes females more susceptible to UTIs & pyelonephritis than men
• urinary obstruction, especially prostatic hypertrophy predisposes men to UTIs
• etiologic agents

• Escherichia coli* (most common etiologic agent)
• Proteus mirabilis
• Klebsiella pneumoniae
• Pseudomonas aeruginosa
• Enterobacter species
• Staphylococcus saprophyticus
• Staphylococcus aureus
• Streptococcus viridans
• Enterococcus
• Candida albicans

• risk factors

• female sex (especially if sexually active)
• diabetes
• pregnancy
• spermicide use in women
• urinary tract instrumentation
• neurogenic bladder [15]
  

• * inadequate data linking multidrug-resistant uropathogenic E coli to beef or other animal sources of food [9]

Epidemiology

• in neonates the female/male ratio is < 1
• in children, the female/male ratio is > 1
• in adults, UTIs are largely a disease of sexually-active women
• the female/male ratio is 2:1 after age 60
• UTIs are the most common bacterial infection in elderly

• commonly overdiagnosed in the elderly & treated [14]

• UTIs are a common source of sepsis

Pathology

• toll like receptor 11 involved with clearance of uropathogenic bacteria in mice [8]

Clinical-manifestations

• lower urinary tract infection (also see cystitis & urethritis)

• dysuria
• urinary frequency
• nocturia
• suprapubic pain/tenderness
• hematuria
• malodorous & cloudy urine*
• urinary urgency
• urinary incontinence

• upper urinary tract infection (also see pyelonephritis)

• fever/ chills
• nausea/vomiting
• back or flank pain ( costovertebral angle tenderness)
• symptoms of cystitis
• tachypnea
• tachycardia
• altered mental status (elderly)

• in the elderly, atypical presentations are common

• altered mental status, falls, anorexia, failure to thrive

Laboratory

• urinalysis

• clean-catch or in & out catheterization prior to antibiotic therapy
• for patient < 2 years of age, either catheterization or suprapubic aspiration [18]
• > 10 WBC/ mL in fresh unspun urine ( pyuria)
• spun urine specimen with >5 WBC/ high-power field
• gram stain: >1 bacteria/ hpf (oil) in unspun urine, or >10 bacteria/ hpf (oil) in centrifuged urine correlates with: >10E5 colony forming units per mL on culture
• RBC (non-specific)
• WBC casts suggest pyelonephritis

• urine culture

• indications

• elderly, men
• an unusual or antimicrobial-resistant organism is suspected (in a patient recently infected with a non E coli organism or who recently received antimicrobial therapy)
• pregnancy (obtain after empiric treatment)
• represents a relapse or treatment failure [15]

• > 10E6 colonies/ mL indicates significant infection
• pyuria with negative culture suggests infection by:

• Chlamydia
• Neisseria gonorrhoeae
• tuberculosis

• presence of multiple organisms suggests contamination

• blood cultures in toxic or elderly patients with signs of pyelonephritis
• biochemical screening tests (urine)

• glucose oxidase
• catalase
• nitrite reductase
• leukocyte esterase

Radiology

• routine imaging not indicated [15]
• ultrasound*
• abdominal radiograph* ( KUB)
• intravenous pyelogram

• * initial tests in men [6]

Differential-diagnosis

• lower urinary tract infection ( cystitis)

• urethritis
• vaginitis
• genital Herpes
• chemical irritation from:

• feminine hygiene products
• contraceptive agents

• prostatitis
• epididymitis
• torsion of testes

• see pyelonephritis
• symptomatic bacteriuria

Management

• acute uncomplicated bacterial lower UTI in women

• does not always require culture (see above)
• 3-5 days of oral antibiotics as outpatient*

• 3 days adequate treatment for women > 65 years* [7]
• 3 days for Bactrim, 5 days for nitrofurantoin [13]
• fluoroquinolone & fosfomycin are alternatives [15]
• ciprofloxacin clearly superior to cefpodoxime [20]

• if pregnant

• empiric treatment for 7 days with amoxicillin or nitrofurantoin
• obtain urine cultures after treatment [15] (logic here is elusive)

• acute uncomplicated bacterial lower UTI in men

• 10-14 days of oral or IV antibiotics
• may require hospitalization

• complicated bacterial UTI:

