The effect of phytoneering extracts BNO 1016 and BNO 1030 on the adhesion of typical respiratory pathogens: an experimental study

Rhinosinusitis and tonsillitis are associated with the formation of bacterial biofilms, which complicates treatment and contributes to frequent relapses. Microbial adhesion to host cells is a key initial step in colonization and biofilm development. Phytoneering extracts BNO1016 and BNO1030 are widely used in respiratory phytotherapy, yet their effects on quantitative adhesion parameters have not been fully characterized. The objective of this study was to evaluate and compare the effects of the phytoneering extracts BNO1016 and BNO1030 on the adhesion of clinically relevant bacterial and fungal pathogens. Clinical isolates of Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae (two strains), Streptococcus pyogenes, Streptococcus dysgalactiae ssp. equisimilis, and Candida albicans were examined using a human erythrocyte adhesion model. Extracts BNO1016 and BNO1030 were applied at a 1:5 dilution to simulate expected in vivo dilution by mucosal secretions. Average adhesion index (AAI), adhesion coefficient (AC), and microbial adhesion index (MAI) were used as quantitative indicators of microbial adhesion. BNO1016 significantly reduced AAI and MAI in S. aureus, S. pyogenes, S. dysgalactiae ssp. equisimilis, S. epidermidis, and C. albicans, while AC decreased significantly only in S. aureus and S. pyogenes. No inhibitory effect was observed for either strain of S. pneumoniae. BNO1030 significantly decreased AAI and MAI in S. epidermidis, S. dysgalactiae ssp. equisimilis, S. pneumoniae (M), and C. albicans, whereas AC remained unchanged across all strains. Both phytoneering extracts demonstrated strain‑specific anti‑adhesive activity, reflected by reductions in AAI, AC, and MAI. MAI proved to be the most informative indicator, reflecting reductions in both the number of adherent cells and the total microbial biomass with biofilm‑forming potential. These findings indicate that BNO1016 and BNO1030 may limit early microbial attachment and reduce the initial biomass available for biofilm formation, supporting their potential role in phytotherapeutic management of upper respiratory tract infections.