Tigecycline for Vancomycin-Resistant Enterococcus faecalis Bacteremia
Tigecycline should NOT be used for vancomycin-resistant Enterococcus faecalis bacteremia due to its poor serum concentrations and significantly higher risk of treatment failure in bloodstream infections. 1
Why Tigecycline Fails in Bacteremia
Tigecycline achieves inadequate plasma concentrations due to its large volume of distribution, resulting in poor performance in bacteremic patients with a much higher risk of failing to clear bacteremia. 2
The drug's pharmacokinetic profile makes it fundamentally unsuitable for intravascular infections—maximum serum concentrations with standard dosing do not exceed 0.87 mg/L, which is insufficient for effective therapy of bloodstream infections. 3
Tigecycline should not be considered as first-line therapy in patients with bacteremia, regardless of the causative organism. 2
Recommended Alternative: High-Dose Daptomycin
For VRE bacteremia (including vancomycin-resistant E. faecalis), high-dose daptomycin at 8-12 mg/kg IV daily is the preferred treatment, either alone or in combination with β-lactams. 1
Daptomycin demonstrates bactericidal activity against enterococci and has proven clinical efficacy in clearing enterococcal bacteremia, including cases unresponsive to vancomycin. 4
High-dose daptomycin (at least 8 mg/kg and up to 10-12 mg/kg) is preferred for serious VRE infections due to its bactericidal properties. 2
When Tigecycline IS Appropriate for VRE
Tigecycline remains an excellent option for non-bacteremic VRE infections:
Intra-abdominal infections caused by VRE: Tigecycline is the drug of choice with an overall success rate of 97.6% in polymicrobial infections. 1, 2
Complicated skin and soft tissue infections involving VRE in polymicrobial contexts (excluding diabetic foot infections). 5
Standard dosing for these indications is 100 mg IV loading dose followed by 50 mg IV every 12 hours. 1
Critical Clinical Pitfall
The most important distinction is infection site: tigecycline excels in tissue-based VRE infections (abdomen, soft tissue) where it achieves excellent penetration, but it categorically fails in bloodstream infections where adequate serum levels cannot be achieved. 2, 1
- Even when VRE is isolated from blood cultures in a patient with intra-abdominal infection, the presence of bacteremia mandates switching from tigecycline to daptomycin-based therapy. 1