An investigation into alternative materials to silicone rubber for reducing Candida albicans biofilm formation in in-dwelling urinary catheters An investigation into alternative materials to silicone rubber for reducing Candida albicans biofilm formation in in-dwelling urinary catheters

Abstract

Candida albicans is a dimorphic yeast-like fungus that can adhere to indwelling medical devices such as catheters, produce biofilms and then disseminate. This dissemination can lead to invasive candidiasis and sepsis. Catheters are most commonly made from silicone rubber, a material that has been extensively studied for its capability for microbial growth. In this study, C. albicans biofilms were grown on 2mm diameter, 1.5mm thick discs made from silicone rubber, neoprene (also known as polychloroprene) and butyl rubber (also known as Isobutylene-isoprene) with of aim of investigating a potential alternative to silicone as a catheter material. The discs were inoculated for 2 hours in an orbital shaker at 370C at 180rpm then statically incubated at either 30 or 370C for 24 or 48 hours in malt extract broth or Rosewell park memorial institute 1640. Wells were stained with crystal violet to detect biomass. The greatest average growth came from the 370C incubated plates, with neoprene having the most overall growth in malt extract broth and butyl having the most overall growth when grown in Rosewell park memorial institute 1640. Interestingly, silicone and butyl in MEB had more growth on average at 370C after 24 hours incubation than after 48 hours, though dissemination could have been responsible for this reduction. Some biofilms were significantly different from each other- in particular silicone and butyl. There appeared to be a combination of factors that affected biofilm growth with varying levels of influence, but duration did not play a significant role in the amount of growth in this study. Surface topography appeared to be a factor, as did media. Overall, the results from this study showed that the difference in growth was not great enough to warrant the cost and effort required to switch materials from silicone to either neoprene or butyl.