Some Observations in Mice Infected with a Salmonella Typhimurium Isolate

Authors: K. Tayfun ÇARLI, Ayşin ŞEN, M. Müfit KAHRAMAN, Özlem ÖZMEN

Abstract: This study was conducted to observe clinicopathologic alterations caused by chicken isolate of Salmonella typhimurium in conventional mice and, to examine excretion of the agent during experiment and to calculate Lethal Dose 50 (LD50). The mice were infected orally with. S. typhimurium at various doses. Clinically, tremors, sudden onset of anorexia, ruffled fur and flocking together were observed. Death ratios in the groups according to dose of bacteria were as follows: 109: 6/6 (100 %), 108: (66.6 %), 107: 4/7 (57.1 %), 106: 2/6 (33.3 %) and 105: 0/8 (0.00 %). LD50 of S. typhimurium was calculated as 1.137 x 107. It was determined that survivors in each group, except mice of 105 and 106 groups, excreted the agent into their feces during the 32 days. Macroscopically, no lesions were observed in dead mice. Histopathologically, examinations of the all tissues of the mice from 109, 108 and 107 dosage groups revealed mild to moderate degrees of hypremia. In addition to Kuppfer cell activation, necrosis and mono-polymorphnuclear cell infiltration with different intensity and severity in the liver, hyperplasia and reticular cell activity in the lymphoid tissues were observed. Small and large intestines were in normal appearence.

Keywords: S. typhimurium, mice, experimental infection.