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

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. 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 alamarBlue™ 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). Across species, the MIC was 50 % (v/v) and MBC exceeded 50 % (v/v). On both lens materials, Oftasecur® 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. 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.