Experimental Mycobacteria Infection in Keratomileusis

Abstract

Abstract: : Purpose: To develop an experimental animal model of infection by M. chelonae in keratomileusis. Methods: Double masked, prospective study consisting of 2 experiments, each one with 8 adult male New Zealand rabbits. Eight eyes of 8 rabbits underwent uneventful partial keratomileusis with nasal hinge by the automatic corneal shaper (ACS^® by Bausch&Lomb) under general anesthesia. Every eye was immunossupressed by local injection of methyl prednisolone. Controls: 4 animals underwent left keratomileusis. Inoculum consisting of 1 microliter of 10⁷ heat-inactivated bacteria was inoculated in the interface<strike>s</strike> . Subjects: 4 animals underwent exactly to the same procedure as control. Inoculum consisted of 1 microliter of 10⁷.active bacteria. Trimethoprim 0.1% drops were administrated each 4 hours as antibiotic prophylaxis. Animals were examined by 2 observers on slit lamp on the 1^st , 3 rd, 5th, 7th, 11th and 16th post-operative days. Slit lamp photos were taken to evaluate clinical signs. Animals were sacrificed when corneal disease emerged. Cornea samples were taken for microbiologic studies. Results: First series: three control rabbits did not present corneal disease. One presented secondary infection. Subjects: three subject rabbits developed corneal disease and we were able to isolate M. chelonae. Second series: None of control rabbits developed clinical disease and four of subject rabbits developed corneal disease. We were able to isolate M. chelonae in three of subject rabbits. Conclusions:Corneal infection by M. chelonae has been succesfully induced in rabbits undergoing keratomileusis.

Keywords: animal model • bacterial disease • keratitis