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Title: Food safety concerns in the U.S. and research on Shiga Toxin-producing E. coli

item Fratamico, Pina
item BARANZONI, GIANMARCO - University Of Bologna, Italy

Submitted to: UJNR Food & Agricultural Panel Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/4/2013
Publication Date: 12/8/2013
Citation: Fratamico, P.M., Baranzoni, G. 2013. Food safety concerns in the U.S. and research on Shiga Toxin-producing E. coli. UJNR Food & Agricultural Panel Proceedings. P.

Interpretive Summary:

Technical Abstract: In the U.S., there are several government agencies that deal with food safety. Under the Department of Health and Human Services, there are the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC). The CDC collaborates with state agencies, private organizations, and other federal agencies to provide health information in the area of disease prevention, and it is also involved in surveillance and investigation of illnesses associated with food consumption. One of the missions of the FDA is to protect the public’s health by ensuring that the nation's food supply is safe, sanitary, wholesome, and honestly labeled, and that cosmetic products are safe and properly labeled. Agencies under the USDA include the Agricultural Marketing Service and the Food Safety and Inspection Service (FSIS), which is responsible for the safety, wholesomeness, and correct labeling of commercial meat, poultry, and egg products. The Agricultural Research Service is the research arm of the USDA, and one of the research areas is food safety. Scallan et al. (2011) estimate that 9.4 million cases of food-borne illness, 55, 961 hospitalizations, and 1,351 deaths occur each year in the U.S. due to 31 major pathogens. A large portion of the illnesses are due to infection with norovirus, followed by Salmonella, Clostridium perfringens, and Campylobacter. Salmonella, Toxoplasma gondii, Listeria monocytogenes, and norovirus were the leading causes of deaths. Shiga toxin-producing E. coli (STEC) are estimated to cause more than 265,000 illnesses each year in the U.S. with more than 3600 hospitalizations and 30 deaths. Most of the deaths and hospitalizations are estimated to be due to infection with STEC O157:H7. FoodNet is the principal food-borne disease component of the CDC’s Emerging Infections Program and provides the data necessary for measuring the progress in food-borne disease prevention. E. coli O157:H7 infections have been monitored through FoodNet since its inception in 1996, and surveillance for non-O157 STEC infections began in 2000 when they became nationally reportable. From 2000 to 2010, 7695 STEC cases were reported; 5688 were associated with the serogroup O157, and 83% of the other STEC belonged to serogroups O26, O45, 103, O111, O121 and O145 (Gould et al., 2013). However, other serogroups, including O91, O113, and O104 have also caused serious human illness. Prior to 2011, STEC serogroup O104 was not considered as an important STEC; although it caused an outbreak involving 11 cases in the U.S. and many sporadic human cases in Germany, the United Kingdom, Korea, France, Finland, Norway, Denmark, Belgium, Sweden, and Austria, and other countries. A large outbreak due to STEC O104:H4 linked to sprouts from fenugreek seeds occurred in Europe in 2011, and it involved close to 4000 cases of illness, 855 cases of hemolytic uremic syndrome, and over 50 deaths. The DNA sequence of the genome of the outbreak strain revealed that it carried virulence genes associated with both STEC (stx2, iha, lpfO26, lpfO113) and enteroaggregative E. coli (EAEC) (aggA, aggR, set1, pic, aap) (Bielaszewska et al., 2011). Studies confirmed that E. coli O104:H4 is an EAEC that had increased pathogenicity due to transfer of the gene encoding for Shiga toxin 2 (stx2) and antibiotic resistance genes. Similar to STEC O91 and O113, STEC O104 strains that have caused outbreaks and cases of human illness do not carry the eae gene that encodes for intimin; however, many carry the STEC enterohemolysin gene (ehxA). The objective of our research was to develop a methodology to enhance the ability to detect and isolate STEC O104 by incorporating immunomagnetic separation (IMS) for concentration of the target pathogen and latex agglutination to confirm presumptive positive colonies picked from selective-differential agars. The