Salmonella Heidelberg isolates from poultry in Brazil and the United States share a large number of resistance and virulence determinants

Abstract

Salmonella enterica subps. enterica serovar Heidelberg (SH) is one of the most common serovars isolated from poultry and associated with severe infections in humans. Commonly considered multidrug-resistant, it represents a risk to public health. We analyzed 317 SH genomes, including 314 from the Enterobase database from Brazil and the United States (US), and added three recently sequenced Brazilian isolates. In genomes from both countries, the main identified resistance genes were: aac(6′)-Iaa, fosA7, sul2, tet(A), and blaCMY-2. Mutations in GyrA (S83Y only from US genomes and S83F and D87N from Brazilian genomes) were observed in 17 % and 90.62 % of genomes from US and Brazil, respectively, and ParC mutation (T57S), was identified in all genomes. The plasmid replicons most identified in both countries were ColpVC, IncC, IncI1-I(Gamma), and IncX1. The core and soft-core genes were utilized as the basis for conducting a phylogenetic analysis, showing seven clusters of strains, of which only one was shared between strains from the US and Brazil. Overall, this study highlights the variation in genomic profiles of SH circulating in poultry production in both countries, emphasizing the need for improved surveillance measures to protect human and animal populations from potential outbreaks worldwide.