IC13 UTI Flashcards
What are the differences between Asymptomatic Bacteriuria (ASB) and Urinary Tract Infection (UTI)
Asymptomatic bacteriuria (ASB):
- Isolation of significant colony of bacteria in the urine
- NO symptoms of UTI
Urinary Tract Infection (UTI):
- Isolation of significant colony of bacteria in the urine
- Symptoms of UTI (urinary and/or systemic) present
Which patient populations should and should not be screened and treated for ASB? How to treat the patient populations if indicated?
Those to be screened and treated with antibiotics:
- Pregnant Women
- Prevent pyelonephritis, preterm labour and infant low birth weight
- Screen in 1 of the first visits (during 12-16th week of gestation)
- Use antibiotics (based on AST) if found to have ASB (4-7 days) - Patients going for urologic procedures (e.g. TURP, cystoscopy with biopsy) where mucosal trauma/bleeding is expected
- Prevent bacteremia and urosepsis
- Screen before going for the procedure
- If found to have ASB, give antibiotics as SAP
- Does not include placement of a urinary catheter (urinary catheter is not considered as a urologic procedure that would cause mucosa trauma/bleeding)
Do NOT screen or treat ASB:
- If patients have ASB and mental status change (delirium, confusion, falls)
o Mental status change here most likely due to old age, dehydration –> careful observation
o Both can happen simultaneously but are not linked
- Unless patient has bacteriuria, mental status changes AND urinary symptoms / systemic signs of infection –> culture and treat
What is the Pathophysiology of UTI?
2 ways
- Ascending
- Possibly from the gut/fecal flora and anorectal area, spreads to the periurethral area, which enters into the urethra and ascends to the bladder and possibly the kidneys
- Higher risk in females, those using diaphragm and spermicides
- Common bacteria involved:
o E. coli, Klebsiella, Proteus (gut gram-negative bacteria) - Descending (hematogenous spread)
- Infection from other sites of the body (heart valves, bones, lungs etc.)
- Goes into the blood and enters the kidneys and then to the bladder/urinary tract
- Common bacteria involved:
o Staphylococcus Aureus
o Mycobacterium Tuberculosis
What are the Normal Host Defense Mechanisms against UTIs?
- Micturition (remove waste filtered from kidneys)
a. Presence of bacteria in the urine would increase diuresis empty the bladder to “flush” out the bacteria - Anti-bacterial properties of the urine and prostate secretion (males)
- Anti-adherence properties of the bladder prevents microbes from adhering to the bladder walls
- Leukocytes phagocytose the microbes prevent/control infection
What are the risk factors of UTI?
Age and gender:
0-6months –> males > females
- More functional and structural abnormalities in males
1 y/o – adult –> female > males
- Female has shorter urethra
- Males have prostate that secretes antimicrobial secretions
Elderly (>65 y/o) equal
1. Female > males
2. Sexual intercourse
3. Abnormalities of urinary tract e.g. prostatic hypertrophy, kidney stones, urethral strictures, vesicoureteral reflux
4. Diaphragm and Spermicides
5. Pregnant women
6. DM
7. Neurologic dysfunction/damage to nerves e.g. stroke, diabetes, spinal cord
8. Anti-cholinergic drugs (muscles can’t relax, urinary retention)
9. Use of catheter
10. Genetic association
11. Previous UTI
What are the subjective and objective evidence of UTI?
Subjective (Symptoms)
1. LUTI (cystitis) –> Local Urinary Symptoms
- Increase urgency, frequency, dysuria, nocturia, hematuria, suprapubic heaviness and pain
2. URTI (pyelonephritis) –> Systemic Symptoms
- Fever, rigors, headaches, nausea, vomiting, malaise, mental status changes (delirium), flank pain, costovertebral tenderness (renal punch), abdominal pain
Objective evidence
Urine Culture NOT for uncomplicated cystitis in women
- Microscopic Urinalysis (e.g. UFEME)
- WBC in urine
o >10WBC/mm3 –> pyuria
o If symptomatic + pyuria –> high chance is UTI
o Pyuria on its own only suggest inflammation
o If pyuria absent, UNLIKELY UTI - RBC in urine
o >5/HPF –> hematuria
o But not specific to UTI - Identity of microbe (bacteria/yeast) using gram stain
- WBC casts
o If WBC cast form in renal tubules –> upper tract infection / disease
- Chemical analysis (dipstick)
- Nitrite
o Only gram-negative will reduce nitrates to nitrites
o At least 10^5 bacteria/mL –> positive
o have false negative (show no microbes) for gram-positive, pseudomonas aeruginosa, low urine pH, frequent voiding and dilute urine - Leukocyte Esterase
o To check the presence of esterase activity produced by leukocytes in urine
o Correlates with significant pyuria (suggest inflammation)
- Culture
- Gram stain
- AST
Collect urine:
- Mid-stream clean catch
- Right after changing to a new catheter
- Suprapubic Bladder aspiration
When to NOT carry out urine test?
