¹University of Tunis El Manar (UTM), Laboratory of Epidemiology and Veterinary Microbiology, Group of Bacteriology and Biotechnology Development, Institut Pasteur de Tunis, Tunis, Tunisia DOI : 10.29228/jrp.387 Thermotolerant campylobacters, particularly C. jejuni and C. coli, have emerged as the most common cause of bacterial foodborne disease worldwide, with a significant impact on human health and a corresponding economic burden. The major source of human infection is the handling and consumption of contaminated chicken meat. Furthermore, the emergence of antibiotic resistance in foodborne pathogens is currently considered a real global health concern. This is why we have undertaken a study to assess the occurrence of Campylobacter contamination in chicken carcasses and to investigate antimicrobial resistance (AMR), as well as the AMR molecular mechanisms. The study was performed on 257 samples collected from abattoirs and retail shops in northeastern Tunisia. The overall isolation rate (IR) was 18.7%, including 68.7% of C. jejuni and 31.2% of C. coli. The occurrence of Campylobacter was 23.2%, and 13% in samples from slaughterhouses and retail shops, respectively. The highest rate of Campylobacter contamination was observed in neck skin samples (31.3%), followed by giblets (14.7%), and meet (10%). Antibiotic resistance was tested against eight antibiotics and high resistance rates were observed against tetracycline (100%), erythromycin (97.9%), ciprofloxacin (73%), nalidixic acid (85.4%), ampicillin (83.3%), amoxicillin/clavulanic acid (22.9%), chloramphenicol (75%), and gentamicin (27.1%). All isolates were multidrug-resistant, and 22 resistance patterns were found. All isolates were screened for AMR genes and we detected: tet(O), tet(A), tet(B), tet(L), cmeB, ermB, blaOXA-61, and aphA-3. Moreover, we detected mutations in gyrA (C257T) and 23S rRNA (A2075G/A2074C) genes. The virulence genotypes were also determined, and all isolates carried the motility (flaA) and invasion (cadF) genes. Most of them also harbored the cdtA, cdtB, and cdtC genes, encoding the Campylobacter toxin. The screening of the cgtB and the wlaN genes, involved in Guillain- Barré Syndrome expression, revealed the presence of the cgtB in 21.2% of C. jejuni strains, whereas none of them carried the wlaN gene. Our findings highlight the emergence of Campylobacter strains simultaneously harboring several virulence and AMR determinants, which emphasizes the risk of transmission of MDR strains to humans via the food chain. Keywords : Campylobacter, chicken, antimicrobial resistance, AMR determinants