Antimicrobial resistance of Salmonella spp. detected in animal products in 2022–2024

Introduction . Although antibiotics represent one of humanity’s greatest discoveries, their improper use can cause significant harm and lead to severe consequences. Objective. Testing of animal product samples followed by Salmonella spp. isolation, typing, identification and assessment of their antimicrobial resistance dynamics. Materials and methods . The study was carried out at the Department for Microbiological Testing of the Vladimir Testing Laboratory of the Federal Centre for Animal Health. The disc diffusion test was used to determine bacteria resistance to antibiotics. The sizes of the microorganism growth inhibition zones were interpreted according to the Russian recommendations “Determination of the sensitivity of microorganisms to antimicrobial drugs” (IACMAC, version 2025-01), prepared on the basis of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) recommendations and using CLSI M100 standard. PETSAL® monovalent and polyvalent O- and H-sera (The Saint Petersburg Scientific Research Institute ofVaccines and Serums of the FMBA of Russia) were used for serological identification. Antimicrobial resistance genes (blaCTX-M, blaOXA10, blaDHA, blaDES, blaKPC, blaOXA48-like, blaNDM, blaVIM) were identified by real-time polymerase chain reaction using the RESISTOM test systems (“LITECH”Co. Ltd., Russia). Results . Forty-two Salmonella spp. isolates were recovered from animal product samples in 2022–2024. S. Enteritidis was the most frequently isolated serovar, and Salmonella spp. were predominantly isolated from poultry meat products. The detected isolates demonstrated maximum resistance to benzylpenicillin, erythromycin, norfloxacin, and tetracycline. Most of the isolates showed multiple resistance to several antimicrobials. Increased resistance to cephalosporins, fluoroquinolones, tetracyclines, aminoglycosides, chloramphenicol/levomycetin and sulfamethoxazole/trimethoprim was demonstrated for Salmonella spp. isolates. No antimicrobial resistance genes were detected when the isolates were tested with real-time polymerase chain reaction. Conclusion . The study demonstrated widespread antimicrobial resistance, including multiple resistance, among Salmonella spp. isolates detected in animal products in 2022–2024.