Treatment of ESBL Cystitis
For ESBL-producing bacterial cystitis, carbapenems are the gold standard treatment, with ertapenem being the preferred option for uncomplicated cases without Pseudomonas risk. 1
First-line Treatment Options
Parenteral Therapy
- Carbapenems (first choice):
Carbapenem-sparing Alternatives (if susceptible)
- Ceftazidime-avibactam (2g/0.5g IV every 8 hours) - demonstrated 72.2% combined clinical and microbiological cure rate in UTIs caused by resistant pathogens 3
- Piperacillin-tazobactam - may be considered for ESBL-E. coli with MIC ≤4 mg/L when low bacterial burden is suspected 4, 1
- Aminoglycosides - can be effective, particularly when combined with carbapenems for synergistic effect 5
Oral Step-down Options (if susceptible)
After clinical improvement with parenteral therapy, consider step-down to oral therapy:
- Fosfomycin (3g single dose or multiple doses)
- Nitrofurantoin (for lower UTIs only, not for pyelonephritis)
- Pivmecillinam (if available and susceptible) 1
Treatment Duration
- Uncomplicated cystitis: 5-7 days
- Complicated UTI: 7-14 days
- Duration should be guided by clinical response 1
Special Considerations
Renal Insufficiency
- In patients with renal insufficiency (CrCl <50 ml/min) and alkaline urinary pH, time to negative urine cultures may be prolonged (>3 days) 6
- Dose adjustment of antimicrobials may be required based on creatinine clearance
Antimicrobial Stewardship
- Narrow-spectrum antibiotics should be used whenever possible
- De-escalate therapy once susceptibility results are available
- Reserve carbapenems for confirmed ESBL infections to prevent further resistance development 4, 1
Monitoring and Follow-up
- Assess clinical response daily
- Consider follow-up urine culture 5-7 days after completing therapy to confirm eradication
- For recurrent infections, consider urological evaluation to identify anatomical abnormalities or foreign bodies 1
Pitfalls to Avoid
- Do not use third-generation cephalosporins even if in vitro testing shows susceptibility, as they are ineffective against ESBL-producing organisms in vivo
- Avoid fluoroquinolones if local resistance rates are high or if the patient has had recent exposure
- Do not rely on piperacillin-tazobactam for high-inoculum infections or isolates with MIC >4 mg/L 4
- Be cautious with oral options - ensure susceptibility is confirmed before transitioning from IV therapy
Ertapenem has demonstrated high efficacy (91.7% early clinical cure rate) for outpatient treatment of recurrent cystitis caused by ESBL-producing E. coli 2, making it an excellent option for these infections while sparing broader carbapenems that might select for resistance in Pseudomonas and Acinetobacter species.