EXPERIMENTAL ENDOCARDITIS DUE TO PSEUDOMONAS-AERUGINOSA .1. DESCRIPTION OF A MODEL

Rabbits with sterile right ventricular cardiac vegetations were challenged with Staphylococcus aureus and serum-susceptible or resistant isolates of P. aeruginosa. None of the rabbits challenged with serum-susceptible P. aeruginosa died or had > 102 colony-forming units (cfu)/g cultured from vegetations 2 wk later. Of the animals challenged with serum-resistant P. aeruginosa 79% died within 3 wk and 74% sacrificed at 3 days had organisms cultured from vegetations. All of the animals challenged with S. aureus died, and all had > 108 cfu of P. aeruginosa/g in vegetation tissue at 3 days. There was a significantly greater number of organisms (P < 0.001) in the vegetations of animals dying of S. aureus infection than in those of animals with P. aeruginosa endocarditis (mean, 109.6 vs. 107.5 cfu/g, respectively). Left-sided endocarditis was produced in 100% of rabbits injected with serum-resistant P. aeruginosa. These models could be used for studies of the pathogenesis and therapy of P. aeruginosa endocarditis.