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': 'Most common cause of infection caused by intravascular catheter ? \nSelect and explain. \nA. E coli, B. Coagulase negative staphylococci, C. Staph aureus, D. Pseudomonas', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. is \'b\' i.e., Coagulase negative staphylococci "Staph. epidermidis is a coagulase negative staphylococcus, which has predilection for growth on implanted foreign bodies such as intravascular catheters, shunts, aificial hea valves and prosthetic appliances, leading to bacteremia".', 'role': 'assistant'}]