CHARACTERISTICS OF SALMONELLA STRAINS ISOLATED FROM ANIMAL FEED

The aim of the study is to evaluate the level of contamination of animal feed with Salmonella bacteria in the Central District of the Russian Federation from 2021 to 2024. Objectives: to evaluate the level of contamination of feed with Salmonella bacteria; to identify the serotype composition of Salmonella enterica strains; to study the sensitivity of Salmonella strains isolated from feed in the Central District of the Russian Federation to antimicrobial agents. The object of the study was feed for non-productive and productive animals, including raw materials for its production. Feed samples were collected in the Central District of the Russian Federation: Moscow, Tula, and Lipetsk Regions. Sampling was carried out in accordance with GOST R 59369-2021, the Rules for the Bacteriological Examination of Feed dated June 10, 1975. Bacteriological studies with subsequent study of morphological, tinctorial, cultural, biological and serological properties were carried out in the bacteriology department of the Testing Central Scientific and Methodological Veterinary Laboratory of the Federal State Budgetary Institution All-Russian Research Institute of Animal Health. High levels of contamination of animal feed were detected. A study of the feed isolated 55 strains of Salmonella enterica subsp. enterica, belonging to 14 serological variants. A significant portion of the Salmonella strains belonged to the serological variants S. Enteritidis, S. Typhimurium, and S. Infantis. The predominant serotype was S. Enteritidis. Monophasic variants of S. Typhimurium were identified. Long-term penetration of these variants into the Russian Federation was established. Multiple resistance to major antibiotic groups was detected in the strains. Resistant strains exhibited resistance to the following groups of drugs: beta-lactams, extended-spectrum cephalosporins, quinolones, aminoglycosides, nitrofurans, and combination drugs (trimethoprim/sulfamethoxazole).