Antifungal and anti-biofilm effects of 6-shogaol against Candida auris.

AIMS: This study aimed to assess the antifungal and anti-biofilm effects of 6-shogaol against Candida auris using in vitro phenotypic and genotypic analyses. METHODS AND RESULTS: Our results showed that 6-shogaol exhibited antifungal as well as anti-biofilm activity by inhibiting biofilm formation and eradicating the preformed biofilms of C. auris. The rate and extent of antifungal activity were further confirmed by a time-kill assay. The XTT reduction assay confirmed that 6-shogaol decreased cellular metabolic activity in the biofilm. The effect of 6-shogaol on established C. auris biofilms was visualized by confocal laser scanning microscopy. Also, this study demonstrated that 6-shogaol reduced the levels of aspartyl proteinases and downregulated the expression of the efflux pump-related CDR1 gene in C. auris. CONCLUSIONS: The data indicated that 6-shogaol extracted from ginger had antifungal and anti-biofilm effects on C. auris. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrated the value of the plant-derived 6-shogaol as a promising and potent bioactive compound. The mode of action of this compound against C. auris biofilm was also proposed.

Repurposing auranofin to combat uropathogenic Escherichia coli biofilms.

AIMS: The aim of this study was to assess anti-biofilm and antimicrobial effects of auranofin, an anti-rheumatic agent, on uropathogenic Escherichia coli (UPEC) biofilm formation. METHODS AND RESULTS: The minimum inhibitory concentration and biofilm inhibition concentration of auranofin against UPEC ranged from 24 to 32 µg ml-1 . Biofilm eradication concentration and XTT reduction concentration of auranofin were found to be at 112 µg ml-1 . Confocal laser scanning microscopy results confirmed that biofilm was inhibited by auranofin. These results indicate that auranofin possesses potent anti-biofilm and antimicrobial activities against UPEC. Effects of auranofin on type 1 fimbriae gene (fimH) and response regulator gene (rpoS) to stress were explored using quantitative real time-polymerase chain reaction. In addition, combination of auranofin and tetracycline showed synergistic effect. CONCLUSIONS: These data indicate that auranofin has inhibitory effect on biofilm formation and synergistic effect on UPEC infection when it is combined with tetracycline. SIGNIFICANCE AND IMPACT OF THE STUDY: Our study strongly suggest that auranofin is a promising alternative anti-biofilm and antimicrobial agent to prevent UPEC biofilm formation in UTIs. Auranofin already approved for human use have the advantage of being able to be put into clinical use relatively quickly.