Molecular epidemiological investigation of Salmonella isolated from the environment, animals, foods and patients in China.

Salmonella as a foodborne pathogen, has a very important impact on human health. This study characterized the serotype, plasmid replicon, MLST typing, resistance phenotype and resistance gene of 282 strains of Salmonella isolated from the environment, animals, foods, and patients in China. These strains are classified into four sources: poultry farms (39/282), animals (30/282), foods (164/282), and hospitals (49/282) their resistance to ciprofloxacin, levofloxacin and ceftazidime is gradually increasing. Among them, ST11, ST19 and ST314 are dominant ST types; Salmonella enteritidis, Salmonella typhimurium and Kentucky Salmonella enteritidis serotypes are the dominant serotypes. This study conducted a comprehensive molecular epidemiological investigation of Salmonella from the unique perspective of Onehealth. It was revealed that the mcr-1 carried by Salmonella mainly relies on the horizontal transfer of Inc I2 and Inc Q plasmids. And a novel integron variable region cassette arrangement pattern aadA2-aadA23-catB3-tet(B)-dfrA12-eptB has emerged in Salmonella strains. More noteworthy is the outbreak of blaTEM-148 subtype in Salmonella from food sources, in which the Inc HI plasmid played an important role.