Genetic diversity with potential ESBL-producing and multidrug-resistantstrains from chicken meat.

Abstract

OBJECTIVES: , a major foodborne pathogen, is a primary concern due to its role in spreading antibiotic resistance. Raw chicken meat samples ( = 210) were collected from various retail locations in Istanbul. METHODS: The food samples were isolated according to ISO 6579-1 and 13 (6.2%) ofstrains confirmed through PCR, agglutination tests, and Sanger sequencing;Infantis (84.6%) was identified as the dominant type. The other types found includedEnteritidis (7.7%) andVirchow (7.7%). Additionally, antibiotic susceptibility was tested according to EUCAST and CLSI standards in differentserotypes. The serotypes were analyzed for susceptibility to 13 antibiotics using agar-disk diffusion assays, and resistance levels were determined via E-test. RESULTS: The disc diffusion method revealed resistance to cefazolin across allserotypes. High resistance rates were also observed for pefloxacin (84.6%), azithromycin (76.9%), and tetracycline (84.6%). Multidrug resistance was identified in 11 (84.6%) strains by the disc diffusion test. The minimum inhibitory concentration testing with MIC test strips showed high tetracycline resistance at 84.6%. Thegene was found in 30.7% of strains, whilesubgroup 1 (7.7%) andsubgroup 9 (30%) were detected by multiplex PCR; however, and,, andgenes were not present. Resistance to carbapenem and colistin was also checked via PCR, and,,,, andgenes were not detected in the Salmonella serotypes. CONCLUSION: This pioneering study provides a comprehensive analysis of serotyping and ESBL production in Salmonella strains isolated from Istanbul.