Modeling of bacterial keratitis of Pseudomonas aeruginosa etiology in the experimental model

Abstract

Background: Pseudomonas aeruginosa keratitis demonstrates an aggressive course, high resistance to antimicrobial therapy, and it also leads to a significant reduction of visual acuity. The purpose of our study was to develop an experimental model of Pseudomonas aeruginosa keratitis and investigate clinical features of corneal lesions in rabbits. Material and methods: A total of 32 rabbits were divided randomly into three groups. The animals of the experimental group 1 (8 rabbits) underwent scarification of the cornea and instillation of archival strain suspension of P. aeruginosa into the conjunctival sac. In group 2 (12 rabbits), corneal de-epithelialization followed by instillation of microbial suspension was performed. In animals of group 3 (12 rabbits), after the de-epithelialization followed by instillation of one-day suspension of the pathogen, the cornea’s surface was covered with a sterile soft contact lens for 16–24 hours. In half of the animals (6 rabbits), the contact lenses with bacterial films of P. aeruginosa were used as a modification. Results: The technique used in group I resulted in bacterial conjunctivitis with mild corneal changes in all cases. In group II, keratitis development was noted in all animals, being defined as moderate in nine cases and semi-severe in three. In animals of group III, severe purulent keratitis occurred in 11 of 12 eyes and semi-severe — in one. Four cases of ulcers and two cases of corneal abscess were recorded, resulting in perforations and keratomalacia (2 cases each). Conclusions: Modeling of purulent P. aeruginosa keratitis in rabbits of varying severity requires complete deepithelialization cornea segment and prolonged presence of the pathogen on the affected surface. The effective way to keep infectious organisms on the cornea surface in sufficient concentration is to use soft contact lenses.