Development of bacteraemia or fungaemia after removal of colonized central venous catheters in patients with negative concomitant blood cultures

There are limited data on the clinical significance of positive central venous catheter (CVC) tip cultures associated with concomitant negative blood cultures performed at the time of CVC removal. A retrospective cohort study of all patients who yielded isolated positive CVC tip cultures was conducted in a tertiary-care hospital with 2200 beds during a 10-year period. All patients with isolated positive CVC tip cultures were observed for the development of subsequent bacteraemia or fungaemia between 2 and 28 days after CVC removal. An isolated positive CVC tip culture was defined as a case in which (i) a CVC tip culture yielded 15 colonies using a semiquantitative culture method and (ii) at least two sets of blood samples revealed no organism at, or close to, the time of CVC removal (48 h before to 48 h after CVC removal). During the study period, 312 patients with isolated positive CVC cultures were enrolled. Eight (2.6%; 95% CI 1.2-5.1) of the 312 patients yielding isolated bacterial or fungal CVC tip cultures developed subsequent bloodstream infection (BSI) caused by the same species as that isolated from the tip culture (Staphylococcus aureus, 1: Enterococcus spp.; 2: Pseudomonas aeruginosa; and 3: Candida spp.). Among 125 patients from whose CVC tips the above four organisms were grown, seven (12.3%) of 57 patients who did not receive appropriate antibiotic therapy within 48 h after CVC removal subsequently developed BSI, but only one (1.5%) of 68 patients who did receive appropriate therapy developed BSI (OR 0.11, p 0.02).