Phenotypic and Genotypic Characterization of Salmonella spp. Isolated from Foods Involved in Human Salmonellosis Outbreaks in Minas Gerais State, Brazil.

Salmonella spp. is one of the primary pathogens that cause foodborne diseases worldwide. In the present study, we deeply characterized Salmonella spp. originated from foods related to human salmonellosis outbreaks in Minas Gerais - Brazil, from 2003 to 2017. In this regard, the serotyping, antimicrobial susceptibility, virulence genes and genetic polymorphism determined by rep-PCR were performed in 70 Salmonella spp. isolates. Thirteen serotypes of Salmonella spp. were identified, and S. Enteritidis and S. Typhimurium were the most prevalent, both corresponding to 74.3% (52/70) of all isolates. Sixty-five (92.8%) isolates demonstrated to be resistant to at least one of the 15 antimicrobials tested. Ten isolates (14.2%) showed a multidrug-resistant phenotype. Sixteen virulence genes were screened and detection ranged from 75.7 to 100% of all isolates. There was a statistical difference among Salmonella spp. serotypes in detecting the sipB , sopE , lfpA , sefA and spvC genes. Forty isolates of S. Enteritidis from 16 outbreaks were grouped into 14 fingerprints, while 12 S. Typhimurium retrieved six fingerprints. The bacteria presented a serological pattern like those reported by main public health centers worldwide. One major concern of our findings is the high levels of both detection of virulence genes and resistance to antimicrobials, especially to critically important drugs. In this concern, especial attention should be given to the serotype S. Enteritidis. Although the isolates of Salmonella spp. have presented a relatively variable genome, high genetic similarity was observed among them, with some of them sharing identical fingerprints. These results corroborate the hypothesis of clonal circulation of Salmonella spp. in human infections in Minas Gerais.