What antibiotics are used to treat vancomycin-resistant Enterococcus (VRE) infections?

Treatment Options for Vancomycin-Resistant Enterococcus (VRE) Infections

Linezolid and high-dose daptomycin are the first-line treatments for vancomycin-resistant Enterococcus (VRE) infections, with the choice depending on the site of infection, patient factors, and susceptibility patterns. 1, 2

First-Line Treatment Options

Systemic VRE Infections (Bacteremia)

• Linezolid 600 mg IV or PO every 12 hours is strongly recommended as first-line therapy for VRE bacteremia (Strong recommendation, low quality of evidence) 1, 2
• High-dose daptomycin 8-12 mg/kg IV daily is an effective alternative, particularly at doses ≥9 mg/kg 1, 2
• Daptomycin in combination with β-lactams (including penicillins, cephalosporins, or carbapenems) shows improved outcomes for VRE bacteremia (Weak recommendation, low quality of evidence) 1, 2

Intra-abdominal VRE Infections

• Tigecycline 100 mg IV loading dose followed by 50 mg IV every 12 hours is recommended for intra-abdominal infections due to VRE (Weak recommendation, very low quality of evidence) 1

Urinary Tract VRE Infections

• For uncomplicated urinary tract infections due to VRE, several options are available:
  • Fosfomycin 3 g PO as a single dose (Weak recommendation, very low quality of evidence) 1, 2
  • Nitrofurantoin 100 mg PO every 6 hours (Weak recommendation, very low quality of evidence) 1, 3
  • High-dose ampicillin (18-30 g IV daily in divided doses) or amoxicillin 500 mg IV/PO every 8 hours if the strain is susceptible (Weak recommendation, very low quality of evidence) 1, 3

Comparative Efficacy

• Linezolid has demonstrated overall microbiological and clinical cure rates of 86.4% and 81.4%, respectively 2, 4
• Meta-analyses comparing linezolid and daptomycin have shown conflicting results, but microbiological cure rates are generally comparable (93% vs. 91%) 2, 5
• In pediatric patients with VRE infections, linezolid showed a clinical cure rate of 75% 4

Special Considerations

Combination Therapy

• Daptomycin combined with β-lactams has shown improved outcomes and may help prevent resistance development 1, 6
• Other combinations (with gentamicin, linezolid, rifampin, or tigecycline) have been reported but require further study 6

Emerging Options

• Newer agents such as oritavancin and dalbavancin are being investigated for VRE infections 6
• Quinupristin/dalfopristin is active against VRE faecium but not against VRE faecalis 5

Common Pitfalls to Avoid

• Failing to differentiate between colonization and true infection before initiating treatment 2, 3
• Not removing central venous catheters or other potential sources of persistent infection 2
• Using tigecycline for VRE bacteremia (not recommended due to large volume of distribution and low serum levels) 2
• Treating asymptomatic bacteriuria with VRE, which is common in hospitalized patients and often doesn't require treatment 3
• Neglecting to implement appropriate infection control measures to prevent VRE transmission 7

Treatment Algorithm Based on Infection Site

1. VRE Bacteremia:

   • First choice: Linezolid 600 mg IV/PO every 12 hours 1, 2
   • Alternative: High-dose daptomycin 8-12 mg/kg/day IV, preferably in combination with a β-lactam 1, 2

2. VRE Intra-abdominal Infection:

   • Tigecycline 100 mg IV loading dose, then 50 mg IV every 12 hours 1

3. VRE Urinary Tract Infection:

   • Uncomplicated cystitis: Fosfomycin 3 g PO single dose, nitrofurantoin 100 mg PO every 6 hours, or ampicillin/amoxicillin if susceptible 1, 3
   • Complicated UTI: Linezolid or daptomycin if systemic involvement 2, 3

4. VRE Skin and Soft Tissue Infections:

   • Linezolid 600 mg IV/PO every 12 hours 4, 5
   • Alternative: Daptomycin 8-12 mg/kg/day IV 1