UTI Flashcards
What is asymptomatic bacteriuria?
Defined as isolation of significant colony counts of bacteria in the urine (bacteriuria) from a person w/o UTI symptoms (asymptomatic)
When is screening of asymptomatic bacteriuria indicated?
- Pregnant women - ~12-16 weeks gestation
- Patients going for urologic procedure where mucosal trauma/bleeding is expected - 2-3 days prior to procedure
Why is asymptomatic bacteriuria screened for in pregnant women?
Prevent pyelonephritis (risk increases by 20-30 fold), preterm labour and low infant birth weight
What should be done if a pregnant woman’s urine sample comes back positive for asymptomatic bacteriuria?
Treat w active antibiotics based on AST for 4-7 days
Why is screening of asymptomatic bacteriuria done for urologic procedures?
Prevent bacteremia and urosepsis from bacteria moving to the bloodstream
What urologic procedure that causes trauma to the mucosal lining DOES NOT need asymptomatic bacteriuria testing?
Urinary catheter placement
What are the possible routes of infection for a UTI?
Ascending route and Descending route
What are the likely pathogens to be found for a UTI caused by the ascending route?
Gut flora - E.coli, Klebsiella spp, Proteus spp
Why are adult females more predisposed to getting UTIs than men?
Shorter urethra
Possible use of spermicides and diaphragms
When would descending route of UTI pathogenesis be suspected?
- Non-GI bacteria appear in the culture
- Patient has bacteremia
- Patient has another primary infection going on
List 5 ways to prevent a UTI.
- Drink more fluid to flush bacteria – drink as much as possible/as comorbidities allow
- Urinate frequently, go when got urge – bacteria can grow when urine stays in bladder for too long
- Urinate shortly after sex – can flush away bacteria that might have entered urethra during sex
- Women should wipe front to back to avoid spreading bacteria from anal area to urethral area
- Wear cotton underwear and loose-fitting clothes so that the area remains dry
- Avoid tight-fitting jeans and nylon underwear – trap moisture, promote bacterial growth
- Consider changing to birth control other than diaphragms and spermicides
- Cranberry juice
- Intravaginal estrogen cream (controversial) – restore vaginal flora, prevent E. coli colonisation
- Lactobactillus probiotics (evidence not reliable yet) – restore normal vaginal flora, protect against E. coli
When is a UTI considered complicated?
→ Men, children, pregnant women
→ Presence of complicating factors: functional and structural abnormalities of urinary tract, genitourinary instrumentation, diabetes mellitus, immunocompromised host
(uncomplicated - premenopausal, non-pregnant women w normal urinary tract)
What are the symptoms of lower urinary tract infection/cystitis?
Dysuria, urgency, frequency, nocturia, suprapubic heaviness or pain, gross haematuria
What are the distinguishing factors of pyelonephritis from cystitis?
Most obvious: flank pain, costovertebral tenderness (renal punch)
Others: Fever, rigors, headache, nausea, vomiting, malaise, abdominal pain
What are the potential lab tests to diagnose UTI?
UFEME, Dipstick (Nitrite, Leukocyte Esterase), Cultures
What is the cut off number of white blood cells in a urine sample for pyuria?
> 10 WBC/mm3
What does pyuria indicate in UTI?
Signifies presence of inflammation
In a patient symptomatic for UTI, pyuria is correlated w significant bacteriuria
What would a positive nitrite dipstick indicate for a UTI patient?
Presence of gram-negative bacteria
Why can a false negative nitrite dipstick test occur?
False-negatives can occur due to presence of Gram-positives, P.aeruginosa, low urinary pH, frequent voiding and dilute urine
What does a positive leukocyte esterase dipstick indicate for UTI?
Positive test indicates esterase activity of leukocytes in urine, correlates w significant pyuria
When are urine cultures needed for UTI?
- Pregnant women
- Recurrent UTI (relapse within 2 weeks, frequent UTI)
- Pyelonephritis
- Catheter-associated UTI
- Male UTI
What are the first-line empiric regimens for uncomplicated cystitis in women?
List the route, drug, dose, frequency and length of regimen.
