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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Environmental Microbial & Food Safety Laboratory » Research » Publications at this Location » Publication #419608
Research Project: Intervention Strategies to Mitigate the Food Safety Risks Associated with the Fresh Produce Supply Chain

Location: Environmental Microbial & Food Safety Laboratory

Title: Genomic comparison of reoccurring, emerging, and persistent (REP) Shiga toxin-producing Escherichia coli O157:H7

Author
item YANG, YISHAN - Oak Ridge Institute For Science And Education (ORISE)
item Yan, Xianghe
item Haley, Bradd
item Li, Charles
item Nou, Xiangwu

Submitted to: Foodborne Pathogens and Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/2024
Publication Date: 12/20/2024
Citation: Yang, Y., Yan, X., Haley, B.J., Li, C.Z., Nou, X. 2024. Genomic comparison of reoccurring, emerging, and persistent (REP) Shiga toxin-producing Escherichia coli O157:H7. Foodborne Pathogens and Disease. https://doi.org/10.1089/fpd.2024.0144.
DOI: https://doi.org/10.1089/fpd.2024.0144

Interpretive Summary: In recent years, several E. coli O157:H7 outbreaks have been linked to romaine lettuce. CDC and FDA have designated these outbreak-associated E. coli O157:H7 strains as "reoccurring, emerging, and persistent (REP)". Our recent study showed that these REP strains have high potential of forming biofilm, a structure that helps the bacterium to survive in stressful environments. In this study, ARS scientists compared the genomes of these REP strains with several past landmark outbreak strains for changes that could be responsible for their enhanced biofilm formation. Several mutations affecting multiple cellular functions were identified. The better understanding of how these REP strains persist offers valuable insights that could lead to improved strategies for preventing future outbreaks, ultimately helping to protect public health.

Technical Abstract: Escherichia coli O157:H7 strains implicated in several recent (2017-2020) multi-state outbreaks linked to leafy green vegetables have been characterized as "reoccurring, emerging, and persistent" (REP). Our recent work showed that the REP strains had significantly enhanced potential for biofilm formation. In this study, comparative genomic analyses were conducted for better understanding the mechanisms of the enhanced biofilm formation, and hence potentially increased environmental fitness, by the REP strains. Phylogenetically, the recent outbreak strains formed two distinct clusters represented by REPEXH01 and REPEXH02, respectively. In comparison to EDL933 and other previous outbreak strains as reference, the REP strains (clustering with REPEXH02) that were shown for strong biofilm formation were determined to have gained two genes encoding proteins of unknown functions (hypothetic proteins) and lost certain prophage related genes. Several SNPs in genes related to biofilm formation were also determined.