The pathogenesis of experimental infection by Staphylococcus aureus in rabbits

Abstract

Abstract: The present study was carried out on experimental infected rabbit with Staphylococcus aureus to study some aspects of pathogenesis of staphylococcal infection. Twelve rabbit were randomly divided into two equal groups: group1 (treated group) were inoculated subcutaneously with (0.5ml) of bacterial inocula contain (30x1010) CFU and group2 (control). Blood samples were taking to evaluate some of blood parameters include: WBC counts,(LYM., Mon.and GRA.) percentage, Mon.#,GRA.#,RBC counts, HB, PCV, MCV, MCH, MCHC, RDW, PLT counts, MPV, PCT and PDW. Most clinical signs noticed in treated group were: mild fever, depression, decreased appetite, respiratory distress and abscess formation in some cases at site of injection. Also the P.M. lesion included: congestion of internal organs (liver, lung) and signs of pneumonia. Histopathological investigations were carried on liver, lung and bone. The statistical analysis revealed that there were significant increased in WBC count and GRA % (P<0.05) in treated group as compared with control. The MCV, MCH, MCHC and RDW (P<0.05) showed significant differences between groups. The PLT counts and PCT (P<0.05) revealed significant decreased in treated group as compared with control. Other parameters studied did not show significant differences between two groups. Histopathological study revealed that there were: hydropic degeneration, necrosis and occluded of bile sinusoid with bile pigment in the livers of infected animals, in lung: there were edema, hemorrhage and necrosis with thickening of the wall of alveoli and infiltration of inflammatory cells and in bone there were sever necrosis of osteoblast, osteoclast and osteocyte cells in the infected animals.