Antimicrobial Stewardship (AMS)

Resources to help you ensure the safe and effective use of antimicrobials in NSHA patients.

Asymptomatic Bacteriuria

  • Bacteria present in a urine culture without signs or symptoms of a urinary tract infection (UTI)
  • Many people, especially the elderly and those with indwelling urethral or suprapubic catheters, will have asymptomatic carriage of bacteria in the urinary tract
  • Antimicrobial treatment is not recommended (exceptions: pregnancy and patients scheduled to undergo urological procedures in which mucosal trauma is expected)

Last reviewed February 2019

  • Gram-negative bacilli (E. coli, Klebsiella spp., Proteus spp.)
  • Enterococcus spp.

Last reviewed February 2019

  • Absence of typical UTI symptoms: dysuria, increased frequency, urgency, suprapubic tenderness, costovertebral tenderness
  • Cognitive changes, hematuria, or fever alone are not sufficient to diagnose UTI
  • Isolated leukocytosis (in blood), positive leukocyte esterase and/or nitrites do not confirm that there is a UTI
  • Screening with urine culture is recommended only for:
    • Pregnancy: at first prenatal visit
    • Prior to invasive urological procedures
  • DO NOT perform culture for:
    • Malodorous and/or cloudy urine without UTI symptoms
    • Change/insertion of catheter, blocked catheter, or as a test of cure (unless in pregnancy)

Last reviewed February 2019

  • Prescribing antibiotics for asymptomatic bacteriuria does not improve outcomes and increases the patient’s risk of adverse drug reactions, C. difficile infection, and promotes development of colonization and/or infection with multidrug resistant bacteria
  • Supportive treatment should be considered, including correcting dehydration
  • Remove urinary catheter if possible

Last reviewed February 2019

  • Pregnancy: see IWK spectrum app section Women’s Health- Genito-urinary PregnancyAsymptomatic Bacteriuria for treatment options, suggested duration and pregnancy consideration for antimicrobials
  • Invasive urological procedures in which mucosal trauma is likely:
    • Single antibiotic dose 1-2 hours pre-op.
    • Antimicrobial choice should be based on urine culture and sensitivity results.
  • Post renal transplant: limited evidence assessing routine treatment of ASB to prevent progression to symptomatic urinary tract infections or graft failure. More evidence is needed to make a definitive recommendation.

Last reviewed February 2019

If Staphylococcus aureus is isolated in the urine, bacteremia may be present. The patient must be assessed for other sources of infection.

Last reviewed February 2019

1. Nicolle LE, Bradley S, Colgan R, Rice JC, Schaeffer A, et al. Infectious Diseases Society of America Guidelines for the Diagnosis and Treatment of Asymptomatic Bacteriuria in Adults. Clin Infect Dis; 2005;40:643-54.

2. AMMI Canada. Symptom-Free Pee: Let It Be. Accessed on-line 07/2018. https://www.ammi.ca.

3. Reproductive Care Program of Nova Scotia. http://rcp.nshealth.ca.

4. Coussement J, et al. Scemla A, Abramowicz D, Nagler EV, Webster AC. Antibiotics for asymptomatic bacteriuria in kidney transplant recipients. Cochrane Database Syst Rev. 2018 Feb 1;2:CD011357.

Last reviewed February 2019

Catheter-Associated UTI (CAUTI)

  • Patients with urinary catheters develop bacteriuria at a rate of 3-7% per day.
  • At 30 days, all urinary catheters are colonized with bacteria.
  • High rates of bacterial colonization and non-specific signs of infection, such as cognitive or functional changes, make differentiating between asymptomatic bacteriuria and CAUTI challenging. 
  • Every effort should be made to remove urinary catheters. Elimination of unnecessary catheters is the best way to prevent CAUTI.

