This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: miscellaneous, Subject name: Microbiology
[{'content': 'The most common pathogens responsible for nosocomial pneumonia in the ICU are \nSelect and explain. \nA. Gram positive organisms, B. Gram negative organisms, C. Mycoplasma, D. Viral infection', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Mainly responsible organisms are acinetobacters which are Gram-negative aerobic bacteria. Ref: Ananthanarayan& Paniker&;s textbook of microbiology, 9th edition. Pg no.397', 'role': 'assistant'}]