A specific strain of Salmonella Enteritidis is believed to have been introduced into South Korea from the United Kingdom, according to a recent study published in the journal Emerging Infectious Diseases. Scientists examined whole genome sequences of Salmonella isolates in South Korea, noting a distinct pulsed-field gel electrophoresis (PFGE) pattern that has been present in the country since 2020. This strain has been linked to two fatal infections in patients without documented underlying health conditions.
The study analyzed isolates from eight outbreaks between 2020 and 2023, alongside other Salmonella Enteritidis strains collected from chicken farms in South Korea and human cases from the UK. Data from the Food and Agriculture Organization of the United Nations indicates that approximately 177,000 live chickens were imported from the UK to South Korea each year from 2015 to 2020. Researchers suggest that this trade route may have facilitated the introduction of the Salmonella strain.
Salmonella Enteritidis and Public Health Impact
In South Korea, Salmonella Enteritidis is a major contributor to foodborne illness, particularly through poultry products such as eggs. The Korea Disease Control and Prevention Agency (KDCA) has reported that surveillance of this pathogen has evolved from using pulsed-field gel electrophoresis to whole genome sequencing since 2020. The frequency of isolates exhibiting the studied PFGE pattern surged from 3.2 percent in 2018 to 96.5 percent by August 2024. Concurrently, the percentage of related outbreaks increased from 33.3 percent in 2020 to 91.7 percent in 2024.
Among the 23 outbreaks recorded from 2020 to 2024, a significant number were attributed to egg-associated foods, while others were linked to unknown sources. Researchers compared the isolates from this study to 223 other Salmonella Enteritidis genome sequences from South Korea, as well as 1,230 global genome sequences, finding that the South Korean isolates within a certain clade shared recent common ancestors with human isolates from the UK.
Recommendations for Enhanced Biosecurity
The findings indicate that after the strain’s initial introduction, poultry products contributed significantly to its dissemination, resulting in multiple foodborne outbreaks. Researchers stress the necessity for enhanced biosecurity measures to prevent the introduction and spread of Salmonella Enteritidis within the poultry industry. They caution against underestimating the role of human activities in the spread of this pathogen.
“Continued genomic surveillance remains invaluable for monitoring the spread of foodborne pathogens; such efforts could further the design of improved prevention strategies,” the researchers stated. This emphasis on ongoing surveillance highlights the importance of proactive measures in safeguarding public health and food safety in South Korea and beyond.
