Category Archives: E.coli O157:H7

USA – FDA – Investigations of Foodborne Illness Outbreaks

FDA

What’s New

  • For the outbreak of E. coli O157:H7 (ref #1166), the case count has increased from 11 to 12.
  • For the outbreak of Cyclospora cayetanensis (ref #1163), the case count has increased from 112 to 118 cases.
  • For the outbreak of Cyclospora cayetanensis (ref #1159), the case count has increased from 38 to 43 cases. This incident now includes additional illnesses based on similarities in reported exposures.
  • For the outbreak of Salmonella Enteritidis (ref #1156) linked to raw cookie dough, the advisory was updated on July 13, 2023. The outbreak has ended and FDA’s investigation is closed.
  • For the investigation linked to Morel mushrooms (ref #1152), the advisory was updated on July 19, 2023. The outbreak has ended, and FDA’s investigation is closed.

Research -Fermenting a place in history: The first outbreak of Escherichia coli O157 associated with kimchi in Canada

Cambridge Org

Abstract

A Canadian outbreak investigation was initiated in January 2022 after a cluster of cases of Shiga-toxin-producing Escherichia coli (STEC) O157 was identified through whole genome sequencing (WGS). Exposure information was collected through case interviews. Traceback investigations were conducted, and samples from case homes, retail, and the manufacturer were tested for STEC O157. Fourteen cases were identified in two provinces in Western Canada, with isolates related by 0–5 whole genome multi-locus sequence typing allele differences. Symptom onset dates ranged from 11 December 2021 to 7 January 2022. The median age of cases was 29.5 (range 0–61); 64% were female. No hospitalisations or deaths were reported. Of 11 cases with information available on fermented vegetable exposures, 91% (10/11) reported consuming Kimchi Brand A during their exposure period. The traceback investigation identified Manufacturer A in Western Canada as the producer. One open and one closed sample of Kimchi Brand A tested positive for STEC O157, with isolates considered genetically related by WGS to the outbreak strain. Napa cabbage within the kimchi product was hypothesised as the most likely source of contamination. This paper summarises the investigation into this STEC O157 outbreak associated with kimchi, the first reported outside of East Asia.

USA – FDA- Investigations of Foodborne Illness Outbreaks

FDA

What’s New

  • A new outbreak of E. coli O157:H7 (ref #1166) in a not yet identified product has been added to the table. FDA has initiated traceback.
  • For the outbreak of Cyclospora cayetanensis (ref #1163), the case count has increased from 105 to 112 cases.
  • For the outbreak of Cyclospora cayetanensis (ref #1159), FDA has initiated an onsite inspection, sample collection and analysis, and the case count has increased from 37 to 38 cases.

Research – Molecular and Genetic Characterization of Colicinogenic Escherichia coli Strains Active against Shiga Toxin-Producing Escherichia coli O157:H7

MDPI

Abstract

The objective of this work was to molecularly and genotypically characterize and test the inhibitory activity of six colicinogenic Escherichia coli strains (ColEc) and their partially purified colicins against STEC O157:H7 isolated from clinical human cases. Inhibition tests demonstrated the activity of these strains and their colicins against STEC O157:H7. By PCR it was possible to detect colicins Ia, E7, and B and microcins M, H47, C7, and J25. By genome sequencing of two selected ColEc strains, it was possible to identify additional colicins such as E1 and Ib. No genes coding for stx1 and stx2 were detected after analyzing the genome sequence. The inhibitory activity of ColEc against STEC O157:H7 used as an indicator showed that colicins are potent growth inhibitors of E. coli O157:H7, being a potential alternative to reduce the presence of pathogens of public health relevance.

Research – Use of Essential Oil Emulsions to Control Escherichia coli O157:H7 in the Postharvest Washing of Lettuce

MDPI

Abstract

Essential oils (EOs) have strong antibacterial properties and can be potential sanitizers to reduce pathogen load and prevent cross-contamination during postharvest washing. The objective of this study was to investigate the efficacy of emulsions containing oregano (OR; Origanum vulgare) and winter savory (WS; Satureja montana) EOs at different concentrations (0.94 and 1.88 µL/mL) and storage times (0 h, 24 h, and 7 days), in reducing Escherichia coli O157:H7 on the surface of three types of lettuce (romaine, crisphead, and butterhead). The EO emulsions were compared with one no-rinse treatment and three rinse treatments using water, 200 ppm chlorine, and 80 ppm peroxyacetic acid (PAA), respectively, in a simulated washing system. The results showed that while the EO emulsions significantly reduced E. coli O157:H7 on crisphead lettuce over time, not all treatments were effective for romaine and butterhead lettuce. The mixture of OR and WS at concentrations of 0.94 and 1.88 µL/mL was found to be the most effective in reducing E. coli O157:H7 on inoculated lettuce, resulting in reductions of 3.52 and 3.41 log CFU/g, respectively. Furthermore, the PAA and the mixture of OR and WS at 1.88 µL/mL effectively limited bacterial cross-contamination close to the detection limit for all lettuce types during all storage times. These results suggest that OR and WS EOs could serve as potential alternatives to chemical sanitizers for postharvest lettuce washing.

