Comparative histopathology in mouse typhoid among genetically diverse mice

Area of Science:

• Immunology
• Pathology
• Microbiology

Background:

• Salmonella typhimurium infection elicits varied host responses based on genetic susceptibility.
• Understanding the histopathological differences between resistant and susceptible hosts is crucial for disease management.

Purpose of the Study:

• To compare the histopathological progression of Salmonella typhimurium infection in genetically resistant and susceptible mouse strains.
• To identify distinct tissue responses that differentiate resistant from susceptible hosts.

Main Methods:

• Genetically resistant (CBA, A/J) and susceptible (BALB/c, C57BL/6) mice were infected with Salmonella typhimurium.
• Histopathological examination of tissue sections using JB-4 Plus resin embedding.
• Comparison of lesion development and progression between mouse groups.

Main Results:

• Initial lesions (focal abscesses) appeared within three days in both resistant and susceptible mice.
• Mononuclear cell infiltration led to granuloma formation by day 7.
• Resistant mice, when sublethally infected, developed discrete, self-limiting granulomata.
• Lethal infections in susceptible mice showed massive bacterial proliferation and extensive tissue degeneration.

Conclusions:

• Histopathological features of Salmonella typhimurium infection are initially similar in resistant and susceptible mice.
• The key difference lies in the ability of resistant hosts to contain and resolve lesions, forming self-limiting granulomata.
• Lesion progression is slower and more contained in sublethally infected resistant mice.