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': 'Staph.aureus causes vomiting in 6-8 hours. The mechanism of action is: \nSelect and explain. \nA. Stimulation of cAMP, B. Vagal stimulation, C. Stimulation of cGMP, D. Acts through ganglioside GM receptor', 'role': 'user'}, {'content': 'Answer: B \nExplanation: From Harrison:\n“Staph. food poisoning result from heat stable preformed enterotoxin. Due to preformed nature, incubation period is short. Toxin stimulates the vagus nerve and vomiting centre of brain. It also\xa0appears to stimulate intestinal persistaltic activity”.', 'role': 'assistant'}]