A recent study has identified a strain of Salmonella Enteritidis likely introduced into South Korea from the United Kingdom, raising concerns about food safety. Researchers analyzed whole genome sequences of Salmonella isolates in South Korea, revealing a specific pulsed-field gel electrophoresis (PFGE) pattern that has circulated since 2020 and has been linked to two fatal infections. Both patients had no documented underlying health conditions, according to clinical data from the Korea Disease Control and Prevention Agency (KDCA).
The research, published in the journal Emerging Infectious Diseases, examined isolates from eight outbreaks between 2020 and 2023 as well as other Salmonella Enteritidis strains from local chicken farms. Data from the Food and Agriculture Organization of the United Nations indicates that approximately 177,000 live chickens were imported into South Korea annually from the UK during the period of 2015 to 2020. This established trade route is considered a plausible pathway for the introduction of the strain.
Salmonella Enteritidis and Foodborne Illness in South Korea
In South Korea, Salmonella Enteritidis is among the leading causes of foodborne illness, with poultry products, particularly eggs, consistently identified as primary transmission sources. The surveillance system for Salmonella Enteritidis shifted in 2020 from pulsed-field gel electrophoresis to whole genome sequencing, enhancing the ability to track and identify strains.
The frequency of isolates exhibiting the PFGE pattern rose dramatically, increasing from 3.2% in 2018 to 96.5% by August 2024. Correspondingly, the percentage of related outbreaks soared from 33.3% in 2020 to 91.7% in the current year. From 2020 to 2024, there were 23 reported outbreaks, with 13 associated with egg-related foods, nine from unknown sources, and one from another food type.
Researchers compared the isolates from South Korea with 223 other Salmonella Enteritidis genome sequences from within the country and 1,230 global sequences. The findings suggest that isolates from South Korea within a specific clade share common ancestors with human isolates from the UK, supporting the hypothesis of the strain’s introduction from that region. Following its introduction, poultry products have played a significant role in the strain’s dissemination, leading to numerous foodborne outbreaks.
Call for Enhanced Biosecurity Measures
The researchers emphasized the need for increased biosecurity measures to prevent both the introduction and spread of Salmonella Enteritidis within the poultry industry. They noted the critical impact of human activities on the spread of this pathogen. Continued genomic surveillance is deemed essential for monitoring foodborne pathogens, and such efforts could aid in developing improved prevention strategies.
As South Korea grapples with these challenges, the findings underscore the importance of international cooperation in food safety and biosecurity practices to protect public health.
