Targeting Multidrug-Resistant Pseudomonas aeruginosa from Companion Animals Using Bacteriophages

Antimicrobial resistance poses a major challenge to veterinary and human medicine, particularly in the context of difficult-to-treat infections caused by multidrug-resistant (MDR) bacteria. Pseudomonas aeruginosa, a WHO priority pathogen, is known for its resistance profile and ability to form biofilms. As an alternative to conventional antibiotics, bacteriophage therapy has gained attention due to its specificity for target bacteria, including those in biofilms, without disrupting the host microbiota. This study aimed to evaluate the antimicrobial potential of bacteriophages JG005 and JG024 against P. aeruginosa isolates obtained from companion animals, in their planktonic and biofilm forms. First, a total of 29 clinical isolates were characterized in terms of their antimicrobial resistance profile and biofilm-forming ability. Then, phage activity against planktonic cells was assessed using spot tests and time-kill assays, while antibiofilm activity was evaluated in a microplate assay. The results showed that 68.97% of the isolates were MDR and 41.38% were biofilm producers. JG005 and JG024 demonstrated activity against 58.62% and 65.52% of the isolates, respectively, with time-kill assays confirming strong growth inhibition. Antibiofilm activity was limited and observed after short phage exposure times. These findings support the potential of bacteriophages as a complementary strategy against resistant P. aeruginosa infections in animals.