• 14 days of antibiotic therapy
• factors designating UTI as complicated

• age > 65 years* (may NOT indicate complicated UTI) [7]
• indwelling catheter
• recent genitourinary instrumentation
• diabetes mellitus
• renal transplantation
• neutropenia
• recent antibiotic therapy
• recurrent UTI
• pregnancy
• glucocorticoid therapy
• immunocompromised host
• structural of functional urinary tract impairment

• empiric antibiotics

• oral [19]

• trimethoprim-sulfamethoxazole 160/800 mg ( Bactrim DS, Septra DS) every 12 hours (1st line) [11]
• trimethoprim 200 mg every 12 hours
• doxycycline 100 mg every 12 hours day 1, then 100-200 mg QD
• fluoroquinolone

• agent of choice in complicated UTIs
• norfloxacin ( Noroxin) 400 mg every 12 hours
• ciprofloxacin* ( Cipro) 500-750 mg every 12 hours
• levofloxacin
• risk factors for fluoroquinoline resistance

• fluoroquinolone use during the preceding 6 months
• use of a urinary catheter
• recent hospitalization [16]

• sulfisoxazole 120-150 mg/kg/day every 6 hours
• nitrofurantoin; first list all women [11]

• contraindicated with renal insufficiency
• Macrodantin: 5-7 mg/kg/day every 6 hours (1st line) [11]
• sustained-release nitrofurantoin ( MacroBid) 100 mg BID for 5 days - pregnant women
• 3-7 days of therapy

• amoxicillin clavulanate ( Augmentin) 250-500 mg every 6 hours
• cephalexin ( Keflex) 250-500 mg every 6 hours
• ampicillin 250-500 mg every 6 hours

• intravenous

• ticarcillin clavulanate ( Timentin) 3.1 g every 4-6 hours
• amoxicillin clavulanate 1.5-3.0 g every 6 hours
• cefazolin ( Ancef, Kefzol) 0.25-1.5 g every 6 hours
• cephalothin ( Keflin) 0.5 g every 6 hours - 2.0 g every 4 hours
• ceftazidime ( Fortaz) 1-2 g every 6-12 hours
• ceftriaxone ( Rocephin) 1-2 g every 12-24 hours
• gentamicin 3-5 mg/kg/day divided every 8 hours

• UTI during pregnancy

• quinolones cannot be used during pregnancy
• sulfonamides cannot be used close to delivery
• nitrofurantoin
• amoxicillin
• cephalexin ( Keflex) 250-500 mg every 6 hours
• 3-7 days of therapy

• UTI in the elderly

• 10 days of therapy for women ( cystitis)
• 14 days of therapy for men ( cystitis)

• prophylactic antibiotics

• indications

• recurrent UTI
• vesicoureteral reflux (maybe not) [18]

• Bactrim QD
• single dose of antibiotic after intercourse [15]

• patient education

• patients should improve after 2-3 days of therapy
• patients should complete full course of antibiotics
• voiding ofter sexual intercourse can decrease frequency of UTIs in some women
• consider alternate form of contraception if UTI is associated with use of diaphragm
• adequate hydration is important

• follow-up

• no indication for routin urinalysis or culture for non- pregnant women with acute uncomplicated cystitis after treatment
• UTI in men

• follow-up culture after completion of therapy
• genitourinary exam: especially prostate exam
• see radiology (above)

• recurrent UTI in women:

• IVP of little value
• low dose antibiotics for 4-6 months

• Septra DS 1 tab QD
• macrodantin 50-100 mg QD

• genitourinary exam
• cranberry juice:

• conflicting reports suggest little or no benefit [3]
• perhaps some benefit but less so than Bactrim [17]

• switch from spermicide-based contraception to non- spermicide based contraception
• post-coital antibiotic prophylaxis, particularly if UTIs are temporally associated with coitus
• continuous antibiotic prophylaxis, particularly if UTIs are not associated with coitus or used of spermicide-based contraception
• self-initiated therapy for frequent recurrent episodes not associated with coitus

• UTI in children

• follow-up culture 3-7 days after completion of therapy
• children under 5

• renal ultrasound
• voiding cystourethrogram ( VCUG) - fluoroscopic VCUG in males
• radionuclide cystogram ( RCG)

• surgical indications: vesicoureteral reflux
  
• * ciprofloxacin superior to Bactrim for empiric treatment of urinary tract infection in elderly women [5] & superior to Augmentin in younger women [10]

