Characteristics of Shiga Toxin–Producing Escherichia coli O157 in Slaughtered Reindeer from Northern Finland

Zweifel, Claudio; Fierz, Lisa; Cernela, Nicole; Laaksonen, Sauli; Fredriksson-Ahomaa, Maria; Stephan, Roger

doi:10.4315/0362-028x.jfp-16-457

Cited by 6 publications

(4 citation statements)

References 35 publications

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“…More than 80 studies on the genotyping und virulence profiling of STEC and EHEC were published in the past 10 years, examples of which are given in several studies [ 23 , 61 , 62 , 63 ]. In general, all of these screening studies aimed to elucidate the serotypes and virulence properties of STEC including Stx-variants, LEE, further toxins, and other adhesion factors such as the ones mentioned above.…”

Section: Toxins Of Lee-negative Stecmentioning

confidence: 99%

Toxins of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli

Krause

Barth

Schmidt

2018

Toxins

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Studies on Shiga toxin-producing Escherichia coli (STEC) typically examine and classify the virulence gene profiles based on genomic analyses. Among the screened strains, a subgroup of STEC which lacks the locus of enterocyte effacement (LEE) has frequently been identified. This raises the question about the level of pathogenicity of such strains. This review focuses on the advantages and disadvantages of the standard screening procedures in virulence profiling and summarizes the current knowledge concerning the function and regulation of toxins encoded by LEE-negative STEC. Although LEE-negative STEC usually come across as food isolates, which rarely cause infections in humans, some serotypes have been implicated in human diseases. In particular, the LEE-negative E. coli O104:H4 German outbreak strain from 2011 and the Australian O113:H21 strain isolated from a HUS patient attracted attention. Moreover, the LEE-negative STEC O113:H21 strain TS18/08 that was isolated from minced meat is remarkable in that it not only encodes multiple toxins, but in fact expresses three different toxins simultaneously. Their characterization contributes to understanding the virulence of the LEE-negative STEC.

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Section: Toxins Of Lee-negative Stecmentioning

confidence: 99%

Toxins of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli

Krause

Barth

Schmidt

2018

Toxins

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“…It is logical that the regurgitation can reach lungs more easily if the animal is in horizontal position during commonly occurring reflexive gasping [ 32 ]. Aspiration of rumen content is also a concern for meat hygiene, since potential pathogens are transported to the clean side of the abattoir and can contaminate other carcasses and organs [ 38 , 39 ].…”

Section: Discussionmentioning

confidence: 99%

Is transport distance correlated with animal welfare and carcass quality of reindeer (Rangifer tarandus tarandus)?

et al. 2017

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BackgroundSlaughter reindeer are exposed to stress caused by gathering, handling, loading and unloading, and by conditions in vehicles during transport. These stress factors can lead to compromised welfare and trauma such as bruises or fractures, aspiration of rumen content, and abnormal odour in carcasses, and causing condemnations in meat inspection and lower meat quality. We investigated the statistical association of slaughter transport distance with these indices using meat inspection data from years 2004–2016, including inspection of 669,738 reindeer originating from Finnish reindeer herding areas.ResultsIncreased stress and decreased welfare of reindeer, as indicated by higher incidence of carcass condemnation due to bruises or fractures, aspiration of rumen content, or abnormal odour, were positively associated with systems involving shorter transport distances to abattoirs. Significant differences in incidence of condemnations were also detected between abattoirs and reindeer herding cooperatives.ConclusionsThis study indicates that in particular the short-distance transports of reindeer merit more attention. While the results suggest that factors associated with long distance transport, such as driver education, truck design, veterinary supervision, and specialist equipment, may be favourable to reducing pre-slaughter stress in reindeer when compared with short distance transport systems, which occur in a variety of vehicle types and may be done by untrained handlers. Further work is required to elucidate the causal factors to the current results.Electronic supplementary materialThe online version of this article (doi:10.1186/s13028-017-0286-z) contains supplementary material, which is available to authorized users.

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“…The genes encoding the subtilase cytotoxin (SubAB) are present in various Shiga toxin-producing Escherichia coli (STEC) strains [1][2][3]. SubAB was originally found and characterized in the E. coli O113:H21 strain 98NK2, which was isolated from a patient suffering from hemolytic uremic syndrome (HUS) [4,5].…”

Section: Introductionmentioning

confidence: 99%

“…Several virulence profiling studies showed that subAB genes are often present in sheep and wild ruminant STEC isolates. [3,6,7]. In addition, such STEC did not contain the locus of enterocyte effacement (LEE) [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Variants of Escherichia coli Subtilase Cytotoxin Subunits Show Differences in Complex Formation In Vitro

Krause

Sessler

Kaziales

et al. 2019

Toxins

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The subtilase cytotoxin (SubAB) of Shiga toxin-producing Escherichia coli (STEC) is a member of the AB5 toxin family. In the current study, we analyzed the formation of active homo- and hetero-complexes of SubAB variants in vitro to characterize the mode of assembly of the subunits. Recombinant SubA1-His, SubB1-His, SubA2-2-His, and SubB2-2-His subunits, and His-tag-free SubA2-2 were separately expressed, purified, and biochemically characterized by circular dichroism (CD) spectroscopy, size-exclusion chromatography (SEC), and analytical ultracentrifugation (aUC). To confirm their biological activity, cytotoxicity assays were performed with HeLa cells. The formation of AB5 complexes was investigated with aUC and isothermal titration calorimetry (ITC). Binding of SubAB2-2-His to HeLa cells was characterized with flow cytometry (FACS). Cytotoxicity experiments revealed that the analyzed recombinant subtilase subunits were biochemically functional and capable of intoxicating HeLa cells. Inhibition of cytotoxicity by Brefeldin A demonstrated that the cleavage is specific. All His-tagged subunits, as well as the non-tagged SubA2-2 subunit, showed the expected secondary structural compositions and oligomerization. Whereas SubAB1-His complexes could be reconstituted in solution, and revealed a Kd value of 3.9 ± 0.8 μmol/L in the lower micromolar range, only transient interactions were observed for the subunits of SubAB2-2-His in solution, which did not result in any binding constant when analyzed with ITC. Additional studies on the binding characteristics of SubAB2-2-His on HeLa cells revealed that the formation of transient complexes improved binding to the target cells. Conclusively, we hypothesize that SubAB variants exhibit different characteristics in their binding behavior to their target cells.

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Characteristics of Shiga Toxin–Producing Escherichia coli O157 in Slaughtered Reindeer from Northern Finland

Cited by 6 publications

References 35 publications

Toxins of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli

Toxins of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli

Is transport distance correlated with animal welfare and carcass quality of reindeer (Rangifer tarandus tarandus)?

Variants of Escherichia coli Subtilase Cytotoxin Subunits Show Differences in Complex Formation In Vitro

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