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United States Department of Agriculture

Agricultural Research Service


Location: Molecular Characterization of Foodborne Pathogens Research

Title: VTEC in the USA

item Fratamico, Pina

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/22/2013
Publication Date: 10/16/2013
Citation: Fratamico, P.M. 2013. VTEC in the USA. Meeting Abstract. MA.

Interpretive Summary:

Technical Abstract: The Centers for Disease Control and Prevention estimates that in the U.S., non-O157 Shiga toxin-producing Escherichia coli (STEC; also known as verocytotoxin-producing E. coli, VTEC) cause more illnesses than STEC O157:H7, and the majority of cases of non-O157 STEC infections is due to serogroups O26, O45, O103, O111, O121, and O145, referred to as the top six non-O157 STEC. The diseases caused by non-O157 STEC are generally milder than those induced by O157 STEC; nonetheless, non-O157 STEC strains have also been associated with outbreaks and serious illnesses, including hemorrhagic colitis and hemolytic uremic syndrome, as well as death. Ruminants, particularly cattle, are reservoirs for both O157 and non-O157 STEC, which are transmitted to humans by person-to-person or animal contact and by ingestion of food or water contaminated with animal feces. Similar to O157:H7, the top six non-O157 STEC are classified as adulterants in beef by the USDA Food Safety and Inspection Service, and regulatory testing for these pathogens began in June, 2012. From January 1 to September 1, 2013, there were 1,650 trim verification samples analyzed for non-O157 STEC from federal plants and 322 samples from imports. There were 13 (0.79 %) and zero positive samples, respectively, with 7 of these 13 trim samples positive for STEC serogroup O103. The Food and Drug Administration is also involved in programs to monitor for non-O157 STEC. Not all strains belonging to the top six serogroups may cause severe illness, and other non-O157 STEC serogroups besides the top six have also caused illness in the U.S. and other countries. Thus, the identification of the combination(s) of STEC genes that is most critical for causing disease is essential for understanding this heterogeneous group of pathogens and for determining which STEC strains may be more important to target in control strategies. Due to the genetic and phenotypic variability of non-O157 STEC strains, the development of accurate and reliable methods for detection and isolation of these pathogens has been challenging. Currently, many laboratories worldwide are involved in projects to sequence numerous STEC genomes, and comparative genomic analyses of the sequence data will help in the identification of genes that contribute to virulence, colonization, persistence, and stress responses, as well as in the identification of markers that may be used in the development of detection and typing systems. Since non-O157 STEC are responsible for a large portion of STEC-related illnesses, more rigorous studies on their physiology, genetics, pathogenicity, and evolution are needed to develop effective control strategies.

Last Modified: 06/26/2017
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