More General Terms

• urologic disease
• infection (infectious disease)

Additional Terms

• bacteriuria

References

1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 544-49
2. The Sanford Guide to Antimicrobial Therapy, 29th ed., Gilbert, DN et al (editors), Antimicrobial Therapy, Inc., Hyde Park VT, 1999
3. Journal Watch 21(17):138, 2001 Kontiokari T et al Randomised trial of cranberry-lingonberry juice and Lactobacillus GG drink for the prevention of urinary tract infections in women. BMJ 322:1571 2001 PMID: [1]
   - Barbosa-Cesnik C et al. Cranberry juice fails to prevent recurrent urinary tract infection: Results from a randomized placebo-controlled trial. Clin Infect Dis 2011 Jan 1; 52:23. PMID: [2]
4. Norman D, UCLA Intensive Course in Geriatric Medicine & Board Review, Marina Del Ray, CA, Sept 12-15, 2001
5. Journal Watch 22(3):25, 2002 Gomolin IH, Siami PF, Reuning-Scherer J, Haverstock DC, Heyd A; Oral Suspension Study Group. Efficacy and safety of ciprofloxacin oral suspension versus trimethoprim-sulfamethoxazole oral suspension for treatment of older women with acute urinary tract infection. J Am Geriatr Soc. 2001 Dec;49(12):1606-13. PMID: [3]
6. Journal Watch 22(8):65-66, 2002 Andrews SJ et al Ultrasonography and abdominal radiography versus intravenous urography in investigation of urinary tract infection in men: prospective incident cohort study. BMJ 324:454, 2002 PMID: [4]
7. Journal Watch 24(6):47, 2004 Vogel T et al Optimal duration of antibiotic therapy for uncomplicated urinary tract infection in older women: a double-blind randomized controlled trial. CMAJ 170:469, 2004 PMID: [5]
8. Journal Watch 24(9):72, 2004 Zhang D, Zhang G, Hayden MS, Greenblatt MB, Bussey C, Flavell RA, Ghosh S. A toll-like receptor that prevents infection by uropathogenic bacteria. Science. 2004 Mar 5;303(5663):1522-6. PMID: [6]
9. Journal Watch 25(4):32-33, 2005 Ramchandani M, Manges AR, DebRoy C, Smith SP, Johnson JR, Riley LW. Possible animal origin of human-associated, multidrug-resistant, uropathogenic Escherichia coli. Clin Infect Dis. 2005 Jan 15;40(2):251-7. Epub 2004 Dec 22. PMID: [7]
10. Journal Watch 25(8):64, 2005 Hooton TM, Scholes D, Gupta K, Stapleton AE, Roberts PL, Stamm WE. Amoxicillin-clavulanate vs ciprofloxacin for the treatment of uncomplicated cystitis in women: a randomized trial. JAMA. 2005 Feb 23;293(8):949-55. PMID: [8]
11. Kallen AJ, Welch HG, Sirovich BE. Current antibiotic therapy for isolated urinary tract infections in women. Arch Intern Med. 2006 Mar 27;166(6):635-9. PMID: [9]
12. Prescriber's Letter 13(5): 2006 Treatment of Uncomplicated Urinary Tract Infections Detail-Document#: [10] (subscription needed) [11]
13. Prescriber's Letter 15(1): 2008 Nitrofurantoin (Macrobid) Shortened Treatment Duration for Acute Uncomplicated Cystitis Detail-Document#: [12] (subscription needed) [13]
14. Woodford HJ and George J Diagnosis and management of urinary tract infection in hospitalized older people. J Am Ger Soc 2009, 57:107 PMID: [14]
15. Medical Knowledge Self Assessment Program (MKSAP) 14, 15, American College of Physicians, Philadelphia 2006, 2009
16. van der Starre WE et al. Risk factors for fluoroquinolone-resistant Escherichia coli in adults with community-onset febrile urinary tract infection. J Antimicrob Chemother 2011 Mar; 66:650. PMID: [15]
17. Beerepoot MAJ et al. Cranberries vs antibiotics to prevent urinary tract infections: A randomized double-blind noninferiority trial in premenopausal women. Arch Intern Med 2011 Jul 25; 171:1270 PMID: [16]
    - Gurley BJ. Cranberries as antibiotics? Arch Intern Med 2011 Jul 25; 171:1279 PMID: [17]
18. Subcommittee on Urinary Tract Infection. Urinary tract infection: Clinical practice guideline for the diagnosis and management of the initial UTI in febrile infants and children 2 to 24 months. Pediatrics 2011 Sep; 128:595. PMID: [18]
19. Prescriber's Letter 18(12): 2011 Choosing a UTI Antibiotic for Elderly Patients Detail-Document#: [19] (subscription needed) [20]
20. Hooton TM et al. Cefpodoxime vs ciprofloxacin for short-course treatment of acute uncomplicated cystitis: A randomized trial. JAMA 2012 Feb 8; 307:583. PMID: [21]
