Experimental Eikenella corrodens endocarditis in rabbits.

The ability of Eikenella corrodens to cause endocarditis in catheterized rabbits was studied. E. corrodens 1073, the serum-resistant strain used in the study, was isolated from a human periodontitis lesion. Thirty-four rabbits, surgically catheterized across the aortic valve and injected intravenously 24 to 48 h later with 10(7) to 10(9) log-phase organisms, were studied. Only three rabbits developed positive blood cultures and only two rabbits died before the time of sacrifice at 14 days after infection. Autopsies showed that all rabbits developed aortic vegetations, 52% of which were culture positive for E. corrodens. The organisms were recovered from aortic vegetations in a mean concentration of 10(5.3) colony-forming units/g of tissue and from liver or kidney in 28% of the animals in concentrations from 10(2) to 10(4) colony-forming units/g. Indirect immunofluorescent staining of vegetations, with the use of specific rat antiserum to E. corrodens 1073 and fluorescein isothiocyanate-labeled goat antirat serum, revealed colonies of E. corrodens in culture-negative vegetations as well as in those which were culture positive. The results showed that E. corrodens was an effective pathogen in the rabbit model of endocarditis, in which the disease was infrequently bacteremic and rarely fatal.