Category Archives: E.coli O121

USA – Outbreak Investigation of E. coli Linked to Ground Bison from Northfork Bison Distributions, July 2019

FDA

September 13, 2019

The U.S. Food and Drug Administration (FDA), along with the Centers for Disease Control and Prevention (CDC), state and local partners in the U.S., and with the support of the Canadian Food Inspection Agency (CFIA), investigated a multistate outbreak of E. coli O121 and E. coli O103 illnesses likely linked to ground bison supplied by Northfork Bison Distributions Inc. of Saint-Leonard, Québec, Canada.

On September 13, 2019, CDC announced that the outbreak appears to be over.

During the investigation, FDA and CDC analyzed traceback and epidemiological information to determine that ground bison supplied by Northfork Bison Distributions Inc. was the likely cause of the illnesses. FDA laboratory analysis of bison patties packed by the firm on February 26th, 2019, confirmed the presence of one of the outbreak strains of E. coli.

Northfork Bison Distributions Inc. was forthcoming with information to aid in the investigation, and publicly announced a voluntary recall on July 16, 2019. This recall included ground bison meat and bison patties produced between February 22 and April 30, 2019.

FDA regulates bison meat because the authority is not assigned specifically to the United States Department of Agriculture’s (USDA) Food Safety Inspection Service (FSIS) in the Federal Meat Inspection Act (FMIA).

Recommendation

Because the product is frozen and may still be in freezers, distributors, retailers and restaurants should not distribute, use or serve ground bison (including bison burgers) recalled by Northfork Bison Distributions Inc.

Consumers should not eat products prepared using recalled ground bison (including bison burgers) sold under the Northfork Bison label including bison burgers sold to retailers in 4 x 4-ounce packages with expiration dates through October 8, 2020.

Buffalo Burger Canadian Bison Meat

Research – Desiccation and Thermal Resistance of Escherichia coli O121 in Wheat Flour

Journal of Food Protection

ABSTRACT

Non-O157 Shiga toxin–producing Escherichia coli infections have recently been associated with wheat flour on two separate accounts in the United States and Canada. However, there is little information regarding the thermal resistance and longevity of non-O157 Shiga toxin–producing Escherichia coli during storage in low-moisture environments. The objectives of this study were to determine the thermal inactivation kinetics of E. coli O121 in wheat flour and to compare the thermal inactivation rates with those of other pathogens. Wheat flour, inoculated with E. coli O121, was equilibrated at 25°C to a water activity of 0.45 in a humidity-controlled conditioning chamber. Inoculated samples were treated isothermally at 70, 75, and 80°C, and posttreatment population survivor ratios were determined by plate counting. D– and z-values calculated with a log-linear model, were compared with those obtained in other studies. At 70, 75, and 80°C, the D-values for E. coli O121 were 18.16 ± 0.96, 6.47 ± 0.50, and 4.58 ± 0.40 min, respectively, and the z-value was 14.57 ± 2.21°C. Overall, E. coli O121 was observed to be slightly less thermally resistant than what has been previously reported for Salmonella Enteritidis PT30 in wheat flour as measured under the same conditions with the same methods.

HIGHLIGHTS
  • Thermal resistance of E. coli O121 in wheat flour was studied.

  • E. coli O121 exhibited greater survival upon desiccation than E. coli O157:H7.

  • E. coli O121 was slightly less thermally resistant than was previously reported for Salmonella in wheat flour.

Information – Two varieties of E. coli behind multiple U.S. outbreak infections – O103 and O121

Food Safety News

This is a link to a  list of outbreaks in recent years that were caused by E. coli O103 and E. coli O121.

Canada -Food Recall Warning – Ground bison products recalled due to E. coli O121 and O103

CFIA Natural Frontier Foods - Bison – ground meat

Recall details

Ottawa, July 16, 2019 – Northfork Bison Distributions Inc. is voluntarily recalling ground bison products from the marketplace due to possible E. coli O121 and O103 contamination. Consumers should not consume the recalled products see link above.

This recall was triggered by the company and a recall in another country. The CFIA is conducting a food safety investigation, which may lead to the recall of other products. If other high-risk products are recalled, the CFIA will notify the public through updated Food Recall Warnings.

The CFIA is verifying that industry is removing recalled product from the marketplace.

Illnesses

There have been no reported illnesses associated with the consumption of these products in Canada. However, there have been reported illnesses in the United States linked to these products.

