Related Experiment Video
Updated: Oct 9, 2026
Experimental Endocarditis Model of Methicillin Resistant Staphylococcus aureus (MRSA) in Rat
Published on: June 4, 2012
Treatment of experimental endocarditis caused by penicillin-resistant Streptococcus sanguis with different doses of
F Martínez1, F Martín-Luengo, A García
1Department of Microbiology, School of Medicine, University of Murcia, Spain.
Abstract:
Streptococcus viridans continues to be the most frequent causal agent of infective endocarditis. Treatment has become more complicated due to the increase in resistance to penicillin and cephalosporins. In order to study the possible efficacy of teicoplanin at low and high doses, this antibiotic was investigated in rabbits as a monotherapy and in association with gentamicin. The effects were compared with a control group and a group given classical penicillin-gentamicin treatment. Infective endocarditis was induced in 120 rabbits with a clinical isolate of Streptococcus sanguis. Treatment was started 48 h after infection, and lasted 5 days. Animals were divided into 6 groups of 20 rabbits each: G1, untreated controls; G2, penicillin+gentamicin; G3 low-dose teicoplanin; G4, low-dose teicoplanin+gentamicin; G5, high-dose teicoplanin; and G6, high-dose teicoplanin+gentamicin. Response to therapy was evaluated with mortality curves, negativization of blood cultures, concentration of S. sanguis in aortic vegetations and rate of sterilization of vegetations. Vegetation weight was significantly lower in treated groups than in controls; lower weights were found in G4, the only treatment that sterilized 65% of vegetations. Death occurred only in the control group (10% mortality). Negativization of blood cultures was greatest and most rapid in G4, followed by G6. Concentrations of S. sanguis in aortic vegetations were significantly lower in all treated groups compared with controls, with the lowest being in groups G4 and G6. Combined treatment with teicoplanin+gentamicin may be highly efficacious in patients with endocarditis caused by penicillin-resistant Streptococcus sanguis. High-dose teicoplanin+gentamicin does not seem to be more efficacious than low-dose teicoplanin+gentamicin.
Insights
Combined teicoplanin and gentamicin therapy shows high efficacy for treating infective endocarditis caused by penicillin-resistant Streptococcus sanguis in rabbits. Low-dose teicoplanin with gentamicin was particularly effective, sterilizing 65% of vegetations.
Area of Science:
- Infectious Diseases
- Pharmacology
- Microbiology
Background:
- Streptococcus viridans is the leading cause of infective endocarditis.
- Increasing penicillin and cephalosporin resistance complicates treatment options.
- Novel therapeutic strategies are needed for resistant bacterial endocarditis.
Purpose of the Study:
- To evaluate the efficacy of teicoplanin, alone and with gentamicin, for treating experimental infective endocarditis.
- To compare teicoplanin-based regimens against standard penicillin-gentamicin treatment.
- To assess the impact of low versus high teicoplanin doses in combination therapy.
Main Methods:
- Infective endocarditis was induced in 120 rabbits using Streptococcus sanguis.
- Rabbits were divided into six groups receiving different treatments (control, penicillin-gentamicin, low/high-dose teicoplanin +/- gentamicin).
- Treatment efficacy was assessed by mortality, blood culture negativity, vegetation bacterial load, and vegetation sterilization rates.
Main Results:
- Teicoplanin-gentamicin combinations significantly reduced vegetation weight and bacterial concentrations compared to controls.
- Low-dose teicoplanin plus gentamicin (G4) achieved the highest vegetation sterilization rate (65%) and most rapid blood culture negativization.
- No significant difference in efficacy was observed between high-dose and low-dose teicoplanin when combined with gentamicin.
Conclusions:
- Combined teicoplanin-gentamicin therapy is a promising treatment for infective endocarditis caused by penicillin-resistant S. sanguis.
- Low-dose teicoplanin in combination with gentamicin appears to be a highly effective regimen.
- Further clinical investigation is warranted to confirm these findings in human patients.
