--- title: Non-O157 STEC date: 2012-07-12T18:53:00-07:00 author: admin canonical_url: "https://marlerclark.com/foodborne-illnesses/e-coli/non-o157-stec" section: Resource Library --- [Foodborne Illnesses](/foodborne-illnesses) / [E. coli](https://marlerclark.com/foodborne-illnesses/e-coli) / # Non-O157 STEC ### Non-O157 Shiga Toxin-Producing *E. coli* can also cause food poisoning. *E. coli* O157:H7 may be the most notorious serotype of Shiga toxin-producing *E. coli* (STEC), but there are at least 150 other serotypes of STEC that cause illness in humans – these are referred to as non-O157 STEC. For many years, most recognized STEC outbreaks were associated with *E. coli* O157:H7. However, that was mostly because *E. coli* O157 was easily detected by stool cultures ordered by health care providers and conducted by clinical laboratories. Conversely, stool cultures were not useful in identifying non-O157 STEC at clinical laboratories because cultures could not differentiate non-O157 STEC from the numerous non-disease-causing *E. coli* strains normally found in the human intestine. Therefore, for years, pathogenic non-O157 STEC infections went largely undiagnosed. That all changed in the early 2000s when tests to detect Shiga toxin (Stx), rather than the bacteria itself, became available and were increasingly used by clinical laboratories. A rapid antibody/antigen test to differentiate between O157 and non-O157 could be done at that point, or the Stx-positive specimen could be sent to a public health department lab to determine the STEC serotype. As a result of this change in laboratory testing practices, detection of non-O157 STEC increased markedly, and we now know that, as a group, non-O157 STEC infections in humans are actually much more common than O157 infections. About 80% or more of human non-O157 STEC infections in the United States are caused by six serogroups: O126, O111, O103, O121, O45, and O145. Whereas almost all O157 strains isolated from ill humans contain Stx2 (alone or in combination with Stx1), many non-O157 STEC strains possess only Stx1. Therefore, non-O157 STEC as a whole do not cause as severe a disease as O157. However, non-O157 STEC are very heterogeneous with respect to virulence, and some strains certainly can be as severe as O157, including the ability to cause hemolytic uremic syndrome (HUS) and death. ![](https://s3.us-west-2.amazonaws.com/aboutecolicom-images/outbreaks/image7.jpeg)E. coli pathogens that affect the GI tract and those that typically do not All pathogenic strains of non-O157 STEC can cause bloody diarrhea and hospitalization. However, only the strains that carry Stx2 (as opposed to only Stx 1) typically cause HUS. *E. coli* O157:H7 still causes vastly more HUS cases in the United States than non-O157 serogroups; about 95% of HUS cases with confirmed STEC infection have *E. coli* O157:H7, and 5% have a non-O157 serogroup. One percent or less of non-O157 STEC infections result in HUS, but when they do, the HUS can be fatal. Non-O157 STEC generally have similar outbreak sources and risk factors as *E. coli* O157:H7. Transmission is primarily foodborne, but can occur from water, animal contact, and person-to-person transmission. A higher percentage of non-O157 STEC infections than O157 are acquired during foreign travel, although most are still acquired domestically in the United States. As with *E. coli* O157:H7, the highest percentage of non-O157 STEC cases occur during the summer and early fall months. [ Next: Sources of E. coli › ](https://marlerclark.com/foodborne-illnesses/e-coli/sources-of-e-coli) ### More information about E. coli [November 08, 2022 ###### 16 days hospitalized: Summer E. Coli outbreak linked to Wendy's takes a toll on Michiganders The Marler Clark, E. coli attorneys represent 48 victims of the Wendy's E. coli outbreak. A total of 109 people from six states, including