The bactericidal effect of two photoactivated chromophore for keratitis-corneal crosslinking protocols (standard vs. accelerated) on bacterial isolates associated with infectious keratitis in companion animals.
Authors: Suter Anja, Schmitt Sarah, Hübschke Ella, Kowalska Malwina, Hartnack Sonja, Pot Simon
Journal: BMC veterinary research
Summary
# Editorial Summary: Photoactivated Chromophore Crosslinking for Bacterial Keratitis Corneal infections caused by bacteria remain a significant clinical challenge across companion animal species, with antibiotic resistance increasingly limiting conventional treatment options. Suter and colleagues investigated whether photoactivated chromophore for keratitis-corneal crosslinking (PACK-CXL)—a novel oxygen radical-mediated approach—could effectively eliminate bacteria from clinical isolates, comparing a standard protocol (30 minutes at 3 mW/cm²) against an accelerated variant (5 minutes at 18 mW/cm²), both delivering identical energy doses of 5.4 J/cm². Bacterial isolates from 18 companion animals (predominantly dogs and horses) were suspended with riboflavin and exposed to UVA light at 365 nm, with bactericidal efficacy assessed by counting colony-forming units (CFU) post-treatment. Both protocols produced statistically significant reductions in bacterial viability across all tested isolates compared to untreated controls, with no meaningful difference in efficacy between approaches. For equine and small animal practitioners, the accelerated protocol offers a practical advantage: treatment can be initiated promptly while awaiting culture results, substantially reduces anaesthetic time, and may even eliminate the need for general anaesthesia entirely—particularly valuable in equine cases where prolonged sedation presents its own risks.
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Practical Takeaways
- •Accelerated PACK-CXL can be used clinically while awaiting culture results, enabling immediate treatment of suspected bacterial corneal infections
- •The 5-minute accelerated protocol reduces anesthetic time requirement and may eliminate need for general anesthesia in some cases
- •Both protocols were effective against bacterial isolates from dogs, horses, cats and other species, suggesting broad applicability across companion animals
Key Findings
- •Both standard (30 min at 3mW/cm²) and accelerated (5 min at 18mW/cm²) PACK-CXL protocols demonstrated significant bactericidal effect against all tested bacterial isolates
- •No significant efficacy difference was observed between standard and accelerated PACK-CXL protocols when delivering the same total energy dose of 5.4 J/cm²
- •Accelerated protocol reduced treatment time by 83% (from 30 to 5 minutes) while maintaining equivalent bactericidal efficacy