Microbial contamination of three-way taps on arterial lines

Arterial lines with three-way taps are used to measure blood pressure and aspirate blood, and are a potential source of catheter-related sepsis. Swabs were taken daily from 118 three-way taps on 98 arterial lines in a general intensive care unit. Infusion lines were changed weekly but arterial cannulae were not changed routinely. An overall contamination rate of 24.6% was found with the predominant organism being coagulase negative staphylococcus. The three-way taps became increasingly contaminated with time but this was shown to be unrelated to the manipulation rates. Blood culture organisms in those showing contamination of the three-way taps showed no relationship to the bacteria causing the contamination.