Abstract:
183 Some Studies on Three Strains of Streptococcus bovis Isolated from Cattle and Sheep after Overfeeding with Wheat Q. Shu , , and A. Liu 12 1 `Department o f Animal Science, University of New England, Armidale NSW 23 5 1, Australia 2Cooperative Research Centre for the Cattle and Beef Industry, University of New England, Armidale NSW 235 1, Australia Antibiotic resistance analysis indicated that the MIC (minimum inhibition concentration) of virginiamycin to Sb-CS was about 40 @ml irt vitro, but the other two strains were much more sensitive to this antibiotic(table). This test was conducted by adding virginiamycin into the culture broth and making into different final concentrations, and then observed the growth of the strains in the virginiamycin containing broths. Some differences of substrate fermentation in the strains were also detected (Table 1). ELISA analysis showed that Sb-CS had less ability to bind with the antibody in the standard serum by coating the plates with the three strains( 1 O8 cells/ ml),separately. The serum was obtained from the animals vaccinated by anti-S. bovis vaccine. When the antibody unit was 1 OO(Serum dilution: 1:8000), the OD was 1.415 for Sb-C5, while the OD value was higher than 2.255 for the other two strains(Figure 1). These results suggested that the antigenic property of Sb-C5 is markedly different from those of the other two strains. Figure 1 Quantitative reaction in ELISA between the strains and the serum from cattle immunised with vaccine References De Herdt, P.,Haesebrouck, F., Devriese, L.A., and Ducatelle, R. 1992. Biochemical and antigenic properties of Streptococcus bovis isolated from pigeons. Journal of Clinical Microbiology, 30: 2432-2434 Kane, J.A. and Karakawa, W.W. 1969. Immunochemical studies on the cross-reactivity between Streptococcus bovis, strain S19, and Group A streptococcal carbohydrates. The Journal ofImmunology, 102: 870-876 Recent Advances in Animal Nutrition in Australia: July 1995 University of New England, Armidale NSW 2351, Australia
