scholarly journals Comparison between human and animal isolates of Shiga toxin-producing Escherichia coli O157 from Australia

2002 ◽  
Vol 128 (3) ◽  
pp. 357-362 ◽  
Author(s):  
N. FEGAN ◽  
P. DESMARCHELIER
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Human Infection ◽  
Pulsed Field Gel Electrophoresis ◽  
Toxin Gene ◽  
Escherichia Coli O157 ◽  
Animal Population ◽  
E Coli ◽  
Virulence Markers ◽  
Animal Isolates

There is very little human disease associated with enterohaemorrhagic Escherichia coli O157 in Australia even though these organisms are present in the animal population. A group of Australian isolates of E. coli O157:H7 and O157:H- from human and animal sources were tested for the presence of virulence markers and compared by XbaI DNA macrorestriction analysis using pulsed-field gel electrophoresis (PFGE). Each of 102 isolates tested contained the gene eae which encodes the E. coli attaching and effacing factor and all but one carried the enterohaemolysin gene, ehxA, found on the EHEC plasmid. The most common Shiga toxin gene carried was stx2c, either alone (16%) or in combination with stx1 (74%) or stx2 (3%). PFGE grouped the isolates based on H serotype and some clusters were source specific. Australian E. coli O157:H7 and H- isolates from human, animal and meat sources carry all the virulence markers associated with EHEC disease in humans therefore other factors must be responsible for the low rates of human infection in Australia.

scholarly journals Molecular analysis of Escherichia coli O157 strains isolated from cattle and pigs by the use of PCR and pulsed-field gel electrophoresis methods

2012 ◽  
Vol 47 (No. 6) ◽  
pp. 149-158 ◽  
Author(s):  
J. Osek ◽  
P. Gallien
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Genetic Relatedness ◽  
Rflp Analysis ◽  
Toxin Gene ◽  
Escherichia Coli O157 ◽  
Chromosomal Dna ◽  
E Coli ◽  
Shiga Toxin Genes ◽  
Porcine Origin

Fourteen Escherichia coli O157 strains isolated from cattle and pigs in Poland and in Germany were investigated, using PCR, for the genetic markers associated with Shiga toxin-producing E. coli (STEC). Only two strains, both of cattle origin, were positive for the fliC (H7) gene and could be classified as O157 : H7. Nine isolates had stx shiga toxin genes, either stx1 (1 strain), stx2 (4 isolates) or both (4 strains). The stx2-carrying samples were further subtyped by PCR for the stx2c, stx2d, and stx2e toxin variants. It was shown that all but one stx2-positive bacteria possessed the stx2c Shiga toxin gene type and one stx2 STEC isolate had the stx2d virulence factor sub-type. The eaeA (intimin) gene was found in 9 strains (8 isolates from cattle and one strain from pigs); all of them harboured the genetic marker characteristic of the gamma intimin variant. The translocated intimin receptor (tir) gene was detected in 7 isolates tested and among them only one tir-positive strain was recovered from pigs. The ehly E. coli enterohemolysin gene was amplified in all but one strains obtained from cattle and only in one isolate of porcine origin. The genetic relatedness of the analysed E. coli O157 strains was examined by restriction fragment length polymorphism (RFLP) of chromosomal DNA digested with XbaI. Two distinct but related RFLP pattern clusters were observed: one with 9 strains (8 isolates of bovine origin and one strain obtained from pigs) and the other one comprises the remaining 5 E. coli isolates (4 of porcine origin and one strain recovered from cattle). The results suggest that pigs, besides cattle, may be a reservoir of E. coli O157 strains potentially pathogenic to humans. Moreover, epidemiologically unrelated isolates of the O157 serogroup, recovered from different animal species, showed a clonal relationship as demonstrated by the RFLP analysis.

scholarly journals Shiga Toxin Gene Loss and Transfer In Vitro and In Vivo during Enterohemorrhagic Escherichia coli O26 Infection in Humans

2007 ◽  
Vol 73 (10) ◽  
pp. 3144-3150 ◽  
Author(s):  
Martina Bielaszewska ◽  
Rita Prager ◽  
Robin Köck ◽  
Alexander Mellmann ◽  
Wenlan Zhang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Gene Loss ◽  
Pulsed Field Gel Electrophoresis ◽  
Enterohemorrhagic Escherichia Coli ◽  
Toxin Gene ◽  
Shiga Toxins ◽  
E Coli

