Genotypic and phylogenetic characterization of Salmonella Minnesota ST548 strains with potential risk to public health

Salmonella Minnesota ST548 has emerged as an important serovar in the poultry industry and has been detected in food products. Five nonclonal S. Minnesota isolates from poultry in southeastern Brazil were characterized using whole-genome sequencing (WGS), and 263 database sequences were analyzed for virulence genes, antimicrobial resistance genes, and phylogenetic relationships. Among the analyzed sequences, 191 multidrug-resistant (MDR) strains carried antimicrobial resistance genes (ARGs) conferring resistance to aminoglycosides ( aac(6′)-Iaa , aph(3′)-Ia and aadA1 ), quinolones ( qnrB19 ), tetracycline ( tetA ), sulfonamides ( sul2 ), and beta-lactams ( bla CMY−2 , bla CTX-M-8 , bla CTX−M−55 and bla TEM−126 ). Furthermore, several genes associated with virulence factors were identified, including adherence ( faeC , faeE , and fimB ), fimbrial adherence determinants ( pegA , staA , fimA , and csgD ), magnesium uptake ( mgtB and mgtC ), macrophage inducible genes (mig-14 ), toxin ( cdtB ) and secretion system ( ssaM , sseE and sseJ ). Twenty-five plasmid replicons and 53 distinct prophages were identified in the analyzed sequences. Phylogenetic analysis showed close relationships between nonclonal S . Minnesota poultry isolates from southeastern Brazil and S . Minnesota sequences associated with human outbreaks from other sources and countries. These findings highlight the need for surveillance of this serovar in both public and veterinary health.