Antifungal Activity of Commercial Mouthrinses Against Candida Albicans

Abstract

To investigate the effectiveness of a delmopinol, sodium chlorite, povidone iodine, and lactoferrin-lysozyme-lactoperoxidase
mouthrinse against C. albicans planktonic cells and biofilms.
Methods Two-fold dilutions of the mouthrinse solutions were prepared (1:2, 1:4, 1:8, 1:16, 1:32, 1:64), and dispensed into 96 well microtitre plates. Standardized inocula of wild type C. albicans SC5314 was added and the minimum inhibitory concentrations (MICs)
were determined in accordance with Clinical and Laboratory Standards Institute (CLSI) Guidelines for the broth microdilution
assay. Optically clear wells were cultured for determination of minimum fungicidal concentrations (MFCs). The effect of the
mouthrinses against C. albicans mature biofilms was also evaluated. The metabolic activity of the biofilms was semi-quantitatively
determined with a standard 2,3-bis(2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction assay.
Results The lowest MICs were exhibited by delmopinol (1:16), followed by sodium chlorite (1:8), povidone iodine (1:4), and lactoferrin lysozyme- lactoperoxidase (1:4). Delmopinol exhibited fungicidal activity at 1:16 dilution, while MFCs were achieved by higher concentrations of povidone iodine (1:4) and sodium chlorite (1:2). Lactoferrin-lysozyme-lactoperoxidase did not exhibit fungicidal
activity at all tested concentrations. Among the four agents at two-fold dilution, sodium chlorite and povidone iodine exhibited
the greatest reductions (>90%) in C. albicans biofilms (p<0.005). Significantly greater reductions in metabolic activity were achieved
with sodium chlorite compared to the other agents at dilutions of 1:4 through to 1:32 (p<0.005). Conclusions Delmopinol exhibited the highest activity against planktonic C. albicans, while sodium chlorite exhibited greater effects against
mature biofilms. Clinical Significance Sodium chlorite was shown in this study to exhibit potent antifungal activity against C. albicans biofilms, and products containing this active ingredient deserve consideration for inclusion in oral health promotion measures conducted amongst vulnerable patient groups.