A water-soluble silver(I) formulation as an effective disinfectant of contact lenses cases

Highlights: • Silver(I) Metallotherapeutic formulation • Antimicrobial chemotherapeutics • Pseudomonas aeruginosa; Staphylococcus aureus strains inhibition • Corneal infections chemoprevention • Effective disinfectant of contact lenses cases - Abstract: The antibacterial effect of the already known water-soluble compound {[Ag₆(μ₃-Hmna)₄(μ₃-mna)₂]²⁻·[(Et₃NH)⁺]₂·(DMSO)₂·(H₂O)} (AGMNA) (H₂mna = 2‑mercapto‑nicotinic acid) was evaluated by the mean of the Minimum Inhibitory Concentration (MIC), the Minimum Bactericidal Concentration (MBC) and the Inhibitory Zone (IZ), against the bacterial strains Pseudomonas aeruginosa (PAO1) and Staphylococcus aureus (St. aureus) which settle in the cornea, in bacterial keratitis. The MICs' of AGMNA against PAO1 and St. aureus were 25.7 ± 2.4 μM and 42.0 ± 0.3 μM respectively. Τhe Biofilm Elimination Concentration (ΒΕC) was used to evaluate the influence of AGMNA on the formation of biofilm of PAO1. AGMNA exhibits stronger antimicrobial activity than that of H₂mna or AgNO₃. The toxicity of AGMNA was examined against normal human corneal epithelial cells (HCET cells) and by micronucleus (MN) assay in HCET cells. Thus, the IC₅₀ value of AGMNA, towards HCET cells is higher than 120 μΜ, while its effect on MN frequency, of HCET cells, is meaningless, when they are treated with it at 120 μΜ, suggesting no in vitro genotoxicity. The Mitotic Index (MI), Chromosomal Aberrations (CA) and Nuclear Abnormalities (NA) analyses of Allium cepa reveal insignificant variations between treated and untreated ones indicating no in vivo genotoxicity.