This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic Bacteriology (Gram Positive Bacilli, Gram Negative Bacilli), Subject name: Microbiology
[{'content': 'Which salmonella is anaerogenic : \nSelect and explain. \nA. S. typhi, B. S.paratyphi A, C. S. paratyphi B, D. All of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Salmonella typhi is anaerogenic. Option 1 All Salmonellae produce acid and gas (aerogenic) when they ferment sugars except S. typhi which only produces acid (anaerogenic). Option 2, 3, 4 Salmonellae : Ferment glucose, mannitol, and maltose,forming acid and gas. S. Typhi is an exception, which does not ferment the sugars. Produces H2S except S. paratyphi A, S. choleraesuis. Do not hydrolyze urea. MR positive ,VP negative ,citrate positive. Catalase positive ,oxidase negative.', 'role': 'assistant'}]