Changing Diagnostic Methods and Increased Detection of Verotoxigenic<i>Escherichia coli</i>, Ireland

Rice, Thomas E.; Quinn, N.; Sleator, Roy D.; Lucey, Brigid

doi:10.3201/eid2209.160477

Cited by 12 publications

(3 citation statements)

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“…Examples include serotypes such as O8:H19, O178:H19, and O100:H20 which have been reported in European countries [45][46][47]. The diversity of STEC serotypes currently observed in Brazil is in agreement with reports from other countries [48,49] where due to the broader use of molecular tools such as PCR and whole genome sequencing in the characterization of STEC isolates a wider spectrum of serotypes is being detected. This is important because since the large outbreak caused by EHEC/EAEC O104:H4 in 2011, there is growing concern regarding non-O157 STEC serotypes, since their significance in human diseases is not yet well established, contrasting STEC O157 or a few non-O157 serogroups such as those forming the "big six," which are undoubtedly major human threats.…”

Section: Discussionsupporting

confidence: 73%

Virulence Profiling and Molecular Typing of Shiga Toxin-Producing E. coli (STEC) from Human Sources in Brazil

et al. 2020

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Since no recent data characterizing Shiga toxin-producing E. coli (STEC) from human infections in Brazil are available, the present study aimed to investigate serotypes, stx genotypes, and accessory virulence genes, and also to perform pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) of 43 STEC strains recovered from 2007 to 2017. Twenty-one distinct serotypes were found, with serotype O111:H8 being the most common. However, serotypes less frequently reported in human diseases were also found and included a hybrid STEC/ETEC O100:H25 clone. The majority of the strains carried stx1a as the sole stx genotype and were positive for the eae gene. Regarding the occurrence of 28 additional virulence genes associated with plasmids and pathogenicity islands, a diversity of profiles was found especially among the eae-harboring strains, which had combinations of markers composed of up to 12 distinct genes. Although PFGE analysis demonstrated genetic diversity between serotypes such as O157:H7, O111:H8, O26:H11, O118:H16, and O123:H2, high genetic relatedness was found for strains of serotypes O24:H4 and O145:H34. MLST allowed the identification of 17 distinct sequence types (STs) with ST 16 and 21 being the most common ones. Thirty-five percent of the strains studied were not typeable by the currently used MLST approach, suggesting new STs. Although STEC O111:H8 remains the leading serotype in Brazil, a diversity of other serotypes, some carrying virulence genes and belonging to STs incriminated as causing severe disease, were found in this study. Further studies are needed to determine whether they have any epidemiological relevance.

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Section: Discussionsupporting

confidence: 73%

Virulence Profiling and Molecular Typing of Shiga Toxin-Producing E. coli (STEC) from Human Sources in Brazil

et al. 2020

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“…This switch is particularly important for STEC, as the case definitions for STEC in the European Union/ European Economic Area (EU/EEA) and Switzerland are not limited to culture-confirmed cases, but include the detection of the Stx1 or Stx2 antigen or their respective genes [20]. Increases in STEC notifications in Ireland were explained by the shift from culture-dependent to culture-independent diagnostic methods; the latter showing higher sensitivity and ability to detect non-O157 STEC [21,22].…”

Section: Culture-independent Diagnostic Tests For Stecmentioning

confidence: 99%

Do changes in STEC diagnostics mislead interpretation of disease surveillance data in Switzerland? Time trends in positivity, 2007 to 2016

et al. 2020

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Background: Laboratory-confirmed cases of Shiga toxin-producing Escherichia coli (STEC) have been notifiable to the National Notification System for Infectious Diseases in Switzerland since 1999. Since 2015, a large increase in case numbers has been observed. Around the same time, syndromic multiplex PCR started to replace other diagnostic methods in standard laboratory practice for gastrointestinal pathogen testing, suggesting that the increase in notified cases is due to a change in test practices and numbers. Aim: This study examined the impact of changes in diagnostic methods, in particular the introduction of multiplex PCR panels, on routine STEC surveillance data in Switzerland. Methods: We analysed routine laboratory data from 11 laboratories, which reported 61.9% of all STEC cases from 2007 to 2016 to calculate the positivity, i.e. the rate of the number of positive STEC tests divided by the total number of tests performed. Results: The introduction of multiplex PCR had a strong impact on STEC test frequency and identified cases, with the number of tests performed increasing sevenfold from 2007 to 2016. Still, age-and sex-standardised positivity increased from 0.8% in 2007 to 1.7% in 2016. Conclusion: Increasing positivity suggests that the increase in case notifications cannot be attributed to an increase in test numbers alone. Therefore, we cannot exclude a real epidemiological trend for the observed increase. Modernising the notification system to address current gaps in information availability, e.g. diagnostic methods, and improved triangulation of clinical presentation, diagnostic and serotype information are needed to deal with emerging disease and technological advances.

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“…accelerates more sensitive and accurate detection in comparison with traditional methods [10]. So this study was planned for isolation, identification and molecular characterization of currently circulating E-coli between diarrhic calves and contact workers to determine the role of virulence genes and pathotypes in diarrhea in both calves and humans.…”

Section: Introductionmentioning

confidence: 99%

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Changing Diagnostic Methods and Increased Detection of VerotoxigenicEscherichia coli, Ireland

Cited by 12 publications

References 10 publications

Virulence Profiling and Molecular Typing of Shiga Toxin-Producing E. coli (STEC) from Human Sources in Brazil

Virulence Profiling and Molecular Typing of Shiga Toxin-Producing E. coli (STEC) from Human Sources in Brazil

Do changes in STEC diagnostics mislead interpretation of disease surveillance data in Switzerland? Time trends in positivity, 2007 to 2016

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