 

USA – Outbreak Investigation of E. coli Linked to Ground Bison from Northfork Bison Distributions, July 2019 – E.coli O121 – E.coli O103

FDA

July 16, 2019

The U.S. Food and Drug Administration (FDA), along with the Centers for Disease Control and Prevention (CDC), state and local partners in the U.S., and with the support of the Canadian Food Inspection Agency (CFIA), are investigating a multistate outbreak of E. coli O121 and E. coli O103 illnesses likely linked to ground bison supplied by Northfork Bison Distributions Inc. of Saint-Leonard, Québec, Canada.

The FDA and CDC analyzed traceback and epidemiological information to determine that ground bison supplied by Northfork Bison Distributions Inc. is the likely cause of the illnesses.

FDA regulates bison meat because the authority is not assigned specifically to the United States Department of Agriculture’s (USDA) Food Safety and Inspection Service (FSIS) in the Federal Meat Inspection Act (FMIA).

Recommendation

Buffalo Burger Canadian Bison Meat

Distributors, retailers and restaurants should not distribute, use or serve ground bison (including bison burgers) recalled by Northfork Bison Distributions Inc.

As of July 16, 2019, Northfork Bison Distributions Inc. is voluntarily recalling its ground bison, referred to as Bison Ground, and its ground bison patties, referred to as Bison Burgers and/or Buffalo Burgers, produced between February 22, 2019, and April 30, 2019.

Consumers should not eat products prepared using recalled ground bison (including bison burgers) sold under the Northfork Bison label including Bison Burgers sold to retailers in 4 x 4-ounce packages with expiration dates through October 8, 2020.

Northfork Bison Distributions Inc. has been quick to initiate a voluntary recall and has been forthcoming with information to aid in the investigation. The investigation is ongoing and updates will be provided when available.

Research – Response to Questions Posed by the Food and Drug Administration Regarding Virulence Factors and Attributes that Define Foodborne Shiga Toxin–Producing Escherichia coli (STEC) as Severe Human Pathogens

Journal of Food Protection

EXECUTIVE SUMMARY

The National Advisory Committee on Microbiological Criteria for Foods (NACMCF or Committee) was asked to report on (i) what is currently known about virulence and pathogenicity of Shiga toxin–producing Escherichia coli (STEC) and how they cause illness in humans; (ii) what methods are available to detect STEC and their specific virulence factors; and most importantly (iii) how to rapidly identify foodborne STEC that are most likely to cause serious human disease. Individual working groups were developed to address the charge questions, as well as to identify gaps and give recommendations for additional data or research needs. A complete list of Committee recommendations is in Chapter 4.

STEC infections cause illnesses that range in severity from diarrhea to diarrhea with grossly bloody stools, called hemorrhagic colitis (HC), to the life-threatening sequela of infection, the hemolytic uremic syndrome (HUS). STEC are ingested in contaminated food or water or through direct contact with infected animals or people. Of all STEC that cause disease in the United States, E. coli O157:H7 (O157) causes the most outbreaks and the largest number of cases of serious illness (as assessed by the number of patients hospitalized or with HUS). The infectious dose 50% (ID50) of O157 is low (estimated to be 10 to 100 bacteria). As determined in animal models, these bacteria bind to enterocytes in the large intestine through the intimin outer membrane protein (the gene for intimin is eae), attach and efface the mucosa, and elaborate Shiga toxin (Stx) that passes from the intestine through the bloodstream to sites in the kidney. Certain Stx subtypes are more commonly associated with severe STEC human illness, e.g., Stx2a, Stx2c, and Stx2d. The serogroups (O antigen type only) linked to most cases of illness in the United States are O157, O26, O103, O111, O121, O45, and O145 in order of decreasing incidence. STEC disease is linked most often to foods of bovine origin and fresh produce; disease burden attributed to beef and dairy products is broadly similar in numbers to that attributed to fresh produce.

Stx production, a phage-encoded trait, and intimin, but not the O antigen type, are major drivers of pathogenicity. Thus, predictions of the pathogenic potential of STEC can be made based on Stx subtype and the potential of the bacteria to attach in the intestine. The combination of virulence genes in E. coli that has led to the most severe disease is stx2a with aggR (a genetic marker for enteroaggregative E. coli [EAEC]). The second-highest risk group are those O157 STEC that have stx2a and eae, followed by that same combination in O26, O103, O111, O121, O45, or O145. The combinations of stx1a and stx2a, or stx2a and stx2c, or stx2d with eaeare also of particular concern. The lack of eae suggests a reduced potential for human disease except when aggR or stx2d is present. There have been a few exceptions to this hierarchy, such as O103 that produce only Stx1 and O113 that is eae negative.

