Arachidonic acid increases antifungal susceptibility of Candida albicans and Candida dubliniensis.
OBJECTIVE
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.
Ells
Ruan
R
Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa.
Kock
Johan L F
JL
Van Wyk
Pieter W J
PW
Botes
Piet J
PJ
Pohl
Carolina H
CH
D000666:Amphotericin B / Q000494:pharmacology*; D000935:Antifungal Agents / Q000494:pharmacology*; D016718:Arachidonic Acid / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects; D002175:Candida / Q000187:drug effects* / Q000502:physiology; D002462:Cell Membrane / Q000737:chemistry; D003022:Clotrimazole / Q000494:pharmacology*; D004357:Drug Synergism; D004875:Ergosterol / Q000032:analysis; D050296:Microbial Viability; D010743:Phospholipids / Q000032:analysis
D000935:Antifungal Agents; D010743:Phospholipids; D016718:Arachidonic Acid; D000666:Amphotericin B; D003022:Clotrimazole; D004875:Ergosterol