Comparative analysis of two Candida parapsilosis isolates from the patient with a central venous catheter harbouring the Y132F and R398I mutations

This work presents a comparative analysis of 2 clinical isolates of C. parapsilosis; isolated from haemoculture (HC) and central venous catheter (CVC). Both strains harboured Y132F and R398I mutations associated with resistance to fluconazole (FLC). Differences between HC and CVC isolates in terms of virulence, resistance to FLC and lipid distribution were addressed. Expression of the ERG6 and ERG9 genes, lipid analysis, fatty acid composition and lipase activity were assessed by qPCR, thin-layer chromatography/high performance liquid chromatography, gas chromatography and spectrophotometry, respectively. A regulation of the ERG6 and ERG9 genes did not prove any impact on FLC resistance. Analysis of lipid metabolism showed a higher accumulation of lanosterol in both isolates regardless of FLC presence. Additionally, a decreased level in triacylglycerols (TAG) with impact on the composition of total FA was observed for both isolates. Direct impact of the ERG11 mutations to lipid/FA analysis has not been confirmed. The higher lipase activity observed for C. parapsilosis HC isolate could be correlated with the significantly decreased level of TAG. The very close relatedness between both isolates suggests that one isolate was derived from another after the initial infection of the host.