Last reviewed June 2021

  • E. coli and other Gram-negative microorganisms (Klebsiella spp, Proteus spp, Morganella spp, Pseudomonas spp)
  • Gram positive microorganisms such as Enterococcus spp, Staphylococcus aureus 
  • Candida spp

Last reviewed June 2021

Last reviewed June 2021

  • Change the catheter prior to initiating antimicrobial therapy due to poor antimicrobial effect on catheter biofilms. 
  • Treat based on culture results.

Last reviewed June 2021

  • 7 days if symptoms resolve quickly from time of antimicrobial treatment initiation. 
  • 10-14 days for infections with delayed response to antimicrobials.

1. Chenoweth CE, Gould CV, Saint S. Diagnosis, management and prevention of catheter-associated urinary tract infections. Infect Dis Clin N Am. 2014; 28; 105-119.

2. Flores-Mireles A, Hreha TN, Hunstad DA. Pathophysiology, treatment and prevention of catheter associated urinary tract infection. Top Spinal Cord Inj Rehabil. 2019;25(3):228-240.

3. Hooton TM, Bradley SF, Cardenas DD et al. Diagnosis, prevention, and treatment of catheter- associated urinary tract infection in adults: 2009 International Clinical Practice Guidelines from the Infectious Diseases Society of America. Clin Infect Dis. 2010; 50: 625-663.

4. Nicolle LE, Catheter associated urinary tract infections. Antimicrobial Resistance and Infection Control. 2014; 3:23.

5. Nicolle LE. Catheter related urinary tract infection: practical management in the elderly. Drugs Aging. 2014; 31: 1-10.

6. Trautner BW, Grigoryan L, Petersen NJ et al. Effectiveness of an antimicrobial stewardship approach for urinary catheter-associated asymptomatic bacteriuria. JAMA Intern Med. 2015; 175 (7):1120-1127.

Last reviewed June 2021

UTI (uncomplicated)

  • Infection of the lower urinary tract
  • No signs or symptoms that suggest an infection extending beyond the bladder (such as fever, chills, back pain, nausea, vomiting)
  • No risk factors for complicated infection 

Last reviewed February 2019

  • Escherichia coli
  • Other Enterobacteriaceae (Klebsiella sp., Proteus sp.)

Last reviewed February 2019

  • Increasing E.coli resistance to fluoroquinolones. These agents are not recommended for empiric or first-line treatment of uncomplicated UTIs. 
  • Local uropathogens' susceptibilities should be considered when choosing empiric treatment: 
    • Trimethoprim/sulfamethoxazole should not be used if resistance exceeds 20 %
    • Ciprofloxacin should not be used if local resistance exceeds 10%

Last reviewed February 2019

  • Signs and symptoms: dysuria, urgency, frequency, suprapubic pain/tenderness
  • No symptoms of upper urinary tract infection: fever, chills, flank pain, costovertebral angle tenderness
  • No risk factors for complicated infection: 
    • Pregnancy
    • Immunosuppression
    • Diabetes (especially if long term complications) 
    • Indwelling catheter
    • Anatomical abnormality 
    • Voiding dysfunction
    • Obstruction
    • Recent urogenital procedure 
  • A UTI in men is often, but not always, considered complicated. Investigation for anatomical abnormalities or prostatitis should be considered. 
  • Urine culture is not generally recommended unless:
    • Antibiotic use or UTI in last 3-6 months
    • Suspected UTI in a male
    • Travel outside North America in last 6 months
    • Recent hospitalization 
    • History of a UTI caused by a multidrug resistant microorganism 
    • Complicated UTI 
    • Failure to respond to empiric therapy after 48hrs 
  • The reliability of the urine dipstick as a diagnostic tool for UTI is low due to an inability to differentiate between an infection and asymptomatic bacteriuria, and is not recommended as a test for diagnosing UTI. 

