Should Meropenem Be Added Despite Bacterial Resistance?
No, do not add meropenem if the bacteria is documented as resistant to it—this will not improve clinical outcomes and will only promote further antimicrobial resistance. Instead, optimize your current amikacin therapy, replace the catheter if it has been in place ≥2 weeks, and investigate alternative causes of persistent fever.
Why Adding Resistant Antibiotics Doesn't Work
Treating with antibiotics to which bacteria are resistant does not decrease fever or improve outcomes, as demonstrated in studies where antimicrobial therapy failed to reduce fever episodes when bacteriuria was eliminated, and resistant strains commonly replaced susceptible ones 1.
The biofilm on long-term catheters harbors resistant organisms that are protected from both antimicrobials and host immune responses, making treatment with resistant antibiotics futile 2, 3.
Adding meropenem when the organism is resistant will only contribute to the emergence of more resistant organisms in your medical unit without clinical benefit to the patient 1, 4.
What You Should Do Instead
1. Replace the Catheter Immediately (If ≥2 Weeks Old)
Replace the indwelling catheter before continuing antimicrobial therapy if it has been in place for ≥2 weeks, as this significantly decreases polymicrobial bacteriuria, shortens time to clinical improvement, and lowers rates of recurrent UTI 5, 6.
Obtain a fresh urine culture from the newly placed catheter, as the catheter biofilm may harbor organisms not accurately reflected in prior cultures 7.
This intervention alone may resolve the fever by removing the biofilm reservoir of resistant bacteria 6, 2.
2. Optimize Amikacin Therapy
Ensure adequate dosing of amikacin based on the patient's renal function and therapeutic drug monitoring, as aminoglycosides require appropriate peak and trough levels for efficacy 1.
Consider extending treatment duration to 10-14 days given the delayed clinical response (persistent fever), rather than the standard 7-day course 1, 6.
Verify that the organism is truly susceptible to amikacin and that resistance hasn't developed—repeat culture from the fresh catheter 7.
3. Investigate Alternative Fever Sources
Persistent fever despite appropriate antibiotics for a susceptible organism suggests either:
- Inadequate source control (catheter not replaced when indicated)
- Alternative infection source (bloodstream infection, abscess, prostatitis in men)
- Non-infectious fever (drug fever, underlying malignancy, inflammatory conditions)
- Development of complications like renal abscess or perinephric abscess 4, 2
Obtain blood cultures if not already done, as catheterized patients have increased risk of bacteremia from urinary sources 1, 4.
Consider imaging (renal ultrasound or CT) if fever persists beyond 72 hours despite appropriate therapy, as this may indicate complicated infection requiring urologic evaluation 1.
4. Remove the Catheter If Possible
The single most effective intervention is catheter removal, as the duration of catheterization is the principal determinant of infection and complications 1, 2.
Even if the catheter seems "irremovable," reassess daily whether it truly remains medically necessary, as avoiding catheter use or limiting duration are the most effective prevention strategies 2, 3.
Common Pitfalls to Avoid
Do not treat based on the assumption that "more antibiotics are better"—adding resistant antibiotics provides no benefit and promotes resistance 1.
Do not assume all fever in catheterized patients is from UTI—the frequency of fever from urinary sources in long-term catheterized patients varies from 1 per 100 to 1 per 1000 catheter days 2.
Do not delay catheter replacement if it has been in place ≥2 weeks, as this is crucial for treatment success and should be prioritized over adding additional antibiotics 5, 6.
Avoid treating asymptomatic bacteriuria if the patient's fever resolves, as this does not reduce subsequent CAUTI and increases antimicrobial resistance 1, 6.