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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


Suter, Anja; Schmitt, Sarah; Hübschke, Ella; Kowalska, Malwina; Hartnack, Sonja; Pot, Simon (2022). 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. BMC Veterinary Research, 18(1):317.

Abstract

Background: Bacterial corneal infections are common and potentially blinding diseases in all species. As antibiotic resistance is a growing concern, alternative treatment methods are an important focus of research. Photoactivated chromophore for keratitis-corneal crosslinking (PACK-CXL) is a promising oxygen radical-mediated alternative to antibiotic treatment. The main goal of this study was to assess the anti-bactericidal efficacy on clinical bacterial isolates of the current standard and an accelerated PACK-CXL treatment protocol delivering the same energy dose (5.4 J/cm$^{2}$).
Methods: Clinical bacterial isolates from 11 dogs, five horses, one cat and one guinea pig were cultured, brought into suspension with 0.1% riboflavin and subsequently irradiated. Irradiation was performed with a 365 nm UVA light source for 30 min at 3mW/cm$^{2}$ (standard protocol) or for 5 min at 18mW/cm$^{2}$ (accelerated protocol), respectively. After treatment, the samples were cultured and colony forming units (CFU’s) were counted and the weighted average mean of CFU’s per μl was calculated. Results were statistically compared between treated and control samples using a linear mixed effects model.
Results: Both PACK-CXL protocols demonstrated a significant bactericidal effect on all tested isolates when compared to untreated controls. No efficacy difference between the two PACK-CXL protocols was observed.
Conclusion: The accelerated PACK-CXL protocol can be recommended for empirical use in the treatment of bacterial corneal infections in veterinary patients while awaiting culture results. This will facilitate immediate treatment, the delivery of higher fluence PACK-CXL treatment within a reasonable time, and minimize the required anesthetic time or even obviate the need for general anesthesia.

Abstract

Background: Bacterial corneal infections are common and potentially blinding diseases in all species. As antibiotic resistance is a growing concern, alternative treatment methods are an important focus of research. Photoactivated chromophore for keratitis-corneal crosslinking (PACK-CXL) is a promising oxygen radical-mediated alternative to antibiotic treatment. The main goal of this study was to assess the anti-bactericidal efficacy on clinical bacterial isolates of the current standard and an accelerated PACK-CXL treatment protocol delivering the same energy dose (5.4 J/cm$^{2}$).
Methods: Clinical bacterial isolates from 11 dogs, five horses, one cat and one guinea pig were cultured, brought into suspension with 0.1% riboflavin and subsequently irradiated. Irradiation was performed with a 365 nm UVA light source for 30 min at 3mW/cm$^{2}$ (standard protocol) or for 5 min at 18mW/cm$^{2}$ (accelerated protocol), respectively. After treatment, the samples were cultured and colony forming units (CFU’s) were counted and the weighted average mean of CFU’s per μl was calculated. Results were statistically compared between treated and control samples using a linear mixed effects model.
Results: Both PACK-CXL protocols demonstrated a significant bactericidal effect on all tested isolates when compared to untreated controls. No efficacy difference between the two PACK-CXL protocols was observed.
Conclusion: The accelerated PACK-CXL protocol can be recommended for empirical use in the treatment of bacterial corneal infections in veterinary patients while awaiting culture results. This will facilitate immediate treatment, the delivery of higher fluence PACK-CXL treatment within a reasonable time, and minimize the required anesthetic time or even obviate the need for general anesthesia.

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Item Type:Journal Article, refereed, original work
Communities & Collections:05 Vetsuisse Faculty > Veterinärwissenschaftliches Institut > Institute of Food Safety and Hygiene
05 Vetsuisse Faculty > Veterinary Clinic > Equine Department
05 Vetsuisse Faculty > Veterinärwissenschaftliches Institut > Chair in Veterinary Epidemiology
Dewey Decimal Classification:570 Life sciences; biology
630 Agriculture
Scopus Subject Areas:Health Sciences > General Veterinary
Uncontrolled Keywords:General Veterinary, General Medicine
Language:English
Date:17 August 2022
Deposited On:17 Nov 2022 18:20
Last Modified:28 Mar 2024 02:40
Publisher:BioMed Central
ISSN:1746-6148
OA Status:Gold
Free access at:PubMed ID. An embargo period may apply.
Publisher DOI:https://doi.org/10.1186/s12917-022-03397-z
PubMed ID:35978428
Project Information:
  • : FunderStiftung für Kleintiere of the Vetsuisse Faculty of the University of Zürich
  • : Grant ID
  • : Project Title
  • : FunderSchweizerische Vereinigung für Kleintiermedizin (SVK-ASMPA).
  • : Grant ID
  • : Project Title
  • Content: Published Version
  • Language: English
  • Licence: Creative Commons: Attribution 4.0 International (CC BY 4.0)