CPHLN recommendations for the laboratory detection of Shiga toxin-producing Escherichia coli (O157 and non‑O157)

Chui, Linda; Christianson, Sara; Alexander, DC; Arseneau, Véronique; Békal, Sadjia; Berenger, Byron M.; Chen, Y; Davidson, Ross; Farrell, Dj; German, GJ; Gilbert, Lyn; Hoang, L; Johnson, R.P.; Mackeen, A. Dhanya; Maki, Anne; Nadon, Céline; Nickerson, Emma K.; Peralta, A; Arneson, SM Radons; Yu, Yeong-Ju; Ziebell, Kim

doi:10.14745/ccdr.v44i11a06

Cited by 9 publications

(9 citation statements)

References 17 publications

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“…do not yet routinely test for them (10). Nonetheless, by 2016, approximately 35% of all STEC infections reported to the Canadian National Enteric Surveillance Program were caused by non-O157 serotypes (11).…”

Section: Introductionmentioning

confidence: 99%

Shiga toxin–producing Escherichia coli in British Columbia, 2011–2017: Analysis to inform exclusion guidelines

Noftall¹,

Taylor²,

Hoang³

et al. 2019

CCDR

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Background: Shiga toxin-producing Escherichia coli (STEC) can cause severe illness including bloody diarrhea and hemolytic-uremic syndrome (HUS) through the production of Shiga toxins 1 (Stx1) and 2 (Stx2). E. coli O157:H7 was the most common serotype detected in the 1980s to 1990s, but improvements in laboratory methods have led to increased detection of non-O157 STEC. Non-O157 STEC producing only Stx1 tend to cause milder clinical illness. Exclusion guidelines restrict return to high-risk work or settings for STEC cases, but most do not differentiate between STEC serogroups and Stx type. Objective: To analyze British Columbia (BC) laboratory and surveillance data to inform the BC STEC exclusion guideline. Methods: For all STEC cases reported in BC in 2011-2017, laboratory and epidemiological data were obtained through provincial laboratory and reportable disease electronic systems, respectively. Incidence was measured for all STEC combined as well as by serogroup. Associations were measured between serogroups, Stx types and clinical outcomes. Results: Over the seven year period, 984 cases of STEC were reported. A decrease in O157 incidence was observed, while non-O157 rates increased. The O157 serogroup was significantly associated with Stx2. Significant associations were observed between Stx2 and bloody diarrhea, hospitalization and HUS. Conclusion: The epidemiology of STEC has changed in BC as laboratories increasingly distinguish between O157 and non-O157 cases and identify Stx type. It appears that non-O157 cases with Stx1 are less severe than O157 cases with Stx2. The BC STEC exclusion guidelines were updated as a result of this analysis.

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Section: Introductionmentioning

confidence: 99%

Shiga toxin–producing Escherichia coli in British Columbia, 2011–2017: Analysis to inform exclusion guidelines

Noftall¹,

Taylor²,

Hoang³

et al. 2019

CCDR

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“…According to the EU One Health Zoonosis report in 2020, there was an overall trend for reporting STEC cases between 2015 to 2019 due to the awareness of the importance of STEC detection associated with outbreaks in the EU [21]. In Canada, there was a recommendation in 2018 from the Canadian Public Health Laboratories Network for all Canadian laboratories to detect all STEC, especially the non-O157, for better surveillance purposes [14]. An outbreak of O121 in 2016 linked to wheat flour was confirmed using pulsed-field gel electrophoresis and whole genome sequencing [22], of which both techniques require growth of the pathogen.…”

Section: Discussionmentioning

confidence: 99%

“…We have also shown that non-O157 STEC isolates can be difficult to enrich in certain broth media, suggesting a potential for mixed infections that can be missed during an outbreak [13]. Culture-independent diagnostic tests (CIDT), which detect the presence of the stx gene(s), are becoming more readily available, allowing for rapid diagnosis, as well as increased surveillance [14,15]. CIDT are optimal for diagnostic identification, as they do not require culture prior to testing, which greatly decreases the turnaround time.…”

