The Antibiofilm Effect of Blueberry Fruit Cultivars Against Staphylococcus epidermidis and Pseudomonas aeruginosa

The antibiofilm and antibacterial properties against Pseudomonas aeruginosa and Staphylococcus epidermidis and chemical characterization of six hydroethanolic blueberry extracts (blueberry rabbiteye-Vaccinium virgatum) from different cultivars and means of propagation were investigated. The total flavonoid, anthocyanin, and phenolic contents were determined by specific and well-established methods. Among the cultivars, Briteblue showed the lowest content of all metabolites analyzed, while Bluegem showed the highest concentrations of these compounds. All the micropropagated cultivars presented the highest amounts of chlorogenic acid. The blueberry fruit extracts showed strong activity against S. epidermidis biofilm (up to 84% inhibition) without inhibiting bacterial growth. Likewise, Bluegem micropropagated extract, which had the highest anthocyanin, flavonoids, and phenolic compound content, demonstrated the highest S. epidermidis biofilm inhibitory effect. Finally, a linear correlation between the total phenolic content and the percentage of biofilm inhibition was observed.