Which organism is among the most common CLABSI culprits?

• A. Staphylococcus aureus
• B. Streptococcus pyogenes
• C. Coagulase-negative Staphylococci
• D. Candida albicans

Answer: (C)

Coagulase-negative staphylococci are the most common culprits behind CLABSI because they are everyday skin bacteria that readily colonize catheter surfaces. When a central line is inserted, these organisms can be introduced and then form biofilms on the plastic material of the catheter. Biofilms are protective communities that shield bacteria from antibiotics and the immune system, making infections persistent and difficult to treat. Because CoNS are part of normal skin flora, they are frequently encountered in culture, but in the context of a central line, their role as true pathogens in catheter-related bloodstream infections is well established.

Staphylococcus aureus can cause serious bloodstream infections linked to central lines, and Candida albicans is an important fungal cause, especially in long-term catheter use or in immunocompromised patients. Streptococcus pyogenes is not a leading pathogen for CLABSI. The predominance of CoNS reflects their anatomical niche and biofilm-forming ability, which makes them the typical first-line culprits in catheter-associated infections.