21. Urinary Tract Infections: NIH Institute and Center Resources [22]
    - University of Michigan Health System (UMHS) [23]
22. National Guideline Clearinghouse Uncomplicated urinary tract infection in women. ngc-guideline: [24]
    - Urinary tract infection. (University of Michigan Health System) ngc-guideline: [25]
    - Recurrent lower urinary tract infections in women. (American College of Radiology) ngc-guideline: [26]
    - Management of suspected bacterial urinary tract infection in adults. A national clinical guideline. Scottish Intercollegiate Guidelines Network ngc-guideline: [27]
    - Urinary tract infection-child. (American College of Radiology) ngc-guideline: [28]
    - Treatment of urinary tract infections in nonpregnant women. American College of Obstetricians and Gynecologists ngc-guideline: [29]
    - Catheter-associated urinary tract infections. In: Guidelines on the management of urinary and male genital tract infections. European Association of Urology ngc-guideline: [30]
    - Complicated urinary tract infections due to urological disorders. In: Guidelines on the management of urinary and male genital tract infections European Association of Urology ngc-guideline: [31]
    - Urinary tract infections in renal insufficiency, transplant recipients, diabetes mellitus and immunosuppression. In: Guidelines on urological infections. European Association of Urology ngc-guideline: [32]
    - Uncomplicated urinary tract infections in adults. In: Guidelines on the management of urinary and male genital tract infections. European Association of Urology ngc-guideline: [33]
    - Sepsis syndrome in urology (urosepsis). In: Guidelines on urological infections. European Association of Urology ngc-guideline: [34]
    - Specific infections. In: Guidelines on urological infections. European Association of Urology ngc-guideline: [35]
    - Urinary tract infections in children. In: Guidelines on urological infections. European Association of Urology ngc-guideline: [36]
    - Uncomplicated UTIs in adults. In: Guidelines on urological infections. European Association of Urology ngc-guideline: [37]
    - Catheter-associated UTIs. In: Guidelines on urological infections. European Association of Urology ngc-guideline: [38]
    - Urinary tract infection in children: diagnosis, treatment and long-term management. National Collaborating Centre for Women's and Children's Health. ngc-guideline: [39]
    - Diagnosis, prevention, and treatment of catheter-associated urinary tract infection in adults: 2009 international clinical practice guidelines from the Infectious Diseases Society of America. ngc-guideline: [40]
    - Recurrent urinary tract infection. Society of Obstetricians and Gynaecologists of Canada ngc-guideline: [41]
    - Diagnosis and Management of Lower Urinary Tract Infection American College of Obstetricians and Gynecologists (ACOG) Scottish Intercollegiate Guidelines Network (SIGN) Society of Obstetricians and Gynaecologists of Canada (SOGC) ngc-guideline-synthesis: 25745
    - International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: a 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases. ngc-guideline: [42]
    - Urinary tract infection: clinical practice guideline for the diagnosis and management of the initial UTI in febrile infants and children 2 to 24 months. American Academy of Pediatrics ngc-guideline: [43]
    - Diagnosis and Management of Lower Urinary Tract Infection American College of Obstetricians and Gynecologists (ACOG) Infectious Diseases Society of America/European Society for Microbiology and Infectious Diseases (IDSA/ESMI) Society of Obstetricians and Gynaecologists of Canada (SOGC). ngc-guideline-synthesis: 35626 .Submitted guidelines
    - CG54 Urinary tract infection in children: diagnosis, treatment and long-term management: Full guideline (Aug 2007) National Institute for Health and Clinical Excellence [44]
    - Gould CV et al for the Centers for Disease Control and Prevention GUIDELINE FOR PREVENTION OF CATHETER-ASSOCIATED URINARY TRACT INFECTIONS 2009 [45]

urinary tract infection (UTI)