Biochemical changes in serum of pure and mixed Streptococcus faecalis and Bacillus subtilis infections in rats.

Rats inoculated with Streptococcus faecalis developed endocarditis and demonstrated a 6- to 30-fold increase in aldolase, isocitric dehydrogenase, phosphohexose isomerase, and lactic dehydrogenase. The animals infected with Bacillus subtilis did not develop overt disease nor significant increases in enzyme activities, but viable organisms were recovered at 2 weeks. Rats inoculated with mixed culture of these organisms showed a 2- to 10-fold increase of enzyme activities without evidence of pathological anatomic changes. Both organisms were recovered at necropsy. The total protein and glycoproteins followed the patterns of enzyme activities. There were major changes in alpha(1), alpha(2), and beta globulins and glycoglobuulins at the early stages of infection. The protein-bound hexose changes coincided with the severity of S. faecalis infection, but were at normal levels after 72 hr of infection of B. subtilis and S. faecalis mixed infections. The results indicate that B. subtilis infection modified the pathogenicity of S. faecalis and by an unknown mechanism affected protein and glycoprotein production in serum of experimental rats.