Activity of lactic acid bacteria against biofilms formed by Staphylococcus aureus strains involved in acute mastitis

Staphylococcus aureus is the leading cause of acute mastitis during lactation. This species has a remarkable ability to form biofilms and to develop antibiotic resistance, which hampers the effectiveness of current therapeutic approaches. This study aims to evaluate the therapeutic potential of three lactic acid bacteria (LAB) strains (Limosilactobacillus fermentum I7, Limosilactobacillus reuteri 7SNG3-30 and Ligilactobacillus salivarius 22SNG3-30) to interfere with biofilms formed by two S. aureus strains isolated from milk of women with acute mastitis. Both live LAB cells and their respective cell-free supernatants were able to disrupt the S. aureus biofilm structure and significantly reduce its cellular viability. However, the effectiveness of these treatments was dependent on the S. aureus strain, the LAB strain, and the type of LAB preparation (active culture or cell-free supernatant) involved in each interaction. Overall, our results suggest that the tested LAB strains have the potential to be used either as probiotics or postbiotics complementing the current therapies against acute mastitis and other staphylococcal infections.