Abstract
Bacteriological studies were performed on streptococci isolated from pigs with bacterial endocarditis during a period from 1985 to 1987.
Eighty-eight strains of streptococci were isolated from 86 (47.0%) of 183 pigs with endocarditis. Of the 86 cases, Lancefield's group C streptococci were isolated from 40 (S. equisimilis, 30; S. dysgalactiae, 3; and S. spp, 7), group D streptococci from 24 (S. suis II, 14; S. suis I, 7; and S. spp, 3) and other groups of streptococci from 22, respectively. The isolation rate of group C streptococci decreased yearly, namely, 64.3%(9/14) in 1985, 50.0%(21/42) in 1986 and 33.3%(10/30) in 1987, whereas that of group D streptococci increased from 7.1%(1/14) to 23.8%(10/42) and 43.3%(13/30), respectively. Thus, in 1987, the streptococci of group D were detected more frequently than those of group C.
The majority (83.3%, 20/24) of the strains of group D were detected from endocarditis lesions found on the left-side heart valves, whereas 35.0%(14/40) of the group C strains were isolated from the same side lesions. There was a significant difference (P<0.01) between the isolation rates of group C and D streptococci from the left-side endocarditis lesions. On the other hand, group C streptococci were isolated from an average of 4.4 out of five viscera and eight lymph nodes testetl for isolation, against 2.7 organs for group D streptococci. Similarly, 41.7%(10/24) of the group D streptococci were only detected in endocarditis lesions. These results suggest that streptococci of groups C and D have different abilities to cause endocarditis lesions on the left-side valves.
