Medical Management versus PACK-CXL in Dogs with Infectious Keratitis: A Randomized Controlled Trial Protocol

Abstract

Infectious keratitis is a common and painful disease, usually caused by bacteria in dogs. Brachycephalic breeds are at increased risk. Despite medical therapy, enzymatic corneal melting can lead to ulcer perforation and globe loss. Treatment alternatives are needed due to an increase in antibiotic resistance and growing popularity of brachycephalic dogs. Photoactivated Chromophore for Keratitis-Corneal Cross-linking (PACK-CXL) reduces enzymatic collagenolysis and damages multiple targets within microorganisms, resulting in corneal tissue stabilization and elimination of bacteria, irrespective of their antibiotic resistance status. A randomized controlled trial providing evidence of PACK-CXL effectiveness in dogs is lacking. We aim to determine whether PACK-CXL is a viable alternative to conventional medical therapy for canine infectious keratitis. Two hundred-and-seventy client-owned dogs with presumed infectious keratitis will be allocated to two equally sized treatment groups (PACK-CXL or medical therapy) in a masked, randomized, controlled, multicenter trial in eleven clinics. The primary outcome measure is treatment success defined as complete epithelial closure within 28 days. The sample size is based on a group sequential design with two interim analyses, which will be overseen by a Data Safety and Monitoring Board. Ethical approvals have been obtained. The study protocol is preregistered at preclinicaltrials.eu. Publishing trial protocols improves study reproducibility and reduces publication bias.

Progressive ulcerative keratitis in dogs in the United Kingdom: Microbial isolates, antimicrobial sensitivity, and resistance patterns

“…For example, povidone iodine has proven efficacy for treating human microbial keratitis 57,58 and N ‐acetylcysteine has demonstrated in vitro antimicrobial activity against three bacterial species commonly isolated from dogs with infectious keratitis 59 . Photoactivated chromophore for keratitis‐corneal crosslinking results has been demonstrated as a technique that results in non‐antibiotic‐based elimination of bacteria and further research into its efficacy is currently being undertaken 60,61 …”

“…59 Photoactivated chromophore for keratitis-corneal crosslinking results has been demonstrated as a technique that results in non-antibiotic-based elimination of bacteria and further research into its efficacy is currently being undertaken. 60,61 Infected corneal ulcers in this study at the time of sampling were being treated with range of topical and systemic antimicrobial therapy prescribed by the referring veterinary surgeon. Our study demonstrated that over half of the ulcers being treated with a topical antimicrobial at the time of sampling had a positive culture, a figure that is comparable to other similar veterinary and human studies.…”