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
Most common catheter related blood stream infection is - 
Select and explain. 
A. Candida, B. Gram negative organisms, C. Coagulase positive staphylococci, D. Coagulase negative staphylococci
D: Coagulase negative staphylococci
Answer: D: Coagulase negative staphylococci 
Explanation: Ans. is 'd' i.e., Coagulase negative staphylococci "The most common pathogens isolated from vascular device-associated bacteremia include coagulase negative staphylococci, S. aureus, enterococci, nosocomial gram-negative bacilli and candida." "Staph aureus is second only to CoNS as a cause of primary nosocomial bacteremia" So: . M.C. cause of catheter related blood stream infection --> coagulase negative staphylococci 2nd MC cause of catheter related blood stream infection coagulase positive staphylococci (S. aureus)