In endocarditis due to streptococci group D, which antibiotic combination is described as synergistic?

In endocarditis due to streptococci group D, which antibiotic combination is described as synergistic?

• A. Penicillin G and Gentamicin
• B. Ampicillin
• C. Vancomycin
• D. Erythromycin

Answer: (A)

The key idea is antibiotic synergy in treating endocarditis caused by streptococci group D. Penicillin G weakens the bacterial cell wall, which greatly enhances the ability of gentamicin to enter the bacteria and inhibit protein synthesis. When used together, they produce a bactericidal effect that is greater than the sum of their individual effects, which is particularly important for streptococcal endocarditis where high bacterial loads and protected niches exist. Ampicillin is a useful beta-lactam, but on its own it isn’t described here as the synergistic pairing; vancomycin and erythromycin don’t provide the same synergistic interaction with penicillin in this specific setting.

The key idea is antibiotic synergy in treating endocarditis caused by streptococci group D. Penicillin G weakens the bacterial cell wall, which greatly enhances the ability of gentamicin to enter the bacteria and inhibit protein synthesis. When used together, they produce a bactericidal effect that is greater than the sum of their individual effects, which is particularly important for streptococcal endocarditis where high bacterial loads and protected niches exist. Ampicillin is a useful beta-lactam, but on its own it isn’t described here as the synergistic pairing; vancomycin and erythromycin don’t provide the same synergistic interaction with penicillin in this specific setting.