Last reviewed February 2019

Post treatment urine cultures are not recommended if adequate response to therapy

Last reviewed February 2019

  • First line: 
    • Nitrofurantoin macrocrystals 100 mg twice daily x 5 days*
  • Second line:
    • Fosfomycin 3 g x 1 dose
    • Trimethoprim-sulfamethoxazole (TMP-SMX) 1 DS tablet twice daily x 3 days*
    • Cephalexin 500 mg qid x 5-7 days*
    • Amoxicillin-clavulanate 875/125 mg twice daily x 5-7 days*

* Treatment duration of 7 days is recommended in males with uncomplicated cystitis 

Last reviewed February 2019

  • Ciprofloxacin is no longer recommended as fist line treatment due to high risk of adverse effects including tendinopathy, aortic dissection, peripheral neuropathy, central nervous system effects and C. difficile infection.
  • Moxifloxacin should not be used as it does not attain sufficient concentration in the urine 
  • TMP-SMX 
    • Associated with higher risk of renal injury, hyperkalemia, and sudden death if
      • Patients aged 65 years and older
      • Patients on medications that can increase potassium: angiotensin converting enzyme inhibitor (ACEi), angiotensin receptor blocker (ARB), or K+ sparing diuretic (e.g. spironolactone)
    • Regular monitoring of kidney function and electrolytes are recommended for patients with risk factors for hyperkalemia or prolonged duration of therapy.
  • Nitrofurantoin should not be used in patients with: 
    • CrCl less than than 30 ml/min
    • Infections outside lower urinary tract due to poor distribution into serum and tissue
  • If Staphylococcus aureus is isolated in the urine, bacteremia may be present. The patient must be assessed for other sources of infection. 

Last reviewed February 2019

1. Toronto Central Local Health Integration Network. Guidelines for Empiric Treatment of Urinary Tract Infections in Adults. January 2015. Accessed online 09/2017. www.antimicrobialstewardship.com.

2. Gupta K, Hooton TM, Naber KG, Wullt B, et al. International Practice Guidelines for the Treatment of Uncomplicated Cystitis and Pyelonephritis in Women: A 2010 Update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases. Clin Infect Dis. 2011 Mar 1;52(5):e103-20.

3. Fralick M, Macdonald EM, Gomes T, Antoniou T, et al. Co-trimoxazole and sudden death in patients receiving inhibitors of reninangiotensin system: population based study. BMJ. 2014 Oct 30;349:g6196

4. Crellin E, Mansfield KE, Leyrat C, Nitsch D, et al. Trimethoprim use for urinary tract infection and risk of adverse outcomes in older patients: cohort study.BMJ. 2018 Feb 9;360:k341.

Last reviewed February 2019

Complicated Urinary Tract Infections in Adults

The classification of complicated UTIs is not consistent. There are 2 main groupings:

  1. UTIs that may have extended beyond the bladder
    • UTI with fever or other systemic symptoms (such as chills or significant fatigue, malaise, or nausea/vomiting)
    • UTI with sepsis or bacteremia
    • Flank pain or costovertebral angle tenderness (pyelonephritis)
  1. UTIs often considered complicated if at risk of recurrence or progression to severe infection, including:
    • Structural abnormality of urinary tract (strictures, congenital abnormalities, or stones, etc.)
    • Delayed/impaired voiding (neurogenic bladder, ileal conduit, etc.)
    • Recent instrumentation or urological procedure (stents, nephrostomy tubes, etc.)
    • Immunocompromised
    • Poorly controlled diabetes mellitus
    • Catheters: see Catheter Associated UTI
    • Pregnancy (see IWK Firstline guidance)
    • Cystitis in men is often, but not always, considered complicated. Investigation for anatomical abnormalities or prostatitis should be considered.

Last reviewed January 2023

  • Escherichia coli
  • Other Enterobacterales (Klebsiella spp., Proteus spp.)

