Experimental endocarditis in the rat secondary to septic arthritis induced by Staphylococcus aureus

ObjectiveTo develop a modified model for experimental infective endocarditis (IE) in the rat. The goal was to induce a primary infectious focus in the temporomandibular joint (TMJ) of a rat. Hematogenous translocation of the bacteria to the traumatized aortic valve was desired.MethodsCatheterization of the right carotid artery through the aortic valve was performed 7 days after induction of arthritis, which was done by intra-articular injection of glucocorticosteroid (triamcinolone acetonide, 1 mg) and intravenous challenge with 107 CFU Staphylococcus aureus.ResultsTMJ arthritis could be induced by intra-articular triamcinolone acetonide followed by intravenous bacterial challenge. Joints not given glucocorticosteroid were not affected. Only rats with arthritis developed IE subsequent to catheterization as a result of bacteremia generated from the arthritis.ConclusionsThe present model may serve as a complement to the conventional method for induction of IE, in which a high intravenous challenge has to be given. In the present model, IE was instead the result of a continuous low level of bacteremia from an infectious focus in the TMJ. This model mimics the natural development of IE in patients, and may assist as a setting for prophylactic and therapeutic trials