Assessment of central venous catheter colonization using surveillance culture of withdrawn connectors and insertion site skin

Background Culture of catheter hubs and skin surrounding the catheter entry site has a negative predictive value for catheter tip colonization. However, manipulation of the hub for culture requires the hubs to be swabbed, introducing potential dislodging of biofilm and subsequent migration of microorganisms. Hubs are usually closed with needleless connectors (NCs), which are replaced regularly. Our objective was to evaluate whether culture of flushed withdrawn NCs is an alternative to hub culture when investigating central venous catheter colonization. Methods The study population comprised 49 intensive care unit patients whose central venous catheters had been in place for at least 7 days. Cultures of NCs and skin were obtained weekly. Results We included 82 catheters with more than 7 days’ indwelling time. The catheter tip colonization rate was 18.3 % (15/82). Analysis of skin and NC cultures revealed a 92.5 % negative predictive value for catheter colonization. Three episodes of catheter-related bloodstream infection (C-RBSI) occurred in patients with colonized catheters. Conclusion Surveillance of NC and skin cultures could help to identify patients at risk for C-RBSI.