In vitro studies of a novel antimicrobial luer-activated needleless connector for prevention of catheter-related bloodstream infection.

BACKGROUND

We report in vitro studies of a commercially available novel antimicrobial Luer-activated connector with the inner surface coated with nanoparticle-silver to prevent contaminants from forming biofilm and causing catheter-related bloodstream infection.

METHODS

Sterile control nonmedicated connectors and antimicrobial connectors were filled with approximately 1 x 10(5) cfu/mL of Staphylococcus epidermidis, methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, Enterobacter cloacae, Pseudomonas aeruginosa, or Candida albicans; after 24 h of incubation, the numbers of remaining viable microorganisms were quantified and compared with the concentration in control connectors ( approximately 1 x 10(7) cfu/mL). In trials simulating clinical use, septal membranes of connectors were inoculated with E. cloacae, were allowed to dry, and were then actuated and infused with lactated ringer's solution for 72 h, with sampling for microorganisms in downstream efferent fluid and for biofilm in the connector.

RESULTS

Microorganisms suspended in the intraluminal fluid path of antimicrobial connectors were rapidly killed. For 5 species, there was a 5.23-6.80 mean log(10) reduction (>99.999%), and with C. albicans, there was a 99.9% reduction. In clinical simulation trials, heavy contamination of downstream fluid was detected at all time points with control connectors, reaching approximately 1 x 10(5) cfu/mL at 72 h, and heavy biofilm was uniformly present; with the antimicrobial connectors, there was complete prevention of downstream fluid contamination and total absence of biofilm formation.

CONCLUSIONS

These simulation experiments show that needleless connectors readily acquire an internal biofilm when microorganisms gain access to the internal fluid path and that biofilm formation allows an exponential buildup of internal contamination, with shedding back into the fluid path and downstream sufficient to cause bacteremia. Incorporation of nanoparticle silver into the lining surfaces of the novel connector kills microorganisms in the fluid pathway and prevents internal biofilm formation, even with high levels of introduced contamination and continuous fluid flow. This technology deserves to be evaluated in a prospective, randomized clinical trial to determine its capacity to prevent catheter-associated bloodstream infection.