The U.S. Department of Agriculture’s Agricultural Research Service (USDA ARS) recently published a study that observed a population of 181 shiga toxin-producing Escherichia coli (STEC) O157:H7 strains over a period of 23 years. The study aims to understand how STEC O157:H7 populations evolve over time and provide context into strain relatedness in foodborne illness outbreak investigations. STEC O157:H7 is of particular concern as it can cause serious, and sometimes fatal, foodborne illness.
STEC O157:H7 is known to reside in cattle feedlots. The retrospective study collected data from a closed-system feedlot at the U.S. Meat Animal Research Center. All 181 strains collected in the study were subjected to short-read sequencing, and a subset of 36 strains were also subjected to long-read sequencing.