The protocols currently used by the U.S. Food and Drug Administration (FDA), U.S. Department of Agriculture–Food Safety and Inspection Service (USDA-FSIS), clinical laboratories and public health laboratories (PHLs), and the food industry include enrichment, culture, multiplex real-time PCR (RT-PCR), toxin immunoassays, biochemical characterization, DNA-based serotyping, DNA microarray, and whole genome sequencing (WGS). The advantages and limitations of each method are summarized in this report. New and developing high-throughput methods are discussed and include metagenomics, digital PCR, biosensors, and microarray.

STEC disease prevention has been and will continue to be driven by improvement in outbreak detection, investigation, and food industry practices. Highlights of Committee recommendations include the following:

  • Develop a new universal enrichment culture medium that can be broadly used for all STEC in any food.

  • Explore high-throughput methods that can detect STEC virulence factor genes directly from enrichment medium and develop and/or improve methods that can ascertain that all critical STEC markers found in the enrichment broth are within the same cell to eliminate the need to isolate the organism.

  • Expand systematic sampling of food, animals, and water for STEC.

  • Explore ways for industry to share test data anonymously.

  • Fund academic research on (i) the regulation of toxin expression and the phages that encode toxin; (ii) mechanisms of attachment by eae-negative STEC; (iii) oral-infection animal models or cell culture models that are more reflective of human disease; and (iv) human host factors that influence the outcome of STEC infection.

  • Link standardized epidemiological, clinical, and STEC WGS data to monitor trends in recognized and emerging virulence attributes such as Stx type and phage profiles.

  • Further develop WGS methods to (i) predict toxin levels produced by an STEC and (ii) generate a classification scheme based on genomic clusters.

The Committee agrees that a combination of genetic characteristics (attributes) exist that signal potentially high-risk STEC and that these STEC will eventually be identifiable using high-throughput techniques that analyze gene profiles. Thus, to rapidly identify foodborne STEC that are most likely to cause serious human disease, the Committee recommends that STEC analyses move toward using virulence markers rather than serogroup or serotype to identify pathogens. The Committee concurs that as ease of use increases and costs decrease, culture-independent diagnostic tests (CIDTs) based on genomic clusters or lineages will be more broadly used to predict whether an STEC isolate is likely to cause serious human disease.

Executive summary of the charge.

STEC are a large, diverse group of bacteria that are characterized by the production of Stx. There are two main Stx types, designated Stx1 and Stx2, and within each are many subtypes. Currently, there are three known Stx1 (Stx1a, Stx1c, and Stx1d) and seven known Stx2 (Stx2a, Stx2b, Stx2c, Stx2d, Stx2e, Stx2f, and Stx2g) subtypes, but some of these are produced mostly by environmental- or animal-associated strains. Thus far, Stx1a, Stx2a, Stx2c, and Stx2d are the subtypes most frequently implicated in human illness. There are estimated to be >400 known STEC serotypes that can produce any of the Stx types, subtypes, or combination of subtypes. However, only a subset of these STEC serotypes have been associated with human illness. Furthermore, the production of Stx alone without other virulence factors, such as intimin, has been deemed to be insufficient to cause severe human illness.

Research – Detection, Isolation, and Characterization of Shiga Toxin–Producing Escherichia coli in Flour

Journal of Food Protection

Wheat flour has recently been described as a novel vehicle for transmission of Shiga toxin–producing Escherichia coli (STEC). Very recently, an outbreak of STEC O121 and STEC O26 infections was linked to flour in the United States. The aim of the present study was to generate baseline data for the occurrence of STEC in flour samples from different retailers in Switzerland. In total, 70 flour samples were analyzed. After enrichment, the samples were screened for stx1 and stx2 by the Assurance GDS MPX ID assay. STEC strains were isolated and serotyped by the E. coli SeroGenoTyping AS-1 kit. The determination of stx subtypes was performed with conventional PCR amplification. Screening for eae, aggR, elt, and estIa/Ib was performed by real-time PCR. Nine (12.9%) of the flour samples tested positive for stx by PCR. STEC was recovered from eight (88.9%) of the positive samples. Two isolates were STEC O11:H48 harboring stx1c/stx1d, two were O146:H28 containing stx2b, one was O103:H2 containing stx1a and eae, and three were O nontypeable: Ont:H12 (stx2a), Ont:H14 (stx2a/stx2g), and Ont:H31 (stx1c/stx1d). STEC O103 belongs to the “top five” serogroups of human pathogenic STEC in the European Union, and STEC O146 is frequently isolated from diseased humans in Switzerland. Our results show that flour may be contaminated with a variety of STEC serogroups. Consumption of raw or undercooked flour may constitute a risk for STEC infection.