New York, Kentucky, Ohio and Pennsylvania ... ](https://marlerclark.com/news_events/16-days-hospitalized-summer-e-coli-outbreak-linked-to-wendys-takes-a-toll-on-michiganders) [September 27, 2022 ###### Chipotle E. coli Outbreak (2015) The initial, larger STEC O26 outbreak was first detected by public health officials in Washington and Oregon through local foodborne disease surveillance. In late October 2015, officials in those states ... ](https://marlerclark.com/news_events/chipotle-e-coli-outbreak-multistate-2015) [June 04, 2022 ###### E. coli Outbreak linked to Pennsylvania Pool On June 7, 2021, the Pennsylvania Department of Health (PADOH) received multiple complaints of gastrointestinal illness from patrons of a community swimming pool. Two patrons reported positive Shiga toxin-producing Escherichia ... ](https://marlerclark.com/news_events/e-coli-outbreak-linked-to-pennsylvania-pool) [April 28, 2022 ###### Goat contact in Virginia linked to E. coli illnesses The Loudoun County Health Department is notifying the public of the exposure to a specific type of bacterium, called Shiga Toxin Producing E. coli (STEC), by several people who came ... ](https://marlerclark.com/news_events/goat-contact-in-virginia-linked-to-e-coli-illnesses) [1. View all ](/news_events/outbreaks?illness=e-coli&year=all) ## All E. coli Resources [###### E. coli Food Poisoning ](https://marlerclark.com/foodborne-illnesses/e-coli/e-coli-food-poisoning) [###### E. coli O157:H7 ](https://marlerclark.com/foodborne-illnesses/e-coli/e-coli-o157h7) [###### Non-O157 STEC ](https://marlerclark.com/foodborne-illnesses/e-coli/non-o157-stec) [###### Sources of E. coli ](https://marlerclark.com/foodborne-illnesses/e-coli/sources-of-e-coli) [###### Transmission of and Infection with E. coli ](https://marlerclark.com/foodborne-illnesses/e-coli/transmission-of-and-infection-with-e-coli) [###### Symptoms of E. coli infection ](https://marlerclark.com/foodborne-illnesses/e-coli/symptoms-of-e-coli-infection) [###### Complications of E. coli infection ](https://marlerclark.com/foodborne-illnesses/e-coli/complications-of-e-coli-infection) [###### Treatment for E. coli infection ](https://marlerclark.com/foodborne-illnesses/e-coli/treatment-for-e-coli-infection) [###### How is E. coli Infection Diagnosed? ](https://marlerclark.com/foodborne-illnesses/e-coli/how-is-e-coli-infection-diagnosed) [###### Preventing E. coli Infection ](https://marlerclark.com/foodborne-illnesses/e-coli/preventing-e-coli-infection) [###### E. coli Outbreaks ](https://marlerclark.com/foodborne-illnesses/e-coli/e-coli-outbreaks) [###### Real Life Impacts of E. coli Infection and HUS ](https://marlerclark.com/foodborne-illnesses/e-coli/real-life-impacts-of-e-coli-infection-and-hus) [###### E. coli Recalls ](https://marlerclark.com/foodborne-illnesses/e-coli/e-coli-recalls) [###### References ](https://marlerclark.com/foodborne-illnesses/e-coli/references) ### Other foodborne illnesses [Salmonella](https://marlerclark.com/foodborne-illnesses/salmonella) [Listeria](https://marlerclark.com/foodborne-illnesses/listeria) [Hepatitis A](https://marlerclark.com/foodborne-illnesses/hepatitis-a) [Reactive Arthritis](https://marlerclark.com/foodborne-illnesses/reactive-arthritis) [Guillain-Barre Syndrome](https://marlerclark.com/foodborne-illnesses/guillain-barre-syndrome) [Irritable Bowel Syndrome](https://marlerclark.com/foodborne-illnesses/irritable-bowel-syndrome) [Norovirus](https://marlerclark.com/foodborne-illnesses/norovirus) [Botulism](https://marlerclark.com/foodborne-illnesses/botulism) [Campylobacter](https://marlerclark.com/foodborne-illnesses/campylobacter) [Shigella](https://marlerclark.com/foodborne-illnesses/shigella) [Cyclospora](https://marlerclark.com/foodborne-illnesses/cyclospora) [Hemolytic Uremic Syndrome](https://marlerclark.com/foodborne-illnesses/hemolytic-uremic-syndrome)