Detection and molecular characterization of antibiotic resistance genes in salmonella species isolated from chicken meat produced by different integrated poultry enterprises

This thesis investigates the serotype distribution, antibiotic resistance profiles, and molecular characterization of resistance genes in Salmonella strains isolated from chicken meat samples collected in integrated broiler facilities in Adana, Türkiye. Salmonella spp. was isolated from 4% of drumstick and 8% of thigh samples, while no presence was detected in breast or wing samples. Only S. Infantis was identified among the isolates. Phenotypic and molecular analyses revealed multidrug resistance (MDR), with resistance to commonly used antibiotics such as ampicillin, tetracycline, aminoglycosides, trimethoprim-sulfamethoxazole, and ciprofloxacin. PCR confirmed the presence of blaTEM-1, aadA1, aphA1-IAB, and sul1 genes. Despite the absence of qnr genes, fluoroquinolone resistance was likely associated with chromosomal mutations in gyrA and parC. In addition, the antimicrobial effects of natural bioactive compounds—eugenol, carvacrol, and α-terpineol—were assessed, with carvacrol demonstrating the strongest activity. These findings suggest the potential of plant-derived antimicrobials as safer alternatives to synthetic preservatives in food safety and antimicrobial resistance control. Keywords:Salmonella Infantis, antibiotic resistance, MDR, resistance genes, natural antimicrobials