Most common catheter-related bloodstream infection is -
"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 bloodstream infection → coagulase-negative staphylococci
2nd MC cause of catheter-related bloodstream infection → coagulase-positive staphylococci (S. aureus)
Candida
Gram negative organisms
Coagulase positive staphylococci
Coagulase negative staphylococci