What antibiotic is recommended for an 88-year-old male with complicated Urinary Tract Infection (UTI) caused by Enterococcus, and Impaired Renal Function?

From the Guidelines

For an 88-year-old male with a complicated UTI caused by Enterococcus and poor renal function, I would recommend ampicillin or amoxicillin as first-line therapy, with dose adjustment for renal impairment, as suggested by the most recent guidelines 1.

Key Considerations

• The patient's advanced age and poor renal function necessitate careful dose adjustment and monitoring to minimize the risk of adverse effects.
• Enterococci are intrinsically resistant to cephalosporins and trimethoprim-sulfamethoxazole, making these options less favorable 1.
• The guidelines recommend high dose ampicillin (18-30 g IV daily) or amoxicillin (500 mg PO/IV every 8 h) for uncomplicated urinary tract infections due to VRE, which may still be applicable for complicated UTIs with appropriate dose adjustments and close monitoring 1.

Treatment Approach

• Consider amoxicillin 500 mg orally every 12 hours (instead of the standard 8-hour interval) for 7-14 days, depending on clinical response, with adjustments for renal impairment.
• If the patient has a penicillin allergy, nitrofurantoin could be considered if renal function isn't severely impaired (avoid if creatinine clearance <30 mL/min) 1.
• For more severe infections or resistant strains, vancomycin with renal dosing adjustments may be necessary, although it's not the first choice due to potential renal toxicity and the need for close monitoring of drug levels.

Monitoring and Follow-Up

• Close monitoring of renal function, drug levels (if using vancomycin), and clinical response is essential.
• Ensure adequate hydration during treatment.
• Consider follow-up urine cultures after completing therapy to confirm resolution of the infection.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Treatment Options for Complicated UTI with Enterococcus

• For an 88-year-old male with complicated UTI and poor renal function, the choice of antibiotic is crucial due to the limited options available for resistant enterococci 2.
• Aminopenicillins are preferred when enterococci are susceptible, but in cases of vancomycin-resistant enterococci (VRE), daptomycin and linezolid have demonstrated clinical efficacy 2, 3.
• For cystitis, amoxicillin, nitrofurantoin, or fosfomycin are ideal options 2.
• In the case of VRE UTIs, ampicillin, nitrofurantoin, fosfomycin, and doxycycline have intrinsic activity against enterococci, including VRE, and can be considered for oral treatment 3.
• Linezolid and daptomycin should be reserved for confirmed or suspected upper and/or bacteremic VRE UTIs among ampicillin-resistant strains 3.

Considerations for Elderly Patients with Complicated UTI

• Elderly patients with complicated UTI are at a higher risk of treatment failure and serious complications, such as bacteremia and sepsis, perinephric abscess, renal impairment, and emphysematous pyelonephritis 4.
• Appropriate diagnostic procedures, antibiotic and surgical treatment, and follow-up are required to avoid potentially devastating outcomes 4.
• The choice of antibiotic should take into account the patient's renal function and the susceptibility of the enterococci to the antibiotic 5, 6.

Antibiotic Resistance and Treatment

• The rising prevalence of vancomycin-resistant enterococci (VRE) is a concern, and clinicians need to differentiate between VRE-associated urinary colonization, asymptomatic bacteriuria, and UTIs to determine the need for treatment 3.
• Unnecessary use of antibiotics in patients colonized with VRE can lead to increased resistance and healthcare costs 3.
• Quinupristin/dalfopristin and linezolid are approved therapeutic options for VRE, but their use should be evaluated on a case-by-case basis due to concerns of toxicity, resistance, and insufficient supportive data 5.