Patho-Physiological Response of LPS Defective Brucella abortus S19δper in Experimentally Infected Mice

Brucellosis is an anthropozoonotic infectious disease in which infected animals pose a threat to humans. This disease has considerable social, economic and international trade importance. Despite past and current efforts to eradicate brucellosis, a large number of new human cases are reported annually worldwide. In this study, patho-physiological response to Brucella abortus S19Δper infection in BALB/c mice was assessed in comparison to its parent strain, B. abortus S19 and virulent strain, B. abortus 544. Immunohistochemical analysis confirmed the presence of bacteria in liver and spleen. Comparatively lower serum Aspartate aminotranferase (AST) level and observation of less number of microgranulomas in liver indicated that B. abortus S19 Δper was less infectious and failed to cause active infection unlike S19 and 544 strain. S19Δper, thus could be a safer vaccine candidate as an alternate to the S19 vaccine strain. Hematological studies indicated clinical manifestation of thrombocytopenia in different Brucella infected mice including S19Δper. Therefore, measurement of platelets count and serum AST level may offer as reliable indicators of brucellosis in clinical cases.