Last reviewed January 2023

  • Increasing E. coli resistance to fluoroquinolones and trimethoprim/sulfamethoxazole

Last reviewed January 2023

  • Symptoms of upper tract infection or systemic infection
    • Flank pain, fever, chills, nausea, vomiting, and costovertebral angle tenderness with or without symptoms of cystitis
  • Urine culture prior to starting antibiotics recommended for all patients
  • 2 sets of blood cultures if fever or other systemic symptoms

Last reviewed January 2023

  • Asymptomatic bacteriuria does NOT require antibiotic therapy, unless in pregnancy or prior to invasive urological procedure
  • Consider imaging if
    • Persistent clinical symptoms/instability despite 48 to 72 hours of appropriate antimicrobial therapy
    • Suspected urinary tract obstruction (e.g., if renal function has declined below baseline or there is a precipitous decline in the urinary output)
    • Recurrent systemic infection
  • Pregnancy: IWK Firstline App

Last reviewed January 2023

  • Consider recent urine culture results and antimicrobial use prior to selecting empiric antibiotic
  • Adjust following dosing recommendations for renal function when required
  • Lower urinary symptoms at risk of more severe infection without fever/systemic symptoms:
    • Antimicrobial choice as per simple cystitis with close monitoring for progression to systemic infection.
      • First line: Nitrofurantoin macrocrystals 100 mg BID
      • Second line:
        • Fosfomycin 3 g PO every 3 days x 2-3 doses
        • Trimethoprim-sulfamethoxazole 800/160 mg PO BID
        • Cephalexin 500 mg PO QID
        • Amoxicillin-clavulanate 875/125 mg PO BID

Duration: unknown but usually recommend 7 days of therapy

  • Hemodynamically stable with suspected infection extending beyond the bladder (e.g., fever, chills, back pain, nausea, vomiting and fever or additional systemic symptoms)
    • IV or oral depending on circumstance
      • If systemically unwell: consider initial dose of ceftriaxone IV, and then start one of the following based on culture results and clinical response: 
      • Amoxicillin-clavulanate 875/125 mg PO BID
      • Cefixime 400 mg PO daily
      • Ciprofloxacin 500 mg PO BID
      • Trimethoprim-sulfamethoxazole 800/160 mg PO BID
    • Duration: 10 days, up to 14 if slow to respond and beta-lactam is used
      • 7 days if ciprofloxacin is used
    • Nitrofurantoin and oral fosfomycin should not be used because of low renal tissue and systemic concentration
  • Hemodynamically unstable with suspected urinary source
    • Ceftriaxone 1g IV q24h
    • High risk of resistant Gram-negative infection:
      • Colonization or recent infection with resistant Gram-negative microorganisms (e.g., Pseudomonas), or
      • Healthcare associated, or
      • Broad-spectrum antibiotic use in last 3 months
      • Consider following regimens and narrow when sensitivities available:
        • Ceftazidime 1-2 g IV q8h
        • Piperacillin-tazobactam 3.375 g IV q6h (if confirmed or suspected Pseudomonas use 4.5g IV q6h)
        • Tobramycin: Use with caution due to toxicities, refer to aminoglycoside handbook chapter  
    • Duration: 10 days, up to 14 if slow to respond and beta-lactam is used
      • 7 days if ciprofloxacin is used

Last reviewed January 2023

  • Complicated infections with abscess, stents, stones, or other functional/structural abnormalities require an individualized approach and referral to urology for source control considerations.
  • Trimethoprim-sulfamethoxazole
    • Associated with higher risk of renal injury, hyperkalemia, and sudden death if aged 65 years and older or on medications that can increase potassium
    • Regular monitoring of kidney function and electrolytes are recommended for patients with risk factors for hyperkalemia or prolonged duration of therapy.
  • Aminoglycosides: risk of ototoxicity and nephrotoxicity. Monitoring required.

Last reviewed January 2023

  1. Grant J, Le Saux N. Practice point: duration of antibiotic therapy for common infections. J Assoc Med Microbiol Infect Dis Can. Epub 2021 Apr 29. https:// jammi.utpjournals.press/doi/pdf/10.3138/jammi- 2021-04-29.

  2. Wagenlehner FME, Bjerklund Johansen TE, Cai T, Koves B, Kranz J, Pilatz A, Tandogdu Z. Epidemiology, definition and treatment of complicated urinary tract infections. Nat Rev Urol. 2020 Oct;17(10):586-600.

