[Antibacterial effect of the antiseptic picloxydine dihydrochloride on conjunctival isolates of gram-negative bacteria].

Abstract

The preoperative and postoperative use of antiseptics can be an alternative to antibiotics in repeated courses of anti-VEGF therapy for reducing the risk of developing antibiotic resistance in eye microflora. Among gram-negative bacteria, the most frequently isolated pathogen that causes eye infections is Pseudomonas aeruginosa, which is characterized by reduced sensitivity to antibiotics and disinfectants.\n\n\nPURPOSE\nTo study the effect of the antiseptic picloxydine dihydrochloride on the gram-negative bacteria Escherichia coli, Pseudomonas luteola and P. aeruginosa isolated from the conjunctiva.\n\n\nMATERIAL AND METHODS\nThe identification of bacterial isolates and study of their sensitivity to antibiotics were carried out using the automated bacteriological analyzer BD Phoenix 100. To determine the bactericidal concentration, the method of serial dilutions of the antiseptic in a liquid nutrient medium was used. The binding of cationic molecules of picloxydine dihydrochloride to bacterial cells was detected by neutralizing the bacterial surface with increasing amounts of antiseptic, and measuring the zeta potential on the Zetasizer Nano ZS analyzer. The ultrastructure of bacterial cells was studied using the two-beam scanning ion-electron microscope Quanta 200 3D.\n\n\nRESULTS\nThe most resistant was P. aeruginosa. The interaction mechanism of picloxydine dihydrochloride with bacterial cells includes electrostatic binding of positively charged antiseptic molecules to negatively charged cell walls. Picloxydine dihydrochloride has a destructive effect on the bacterial cell wall and plasma membrane, which leads to cell lysis and release of intracellular components.\n\n\nCONCLUSION\nPicloxydine dihydrochloride exhibits bactericidal activity against gram-negative conjunctival isolates and is promising for preventive use during repeated courses of intravitreal injections.