Phylogenetic structure of *Salmonella Enteritidis* provides context for a foodborne outbreak in Peru

Salmonella Enteritidis, an important foodborne zoonosis, has a dramatically increased number of cases around the world. To explore the phylogenetic structure of Peruvian Salmonella Enteritidis strains and their relationship with an outbreak occurred in 2018, we analyzed a comprehensive collection of 180 S. Enteritidis strains received by the National Institute of Health during the period 2000–2018. A total of 180 strains were characterized by microbiological procedures, serotyping and whole genome sequencing. Based on genome sequences annotated, virulence factors and accessory genes were identified. Phylogenetic and population structure analysis were also analyzed based on SNPs. The phylogenetic analysis grouped the genomes into two well-supported clades that were consistent with population structure analysis. The clinical and food strains corresponding to the outbreak were included in the same cluster, which presented the sdhA gene, related to the increase of the virulence of this pathogen. The phylogenetic relationship of Peruvian S. Enteritidis suggests the presence of four S. Enteritidis population with high epidemiological importance.

Willi Quino, Junior Caro-Castro, Orson Mestanza, Carmen V. Hurtado, Maria L. Zamudio, Ronnie G. Gavilan