Urinary Tract Infection (UTI)

Urinary Tract Infection (UTI)

David Ray Velez, MD

Table of Contents

Definition
Risk Factors
Presentation
Diagnosis
Treatment

Definition

Definitions

  • Asymptomatic Bacteriuria: Bacterial in without Any Associated UTI Symptoms
  • Urinary Tract Infection (UTI): Infection of the Urinary Tract (Includes Cystitis and Pyelonephritis)
  • Cystitis: Infection of the Bladder and Lower Urinary Tract
  • Pyelonephritis: Infection of the Kidney and Upper Urinary Tract

The Most Common Infection in Surgery Patients

Complexity

  • Simple UTI:
    • Infection Confined to Bladder
    • Female
    • Not Pregnant
    • Not Immunocompromised
    • No Other Complicated Factors
  • Complicated UTI:
    • Infection Spread Beyond the Bladder (Kidneys, Ureters)
    • Males
    • Pregnant Females
    • Immunosuppression
    • Indwelling Urinary Catheters
    • Associated with Stones or Urinary Obstruction
    • Fever or Urosepsis
  • *Classification of “Complicated UTI” is Heterogenous with Varied Definitions

Catheter-Associated Urinary Tract Infection (CAUTI): A Urinary Tract Infection with an Indwelling Urinary Catheter (IUC) In Place for ≥ 2 Consecutive Days or Diagnosed within 2 Days of Removal

Risk Factors

Risk Factors

  • Indwelling Urinary Catheters (IUC) – Strongest Risk Factor
  • Female Sex
  • Previous UTI
  • Sexual Activity
  • Pregnancy
  • Elderly and Young Children
  • Structural Abnormality
  • Poor Hygiene (Potty-Training)

Specific Risk Factors for Complicated UTI

  • Poorly Controlled Diabetes
  • Immunocompromised
  • Nephrolithiasis
  • Strictures
  • Stents

CAUTI-Specific Risk Factors

  • Duration of Catheterization – Most Important
    • Risk: 3-10% Per Day of Catheterization
  • Poor Catheter Care
  • Female Sex
  • Age > 50
  • Diabetes

Presentation

Symptoms

  • Dysuria (Pain with Urination)
  • Pyuria (Burning with Urination)
  • Urinary Frequency
  • Urinary Urgency
  • Urinary Incontinence
  • Suprapubic Pain/Tenderness
  • Hematuria
  • *Neither Cloudy nor Foul-Smelling Urine are Clearly Associated with UTI

Signs Suggesting Complex Infection

  • Fever
  • Flank Pain
  • Costovertebral Angle (CVA) Tenderness
  • Significant Fatigue
  • Unexplained Systemic Symptoms (AMS, Hypotension, SIRS)

Complications

  • Upper Urinary Tract Involvement
  • Bacteremia
  • Sepsis (Urosepsis) – High Mortality (5-40%)

Diagnosis

No Further Testing is Required for Most Females with Suspected Simple UTI and Classic Symptoms

Urinalysis (UA)

  • Obtain if Unsure of Diagnosis:
  • Indicators of UTI:
    • Presence of Bacteria
    • Elevated WBC
    • Nitrites
    • Leukocyte Esterase
  • Presence of Squamous Epithelial Cells Indicates Contamination with Skin Flora, Making UA Unreliable

Urine Culture

  • Obtained for All Patients at Risk for a Multi-Drug-Resistant Organism, Including Patients with a Recent Inpatient Stay at a Health Care Facility
  • Definitions:
    • Asymptomatic Bacteriuria: Urine Culture ≥ 105 CFU/mL without UTI Symptoms
    • CAUTI: Urine Culture ≥ 103 CFU/mL with Signs/Symptoms
  • Most Common Organisms:
    • Escherichia coli – #1 Most Common
    • Enterococcus
    • Pseudomonas
    • Klebsiella
    • Staphylococcus saprophyticus
    • Candida

Imaging

  • Abdominal CT or US
  • Consider for Complicated UTI if Severely Ill, Suspected Obstruction, or if Fails to Improve After 48-72 Hours

Treatment

CAUTI Prevention

  • Avoid Unnecessary Catheters
  • Use Sterile Technique in Placement
  • Remove as Soon as Possible
  • Intermittent Catheterization if Possible – Lower Risk
  • Interventions Without Proven Benefit:
    • Antibiotic-Coated Catheters
    • Prophylactic Antibiotics
    • Exchanging Catheters at Routine Fixed Intervals
    • Meatal Disinfectants or Antibacterial Lubricants with Routine Care

Indications for Treatment

  • Asymptomatic Bacteriuria: Nothing
    • Antibiotics Do Not Affect Complications or Outcomes
  • Symptomatic or Complicated: Antibiotics

Antibiotic Selection

  • Uncomplicated: Oral Antibiotic Regimen
    • Nitrofurantoin (Macrobid) 100 mg BID x 5 Days – Most Common
    • Fosfomycin 3 g Single Dose
    • TMP-SMX Double Strength (DS) 160/800 mg BID x 3 Days
  • Complicated: IV Antibiotic Regimen for 7-10 Days
    • Not Concerned for a Multi-Drug-Resistant Organism:
      • Ceftriaxone 1 g Daily
      • Ciprofloxacin 400 mg BID
      • Levofloxacin 750 mg Daily
    • Concerned for a Multi-Drug-Resistant Organism:
      • Cefepime 2 g BID
      • Piperacillin-Tazobactam (Zosyn) 3.375 g Q6H
      • Meropenem 1 g Q8H
      • Imipenem 500 mg Q6H
    • If Critically Ill or Suspected Obstruction: Meropenem OR Imipenem AND Vancomycin

Candiduria

  • Asymptomatic Candiduria: Generally Requires No Treatment Unless Neutropenic or Undergoing a Urologic Procedure
  • Symptomatic Candiduria: Fluconazole 200-400 mg PO Daily
    • IV Amphotericin if Resistant to Fluconazole

CAUTI Catheter Management

  • Removal of Catheter if Feasible
  • Intermittent Catheterization has Lower Risk of UTI
  • Replace Catheter After Initiation of Antibiotics if Required