Contamination susceptibility of three needleless and one standard needle injection systems

Abstract

Purpose: To compare in vitro the contamination susceptibility of three needleless and one standard needle injection systems. Methods: The Baxter InterLink, St. Paul Medical Key-Lok, Braun SafSite, and Becton Dickinson heparin lock, were compared. Fifty of each were studied. Each system was connected to a culture bottle and injected 30 times over 72 hr. The manufacturers' directions were followed except for Braun's, which recommend that a new sterile cap be used after each injection. Instead, the same cap was used after each injection to reflect day-to-day clinical practice. Culture bottles were subsequently analyzed for bacterial growth. Results: The contamination rates for the heparin lock, InterLink, Key-Lok, and SafSite were 3/50 (6%), 6/50 (12%), 4/50 (8%), and 36/50 (72%), respectively. All positive cultures grew coagulase-negative staphylococcus species. There was no difference in contamination rates between the InterLink, Key-Lok, and heparin lock designs. The contamination rate of the SafSite was higher (P < 0.001) than the other three systems. Conclusions: The InterLink and Key-Lok systems had a similarly low contamination susceptibility as a standard needle injection system. It was not clear if the high contamination rate found with the SafSite System was due to non-adherence to the manufacturer's directions for handling.