For the management of infective endocarditis (IE) in a patient with a mechanical mitral valve and a history of penicillin allergy, which regimen is recommended?

In the management of infective endocarditis (IE), particularly for a patient with a mechanical mitral valve and a history of penicillin allergy, the recommended regimen involves using vancomycin, rifampin, and gentamicin. This combination targets the likely pathogens associated with infective endocarditis, especially staphylococci and enterococci.

Vancomycin is a key component here as it provides good coverage against methicillin-resistant Staphylococcus aureus (MRSA) as well as other Gram-positive bacteria while avoiding penicillins which the patient is allergic to. Rifampin is added to enhance the efficacy of vancomycin against biofilms and intra-cellular organisms, common considerations in prosthetic valve endocarditis. Gentamicin, an aminoglycoside, is included for its synergy with both vancomycin and rifampin and is particularly effective against certain types of Gram-positive organisms.

The combination effectively addresses the spectrum of bacteria likely to be involved in IE in such patients, providing a broad coverage and increasing the likelihood of successful treatment outcomes.

Other regimens either do not provide adequate coverage for resistant organisms or include penicillin-based drugs, which would pose a risk due to the patient's