Can metabolically generated CO 2 enhance Candida albicans biofilm formation within central venous catheters used in preterm infants?:An in vitro study

Abstract

Candida albicans is responsible for the majority of invasive fungal infections in preterm infants. Biofilm formation within indwelling central venous catheter (CVC) used for these preterm babies leads to CVC related infections and may lead to antifungal resistance. Metabolically generated CO 2 can act as a communicating molecule triggering the yeast to filamentous transition that is essential for the pathological effects caused by C. albicans. The aim of this study was to demonstrate that CO 2 generated by C. albicans contributes to biofilm-formation in central venous catheters utilised in preterm infants. An in vitro model with neonatal CVCs, using established CO 2 bio indicator strain (CO 2 -BIS) to determine whether there is an accumulation of metabolic CO 2 within the catheters, which may be influencing C. albicans biofilm formation was developed. Biofilms formed within CVC lines showed an enhanced recovery of CO 2 -BIS (p=0.06) when co-incubated with another CO 2 donor C. albicans strain CAI4. This indicated that the metabolically generated CO 2 from neighbouring CAI4 cells within the biofilm had generated sufficient CO 2 to complement the growth demand of CO 2 -BIS. Therefore, these results highlight the importance of high concentrations of CO 2 in the circulatory system, which enhances fungal pathogenicity and may lead to invasive candidiasis.

KEYWORDS: Candida albicans, biofilm, central venous catheters, metabolic CO 2