Antibiotic prescribing for catheter-associated UTI (CAUTI)

This topic will discuss the Antibiotic prescribing for catheter-associated urinary tract infection...
Abdelwahab Ward, BS Pharm, PharmD

OVERVIEW ã…¡ Upper urinary tract infection is defined as evidence of urinary tract infection with symptoms suggestive of pyelonephritis (loin pain, flank tenderness, fever, rigors or other manifestations of systemic inflammatory response). Upper urinary tract infection can be accompanied by bacteremia, making it a life-threatening infection.

          Admit to hospital people who are significantly dehydrated or who are unable to take oral fluids and medications. Or have signs of sepsis, including marked signs of illness (such as impaired level of consciousness, perfuse sweating, rigors, pallor, significantly reduced mobility), or have significant tachycardia, hypotension, or breathlessness. Pregnant and pyrexial and who fail to improve significantly within 24 hours of starting antibiotics.

WHEN TO INVESTIGATE

Dipstick test the urine for leucocyte esterase and nitrite in non-catheterized patients 18-70 years for evidence of a UTI. Dipstick testing is less helpful in older patients or catheterized patients; who are more likely to have pre-existing asymptomatic bacteriuria. If the nitrite test is positive, with or without a positive leucocyte esterase test, a UTI is highly (90%) likely. If the leucocyte esterase test alone is positive, a UTI is moderately (50%) likely. If both nitrites and leucocytes are negative, 40-50% of patients will not have culture-positive UTI. Consider and exclude other causes of loin pain and/or fever including pelvic inflammatory disease, appendicitis and renal calculi. If admission not needed, send MSU for culture and susceptibility testing, and start antibiotics.

          How to respond to a positive laboratory report? Single organism ≥ 104 colony forming units (CFU)/mL or ≥ 105 mixed growth with one predominant organism or E. coli or Staphylococcus saprophyticus ≥ 103 CFU/mL usually indicates UTI in patient with urinary symptoms. Review culture and sensitivity results when they become available, and change the antibiotic if indicated. Check micro results for last 6 months and avoid antibiotics for which there has been recent resistance.

ANTIBIOTIC PRESCRIBING

GENERAL PRINCIPLES ã…¡ Antimicrobial therapy recommended for all patients with symptomatic CAUTI. Presence or absence of odorous or cloudy urine alone should not be used as an indication for antimicrobial therapy. Treatment of CAUTI is similar to that of complicated UTI. Consider catheter replacement or removal in patients with indwelling catheter in place > 7 days before starting antimicrobial therapy. Empiric therapy should be broad-spectrum with selection based on local susceptibility patterns. Definitive therapy should be narrowed based on results of culture and susceptibility testing of infecting organism(s), once known. Antimicrobial resistance is a growing problem with uropathogens with rising rates of resistance to fluoroquinolones, broad-spectrum beta lactams, and carbapenems. Empiric treatment options and suggested dosage for adult patients with normal renal functions who require systemic treatment. For gram-negative bacteria (predominant infecting organisms) include (any of the following)...
      • Cefepime 1 g IV every 12 hours (every 8 hours for Pseudomonas).
      • Ceftazidime 1 g IV every 8 hours.
      • Piperacillin-Tazobactam (Tazocin) 3.75 g IV every 8 hours (4.5 g for Pseudomonas).
      • Meropenem 500 mg IV every 8 hours.
      • Aztreonam 500 mg IV every 8 hours.
      • Ciprofloxacin 400 mg IV or 500 mg orally every 12 hours.
      • Levofloxacin 500-750 mg IV or orally every 24 hours for patients who are not severely ill.
      • Gentamicin 5-7 mg/kg IV every 24 hours.
      • Ceftriaxone 1 g IV once daily for less ill patients.

Consider meropenem if suspicion of extended spectrum beta-lactamase (ESBL) producing gram-negative bacteria. Consider vancomycin if suspicion of gram-positive infection. Consider linezolid for patients with suspected vancomycin-resistant enterococci (VRE). Empiric treatment should be adjusted after culture and susceptibility test results are known.

DURATION OF THERAPY ã…¡ 7 days is the standard duration of therapy for patients who have quick resolution of symptoms. 10-14 days recommended for patients with delayed response regardless of whether patient remains catheterized. 5-day course of levofloxacin may be considered in patients who are not severely ill. 3-day treatment course may be considered in women < 65 years old without upper urinary tract symptoms after removal of indwelling catheter.

REFERENCES

Abdelwahab Ward, BS Pharm, PharmD