Location: Produce Safety and Microbiology ResearchTitle: Complete genome sequences of three Shiga toxin-producing Escherichia coli O111:H8 strains exhibiting an aggregation phenotype
Submitted to: Microbiology Resource Announcements
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/26/2018
Publication Date: 1/3/2019
Citation: Parker, C., Huynh, S., Bono, J.L., Miller, W.G., Cooley, M.B., Brandl, M. 2019. Complete genome sequences of three Shiga toxin-producing Escherichia coli O111:H8 strains exhibiting an aggregation phenotype. Microbiology Resource Announcements. 8(1):e01335-18. https://doi.org/10.1128/MRA.01335-18.
Interpretive Summary: Foodborne infections with Shiga toxin-producing Escherichia coli (STEC) are a global burden, responsible for nearly 3 million cases of acute illnesses annually worldwide. STEC O111 infections accounted for about 19% of the illness cases in 2000 to 2010. Many of STEC O111 infections in the United States are sporadic; however, there have been 15 well-documented STEC O111 outbreaks in the United States since 1999, including several associated with produce. This announcement documents the complete-genome sequences of three STEC serovar O111:H8 strains. Two strains were isolated from cattle and an American Crow in a major agricultural region for leafy-green production in California’s Central Coast. The other strain is a clinical isolate from a patient with HUS in a person-to-person outbreak in South Dakota. The environmental strains were highly genetically related and possessed only Shiga toxin producing gene stx-1, whereas the clinical isolate harbored both stx-1 and stx-2. The sequencing data of these STEC strains will add to our understanding of STEC O111 genomics, biology and epidemiology and provide references for other STEC O111 sequencing projects.
Technical Abstract: Produce contaminated with Shiga toxin-producing Escherichia coli (STEC) is a continuing source of foodborne illness in the United States. This report documents the complete genome sequences of three STEC serovar O111:H8 strains, two of which were highly related and isolated from cattle feces and from a crow in a major produce agricultural region in central California, and another from a clinical patient with HUS in a person-to-person outbreak in South Dakota. The genomes of these three STEC strains possessed wild-type rpoS genes and curli operons, required for their aggregation phenotype. pAA and AAF-encoding genes, characteristic of enteroaggregative E. coli were absent from the three genomes. Additionally, all three strains harbored an stx1-containing bacteriophage located adjacent to the tmRNA gene ssrA. The clinical isolate also possessed an stx2-containing bacteriophage adjacent to the tRNAArg gene argW, while neither environmental strain had any bacteriophage at this site. The sequencing data of these STEC strains will add to our understanding of STEC O111 genomics, biology and epidemiology and provide references for other STEC O111 sequencing projects.