Last reviewed September 2023

Pyelonephritis

  • Bacterial infection of the kidney/upper urinary tract 
  • Considered complicated if structural or functional abnormality 

Last reviewed April 2022

  • Escherichia coli
  • Other Enterobacterales (Klebsiella sp., Proteus sp.) 

Last reviewed April 2022

  • Increasing E.coli resistance to fluoroquinolones and trimethoprim/sulfamethoxazole 

Last reviewed April 2022

  • Signs and symptoms: flank pain, fever, chills, nausea, vomiting and costovertebral angle tenderness with or without symptoms of cystitis 
  • Urine culture prior to starting antibiotics recommended for all patients 
  • Blood cultures may be considered in some clinical scenarios such as diagnostic uncertainty and sepsis, persistent fever or other systemic symptoms despite empiric therapy

Last reviewed April 2022

  • Nitrofurantoin and fosfomycin should not be used for pyelonephritis because of low renal tissue concentration
  • Pregnancy: IWK Firstline App

Last reviewed April 2022

  • Outpatient, consider initial, single dose of ceftriaxone IV, and then start one of the following: 
    • Amoxicillin-clavulanate 875/125 mg PO BID x 10 days
    • Cefixime 400mg PO daily x 10 days
    • Ciprofloxacin 500 mg PO BID x 7 days
    • Trimethoprim-sulfamethoxazole 800/160 mg PO BID x 10 days
       
  • Requiring admission or unable to take oral therapy:
    • Ceftriaxone 1 g IV q24h x 10 days
       
  • High risk of resistant Gram-negative infection: 
    • Colonization or recent infection with resistant Gram-negative microorganisms (e.g., Pseudomonas), or 
    • Septic presentation and hospital acquired/frequent outpatient antibiotic use for urinary infections 
    • Consider following regimens and narrow when sensitivities available:
      • Ceftazidime 1-2 g IV q8h x 10 days
      • Piperacillin-tazobactam 3.375 g IV q6h (use 4.5 g IV q6h if confirmed or suspected Pseudomonas infection) x 10 days 
      • Gentamicin/tobramycin: Use with caution due to toxicities, refer to aminoglycoside handbook chapter  

Last updated June 2023

May require longer duration if patients are slow to respond to therapy or in complicated infections such as in the presence of abscess, stents, stones or other functional or structural abnormalities 

Last updated April 2022

  • Complicated infections with abscess, stents, stones or other functional/structural abnormalities require an individualized approach and referral to urology for source control considerations.
  • Trimethoprim-sulfamethoxazole
    • Associated with higher risk of renal injury, hyperkalemia, and sudden death if aged 65 years and older or on medications that can increase potassium
    • Regular monitoring of kidney function and electrolytes are recommended for patients with risk factors for hyperkalemia or prolonged duration of therapy.
  • Aminoglycosides: risk of ototoxicity and nephrotoxicity. Regular monitoring required.

Last updated April 2022

1. Herness, Joel, Buttolph, Amelia, and Hammer, Noa C. Acute Pyelonephritis in Adults: Rapid Evidence Review. American Family Physician 102.3 (2020): 173-80.

2. NICE. Pyelonephritis (acute): antimicrobial prescribing guidelines. October 31, 2018. Available from https://www.nice.org.uk/guidance/ng111/resources/pyelonephritis-acute-antimicrobial-prescribing-pdf-66141593379781

3. Nicole, L. Urinary tract infection. Canadian Pharmacists Association. CPS. April 12, 2021. Available with subscription.

4. BMJ Best Practice. Acute pyelonephritis. June 10, 2021.

5. Hooton TM. Clinical practice. Uncomplicated urinary tract infection. N Engl J Med. 2012 Mar 15;366(11):1028-37.

6. Grant J, Le Saux N. Practice point: duration of antibiotic therapy for common infections. J Assoc Med Microbiol Infect Dis Can. Epub 2021 Apr 29. https:// jammi.utpjournals.press/doi/pdf/10.3138/jammi-2021-04-29

Last reviewed April 2022

UTI Protocol