PO Co-trimoxazole 800/160mg BD for 3/7
PO Nitrofurantoin 50mg 4 times/day for 5/7
PO Fosfomycin 3g as a single dose
(every other day for 3 doses if complicated)
What are the alternative empiric beta-lactam regimens for uncomplicated cystitis in women?
List the route, drug, dose, frequency and length of regimen.
PO Cefuroxime 250mg BD
PO Augmentin 625mg BD
PO Cephalexin 250-500mg 4 times/day
All 5-7 days
What are the alternative empiric non-beta-lactam regimens for uncomplicated cystitis in women?
List the route, drug, dose, frequency and length of regimen.
PO Ciprofloxacin 250mg BD
PO Levofloxacin 250mg OD
Both for 3 days
What are the therapeutic options for empiric treatment of community-acquired pyelonephritis by PO?
PO Co-trimoxazole 800/160mg BD 10-14/7
PO Ciprofloxacin 500mg BD 7/7
PO Levofloxacin 750mg OD 5/7
PO Cefuroxime 250-500mg BD 10-14/7
PO Augmentin 625mg TDS 10-14/7
PO Cephalexin 500mg 4 times/day 10-14/7
What are the therapeutic options for empiric treatment of community-acquired pyelonephritis by IV?
IV Ciprofloxacin 400mg BD OR
IV Cefazolin 1g Q8H OR
IV Augmentin 1.2g Q8H
Can add IV/IM Gentamicin 5mg/kg
What are the therapeutic options to treat UTI in men that have no concern for prostatitis?
Same as complicated cystitis in women
What are the therapeutic options to treat cystitis in men with concern for prostatitis?
PO Ciprofloxacin 500mg BD
PO Co-trimoxazole 800/160mg BD
Both for 10-14 days, increase to 6 weeks if prostatitis is confirmed
What are the IV empiric regimens for healthcare-associated UTI?
IV Cefepime 2g Q12H ± IV Amikacin 15mg/kg/d
IV Imipenem 500mg Q6H
IV Meropenem 1g Q8H
All for 7-14 days
Escalate if patient doesn’t get better after 2 days
What are the PO empiric regimens for healthcare-associated UTI?
PO Levofloxacin 750mg OD
PO Ciprofloxacin 500mg BD
Both for 7-14 days
What are the symptoms of catheter-associated UTI?
- New onset or worsening of fever, rigors, altered mental status, malaise or lethargy with no other identified cause, flank pain, costovertebral angle tenderness, acute haematuria, pelvic discomfort
- If patient is stable and fever is still low grade, consider observation rather than immediate antibiotics therapy
How can catheter-associated UTI be prevented?
- Avoid unnecessary catheter use
- Use for minimal duration
- Change long-term indwelling catheters before blockage is likely to occur
- Use of closed system
- Ensure aseptic insertion technique
What are the empiric regimens for catheter-associated UTI?
IV Imipenem 500mg Q6H 7/7
IV Meropenem 1g Q8H 7/7
IV Cefepime 2g Q12H 7/7 ± 1 dose IV Amikacin 15mg/kg/d
Mild cases: PO/IV Levofloxacin 750mg OD 5/7
Women >65yo w/o upper urinary tract symptoms: PO Co-trimoxazole 800/160mg BD 3/7
What antibiotics should be avoided for treating UTI in pregnant women in all trimesters?
Ciprofloxacin (fetal cartilage damage and arthropathies in animal studies)
Aminoglycosides (use w caution, 8th cranial nerve toxicity in fetuses reported)
Which trimesters should co-trimoxazole be avoided during pregnancy for treatment of UTI?
1st and 3rd
What antibiotics should be avoided for treating UTI in pregnant women in the 3rd trimester?
Co-trimoxazole, nitrofurantoin
How long does it usually take for an improvement in UTI symptoms to appear after initiating effective antibiotic therapy?
2-3 days
If it takes longer than 2-3 days, need to do further investigations
Should repeat urinary cultures be done for a patient who has recovered from UTI?
Not needed
Only required in pregnant women to document clearance of infection
