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Enterococcal Endocarditis — SCE Infectious Diseases MCQ

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HardBone & Joint InfectionEnterococcal EndocarditisSCE Infectious Diseases

A 55-year-old man with a history of aortic valve replacement develops Enterococcus faecalis endocarditis. Susceptibility testing shows high-level Gentamicin resistance (HLAR) but sensitivity to Ampicillin. What is the most appropriate treatment?

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Correct answer: B — Ampicillin IV plus Ceftriaxone IV (double beta-lactam) for 6 weeks

When Enterococcal endocarditis has high-level aminoglycoside resistance (HLAR), the synergistic aminoglycoside-beta-lactam combination cannot be used. The alternative is double beta-lactam therapy: Ampicillin plus Ceftriaxone for 6 weeks. Ceftriaxone saturates PBP3 while Ampicillin saturates PBP4/5, achieving synergistic bactericidal activity against E. faecalis. This regimen avoids aminoglycoside nephrotoxicity and ototoxicity. It is well-validated in clinical studies for E. faecalis endocarditis with HLAR.

Reference: ESC 2023 – Endocarditis; BSAC 2012 – Endocarditis treatment