USA – Notes from the Field: Multistate Outbreak of Escherichia coli O157:H7 Infections Linked to a National Fast-Food Chain — United States, 2022

CDC

In August 2022, the Michigan Department of Health and Human Services alerted CDC to an approximately fivefold increase in regional cases of Escherichia coli O157:H7 infection. Whole genome sequencing was used to characterize isolates from laboratory-confirmed infections in ill persons. Initial patient interviews indicated that many had consumed meals from the same national fast-food chain. Federal, state, and local officials initiated an investigation to identify the outbreak source and prevent additional cases. This activity was reviewed by CDC and was conducted consistent with applicable federal law and CDC policy.*

CDC defined a case as an E. coli O157:H7 infection with an isolate highly related to the outbreak strain (within 0–2 alleles) by core genome multilocus sequence typing, with illness onset during July 26–August 24, 2022. PulseNet, CDC’s national molecular subtyping network for enteric disease surveillance, detected 109 cases from six states, including Michigan (67; 61%), Ohio (24; 22%), Indiana (11; 10%), Pennsylvania (four; 4%), Kentucky (two; 2%) and New York (one; 1%). The median patient age was 22 years (range = 1–94 years), and 49 (45%) were female. Fifty-two (48%) patients were hospitalized, and 13 (12%) developed hemolytic-uremic syndrome, a recognized complication of E. coli O157:H7 infection; no deaths occurred.

England and Wales – Shiga toxin-producing Escherichia coli (STEC) data: 2020

Gov UK

Main points

A total of 402 confirmed cases of Shiga toxin-producing Escherichia coli (STEC) O157 were reported in England and Wales in 2020.

The lowest incidence of STEC O157 was in the London region (0.29 per 100,000 population) and the highest in the South West region (1.04 per 100,000 population).

Children aged 5 to 9 years had the highest incidence of infection (1.50 per 100,000 population, 95% confidence interval (CI) 1.12 to 1.96).

One-third of confirmed STEC O157 cases in England were hospitalised and 3% were reported to have developed Haemolytic Uraemic Syndrome (HUS).

A further 286 specimens in England and 41 in Wales were positive for Shiga toxins (Stx) genes on polymerase chain reaction (PCR) at the Gastrointestinal Bacteria Reference Unit (GBRU) but an organism was not cultured.

The most commonly isolated non-O157 STEC serogroup was STEC O26 (England: n=103 out of 553, 19%; and Wales: n=26 out of 268, 15%).

Three outbreaks of STEC involving 63 cases in England were investigated in 2020.

Research – New insights on bacteria that causes food poisoning

Science Daily

A joint research group has clarified how pathogenic genes in some Providencia spp., which have gained attention as causative agents of food poisoning as well as enterohemorrhagic Escherichia coli. O157 and Salmonella, are transferred within bacterial cells. Their findings are expected to provide new insights into the identification of infection routes of Providencia spp. and the establishment of preventive methods for food poisoning.

Norway searches for source of E. coli outbreak; Austrian outbreak under investigation

Food Safety News

Norwegian officials are investigating an E. coli outbreak that has affected half a dozen people.

The Norwegian Institute of Public Health (FHI) said six people, living in different parts of the country, are sick. E. coli O157:H7 with the same genetic profile has been detected in all patients.

Two people fell ill in October and November 2022, while the remaining four became sick in February, March and May this year. No-one has developed serious illness. They are between the ages of 14 and 49, and five are men.

Two patients live in Rogaland, while Viken, Trøndelag, Vestland, and Oslo all have one case each.

Meanwhile, several children have fallen ill with E. coli infections in a state of Austria beginning in late May.

In recent weeks, 11 children and young people, mostly from three childcare facilities in the Frastanz area, have contracted infections caused by Shiga toxin-producing E. coli (STEC). The serotype was not mentioned by officials.

At least two children developed HUS and another four were hospitalized, said officials in the province of Vorarlberg.

Research – Risk Factors for Non-O157 Shiga Toxin–Producing Escherichia coli Infections, United States

CDC

Abstract

Shiga toxin–producing Escherichia coli (STEC) causes acute diarrheal illness. To determine risk factors for non-O157 STEC infection, we enrolled 939 patients and 2,464 healthy controls in a case–control study conducted in 10 US sites. The highest population-attributable fractions for domestically acquired infections were for eating lettuce (39%), tomatoes (21%), or at a fast-food restaurant (23%). Exposures with 10%–19% population attributable fractions included eating at a table service restaurant, eating watermelon, eating chicken, pork, beef, or iceberg lettuce prepared in a restaurant, eating exotic fruit, taking acid-reducing medication, and living or working on or visiting a farm. Significant exposures with high individual-level risk (odds ratio >10) among those >1 year of age who did not travel internationally were all from farm animal environments. To markedly decrease the number of STEC-related illnesses, prevention measures should focus on decreasing contamination of produce and improving the safety of foods prepared in restaurants.