This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Microbiology
The most common pathogens responsible for nosocomial pneumonia in ICU are 
Select and explain. 
A. Gram positive organisms, B. Gram negative organisms, C. Mycoplasma, D. Virus
B: Gram negative organisms
Answer: B: Gram negative organisms 
Explanation: Nosocomial pneumonia is caused by mainly Multi-drug resistant Gram negative bacilli (MDR-GNB)