Publikationsdatenbank

Bacteriophage therapy against P. aeruginosa induced canine otitis externa (2023)

Art

Vortrag

Autoren

Dalponte, A. (WE 14)

Filor, V. (WE 14)

Fulde, M. (WE 7)

Alter, T. (WE 8)

Müsken, M.

Bäumer, W. (WE 14)

Kongress

15th International Congress of the European Association for Veterinary Pharmacology and Toxicology

Bruges, Belgium, 02. – 05.07.2023

Quelle

Journal of veterinary pharmacology and therapeutics

Bandzählung: 46

Heftzählung: S1

Seiten: 74

ISSN: 1365-2885

Sprache

Englisch

Verweise

URL (Volltext): https://onlinelibrary.wiley.com/doi/10.1111/jvp.13260

DOI: 10.1111/jvp.13260

Kontakt

Institut für Mikrobiologie und Tierseuchen

Robert-von-Ostertag-Str. 7-13
14163 Berlin
+49 30 838 51843 / 66949
mikrobiologie@vetmed.fu-berlin.de

Abstract / Zusammenfassung

Introduction:
Otitis externa is a common disease in dogs. The treatment of P. aeruginosa induced otitis is often a big challenge due to high intrinsic resistance to commonly used antibiotics. Additionally, this bacterium often forms a biofilm that is difficult to eradicate, necessitating alternative treatment options. Bacteriophage therapy is a promising treatment option. Bacteriophages (phages) are viruses that only infect bacteria and replicate within them. The antimicrobial effect results from cell lysis of the host cell by release of the replicated phages. In this project, phages were characterized, purified and incorporated into a gel formulation with nanocarrier. We investigated the phage-skin-interaction ex vivo with infected dog skin and in vitro in a canine skin model in preparation of a planned in-vivo-study.

Material and Methods:
Bacteriophages against P. aeruginosa were isolated from environmental samples, their growth characteristics, the ability to destruct biofilm and the stability against different temperatures and pH values were investigated. The ability of bacteriophages to lyse strains (host range) was tested on 51 clinical isolates from dog infections. To ensure that endotoxin levels are minimized for patient use, phages are purified by filtration, density gradient centrifugation, and dialysis. In Franz-type diffusion cells the bacteriophage-skin-interaction was examined with skin from euthanized dogs. After artificial infection and bacteriophage treatment, samples were collected and CFU/ml were determined. The skin was also examined by electron microscopy and immunohistochemistry. The canine skin model was developed by co-culturing fibroblasts and keratinocytes in an insert-system, to form a differentiated stratum corneum. Following artificial infection and treatment, the expression of the inflammation associated mediators was determined, and the skin was analyzed histologically.

Results:
Eight phages were isolated and could be used to prepare a gel formulation for individual treatment. For 46 of the tested isolates at least one phage showed lytic activity. Preliminary results in the Franz-type diffusion cells indicate that the bacteriophages can reduce the bacterial burden on the surface of the skin. The infection of the canine skin model with P. aeruginosa resulted in increased expression of the inflammation-associated mediators, whereas the treatment with bacteriophages was able to reduce this expression.

Conclusion:
The current results in both ex vivo and in-vitro-models reveal that the bacteriophages can control artificial infection. Due to the stability of the phages, their broad host range towards clinical isolates, the ability of some phages to completely destruct the biofilm, we are confident to successfully use the phages on otitis patients.