Tetracycline, Macrolide and Lincosamide Resistance in Strains from Companion Animals and Its Genetic Determinants.

Growing antimicrobial resistance (AMR) in companion-animal pathogens, including (), is a significant concern for pet treatment as well for public health. Despite the importance of in veterinary and human medicine, studies concerning the AMR of this bacterium are still scarce. A total of 65 strains, isolated from dogs and cats, were assessed to test for susceptibility to six clinically relevant antimicrobials via a microdilution method. The prevalence of the selected acquired-resistance genes was also investigated via PCR. High MIC and MIC values (≥128 μg/mL) were noted for tetracycline, erythromycin and clindamycin. Only a few strains were resistant to the tested beta-lactams (6.2%). Tetracycline resistance was found in 66.2% of the strains. Resistance to erythromycin and clindamycin (ML resistance) was found in 55.4% of the strains. Strains with a phenotype showing concurrent resistance to tetracycline and ML were predominant (53.8%). AMR in the tested strains was associated with a variety of acquired and potentially transferable genes. Tetracycline resistance was conferred by (O) (40.0%), (M) (9.2%), and (T) (1.5%), which is reported for the first time in . In most cases, the (M) gene was detected in relation to the conjugative transposon Tn. The MLS phenotype was confirmed in the strains harboring (B) (43.1%) and (TR) (7.7%). To conclude, a high rate of strains occurring in dogs and cats displayed resistance to antimicrobials important for treatment; moreover, they are a potential reservoirs of various resistance determinants. Therefore, AMR in these pathogens should be continuously monitored, especially regarding the One Health concept.