Penicillinase-resistant penicillins plus gentamicin in experimental enterococcal endocarditis

Area of Science:

• Infectious Diseases
• Pharmacology
• Cardiology

Background:

• In vitro studies suggest synergistic effects of penicillinase-resistant penicillins and gentamicin against enterococci.
• This suggested potential in vivo efficacy for treating enterococcal infections.

Purpose of the Study:

• To evaluate the in vivo effectiveness of combining gentamicin with penicillinase-resistant penicillins (nafcillin, oxacillin, methicillin) for enterococcal endocarditis.
• To determine if high-dose penicillinase-resistant penicillin therapy improves outcomes.

Main Methods:

• Rabbits with experimentally induced enterococcal endocarditis were treated with gentamicin and either nafcillin, oxacillin, or methicillin.
• Therapy duration was 21 days, followed by assessment of valve sterility at autopsy.

Main Results:

• Low percentages of animals in all treatment groups achieved sterile valves post-therapy.
• High-dose penicillinase-resistant penicillin therapy did not significantly improve survival rates compared to lower doses.

Conclusions:

• The combination of penicillinase-resistant penicillins and gentamicin demonstrated limited in vivo efficacy for enterococcal endocarditis.
• Current findings suggest that penicillin should be included with a penicillinase-resistant penicillin and gentamicin for initial treatment of patients with suspected enterococcal endocarditis.