For what purpose is Gentamicin used in combination with Vancomycin in infective endocarditis?

Gentamicin is used in combination with Vancomycin in the treatment of infective endocarditis primarily to enhance the overall therapeutic effect. This combination therapy takes advantage of the synergistic action of the two antibiotics against certain organisms, particularly in cases of endocarditis caused by enterococci or Staphylococcus aureus.

Vancomycin, a glycopeptide antibiotic, is effective against gram-positive bacteria, including MRSA (methicillin-resistant Staphylococcus aureus) and various enterococci. When combined with Gentamicin, an aminoglycoside, the treatment can achieve better bactericidal activity due to the different mechanisms of action and target sites within the bacterial cells. Gentamicin works by interfering with protein synthesis, which, when combined with Vancomycin's cell wall synthesis inhibition, leads to a more effective eradication of the infecting organisms.

This treatment strategy is often employed, especially in cases of prosthetic valve endocarditis or infections caused by resistant organisms, where a combination of antibiotics is crucial to effectively fight the infection and improve patient outcomes.