ABSTRACT Escherichia coli serogroup O26 consists of enterohemorrhagic E. coli (EHEC) and atypical enteropathogenic E. coli (aEPEC). The former produces Shiga toxins (Stx), major determinants of EHEC pathogenicity, encoded by bacteriophages; the latter is Stx negative. We have isolated EHEC O26 from patient stools early in illness and aEPEC O26 from stools later in illness, and vice versa. Intrapatient EHEC and aEPEC isolates had quite similar pulsed-field gel electrophoresis (PFGE) patterns, suggesting that they might have arisen by conversion between the EHEC and aEPEC pathotypes during infection. To test this hypothesis, we asked whether EHEC O26 can lose stx genes and whether aEPEC O26 can be lysogenized with Stx-encoding phages from EHEC O26 in vitro. The stx 2 loss associated with the loss of Stx2-encoding phages occurred in 10% to 14% of colonies tested. Conversely, Stx2- and, to a lesser extent, Stx1-encoding bacteriophages from EHEC O26 lysogenized aEPEC O26 isolates, converting them to EHEC strains. In the lysogens and EHEC O26 donors, Stx2-converting bacteriophages integrated in yecE or wrbA. The loss and gain of Stx-converting bacteriophages diversifies PFGE patterns; this parallels findings of similar but not identical PFGE patterns in the intrapatient EHEC and aEPEC O26 isolates. EHEC O26 and aEPEC O26 thus exist as a dynamic system whose members undergo ephemeral interconversions via loss and gain of Stx-encoding phages to yield different pathotypes. The suggested occurrence of this process in the human intestine has diagnostic, clinical, epidemiological, and evolutionary implications.

Pulsed-Field Gel Electrophoresis Characterization of Shiga Toxin–Producing Escherichia coli O157 from Hides of Cattle at Slaughter

2002 ◽  
Vol 65 (7) ◽  
pp. 1172-1176 ◽  
Author(s):  
S. M. AVERY ◽  
A. SMALL ◽  
C.-A. REID ◽  
S. BUNCIC
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Gel Electrophoresis ◽  
Immunomagnetic Separation ◽  
Pulsed Field Gel Electrophoresis ◽  
Escherichia Coli O157 ◽  
Adult Cattle ◽  
Pulsed Field ◽  
E Coli ◽  
High Prevalence

Contamination of the brisket areas of the hides of healthy adult cattle with Shiga toxin–producing Escherichia coli O157 at slaughter in England was studied. In total, 73 cattle consignments comprising 584 animals delivered to one abattoir over 3 days during 1 week in July 2001 were studied: 26 cattle consignments arriving on Monday, 32 consignments arriving on Wednesday, and 15 consignments arriving on Friday. Consignment sizes ranged from 1 to 23 animals, with a mean consignment size of 8. The hide of the first animal to be slaughtered in each consignment was sampled by using a sponge swab moistened with 0.85% saline to rub an unmeasured brisket (ventral) area (ca. 30 by 30 cm). The process of isolating E. coli O157 from the swabs consisted of enrichment, screening with immunoprecipitation assay kits, and immunomagnetic separation. E. coli O157 was found on 24 of 73 (32.9%) cattle hides examined, and 21 of these 24 isolates produced Shiga toxins. The 24 E. coli O157 isolates produced six different pulsed-field gel electrophoresis profiles, and 18 (75%) of the isolates were of one prevalent clone. The high prevalence of one E. coli O157 clone on the hides of cattle at slaughter could be due to a high prevalence of that clone on the 18 farms involved (not investigated in the current study), in the postfarm transport or lairage environments, or both. Since the lairage environment, but not the farm of origin or the postfarm transport vehicle, was a factor common to all 18 cattle consignments, it could have played an important role in spreading the prevalent E. coli O157 clone to the cattle hides. Lairage pen floors and the stunning box floor were identified as the most probable sites along the unloading-to-slaughter route at which the brisket areas of cattle hides could become contaminated.

