What is the management plan for an 88-year-old male with a complicated Urinary Tract Infection (UTI) and a suprapubic catheter, who has a urine culture growing Enterococcus with greater than 100,000 colonies and Pseudomonas with less than 100,000 colonies, and has Impaired Renal Function with a Glomerular Filtration Rate (GFR) of 12, despite being asymptomatic?

From the Guidelines

For an 88-year-old male with a suprapubic catheter and asymptomatic bacteriuria (Enterococcus >100,000 colonies and Pseudomonas <100,000 colonies) on follow-up for a complicated UTI, no antibiotic treatment is recommended at this time. Asymptomatic bacteriuria in catheterized patients should not be treated with antibiotics as this practice does not improve outcomes but increases the risk of developing antibiotic resistance 1. The patient's severely reduced renal function (GFR of 12) necessitates close monitoring. Key considerations in management include:

• Regular maintenance of the catheter with proper care to prevent infection
• Keeping the insertion site clean
• Ensuring adequate hydration if medically appropriate
• Monitoring for signs of symptomatic infection, such as fever, increased confusion, suprapubic pain, or changes in urine appearance In patients with indwelling catheters, bacteria commonly colonize the urinary tract without causing infection, and treating these colonizations can select for resistant organisms without clinical benefit 1. The focus should be on catheter care and monitoring for signs of symptomatic infection rather than treating positive cultures in the absence of symptoms. According to the guidelines, a 7–14-day regimen is recommended for most patients with CA-UTI, but this should be tailored based on clinical response and culture results 1. Given the patient's current asymptomatic status, the priority is to avoid unnecessary antibiotic use and its associated risks.

From the FDA Drug Label

In patients with creatinine clearance ≤ 40 mL/min and dialysis patients (hemodialysis and CAPD), the intravenous dose of piperacillin and tazobactam for injection should be reduced to the degree of renal function impairment [see Dosage and Administration (2)].

In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

The patient has a GFR of 12, which indicates severe renal impairment. Given this, the dose of piperacillin-tazobactam should be reduced to account for the degree of renal function impairment 2. Additionally, considering the patient's age (88 years), dose selection should be cautious, starting at the low end of the dosing range. It is also important to monitor renal function due to the increased risk of toxic reactions in patients with impaired renal function.

• Key considerations:
  • Reduced dose due to severe renal impairment
  • Cautious dose selection due to advanced age
  • Monitoring of renal function
• Main goal: To minimize the risk of toxic reactions while effectively treating the complicated UTI.

From the Research

Patient Profile

• 88-year-old male with a complicated urinary tract infection (UTI)
• Suprapubic catheter in place
• Urine culture showing Enterococcus growing over 100,000 colonies and Pseudomonas growing less than 100,000 colonies
• Asymptomatic
• Glomerular filtration rate (GFR) of 12

Treatment Considerations

• According to 3, treatment options for UTIs caused by multidrug-resistant (MDR)-Pseudomonas spp. include fluoroquinolones, ceftazidime, cefepime, piperacillin-tazobactam, carbapenems, aminoglycosides, colistin, ceftazidime-avibactam, and ceftolozane-tazobactam
• As stated in 4, treatment options for UTIs caused by MDR-Pseudomonas spp. include fluoroquinolones, ceftazidime, cefepime, piperacillin-tazobactam, carbapenems, fosfomycin, ceftolozane-tazobactam, ceftazidime-avibactam, aminoglycosides, and colistin
• 5 recommends that empiric treatment for serious complicated UTIs, where risk factors for resistant organisms exist, should include broad-spectrum antibiotics such as carbapenems or piperacillin-tazobactam
• According to 6, the antimicrobial regimen is determined by clinical presentation, patient tolerance, renal function, and known or anticipated infecting organisms
• As noted in 7, colistin was found to be the most active antibiotic in vitro against Acinetobacter baumannii and Pseudomonas aeruginosa

Management

• Urine culture and sensitivity testing should be used to guide antibiotic therapy 5, 6
• Consideration of the patient's renal function (GFR of 12) is crucial when selecting an antibiotic regimen 6
• The use of fluoroquinolones for empiric treatment of UTIs should be restricted due to increased rates of resistance 3, 4