Antibiotic Treatment for Enterobacter cloacae UTI
For Enterobacter cloacae urinary tract infections, levofloxacin (750mg daily for 7-10 days) is the recommended first-line oral agent if local resistance rates are below 10%, while carbapenems (meropenem or imipenem) should be used for hospitalized patients requiring IV therapy or when fluoroquinolone resistance is suspected. 1, 2
Treatment Algorithm Based on Clinical Severity
Complicated UTI with Systemic Symptoms (Hospitalized Patients)
- Carbapenems are the preferred empirical IV therapy for Enterobacter cloacae, as this organism is intrinsically resistant to first and second-generation cephalosporins due to AmpC β-lactamase production 2, 3
- Meropenem, imipenem, or ertapenem remain highly effective with low resistance rates in recent surveillance data 4
- Aminoglycosides (tobramycin 5-7mg/kg/day) are an alternative IV option for susceptible isolates, particularly in combination therapy for severe infections 5, 2
Oral Therapy for Mild-Moderate Complicated UTI
- Levofloxacin 750mg once daily for 7-10 days is the preferred oral fluoroquinolone, given its FDA indication for complicated UTI caused by Enterobacter cloacae 1
- This recommendation applies only when local fluoroquinolone resistance rates are <10% 6
- Ciprofloxacin 500-750mg twice daily for 7 days is an alternative, though levofloxacin's once-daily dosing improves adherence 1, 7
Alternative Agents for Resistant Isolates
- Fosfomycin and nitrofurantoin should NOT be used for Enterobacter cloacae UTI, as these agents lack reliable activity against this organism despite their utility for E. coli 2, 3
- For AmpC-producing Enterobacter (which includes E. cloacae), treatment options include cefepime, piperacillin-tazobactam, or carbapenems 2, 3
- Ceftazidime-avibactam and ceftolozane-tazobactam are newer options for multidrug-resistant isolates 3
Critical Considerations and Common Pitfalls
Antimicrobial Resistance Patterns
- Enterobacter cloacae demonstrates high resistance rates to ampicillin (avoid entirely), amoxicillin-clavulanate, first and second-generation cephalosporins (cephalothin, cefuroxime, cefoxitin) 4
- Always obtain urine culture and susceptibility testing before initiating therapy to guide definitive treatment, as resistance patterns vary significantly by institution 6, 4
- Recent data shows emerging carbapenem resistance in some E. cloacae isolates, making susceptibility testing even more critical 4
Duration of Therapy
- Treat for 7-14 days depending on clinical response, with 14 days recommended for men when prostatitis cannot be excluded 6
- Consider shortening to 7 days if the patient is hemodynamically stable and afebrile for ≥48 hours 6
Fluoroquinolone Use Warnings
- Do not use fluoroquinolones empirically if local resistance exceeds 10% or if the patient has received fluoroquinolones in the past 3 months 6
- The FDA issued warnings about serious adverse effects with fluoroquinolones, though these primarily apply to uncomplicated UTI where safer alternatives exist 6
- For complicated UTI caused by resistant organisms like Enterobacter, the benefit-risk ratio may still favor fluoroquinolone use when susceptibility is confirmed 1, 7
Catheter-Associated UTI
- If catheter-associated, remove or replace the catheter when possible in addition to antimicrobial therapy 6
- Follow the same antibiotic recommendations as for complicated UTI 6
What NOT to Do
- Avoid empiric use of third-generation cephalosporins (ceftriaxone, ceftazidime) for Enterobacter cloacae, as these organisms can develop resistance during therapy through AmpC derepression 2, 3
- Do not use trimethoprim-sulfamethoxazole empirically, as resistance rates are high 6, 4
- Never treat without obtaining cultures first, as Enterobacter species are more likely to harbor resistance mechanisms compared to E. coli 6, 4