Experimental Study of Prepared Killed Vaccine For S. Aureus in Local Rabbits

Abstract

This study was performed to estimate the S. aureus prepared killed vaccine in rabbits. The isolate of S. aureus that used in the present study were obtained from the college of veterinary medicine, University of Fallujah which were confirmed by using gram stain and other biochemical tests. A total of 30 local rabbits were used in this study, these were divided into 3 groups, each group contain 10 rabbits, the group 1 used as control negative, group 2 given 1 ml antigen contained 20 mg according to the pilot study that performed, group 3 serve as control positive. At day 21 post-immunization, a skin test was done, at the day 28 post first immunization, the rabbits of group 2 and 3 were challenged intra peritoneal with (1ml) of bacterial suspension containing 1×108 cfu/ml of viable virulent S. aureus. At day 33 post immunization, the rabbits were sacrificed then postmortem examination was carried out to all sacrificed rabbits, pieces from internal organs (liver, spleen and kidney). The results showed that all animals in G2 showed positive reaction after 24 and 48 hrs. for skin test, the result of bacterial isolation after challenge with virulent Staphylococcus aureus showed the isolation of heavy bacterial isolation in control positive group from different organs of body, while immunized groups showed significant decrease in bacterial isolation as compared with control positive. The result of histopathological study of G2 showed PMNs infiltration in liver, spleen and kidney, with vacuolar degeneration of epithelial lining the renal tubule, also, the spleen showed hemorrhage, congestion of red pulp. In conclusion, the killed vaccine that prepared showed a higher effectively when given to the rabbits; furthermore in our conclusion some bacteria were spread from the site of inoculation toward internal organs and during the course of the experiment, activated macrophages engulfed and destroyed most of them.