Antivirulence activities of retinoic acids against Staphylococcus aureus

Multidrug-resistant bacteria such as Staphylococcus aureus constitute a global health problem. Gram-positive S. secretes various toxins associated with its pathogenesis, and biofilm formation plays an important role in antibiotic tolerance virulence. Hence, we investigated if the metabolites of vitamin A 1 might diminish toxin production. Of three retinoic acids examined, 13- cis -retinoic acid at 10 μg/mL significantly decreased without affecting planktonic cell growth (MIC >400 μg/mL) also inhibited by epidermidis μg/mL), but less affected uropathogenic Escherichia coli strain, Vibrio or fungal Candida strain. Notably, all- trans hemolytic activity staphyloxanthin production . Furthermore, transcriptional analysis disclosed that repressed expressions virulence- biofilm-related genes, two-component arlRS system, α-hemolysin hla , nuclease ( nuc1 nuc2 ), psmα (phenol soluble modulins α) In addition, plant nematode toxicity assays showed was only mildly toxic concentrations many folds higher than effective antibiofilm concentrations. These findings suggest particularly acid, be useful for suppressing virulence characteristics