Plasmid-Mediated Quinolone Resistance Genes in Escherichia coli Strains Isolated from Healthy Dogs

Knowledge about the potential roles of pets as reservoirs for plasmid-mediated quinolone resistance is still limited in Türkiye. Thus, in our study, the presence of plasmid-mediated quinolone genes (qnrA, qnrB and qnrS) was examined by multiplex Polymerase Chain Reaction (PCR) in 101 fecal Escherichia coli (Escherichia coli) strains isolated from healthy dogs. Moreover, the relationship between the presence of qnr genes and prevalence of quinolone resistance, extended spectrum beta-lactamase (ESBL) and plasmid replicon types, mostly detected among fecal E. coli isolates (F, K, FIB, N, FIA, FIC, and Y) were investigated. A total of 41 strains (40.6%) carried at least one qnr gene. Qnr genes were found in 38.8% of quinolone-resistant and 40.9% of quinolone-susceptible strains. ESBL production was detected in 27 strains, 10 of which also harbored a qnr gene. Among qnr-positive strains, 19 (46.3%) carried both IncK and IncF plasmids (p < 0.001). IncF plasmids were significantly more prevalent in quinolone-resistant strains than in susceptible ones (p < 0.001), suggesting a potential link between qnr carriage, quinolone resistance, and IncF plasmids. To our knowledge, this is the first study investigating the relationship between qnr genes and specific plasmid replicon types in E. coli from healthy dogs in Türkiye. Our findings suggest that domestic animals may serve as reservoirs for antibiotic-resistant E. coli, underscoring the importance of a One Health approach.