MOLECULAR CHARACTERIZATION OF PATHOGENS AND THEIR RESPONSES TO ENVIRONMENTAL FACTORS
Location: Molecular Characterization of Foodborne Pathogens
Title: Non-O157 Shiga toxin-producing Escherichia coli
Submitted to: Omics Technologies and Microbial Modeling in Food-borne Pathogens
Publication Type: Book / Chapter
Publication Acceptance Date: May 20, 2011
Publication Date: January 5, 2012
Citation: Fratamico, P.M., Smith, J.L. 2012. Non-O157 Shiga toxin-producing Escherichia coli. In: Yan, X., Juneja, V.K., Fratamico, P.M., Smith, J.L., editors. Omics Technologies and Microbial Modeling in Food-borne Pathogens. Lancaster, PA: DESTech Publishers. p. 17-41.
Shiga toxin-producing Escherichia coli (STEC), also known as verocytotoxin-producing E. coli, are important food-borne pathogens responsible for outbreaks of hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). STEC that cause HC and HUS are also referred to as enterohemorrhagic E. coli (EHEC). E. coli O157:H7 is the most commonly recognized STEC in the United States; however, many other STEC serogroups, including E. coli O26, O111, O103, and O145 have been isolated from animals and food and have caused human illness. STEC possess a number of virulence factors, and the production of Shiga toxins (Stx1 and/or Stx2) is the most critical. Non-O157 STEC are a heterogenous group of pathogens comprising many different serogroups/serotypes that show wide genetic diversity and a broad range of virulence gene combinations, and they cause a wide range of clinical symptoms. Although some information is known concerning genes that may play a role in virulence, not much is known about which genes are more important and which gene combinations are carried by strains that are highly pathogenic. The non-O157 STEC have not received the rigorous study that E. coli O157:H7 has undergone. The use of “omics” technologies (genomics/transcriptomics, proteomics, metabolomics, etc.) will provide a more comprehensive understanding of the molecular biology of STEC and help in identifying highly pathogenic strains. The chapter covers molecular serotyping of E. coli/STEC, epidemiology, virulence factors, stress tolerance, quorum sensing, molecular analysis, and SNP typing, with the main emphasis on E. coli O157:H7. The methods used for E. coli O157:H7 should be applicable for studying non-O157 STEC.