JAC Advance Access originally published online on October 29, 2008
Journal of Antimicrobial Chemotherapy 2009 63(1):124-128; doi:10.1093/jac/dkn446
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Original research |
Arachidonic acid increases antifungal susceptibility of Candida albicans and Candida dubliniensis
1 Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa 2 Microscopy Centre, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa
Received 6 June 2008; returned 13 August 2008; revised 18 September 2008; accepted 2 October 2008
* Corresponding author. Tel: +27-51-4019197; Fax: +27-51-4443219; E-mail: pohlch.sci{at}ufs.ac.za
Objectives: During Candida albicans infection, arachidonic acid (AA) is released from phospholipids of infected host cell membranes and used by C. albicans as the sole carbon source and for production of eicosanoids. AA can be incorporated into the phospholipids of yeasts, influencing the saturation level and fluidity of yeast cell membranes. It is suggested that the effectiveness of polyene (e.g. amphotericin B) and imidazole (e.g. clotrimazole) antifungals may depend upon the level of unsaturation and ergosterol in the membrane. Therefore, the aim of this study was to evaluate the effect of AA on the cell membrane and susceptibility of C. albicans and Candida dubliniensis biofilms towards amphotericin B and clotrimazole.
Methods: Both yeasts were grown in the presence and absence of AA and the effect of amphotericin B and clotrimazole was examined by confocal laser scanning microscopy, determination of mitochondrial metabolism, unsaturation index of the phospholipid fractions and ergosterol content of the membranes.
Results: AA had no effect on the viability of the cells in the biofilm; however, there was an increase in ergosterol levels as well as antifungal susceptibility of biofilms grown in the presence of AA.
Conclusions: AA influences phospholipid unsaturation and ergosterol content of both yeasts C. albicans and C. dublininensis, increasing susceptibility towards the antifungals. Pretreatment of biofilms with polyunsaturated fatty acids may result in the reduction in antifungal dose needed to inhibit biofilms.
Keywords: amphotericin B , clotrimazole , phospholipids , ergosterol