Section: Introductionmentioning

confidence: 99%

Molecular Detection of Non-O157 Shiga Toxin-Producing Escherichia coli (STEC) Directly from Stool Using Multiplex qPCR Assays

et al. 2022

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Non-O157 Shiga toxin-producing E. coli (STEC) can cause outbreaks that have great economic and health impact. Since the implementation of STEC screening in Alberta in 2018, it is also essential to have a molecular serotyping method with faster turnaround time for cluster identification and surveillance purposes. This study sought to perform molecular serotyping of the top six non-O157 (O26, O45, O103, O111, O121 and O145) STEC serotypes directly from stools and enrichment broths compared to conventional methods on isolates. Multiplex, serotyping qPCR assays were used to determine sensitivity and specificity of the top six non-O157 STEC serotypes. Sensitivity and specificity were assessed for both singleplex and multiplex qPCR assays for comparison of the top six serotypes. Blinded stool specimens (n = 116) or broth samples (n = 482) submitted from frontline microbiology laboratories for STEC investigation were analyzed by qPCR. Both singleplex and multiplex assays were comparable, and we observed 100% specificity with a limit of detection of 100 colony-forming units per mL. Direct molecular serotyping from stool specimens mostly correlated (88%) with conventional serotyping of the cultured isolate. In cases of discordant serotypes, the top six non-O157 STEC mixed infections were identified and confirmed by culture and conventional serotyping. Detection of non-O157 STEC can be done directly from stool specimens using multiplex PCR assays with the ability to identify mixed infections, which would otherwise remain undetected by conventional serotyping of a single colony. This method can be easily implemented into a frontline diagnostic laboratory to enhance surveillance of non-O157 STEC, as more frontline microbiology laboratories move to culture independent assays.

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“…Classical STEC detection algorithms were primarily targeted at biochemical differences specific to O157 STEC and missed a significant proportion of non-O157 STEC [4]. Newer detection algorithms have been implemented with the aim to improve the detection of non-O157 serogroups [5]. The 2017 Infectious Diseases Society of America (IDSA) guidelines recommended that STEC screening should include an enzyme immunoassay (EIA) or nucleic acid amplification test (NAAT) for the detection of non-O157 along with O157 strains [6].…”

Section: Introductionmentioning

confidence: 99%

Epidemiology of Non-O157 Shiga Toxin-Producing Escherichia coli in the Province of Alberta, Canada, from 2018 to 2021

2022

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Non-O157 serogroups contribute significantly to the burden of disease caused by Shiga toxin-producing Escherichia coli (STEC) and have been underrecognized by traditional detection algorithms. We described the epidemiology of non-O157 STEC in Alberta, Canada for the period of 2018 to 2021. All non-O157 STEC isolated from clinical samples were submitted for serotyping and qPCR targeting the stx1 and stx2 genes. A total of 729 isolates were identified. Increased detection occurred over the summer months, peaking in July. Patients 18 years and younger made up 42.4% of cases, with 31.1% in those 0–9 years of age. There was a slight female predominance (399/729, 54.7%) A total of 50 different serogroups were detected; the most common were O26 (30.3%), O103 (15.9%), O111 (12.8%), O121 (11.0%), O118 (3.3%) and O71 (2.9%). These six serogroups made up 76.2% of all isolates. In total, 567 (77.8%) were positive for stx1, 114 (15.6%) were positive for stx2 and 48 (6.6%) were positive for both stx1 and stx2. A wide variety of non-O157 serogroups have been detected in Alberta, with the most frequent serogroups differing from other locations. These results highlight the need for further characterization of their virulence factors and clinical impact.

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CPHLN recommendations for the laboratory detection of Shiga toxin-producing Escherichia coli (O157 and non‑O157)

Cited by 9 publications

References 17 publications

Shiga toxin–producing Escherichia coli in British Columbia, 2011–2017: Analysis to inform exclusion guidelines

Shiga toxin–producing Escherichia coli in British Columbia, 2011–2017: Analysis to inform exclusion guidelines

Molecular Detection of Non-O157 Shiga Toxin-Producing Escherichia coli (STEC) Directly from Stool Using Multiplex qPCR Assays

Epidemiology of Non-O157 Shiga Toxin-Producing Escherichia coli in the Province of Alberta, Canada, from 2018 to 2021

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