Development of Gendine-Coated Cannula for Continuous Subcutaneous Insulin Infusion for Extended Use

Continuous subcutaneous insulin infusion (CSII) using pumps is a widely used method for insulin therapy in patients with diabetes mellitus. Among the major factors that usually lead to the discontinuation of CSII are CSII set-related issues, including infection at the infusion site. The American Diabetic Association currently recommends rotating sites every 2 to 3 days. This recommendation adds cost and creates inconvenience. Therefore, in order to prevent infections and extend the duration between insertion site changes, we developed a Teflon cannula coated with a combination of gentian violet and chlorhexidine (gendine) and tested its antimicrobial efficacy against different pathogens. The cannulas were coated with gendine on the exterior surface and dried. The efficacy and durability of gendine-coated cannulas were determined against methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis, methicillin-susceptible S. aureus, Streptococcus pyogenes, vancomycin-resistant enterococci, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, and Candida glabrata using a biofilm colonization method. The cytotoxicity of gendine was assessed against mouse fibroblast cell lines. The gendine-coated cannulas showed complete prevention of biofilm colonization of all organisms tested for up to 2 weeks (P < 0.0001) compared to that with the uncoated control. A gendine-coated catheter against mouse fibroblast cells was shown to be noncytotoxic. Our in vitro results show that a novel gendine cannula is highly effective in completely inhibiting the biofilm of multidrug-resistant pathogens for up to 2 weeks and may have potential clinical applications, such as prolonged use, cost reduction, and lower infection rate.