Screening for Antimicrobial Resistance and Genes of Exotoxins in Pseudomonas aeruginosa Isolates from Infected Dogs and Cats in Poland

Pseudomonas aeruginosa has assumed an increasingly prominent role as the aetiological agent in serious hard-to-treat infections in animals and humans. In this study, 271 P. aeruginosa strains collected from dogs and cats were investigated. The aim of the research was to screen these P. aeruginosa strains for antibiotic resistance and the presence of selected virulence factor genes. Antibiotic resistance was determined using the Kirby–Bauer method, while virulence genes were detected by polymerase chain reaction (PCR). The most frequently detected resistance was to fluoroquinolones, ranging in prevalence from 17.3% for ciprofloxacin up to 83% for enrofloxacin. The resistance to carbapenems was 14% and 4.8% for imipenem and meropenem, respectively. Almost all P. aeruginosa strains harboured the exoT (97.8%) and lasB (93.4%) genes, while the lowest prevalence was found for exoU (17.3%) and plcH (17.3%). P. aeruginosa strains isolated from dogs that harboured the toxA gene were more frequently resistant to ceftazidime (p = 0.012), while the presence of the exoU gene was found to be connected with resistance to marbofloxacin (p = 0.025) and amikacin (p = 0.056). In strains originating from cats, only the connection between the presence of the exoU gene and resistance to enrofloxacin (p = 0.054) was observed. The confirmation of associations between virulence-factor-encoding genes and antibiotic resistance indicates that problems of antibiotic resistance may not only cause complications at the level of antibiotic dosage but also lead to changes in the virulence of the bacteria; thus, further studies in this area are required.