This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
[{'content': 'Which of the following is a true statement regarding Enterobacteriaceae: \nSelect and explain. \nA. Motility is by polar flagellum, B. Glucose is not fermented by all members of the family, C. All members are oxidase positive, D. Nitrate reduction negative', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. (c) Shigella does not ferments mannitol "Members of enterobacteriaceae rcduce nitrates to nitrites, form catalase but not oxidase." Enterobacteriaceae: lmpoant features Features Escherichia Salmonella Shigella Motility by peritrichous flagella + + - Gas from glucose + + - Acid from lactose + - - Acid from sucrose d - - Growth in KCN - d - lndole + - d MRA/VP + + + Citrate - + - H2S - + - Urease - - - Phenylalanine deaminase (PPA) - - - Arginine dehydrolase d + - Lysine decarboxylase + + - Omithine decarboxylase d + d (d = result different in different species or strains) Remember: - Polar flagella: Vibrio, pseudomonas, legionella, spirilla, campylobacter, H. pylon, spirochetes. - V. parahemolytic produce both polar and peritrichous flagella.', 'role': 'assistant'}]