In vitro antibacterial efficacy and antibiofilm activity on contact lenses of a new ophthalmic spray containing Biosecur® citrus extract (Oftasecur®)

Purpose: To investigate the in vitro antimicrobial activity of a new commercial ocular spray containing 0.2% Biosecur® citrus extract (Oftasecur®) against Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli and test its efficacy in preventing biofilm formation on etafilcon A and senofilcon A contact lenses. Methods: Antibacterial activity against Staphylococcus epidermidis ATCC 12228, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa PAO1, and Escherichia coli NCTC 10418 was evaluated by microdilution in Mueller–Hinton broth (MHB). Inocula were standardised to OD600 and MIC/MBC determined across a 50 % to 0.195 % (v/v) dilution range of Oftasecur®. Early biofilm formation on etafilcon A and senofilcon A lenses was assessed over 24 h using alamarBlueTM at 10 % (v/v) with fluorescence recorded (Ex 584 nm, Em 590 nm) every 30 min. Lenses were rinsed in sterile phosphate-buffered saline (PBS; 3 × 5 mL) before use. Data were analysed by assumption-checked parametric/non-parametric tests (one-way ANOVA with Tukey or Kruskal–Wallis with Dunn; α = 0.05). Results: Across species, the MIC was 50 % (v/v) and MBC exceeded 50 % (v/v). On both lens materials, Ofta- secur® significantly reduced alamarBlue-measured metabolic activity during early lens–bacteria interactions relative to untreated controls over 24 h (p < 0.05), consistent with inhibition of early biofilm-associated growth. Reductions were observed for all species, with the largest effects for Gram-negative strains. Conclusions: Oftasecur® demonstrated concentration-dependent antibacterial activity against reference ocular pathogens and suppressed early biofilm-associated metabolism on common contact lens materials. These findings support further ex vivo and clinical studies to determine whether Oftasecur® can help prevent contact lens–related bacterial keratitis.