Teicoplanin for VRE Enterococcus faecalis Bacteremia
Teicoplanin will NOT work for vancomycin-resistant Enterococcus faecalis (VRE) bacteremia and should not be used. VRE strains resistant to vancomycin exhibit cross-resistance to teicoplanin due to shared glycopeptide resistance mechanisms, making teicoplanin ineffective for this indication.
Why Teicoplanin Fails Against VRE
The fundamental problem is cross-resistance. Vancomycin-resistant enterococci possess resistance genes (vanA, vanB, vanD) that alter the cell wall target structure, rendering all glycopeptides—including both vancomycin and teicoplanin—ineffective 1, 2, 3.
Specific Resistance Mechanisms
- VanA phenotype: Confers high-level resistance to both vancomycin AND teicoplanin, with teicoplanin MICs reaching ≥128 mg/L within 48 hours of exposure 1.
- VanB phenotype: Initially appears teicoplanin-susceptible but rapidly develops teicoplanin resistance during therapy through mutations in vanRS genes, with documented in vivo emergence during treatment 2, 3.
- VanD phenotype with vanA genotype: Shows complete treatment failure with teicoplanin in both in vitro and in vivo models, with survival rates of infected mice comparable to untreated controls 1.
Evidence-Based Treatment Alternatives for VRE Bacteremia
The 2022 guidelines for multidrug-resistant organisms provide clear treatment pathways that exclude glycopeptides entirely 4.
First-Line Options
- Daptomycin-based regimens: High-dose daptomycin (≥9 mg/kg) combined with beta-lactams (ampicillin, ceftaroline, or carbapenems) reduces mortality by 77% compared to monotherapy in VRE with daptomycin MIC ≤2 mg/L 4.
- Linezolid: 600 mg IV/PO every 12 hours is an effective alternative, though combination with gentamicin, rifampin, or doxycycline may be needed for salvage therapy 4.
Species-Specific Considerations for E. faecalis
E. faecalis VRE has better treatment options than E. faecium VRE because some isolates retain ampicillin susceptibility 4.
- Check ampicillin susceptibility: Even ampicillin-resistant VRE E. faecalis may respond to high-dose ampicillin (18-30 g IV daily) due to high urinary concentrations, with clinical and microbiological eradication rates of 88.1% and 86% respectively 4.
- Ampicillin plus gentamicin: Remains the preferred combination for ampicillin-susceptible VRE E. faecalis bacteremia 4.
Dosing Algorithm for VRE Bacteremia
For complicated VRE bacteremia (including endocarditis):
- Daptomycin 9-10 mg/kg IV daily PLUS ampicillin 2 g IV every 4 hours (if any ampicillin susceptibility) for 4-6 weeks 4.
- Linezolid 600 mg IV/PO every 12 hours as monotherapy or with adjunctive agents for 4-6 weeks 4.
- Avoid tigecycline for bacteremia due to low serum levels despite high tissue penetration 4.
Critical Pitfalls to Avoid
Do not use teicoplanin empirically for suspected VRE. The 2022 guidelines explicitly state that glycopeptides (vancomycin and teicoplanin) have no role in VRE treatment 4.
Do not assume teicoplanin susceptibility based on initial testing of VanB strains. Resistance emerges rapidly during therapy through vanRS gene mutations, particularly in immunosuppressed patients or those with difficult source control 2, 3.
Do not add gentamicin or rifampin to daptomycin for VRE endocarditis. Unlike MRSA endocarditis, these combinations are not recommended for VRE 4.
When Teicoplanin IS Appropriate (Not for VRE)
Teicoplanin remains effective for glycopeptide-susceptible E. faecium (GSEF) bacteremia, with non-inferior clinical success rates compared to vancomycin (64.9% vs 48.9%) and significantly lower acute kidney injury risk (8.1% vs 24.4%, adjusted OR 0.242) 5, 6.
Dosing for GSEF bacteremia: Loading dose of 6-12 mg/kg IV every 12 hours for 3 doses, then 6-12 mg/kg IV once daily, targeting trough levels ≥20 mg/L for severe infections 4, 7.