Streptococcal and enterococcal endocarditis: time for individualized antibiotherapy?

Recommendations for the treatment of streptococcal and enterococcal endocarditis are based on old efficacy studies, but the starting doses have never been reassessed and are associated with significant adverse events. Based on data from other serious infections, we suggest that maintaining a concentration of beta-lactams higher than 4-6 times the responsible bacteria MIC 100% of the time in the heart of the vegetation would be a pertinent therapeutic objective. The data point to a diffusion gradient of beta-lactams in the vegetation. Yet, so far as is known, the ratio of antibiotic concentration at steady state between plasma and vegetation cannot be completely determined. Answering this crucial question would make it possible for each patient to have a targeted beta-lactam plasma concentration, according to the MIC for the responsible bacteria. This would lead the way to personalized antibiotherapy and allow a safe switch to oral medication.

Automated summary

For the treatment of streptococcal and enterococcal endocarditis, it is suggested to maintain beta-lactam concentration higher than 4-6 times the bacteria MIC in the heart of the vegetation. However, the complete determination of the antibiotic concentration ratio between plasma and vegetation is still unknown, which is essential for personalized antibiotherapy.