What is the treatment for Enterobacter bacteremia?

Treatment of Enterobacter Bacteremia

Carbapenems are the first-line treatment for Enterobacter bacteremia due to their efficacy against potential AmpC-producing bacteria and lower risk of resistance development.

Initial Assessment and Empiric Therapy

• For critically ill patients with suspected Enterobacter bacteremia:

  • Start with two antimicrobial agents of different classes with gram-negative activity as initial therapy 1
  • Remove any infected intravascular catheters if present, as they may be the source of infection 1

• Risk factors requiring special consideration:

  • Critically ill status
  • Neutropenia
  • Prior antibiotic exposure
  • Femoral catheter placement
  • Known focus of gram-negative infection 1

Definitive Therapy Based on Susceptibility

First-line options:

1. Carbapenems (preferred):
   • Meropenem 1g IV every 8 hours (extended or continuous infusion preferred for severe infections) 2
   • Imipenem 500mg IV every 6 hours 3
   • Ertapenem 1g IV every 24 hours (for community-acquired infections) 2

Alternative options (based on susceptibility testing):

1. Fourth-generation cephalosporins:

   • Cefepime 1-2g IV every 8-12 hours 4
   • Note: Third-generation cephalosporins should be avoided due to high frequency of resistance developing during therapy 1

2. Other options if susceptible:

   • Fluoroquinolones (with caution due to increasing resistance rates) 5
   • Piperacillin-tazobactam (when MIC ≤4 mg/L for non-severe infections) 2

For carbapenem-resistant Enterobacter:

• Newer agents:

  • Ceftazidime-avibactam 2.5g IV every 8 hours 2, 6
  • Meropenem-vaborbactam 2, 6
  • Cefiderocol 2, 6
  • Eravacycline or tigecycline for non-critically ill patients with adequate source control 2

• Combination therapy may be necessary:

  • Polymyxins (colistin)
  • Aminoglycosides (amikacin preferred)
  • Double carbapenem therapy in selected cases 7

Treatment Duration and Monitoring

• Standard duration: 7-14 days for uncomplicated bacteremia 1, 2

• Extended duration: Consider longer treatment for:

  • Persistent bacteremia
  • Severe sepsis
  • Endovascular infection
  • Metastatic infection 1

• De-escalate therapy once culture and susceptibility results are available to reduce resistance development 1, 2

• Follow-up blood cultures to document clearance of bacteremia

Special Considerations

AmpC Induction Concerns

• Enterobacter species can develop resistance during therapy with third-generation cephalosporins due to AmpC β-lactamase induction 1
• While some studies suggest cefepime may be effective 8, carbapenems remain the most reliable choice for serious infections

Source Control

• Remove infected catheters when possible 1
• Drain abscesses if present
• Surgical intervention may be necessary for complicated intra-abdominal infections

Common Pitfalls to Avoid

1. Using third-generation cephalosporins as monotherapy (high risk of resistance development)
2. Failing to remove infected catheters or achieve adequate source control
3. Not adjusting antibiotics based on susceptibility results
4. Inadequate dosing of antibiotics in critically ill patients
5. Not considering local resistance patterns when selecting empiric therapy

By following this treatment algorithm and considering local resistance patterns, clinicians can optimize outcomes for patients with Enterobacter bacteremia while practicing good antimicrobial stewardship.