Introduction
Non-typhoidal Salmonella enterica causes food-borne salmonellosis
and has become a global health threat . The Salmonella entericaserovar Enteritidis is frequently isolated from human patients with
salmonellosis caused by consumption of contaminated chicken meat and
chicken products such as eggs . Epidemiological sources ofSalmonella outbreaks have been investigated using pulsed-field
gel electrophoresis (PFGE) and multiple locus variable-number tandem
repeats (MLVA) analysis. In previous studies, PFGE and MLVA analysis
successfully detected the genetic relationship between SalmonellaEnteritidis strains isolated from human patients or poultry sources in
Korea . However, the discrimination power of these methods for
genetically closely related Salmonella Enteritidis strains is
limited . The next-generation sequencing methodologies such as
whole-genome sequencing (WGS) has been improved the resolution of genome
analyses, such that sources of Salmonella outbreaks can be traced
without using the genotyping approaches described above . Recently,
isolation of MDR Salmonella has been increased from human and
poultry, and these MDR Salmonella had the same antibiotic
resistance phenotype . However, the genetic relationship betweenSalmonella Enteritidis isolated from human and poultry sources in
Korea has not been investigated using WGS yet. Here, we isolated seven
MDR Salmonella Enteritidis strains from poultry sources in Korea
and sequenced their genomes using the Oxford Nanopore approach. In order
to investigate the relationships between Salmonella strains, the
whole genome sequences of the MDR isolates were compared with whole
genome sequences of the previously reported Korean SalmonellaEnteritidis strains using whole genome single nucleotide polymorphism
(SNP) - based phylogenetic analysis and comparative plasmid analysis.