Monitoring of Antimicrobial Resistance Genes and Susceptibility Profiles in Bacterial Isolates From Animal-Origin Meat.

The excessive use of antibiotics in animal production has contributed to the global spread of antimicrobial resistance (AMR), posing a significant public health threat. To evaluate the antimicrobial susceptibility profiles and detect resistance genes in bacterial isolates from chicken, pork, and fish meat samples collected in the State of Paraná, Brazil, between 2017 and 2023. Meat samples (n = 418) were tested for Escherichia coli and Salmonella spp., while Klebsiella spp. (n = 265) and Pseudomonas spp. (n = 262) were included from 2019 onward. Bacterial isolation followed ISO 17604:2015 standards with MALDI-TOF identification. Susceptibility testing was performed using the Kirby-Bauer disk diffusion method. Detection of resistance genes (bla_TEM, bla_SHV, bla_CTX-M, bla_KPC, bla_NDM, bla_OXA-48, bla_VIM, bla_SPM, and mcr-1) was conducted by real-time PCR. Multidrug resistance (MDR) was widespread, particularly in Salmonella spp. and Pseudomonas spp., followed by Klebsiella spp. and E. coli. Extended-spectrum β-lactamase (ESBL) genes were frequent in E. coli and Klebsiella spp., while plasmid-mediated colistin resistance (mcr-1) and carbapenemase (blaKPC) were also identified. Resistance to third-generation cephalosporins and ampicillin was especially high. Sampling across years and animal species may not fully reflect farm-level resistance. The absence of molecular typing limited the ability to track clonal spread of resistant strains. Widespread AMR in foodborne bacteria was observed, with resistance levels often exceeding those reported in European monitoring. These findings underscore the need for strengthened surveillance and coordinated actions across animal and human health sectors.