A 55-year-old man with a prosthetic mitral valve presents with fever, new regurgitant murmur, and positive blood cultures for Enterococcus faecalis (penicillin MIC 0.5 μg/mL, vancomycin MIC 1 μg/mL, streptomycin high-level resistance present). According to current ESC 2023 IE guidelines, the preferred treatment regimen is:
- A Vancomycin plus gentamicin for 6 weeks
- B Ampicillin plus ceftriaxone for 6 weeks ✓
- C Linezolid monotherapy for 8 weeks
- D Ampicillin plus gentamicin for 4 weeks
Explanation
For Enterococcus faecalis endocarditis with high-level aminoglycoside resistance (HLAR — streptomycin resistance present), gentamicin synergy is lost, making ampicillin/gentamicin combination ineffective. The GAMES prospective study and ESC 2023 guidelines recommend ampicillin plus ceftriaxone (double beta-lactam) for 6 weeks as the preferred regimen in this situation. Ceftriaxone saturates PBP3 and PBP5 complementing ampicillin's PBP4 binding. Vancomycin combinations are suboptimal for aminoglycoside-susceptible enterococcal IE and should not be used if ampicillin is feasible. This regimen avoids nephrotoxic aminoglycosides.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.