Investigating the potential of phage therapy to tackle Pseudomonas aeruginosa infections in dogs

Abstract

Antimicrobial resistance is an issue of increasing importance worldwide with research attention being dedicated to the development of alternative therapeutics, including phage therapy. This involves the use of bacteriophages to fight bacterial infections. The potential of phage therapy in veterinary medicine has not yet been fully exploited. Pseudomonas aeruginosa otitis is a common condition seen in canine veterinary practice and is one of the most challenging ear infections to treat, largely due to resistance of P. aeruginosa to multiple antibiotics. This study aimed to isolate novel lytic bacteriophages with activity against canine otitis isolates and investigate their use as a potential treatment.

Double layer agar (DLA) assays were performed using P. aeruginosa canine otitis isolates to identify and isolate phages from wastewater samples by assessment for plaques.

This resulted in the isolation of five phages. Activity of the phages against 24 P. aeruginosa canine otitis isolates was evaluated using DLA assays and planktonic growth curves. The host ranges of the five phages were relatively limited, with the broadest host range of any phage being five out of the 24 clinical isolates.

Further characterisation of the phages was performed using genome sequencing and transmission electron microscopy. All five phages were assessed to be of Siphovirus morphology. Genome analysis demonstrated that four of these phages were likely to be of a lytic nature. Overall, this study describes five novel phages with activity against P. aeruginosa canine clinical isolates and contributes to the ongoing work to develop alternative therapeutics to antimicrobial resistant infections in companion animal veterinary practice.