A patient with Enterococcus faecalis endocarditis requires combination therapy for synergistic bactericidal activity. The rationale for adding an aminoglycoside to a cell-wall active agent is that:

• A Aminoglycosides independently achieve bactericidal concentrations inside enterococci
• B The aminoglycoside inhibits beta-lactamase produced by Enterococcus
• C Cell-wall disruption by beta-lactams or glycopeptides enhances aminoglycoside uptake into the bacterial cell ✓
• D Aminoglycosides provide anaerobic coverage that beta-lactams lack

Explanation

Enterococci have an intrinsically impermeable cell wall that limits aminoglycoside penetration; alone, aminoglycosides cannot reach bactericidal intracellular concentrations. A cell-wall active agent (penicillin, ampicillin, or vancomycin) disrupts the peptidoglycan barrier, facilitating aminoglycoside entry and ribosomal binding, producing synergistic bactericidal killing. This pharmacodynamic synergy is the cornerstone of enterococcal endocarditis treatment.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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