Urinary Tract Infections Quiz

Urinary Tract Infections (UTIs)

• UTIs are a common infection affecting the urinary system.
• Approximately 40-50% of hospital-acquired infections are UTIs, and 10-20% of community-acquired infections are UTIs.
• UTIs are more common in newborns (boys), middle-aged women (10x more than men), and those over 60 (men).

Types of UTIs

• Lower UTIs: Conditions affecting the bladder (cystitis), urethra (urethritis), and prostate (prostatitis).
• Upper UTIs: Conditions affecting the kidneys and their pelvis (pyelonephritis).

UTI Defense Mechanisms

• Flushing: The constant flow of urine washes bacteria away from the urinary tract lining.
• Normal Flora: The natural bacteria present in the urinary tract can help prevent infection.
• Mucus Epithelium: The protective mucous layer defends against pathogens.
• Tamm-Horsfall Protein: This protein plays a role in preventing infections.

Risk Factors for UTIs

• Upper Part:
  • Structural problems in the urinary system.
  • Urinary reflux (urine flowing back into the kidneys).
  • Kidney stones (renal calculi).
• Lower Part:
  • Bladder obstructions or tumors.
  • Pregnancy.
  • Urinary catheters.
  • Autoinfection (bacteria spreading from another part of the body).
  • Anatomical issues in the urinary tract.
  • Neurological problems affecting bladder control.
  • Sexual activity.
  • Age.

UTI Routes of Infection

• Ascending: The most common route, where bacteria enter the urethra and travel upwards.
• Hematogenous: Bacteria spread through the bloodstream (e.g., Staphylococcus aureus).
• Lymphatic: Bacteria spread through the lymphatic system.
• Tissue contiguous: Infection spreads from nearby infected tissue.
• Fistula: Direct connections between the urinary tract and another organ or area. For example, between the urinary tract and the intestines (uretero-vesico-intestinal) or the vagina/uterus.

UTI Symptoms

• General: 50% of UTIs don't produce noticeable symptoms.
• Newborns: Often present with non-specific symptoms such as fever, vomiting, and failure to thrive.
• Older Children/Adults (Lower UTI):
  • Painful urination (dysuria).
  • Frequent urination (frequency).
  • Blood in the urine (hematuria - about 50% of cases).
  • Fever (often absent).
• Older Children/Adults (Upper UTI):
  • Fever (> 38.5°C).
  • Chills.
  • Kidney pain.
  • More severe cases include vomiting, diarrhea, and rapid heartbeat.

UTI Complications

• Sepsis: UTIs can lead to a life-threatening bloodstream infection.
  • UTIs are a significant source of sepsis especially after other infections and in newborns (20-30% risk).
• Renal Failure.
• High Blood Pressure (Hypertension)
• Pregnancy/Childbirth complications.

UTI Pathogens

• Community-acquired*:
• E. coli (90%)
• Staphylococcus saprophyticus
• Proteus spp.; Klebsiella spp.
• Staphylococcus spp.
• Streptococcus spp.
• Enterococcus spp.
• Viruses, fungi, parasites (Rare)
• Hospital-acquired*:
• E. coli (50%)
• Enterobacter spp.
• Proteus spp.
• Serratia marcescens
• Acinetobacter spp.
• Pseudomonas spp.
• Stenotrophomonas maltophilia
• Providencia stuartii
• Staphylococcus spp.
• Enterococcus spp.
• Corynebacterium urealyticum
• Fungi (Candida spp.)

UTI Diagnosis

• Symptoms: Patient's reported signs and symptoms.
• Urinalysis:
  • Urine strip tests (leukocyte esterase, nitrates).
  • Microscopic exam (pyuria, bacteria, hematuria).
  • Flow cytometry (for specific cell counts).
• Urine Culture: Testing urine for specific bacteria in a lab setting.
• Imaging (e.g., Ultrasound - USG): Used to identify structural abnormalities.
• Blood Cultures: Done in cases of suspected kidney infection or sepsis.

Urine Culture Details

• Specimen Types: Midstream urine, catheter urine, suprapubic aspiration.
• Transport: Transport to lab within 30 minutes, in room temperature.
• Storage (if necessary): In sterile containers at 4°C up to 24 hours or 4°C+boric acid for up to 48 hours; stored in uromedium (a transport/growth medium).
• Microscopic exam: for bacteria and white blood cell counts
• Culture: Grow bacteria using special media (e.g. CLED, MCA). Quantification method based on CFU/ml (Colony Forming Units / millilitre).

UTI Definitions

• Recurrent UTI: Same bacteria in urine within 10-14 days of treatment. 3 or more uncomplicated UTI's in 12 months.
• Reinfection: A different bacteria in urine, within 2-3 weeks of prior infection.

UTI Prevention

• Limiting spermicide use
• Postcoital voiding
• Avoiding harmfulness of cranberry products
• Continuous or postcoital antibiotic prophylaxis

UTI Treatment

• Lower UTI*:
• First line: Co-trimoxazole, fluoroquinolones (e.g., norfloxacin), nitrofurantoin, furagin.
• Second line: Cephalosporins (e.g., cephalexin, cefadroxil), generation II cephalosporins, fluoroquinolones
• Upper UTI*:
• First line: Co-trimoxazole, fluoroquinolones
• Second line: Penicillins with beta-lactamases inhibitors, cephalosporins, and generation II and III cephalosporins
• Complicated Lower UTI*:
• First line/second line Per Oss/In Vena treatment:*
• Co-trimoaxole/penicillins + beta-lactamases inhibitors/ciprofloxacin/penicillins +/- ampicillin + aminoglycosides/II generation Cephlasporin +/- aminoglycosides*

Additional Treatment-specific Considerations

• Pseudomonas spp.: Cephatazidime +/- Aminoglycosides; Piperacillin/carbenicillin +/- aminoglycosides; Carbapenems +/- aminoglycosides.
• Gram-positive cocci: Cephalosporins I or II generation + aminoglycosides; penicillins + beta-lactamases inhibitors +/- aminoglycosides
• Methicillin-Resistant Staphylococcus spp.(MRSA): Glycopeptides.
• Enterococci: Aminoglycosides + glycopeptides; aminoglycosides + ampicillin
• Candida spp.: Fluconazole + Flucytosine; Amphotericin B + Flucytosine.
• Asymptomatic bacteriuria: Treatment may be recommended for pregnant women, pre-surgery patients, patients with indwelling catheters with persistent bacteriuria post-catheter removal.