Objective: Short-term, noncuffed, percutaneously inserted central venous catheters (CVCs) are widely used and cause more than 250,000 bloodstream infections (BSIs) in hospitals each year in the United States. We report a prospective study undertaken to determine the pathogenesis of CVC-related BSI.

Design and setting: Prospective cohort study in a university hospital 24-bed medical-surgical intensive care unit.

Patients and participants: Patients participating in two randomized trials during 1998-2000-one studying the efficacy of a 1% chlorhexidine-75% alcohol solution for cutaneous antisepsis and the other a novel chlorhexidine-impregnated sponge dressing-formed the study population; CVC-related BSIs were considered to be extraluminally acquired if concordance was identified solely between isolates from catheter segments, skin, and blood cultures and intraluminally acquired if concordance was demonstrated only between hub or infusate and blood culture isolates, as confirmed by DNA subtyping of isolates from blood and catheter sites or infusate.

Results: Of 1,263 catheters (6075 CVC days) prospectively studied, 35 (2.7%) caused BSI (5.9 per 1000 CVC days); 27 were caused by coagulase-negative staphylococci. Overall, 45% of infections were extraluminally acquired, 26% were intraluminally derived, and the mechanism of infection was indeterminate in 29%. In the pooled control groups of the two trials, 25 CVC-related BSIs occurred (7.0 per 1000 CVC days), of which 60% of infections were extraluminally acquired, 12% were intraluminally derived and 28% were indeterminate. In contrast, CVC-related BSIs in the treatment groups were most often intraluminally derived (60%, p=0.006).

Conclusions: Most catheter-related BSIs with short-term percutaneously inserted, noncuffed CVCs were extraluminally acquired and derived from the cutaneous microflora. Strategies achieving successful suppression of cutaneous colonization can substantially reduce the risk of catheter-related BSI with short-term CVCs.