Evaluation of flavaspidic acid BB from Dryopteris fragrans (L.) Schott against resistant Staphylococcus haemelyticus in planktonic and biofilm forms

Abstract

Abstract Background Staphylococcus haemolyticus (S. haemolyticus) is the main etiological factor in skin and soft tissue infections (SSTI). S. haemolyticus infections are an important concern worldwide, especially with the associated biofilms and drug resistance. Herein, we investigated the inhibitory effect of Flavaspidic acid BB obtained from plant extractions on clinical S. haemolyticus strains and their biofilms. Moreover, we predicted its ability to bind to the protein-binding site by molecular simulation. Since the combination of Hsp70 and RNase P synthase after molecular simulation with flavaspidic acid BB is relatively stable, enzyme-linked immunosorbent assay (ELISA) was used to investigate Hsp70 and RNase P synthase to verify the potential antimicrobial targets of flavaspidic acid BB.Results The minimal inhibition concentration value of 16 clinical strains of S. haemolyticus was 5 ~ 480 µg/mL, and flavaspidic acid BB had a slightly higher inhibitory effect on the biofilm than MUP. The inhibitory effect of flavaspidic acid BB on biofilm formation was better with an increase in the concentration of BB. Molecular simulation verified its ability to bind to the protein-binding site. The combination of ELISA kits showed that the bacteriostatic activity of flavaspidic acid BB may be achieved by inhibiting the utilization and re-synthesis of proteins and synthesis of tRNA, thus inhibiting bacterial growth and biofilm formation to a certain extent.Conclusions This study could potentially provide a new prospect for the development of flavaspidic acid BB as an antibacterial agent for resistant strains.