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': 'All-cause meningitis in the elderly except - \nSelect and explain. \nA. HSV2, B. Pneumococci, C. Gram negative bacteria, D. Listeria', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Causes of meningitis in elderly \n\nPneumococci (most common)\nGram negative bacilli\nStaphylococcus aureus\nMeningiococci (2nd most common)\nListeria monocytogenes\nStreptococcus\nH. influenza\nM. tuberculosis', 'role': 'assistant'}]