Salmonella is an enteric bacterial pathogen that causes foodborne illness in humans. Third-generation cephalosporin (TGC) resistance in Salmonella remains a global concern. Food workers may represent a reservoir of Salmonella, thus potentially contaminating food products. Therefore, we aimed to investigate the prevalence of Salmonella in food workers and characterize the isolates by serotyping and antimicrobial susceptibility testing. Salmonella was isolated from 583 (0.079%) of 740,635 stool samples collected from food workers between January and December 2018, and then serotyped into 76 Salmonella enterica serovars and 22 untypeable Salmonella strains. High rates of antimicrobial resistance were observed for streptomycin (51.1%), tetracycline (33.1%), and kanamycin (18.4%). Although isolates were susceptible to ciprofloxacin, 12 (2.1%) strains (one S. Infantis, one S. Manhattan, two S. Bareilly, two S. Blockley, two S. Heidelberg, two S. Minnesota, one S. Goldcoast, and one untypeable Salmonella strain) were resistant to the TGC cefotaxime, all of which harbored β-lactamase genes (blaCMY-2, blaCTX-M-15, blaCTX-M-55, and blaTEM-52B). Moreover, 1.3% (4/309) of Salmonella strains (three S. Infantis and one S. Manhattan strains) isolated from chicken products were resistant to cefotaxime and harbored blaCMY-2 or blaTEM-52B. Thus, food workers may acquire TGC-resistant Salmonella after the ingestion of contaminated chicken products and further contaminate food products.

We analyzed the incidence, serovar distribution and antimicrobial resistance of detected in the fecal specimens of food handlers from 2017 to 2019, and obtained the following results. 1. A total of 1,041 strains (0.0955％ incidence) were isolated from 1,090,181 samples. The incidence was 267 (0.0784％) in 2017, 307 (0.0832％) in 2018, and 467 (0.1226％) in 2019, showing an increasing trend. 2. The 629 strains of detected were typed into 84 serovars. The top serovars detected were . Schwarzengrund, . Thompson, . Manhattan and O4: i: ̶.3. The antimicrobial resistance rates were SM (45.8％), TC (29.7％), KM (17.7％), ST (13.7％), ABPC (7.6％), NA (7.3％), CL (2.9％), CP (1.9％), CEZ (1.9％), CTX (1.4％), GM (0.6％), and CPFX (0.3％). High resistance rates were observed in . Schwarzengrund, . Manhattan, and . Blockley. Multi-drug resistant serovars included . Infantis (10-drug resistant) ， . Blockley and . Kentucky (7-drug resistant) ，and . Blockley, . Kentucky, . Megwa, . Muenster, and . Brancaster (6-drug resistant) ． 4. As a result of antimicrobial resistance genotyping, 4strains of CTX-M1 group and 1 strain of CTX-M9 group were detected as extended-spectrum β-lactamase (ESBL) producing strains, and 4 strains of CIT family were detected as AmpC type β-lactamase (AmpC) producing strains. No carbapenemase gene was detected.

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