More than 160,000 central-line-associated bloodstream infections (CLABSIs) are estimated for Europe each year leading to about 25,000 deaths. We aimed at characterising the contamination of administration sets in suspected CLABSI cases in the intensive care unit (ICU).
In ICU patients (period 02/2017-02/2018) with suspected CLABSI, all sampled central venous catheters (CVCs) were examined in 4 segments (from CVC tip to connected tubing systems) for contamination. A risk factor analysis using binary logistic regression was performed.
52 consecutively sampled CVCs with 1,004 elements were analysed with 45 elements being positive for at least one microorganism (4.48%). There was a significant association with the duration of catheterisation (p=0.038, n=50) with a daily increase of contamination risk by 11.5% (OR 1.115). The mean number of CVC manipulations was 40 within 72 hours (SD: 20.5), with no association with contamination risk (p=0.381). The contamination risk of the CVC segments decreased from proximal to distal. Non-replaceable components of the CVC had a high risk (14 times higher; p=0.01). A significant positive correlation was detected between positive tip cultures and microbial growth in the administration set (r(49)=0.437, p=0.001).
Although only a minority of CLABSI-suspect patients had positive blood cultures, the contamination rate of central venous catheters and administration set was high, possibly indicating a relevant under-reporting. The finding of identical species in adjacent segments underlines the role of upward or downward spread of microorganisms within the tubes, therefore aseptic tasks should be emphasized.

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