Prevalence and Characterization of Escherichia coli O157:H7 on Pork Carcasses and in Swine Colon Contents from Provincially Licensed Abattoirs in Alberta, Canada

2020 ◽  
Vol 83 (11) ◽  
pp. 1909-1917
Author(s):  
SAIDA ESSENDOUBI ◽  
XIANQIN YANG ◽  
ROBIN KING ◽  
JULIA KEENLISIDE ◽  
JAVIER BAHAMON ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Gel Electrophoresis ◽  
Mean Value ◽  
Pulsed Field Gel Electrophoresis ◽  
Escherichia Coli O157 ◽  
Pulsed Field ◽  
E Coli ◽  
Swine Farms

ABSTRACT The objective of this study was to determine the prevalence of Shiga toxin–producing Escherichia coli (STEC) O157:H7 in colon contents and on carcasses from pigs slaughtered at provincially licensed abattoirs (PLAs) in Alberta, Canada. In 2017, carcass sponge samples and colon content samples were collected from 504 healthy market hogs at 39 PLAs and analyzed for E. coli O157:H7. Carcass samples were also analyzed for E. coli and aerobic colony count (ACC). Nine (1.8%) of 504 carcass samples were confirmed positive for E. coli O157:H7. Seven (1.4%) of 504 colon content samples were confirmed positive for E. coli O157:H7. These positives were found in 5 (12.8%) of 39 PLAs from hogs originating from eight farms. The E. coli O157:H7 isolates recovered from the positive samples (n = 1 isolate per sample) were clonal, as determined by pulsed-field gel electrophoresis. Six E. coli O157:H7 isolates obtained over 8 months from one PLA that only processed hogs and sourced hogs from one farm had indistinguishable pulsed-field gel electrophoresis patterns. All 16 E. coli O157:H7 isolates harbored eae and ehxA and were of stx2a subtype, suggesting that swine can carry E. coli O157:H7 of importance to human health. All carcass sponge swabs (100%) were positive for ACC. E. coli was present in 72% of carcass swabs. Carcasses from PLAs slaughtering both beef and hogs had a numerically higher ACC mean value but not statistically different compared with the carcasses from PLAs slaughtering only swine (2,799 and 610 CFU/cm2, respectively). E. coli showed a similar trend with a mean value of 0.88 CFU/cm2 in PLAs slaughtering both species and 0.26 CFU/cm2 in PLAs slaughtering only swine (P ≤ 0.05). This study provides evidence that healthy market hogs from different producers and farms in Alberta can carry E. coli O157:H7, and some strains of the organism may be able to establish persistence on some swine farms. HIGHLIGHTS

Association of Prophage Antiterminator Q Alleles and Susceptibility to Food-Processing Treatments Applied to Escherichia coli O157 in Laboratory Media

2007 ◽  
Vol 70 (11) ◽  
pp. 2617-2619 ◽  
Author(s):  
AARON S. MALONE ◽  
AHMED E. YOUSEF ◽  
JEFFREY T. LEJEUNE
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Food Processing ◽  
High Pressure Processing ◽  
Toxin Gene ◽  
Escherichia Coli O157 ◽  
Surrogate Markers ◽  
Processing Efficiency ◽  
E Coli ◽  
Q Gene

Resistance of Escherichia coli O157 to inactivation by high-pressure processing, heat, and UV and gamma radiation was associated with the allele of the prophage-encoded antiterminator Q gene present upstream of the Shiga toxin gene stx2. Increased processing may be required to kill certain strains of E. coli O157, and the choice of strains used as surrogate markers for processing efficiency is critical.

scholarly journals Pathogenic Potential of Emergent Sorbitol-Fermenting Escherichia coli O157:NM

2008 ◽  
Vol 76 (12) ◽  
pp. 5598-5607 ◽  
Author(s):  
Tracy Rosser ◽  
Tracy Dransfield ◽  
Lesley Allison ◽  
Mary Hanson ◽  
Nicola Holden ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Human Infection ◽  
Escherichia Coli O157 ◽  
Pathogenic Potential ◽  
E Coli ◽  
Toxin Exposure ◽  
Uremic Syndrome ◽  
Human Infections ◽  
Main Factor

