A review on strategies for decreasing E. coli O157:H7 risk in animals Pardis Saeedi a , Maryam Yazdanparast b , Elham Behzadi a , Ali Hatef Salmanian c , Seyed Latif Mousavi b , Shahram Nazarian d , Jafar Amani a, * a Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran b Department of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran c Plant Bioproducts Department, Institute of Agricultural Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran d Department of Biology, Faculty of Science, Imam Hossein University, Tehran, Iran article info Article history: Received 6 November 2016 Received in revised form 25 December 2016 Accepted 2 January 2017 Available online 3 January 2017 Keywords: Escherichia coli O157:H7 HUS Vaccine abstract Enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 is a food-borne pathogen that younger children are most prone to this microorganism. Hemolytic Uremic Syndrome (HUS) caused by EHEC, leads to the destruction of red blood cells and kidney failure. The virulence of E.coli O157:H7 is attributed to fimbriae, that facilitate colonization of bacteria within the colon and verotoxins (VT) or Shiga toxins (Stx) that are released into the blood. Although, in most cases, the infection is self-limitedin young children and aged population, it may cause HUS. Therefore, several investigations are performed in order to offer effective therapies and vaccines, which can prevent and treat the infection in appropriate time. As the pathogenesis of this infection is complicated, a multi-targeted strategy is required. Since cattle are the most important reservoir of EHEC and the root of contamination, reducing E. coli O157:H7 at the farm level should decrease the risk of human illness. Several vaccine approaches have been employed with different proper outcomes in animal models, including recombinant proteins (virulence factors such as; Stx1/2, intimin, EspA, fusion proteins of A and B Stx subunits), avirulent ghost cells of EHEC O157:H7, live attenuated bacteria expressing recombinant proteins, recombinant fimbrial proteins. In addition to protein-based vaccines, DNA vaccines have pro- vided proper prevention in the laboratory animal model. This review paper summarizes the previous studies, current status and future perspective of different immunization strategies for eradicating Enterohemorrhagic Escherichia coli O157:H7. © 2017 Elsevier Ltd. All rights reserved. Contents 1. Introduction ...................................................................................................................... 187 2. Epidemiology ..................................................................................................................... 187 3. Incidence ................................................................. ....................................................... 187 3.1. Transmission and reservoir ................................................................................................... 187 4. Mechanisms of bacterial pathogenicity ................................................... ........................................... 188 4.1. Virulence factors ............................................................................................................ 188 4.2. Shiga-like toxin ............................................................................................................. 188 4.3. Adherence factors ........................................................................................................... 188 4.3.1. Bacterial pathobiology and pathophysiology ............................................................................. 189 5. Diagnosis ................................................................ ....................................................... 189 6. Management of E. coli O157:H7 ....................................................... .............................................. 189 7. Immunization strategies (vaccination) ............................................................................................... 190 * Corresponding author. Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Vanak Sq. Molasadra St, P.O. Box 19395-5487, Tehran, Iran. E-mail address: Jafar.amani@gmail.com (J. Amani). Contents lists available at ScienceDirect Microbial Pathogenesis journal homepage: www.elsevier.com/locate/micpath http://dx.doi.org/10.1016/j.micpath.2017.01.001 0882-4010/© 2017 Elsevier Ltd. All rights reserved. Microbial Pathogenesis 103 (2017) 186e195