What is the recommended treatment for Enterobacter gergoviae urinary tract infections (UTI)?

Treatment of Enterobacter gergoviae Urinary Tract Infections

For Enterobacter gergoviae urinary tract infections, carbapenems are the recommended first-line treatment due to the intrinsic resistance of Enterobacter species to cephalosporins and increasing resistance to other antibiotics. 1

Initial Treatment Approach

Empiric Therapy

While awaiting culture and susceptibility results:

• First-line option: Carbapenem (meropenem, imipenem/cilastatin, or ertapenem)

  • Meropenem: 1g IV every 8 hours
  • Imipenem/cilastatin: 500mg IV every 6 hours
  • Ertapenem: 1g IV once daily

• Alternative options (based on local susceptibility patterns):

  • Piperacillin-tazobactam: 4.5g IV every 6-8 hours
  • Fluoroquinolones (if susceptible): Ciprofloxacin 500mg oral twice daily or 400mg IV twice daily
  • Aminoglycosides (for urinary source infections): Gentamicin or amikacin with dosing based on weight and renal function 1

Definitive Therapy (After Susceptibility Results)

Treatment should be guided by antimicrobial susceptibility testing:

• For susceptible isolates:

  • Fluoroquinolones (oral step-down therapy if susceptible)
  • Aminoglycosides (for UTI with urinary source) 1
  • Fosfomycin IV (for complicated UTI with or without bacteremia) - high-certainty evidence supports its use 1

• For multidrug-resistant isolates:

  • Continue carbapenem therapy
  • Consider newer agents: meropenem-vaborbactam, ceftazidime-avibactam, or ceftolozane-tazobactam 2

Treatment Duration

• Uncomplicated lower UTI: 5-7 days 1
• Complicated UTI or pyelonephritis: 7-14 days 1
• Bacteremic UTI: 7 days if patient achieves clinical stability before day 7 3

Special Considerations

Cautions and Pitfalls

• Avoid cephalosporins: Enterobacter species possess inducible AmpC β-lactamases, making them intrinsically resistant to many cephalosporins 1, 2
• Cefepime considerations: While some studies show efficacy of cefepime against Enterobacter species, there is inconsistent evidence regarding its use, particularly with higher MICs. Use with caution and only if susceptibility is confirmed 1, 4
• Fosfomycin safety: When using IV fosfomycin, monitor for heart failure, especially in at-risk patients 1

Follow-up and Management of Recurrent Infections

• Obtain follow-up urine culture 1-2 weeks after completing therapy if symptoms persist
• For recurrent infections, select alternative agents rather than repeating the same antibiotic 1
• Consider infectious disease consultation for multidrug-resistant infections 1

Prevention of Recurrent UTIs

For patients with recurrent UTIs, consider:

• Education on lifestyle and behavioral modifications
• For postmenopausal women: vaginal estrogen with or without lactobacillus-containing probiotics
• For premenopausal women with infections related to sexual activity: low-dose post-coital antibiotics
• Non-antibiotic alternatives: methenamine hippurate and/or lactobacillus-containing probiotics 1

When selecting antibiotics for prophylaxis, consider:

• Patient's prior organism identification and susceptibility profile
• Drug allergies
• Antibiotic stewardship principles 1