**6.1. The prevention of bacterial endocarditis in experimental animal models**

The induction of IE in experimental animals was first achieved in 1970. The technique consisted of introducing a polyethylene catheter into the right side of the heart of the animal to induce a nonbacterial thrombotic endocarditis. Bacteria were then injected via the catheter to induce experimental bacterial endocarditis that served as a suitable model for the study of bacteriological, pathological and immunological aspects of IE [25].

Although experimental studies make it possible to investigate the efficacy of prophylactic antibiotic regimens against IE, there are difficulties associated with animal models both in their methodology and in the extrapolation of results. The plastic catheter acts as a foreign body delaying the successful treatment of established infection in animals, and the pharmacokinetics of antimicrobials in animals differ considerably from those in man [26].

The percentage of positive post-extraction blood cultures in experimental animals receiving antibiotic prophylaxis fell slightly with respect to the controls. However, it was observed that the administration of amoxicillin effectively prevented the onset of IE, allowing the researchers to suggest that the antibiotics had some protective mechanism over and above their bactericidal activity.

Animal research continues to be very useful for the preliminary evaluation of the efficacy and safety of drugs, and studies are being performed on the usefulness of other, alternative drugs to antibiotics for the prevention of IE in at-risk patients [27].