Uncomplicated cystitis in women
What are the possible sites of infection?
- Upper urinary tract infection
a. pyelonephritis - Lower urinary tract infection
a. Cystitis (bladder)
b. Prostatitis
c. Urethritis
d. Epididymitis
What are the usual pathogens that cause uncomplicated / Community acquired (CA) UTI?
- E. coli (>85%)
- Staphylococcus Saprophyticus
- Enterococcus faecalis
- Klebsiella pneumoniae
- Proteus spp.
What are the usual pathogens that cause Complicated UTI / Nosocomial Associated UTI?
- E. coli (~50%)
- Enterococcus
- Klebsiella
- Proteus
- Enterobacter
- Pseudomonas
(Higher chance of them being drug-resistant e.g. ESBL E. coli)
What are the possible pathogens that causes Uncomplicated / Community acquired (CA) UTI and Complicated UTI / Nosocomial Associated UTI?
Uncomplicated / Community acquired (CA) UTI:
1. E. coli (>85%)
2. Staphylococcus Saprophyticus
3. Enterococcus faecalis
4. Klebsiella pneumoniae
5. Proteus spp.
Complicated UTI / Nosocomial Associated UTI:
1. E. coli (~50%)
2. Enterococcus
3. Klebsiella
4. Proteus
5. Enterobacter
6. Pseudomonas
(Higher chance of them being drug-resistant e.g. ESBL E. coli)
Staphylococcus aureus – due to bacteremia, consider other sites of infection
Yeasts or candida – possible contaminant, or consider other sites of infection
What antibiotics can be given for Uncomplicated CA cystitis in women? (choice, dose, ROA, duration)
E. coli, S. saprophyticus, Enterococcus, Klebsiella, Proteus
1st line:
1. PO co-trimoxazole 800/160mg BD (3 days)
2. PO Nitrofurantoin 50mg QDS (5 days)
3. PO Fosfomycin 3g (single dose)
2nd line:
4. PO Cefuroxime 250mg BD (5-7 days)
5. PO Amoxicillin/clavulanate 625mg BD (5-7 days)
6. PO Ciprofloxacin 250mg BD (3 days)
7. PO Levofloxacin 250mg OD (3 days)
What antibiotics can be given for complicated CA cystitis in women? (choice, dose, ROA, duration)
(this for uncomplicated cystitis in women)
1st line:
1. PO co-trimoxazole 800/160mg BD (3 days)
2. PO Nitrofurantoin 50mg QDS (5 days)
3. PO Fosfomycin 3g (single dose)
2nd line:
4. PO Cefuroxime 250mg BD (5-7 days)
5. PO Amoxicillin/clavulanate 625mg BD (5-7 days)
6. PO Ciprofloxacin 250mg BD (3 days)
7. PO Levofloxacin 250mg OD (3 days)
**Same as above, but 5-7 days extend to 7-14 days
While 3 days extend to 5-7 days
For Fosfomycin –> PO Fosfomycin 3g EOD (3 doses)
What antibiotics can be given for CA cystitis in men? (choice, dose, ROA, duration)
Same as complicated CA cystitis in women
What antibiotics can be given for Uncomplicated CA Pyelonephritis in women? (choice, dose, ROA, duration)
Mild-moderate:
1st line:
1. PO Ciprofloxacin 500mg BD (7 days)
(convenient, accumulate in urine)
2. PO Levofloxacin 750mg OD (5 days)
3. PO Co-trimoxazole 800/160mg BD (10-14 days)
4. PO Cefuroxime 250-500mg BD (10-14 days)
5. PO Amoxicillin/clavulanate 625mg TDS (10-14 days)
Severely ill, needs to be hospitalized, can’t take oral meds:
1. IV Ciprofloxacin 400mg BD
2. IV Cefazolin 1g q8hrly
3. IV Augmentin 1.2g q8hrly (10-14 days)
4. +/- IV/IM gentamicin 5mg/kg (ESBL, klebsiella cover)
Generally, should improve after 2-3 days, then switch to PO and complete till total of 10-14 days on active antibiotics
