Antimicrobial therapy of experimental enterococcal endocarditis.

Area of Science:

• Infectious Diseases
• Pharmacology
• Microbiology

Background:

• Enterococcal endocarditis necessitates prolonged synergistic antibiotic treatment.
• Optimal therapeutic strategies are debated for cases involving high-level streptomycin resistance or penicillin allergy.

Purpose of the Study:

• To evaluate the efficacy of antibiotic combinations for enterococcal endocarditis.
• To compare penicillin-gentamicin and penicillin-streptomycin combinations.
• To assess vancomycin-streptomycin efficacy in streptomycin-susceptible strains.

Main Methods:

• In vitro antibiotic susceptibility testing.
• Experimental rabbit model of enterococcal endocarditis.
• Assessment of bacterial killing rates and vegetation eradication.

Main Results:

• Penicillin plus streptomycin or gentamicin enhanced bacterial killing versus penicillin alone in susceptible strains.
• Penicillin plus gentamicin was superior to penicillin alone in highly streptomycin-resistant strains.
• Vancomycin plus streptomycin demonstrated more rapid bactericidal activity than vancomycin alone against susceptible strains.

Conclusions:

• Penicillin-gentamicin combination therapy is effective for enterococcal endocarditis, particularly with streptomycin resistance.
• In vitro bacterial killing rates predict in vivo efficacy in experimental endocarditis.
• Antibiotic synergy is crucial for successful enterococcal endocarditis treatment.