ABSTRACT Non-sorbitol-fermenting (NSF) Escherichia coli O157:H7 is the primary Shiga toxin-producing E. coli (STEC) serotype associated with human infection. Since 1988, sorbitol-fermenting (SF) STEC O157:NM strains have emerged and have been associated with a higher incidence of progression to hemolytic-uremic syndrome (HUS) than NSF STEC O157:H7. This study investigated bacterial factors that may account for the increased pathogenic potential of SF STEC O157:NM. While no evidence of toxin or toxin expression differences between the two O157 groups was found, the SF STEC O157:NM strains adhered at significantly higher levels to a human colonic cell line. Under the conditions tested, curli were shown to be the main factor responsible for the increased adherence to Caco-2 cells. Notably, 52 of 66 (79%) European SF STEC O157:NM strains tested bound Congo red at 37οC and this correlated with curli expression. In a subset of strains, curli expression was due to increased expression from the csgBAC promoter that was not always a consequence of increased csgD expression. The capacity of SF STEC O157:NM strains to express curli at 37οC may have relevance to the epidemiology of human infections as curliated strains could promote higher levels of colonization and inflammation in the human intestine. In turn, this could lead to increased toxin exposure and an increased likelihood of progression to HUS.

scholarly journals Molecular Analysis of Virulence Profiles and Shiga Toxin Genes in Food-Borne Shiga Toxin-Producing Escherichia coli

2009 ◽  
Vol 75 (19) ◽  
pp. 6187-6197 ◽  
Author(s):  
T. Slanec ◽  
A. Fruth ◽  
K. Creuzburg ◽  
H. Schmidt
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Virulence Factors ◽  
Shiga Toxin ◽  
Human Infection ◽  
E Coli ◽  
Virulence Markers ◽  
Food Borne ◽  
Shiga Toxin Genes ◽  
Virulence Spectrum

ABSTRACT In this study, 75 Shiga toxin (Stx)-producing Escherichia coli (STEC) strains originating from foods (n = 73) and drinking water (n = 2) were analyzed for their stx genotype, as well as for further chromosome-, phage-, and plasmid-encoded virulence factors. A broad spectrum of stx genes was detected. Fifty-three strains (70.7%) contained stx 2 or stx 2 variants, including stx 2d, mucus-activatable stx 2d, stx 2e, and stx 2g. Seven strains (9.3%) harbored stx 1 or stx 1c, and 15 strains (20.0%) carried both stx 2 and/or stx 2 variants and stx 1 or stx 1c. Beside stx, the most abundant accessory virulence markers in STEC food isolates were iha (57.3%), ehxA (40.0%), espP (28.0%), and subAB (25.3%). Only four strains were eae positive; three of these belonged to the serogroups O26, O103, and O157 and contained a typical enterohemorrhagic E. coli virulence spectrum. The results of this study show that a number of STEC strains that occur in foods appear to be pathogenic for humans, based on their virulence profiles. Analysis of stx subtypes and detection of additional virulence factors in eae-negative strains may help to better assess the risk of such strains for causing human infection.

scholarly journals Molecular typing of Escherichia coli O157[ratio ]H7 (H−) isolates from cattle in Japan

1999 ◽  
Vol 122 (2) ◽  
pp. 337-341 ◽  
Author(s):  
M. AKIBA ◽  
T. MASUDA ◽  
T. SAMESHIMA ◽  
K. KATSUDA ◽  
M. NAKAZAWA
Keyword(s):  
Escherichia Coli ◽  
Molecular Typing ◽  
Gel Electrophoresis ◽  
Pulsed Field Gel Electrophoresis ◽  
Escherichia Coli O157 ◽  
Outbreak Strain ◽  
Pulsed Field ◽  
E Coli ◽  
Biological Methods ◽  
Pfge Profiles

A total of 77 Escherichia coli O157[ratio ]H7 (H−) isolates from cattle in Japan were investigated by molecular biological methods. Most of these isolates (43 isolates) possessed the stx2 gene, but not stx1. Fifteen bacteriophage types and 50 pulsed-field gel electrophoresis (PFGE) profiles were observed. One isolate was indistinguishable from the human outbreak strain by these methods. This indicates that cattle must be considered as a possible source of human E. coli O157[ratio ]H7 infection in Japan.

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