Experimental bacterial endocarditis in the opossum (Didelphis virginiana). 3. Comparison of spontaneously occurring endocarditis with that induced experimentally by pyogenic bacteria and fungi.

It was possible to induce bacterial endocarditis in opossums with single intravenous injections of Streptococcus viridans or Staphylococcus aureus. Fiftyeight percent of those animals given Streptococcus viridans developed bacterial endocarditis in which most of the lesions were on the left side of the heart. The experimentally induced streptococcal disease was similar to that which may occur spontaneously in opossums, both with respect to the distribution and structure of the vegetations. Single injections of Staphylococcus aureus resulted in endocarditis in 100% of the test animals. These lesions differed from those due to streptococci by having a relatively high frequency of right- as well as left-sided valvular disease and by being somewhat smaller than those due to streptococci.Endocarditis could not be successfully induced with injection of three different fungi.