This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Listeria Monocytogenes, Subject name: Microbiology
[{'content': 'Listeria resists phagocytosis in phogosomes (phagolysosomes) due to - \nSelect and explain. \nA. b-hemolysin, B. Caspases, C. Cell membrane adhesion molecules, D. Opacity associated protein (OAP)', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., b - hemolysin o Most important step in pathogenesis of listeriosis is the survival and multiplication of L monocytogenes in phagocytes (macrophages), host epithelial cells and hepatocytes.o The most important determinant of pathogenesis is listeriolysin O (LLO), a b- hemolysin. LLO causes lysis of membrane of phagosomes within phagocytes and helps in intracellular survival of L monocytogeneso Iron is an important virulence factor. Listeria produce siderophores and are able to obtain iron from transferringo Immunity to listeria is primary cell mediated. Immunity can be transferred by sensitized lymphocytes but not by antibodies.", 'role': 'assistant'}]