Urinary tract infection: Difference between revisions

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== Background ==
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==Background==
   
 
*Bacterial infection of the urinary tract, either lower (cystitis) or upper (pyelonephritis)
 
*Bacterial infection of the urinary tract, either lower (cystitis) or upper (pyelonephritis)
 
*When UTI causes sepsis syndrome, often referred to as urosepsis
 
*When UTI causes sepsis syndrome, often referred to as urosepsis
   
=== Microbiology ===
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===Microbiology===
   
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*Gram-negative bacteria
*Ascending genitourinary infection
 
**''[[E. coli]]''
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**[[Escherichia coli]], most common cause overall
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**[[Proteus]], [[Klebsiella]], [[Enterobacter]]
**''[[S. saprophicitus]]''
 
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**[[Pseudomonas]], [[Acinetobacter]]
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* Gram-positive bacteria
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**[[Staphylococcus saprophyticus]], more common in young women
 
**[[Enterococcus faecalis]]
 
**[[Enterococcus faecalis]]
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**[[Staphylococcus aureus]], as a complication of [[Staphylococcus aureus bacteremia]]
*Bacteremia
 
**[[Staphylococcus aureus]]
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**[[Corynebacterium urealyticum]]
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*Viruses
**[[Candida species]]
 
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**[[Adenovirus]], which can cause [[hemorrhagic cystitis]] in [[hematopoietic stem cell transplantation]] recipients
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**[[BK virus]], in renal transplant recipients
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=== Risk Factors ===
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* '''Premenopausal women:''' sexual intercourse, new partner, no postcoital voiding, spermicide use, prior UTI, [[diabetes mellitus]]
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* '''Postmenopausal women:''' estrogen deficiency, incontinence, postvoid residual, catheterization
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* '''Men:''' reduced prostatic secretions (older men), postvoid residual, incontinence, catheterization
   
 
==Clinical Manifestations==
 
==Clinical Manifestations==
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==Investigations==
 
==Investigations==
   
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*Urinalysis
*Urinalysis has high NPV (~100%) if negative for leukocyst esterase and nitrites
 
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**Leukocyte esterase
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**Nitrite, positive for organisms that convert nitrate to nitrite such as the Gram-negative bacteria
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**High negative predictive value if both LE and nitrite are negative
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*Urine microscopy
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**Pyuria indicated by 5-10 cells per HPF
   
 
[[Category:Genitourinary infections]]
 
[[Category:Genitourinary infections]]

Revision as of 11:45, 24 August 2020

Background

  • Bacterial infection of the urinary tract, either lower (cystitis) or upper (pyelonephritis)
  • When UTI causes sepsis syndrome, often referred to as urosepsis

Microbiology

Risk Factors

  • Premenopausal women: sexual intercourse, new partner, no postcoital voiding, spermicide use, prior UTI, diabetes mellitus
  • Postmenopausal women: estrogen deficiency, incontinence, postvoid residual, catheterization
  • Men: reduced prostatic secretions (older men), postvoid residual, incontinence, catheterization

Clinical Manifestations

  • Diagnostic criteria include clinical and laboratory symptoms:
    • Two or more clinical symptoms:
      • Fever > 38ºC
      • Urinary urgency or frequency
      • Acute dysuria
      • Hypogastric pain
      • Costovertebral angle tenderness
    • One or more laboratory finding:
      • Bacteriuria (> 100,000 CFUs/mL)
      • Pyuria (>10 WBCs/HPF)

Investigations

  • Urinalysis
    • Leukocyte esterase
    • Nitrite, positive for organisms that convert nitrate to nitrite such as the Gram-negative bacteria
    • High negative predictive value if both LE and nitrite are negative
  • Urine microscopy
    • Pyuria indicated by 5-10 cells per HPF

References

  1. ^  Dimitri M. Drekonja, Barbara Trautner, Carla Amundson, Michael Kuskowski, James R. Johnson. Effect of 7 vs 14 Days of Antibiotic Therapy on Resolution of Symptoms Among Afebrile Men With Urinary Tract Infection. JAMA. 2021;326(4):324. doi:10.1001/jama.2021.9899.