Characterization of Escherichia coli O157:H7 and other Shiga toxin-producing E. coli serotypes isolated from sheep.

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

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Characterization of 4 T1-like lytic bacteriophages that lyse Shiga-toxin Escherichia coli O157:H7

Canadian Journal of Microbiology ◽

10.1139/w2012-063 ◽

2012 ◽

Vol 58 (7) ◽

pp. 923-927 ◽

Cited By ~ 14

Author(s):

Yan D. Niu ◽

Kim Stanford ◽

Hans-W. Ackermann ◽

Tim A. McAllister

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Enzyme Digestion ◽

Average Multiplicity ◽

Restriction Enzyme Digestion ◽

Escherichia Coli O157 ◽

Fecal Shedding ◽

E Coli ◽

Phage Types

Bacteriophages are associated with reduced fecal shedding of Shiga-toxin-producing Escherichia coli O157:H7 (STEC O157:H7) in cattle. Four phages exhibiting activity against 12 of 14 STEC O157:H7 strains, representing 11 common phage types, were isolated. Phages did not lyse non-O157 E. coli, with 11 of the 12 STEC strains exhibiting extreme susceptibility (average multiplicity of infection (MOI) = 0.0003−0.0007). All phages had icosahedral heads with tapered, noncontractile tails, a morphology indicative of T1-like Siphoviridae. Genome size of all phages was ∼44 kb, but EcoRІ or HindIII digestion profiles differed among phages. Based on restriction enzyme digestion profiles, phages AHP24, AHS24, and AHP42 were more related (66.7%−82.4%) to each other than to AKS96, while AHP24 and AHS24, isolated from the same feedlot pen, exhibited the highest identity (88.9%−92.3%). Phages AHP24 and AHS24 exhibited the broadest host range and strongest lytic activity against STEC O157:H7, making them strong candidates for biocontrol of this bacterium in cattle.

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Molecular Characterization of Escherichia coli O157:H7 and non-O157 Shiga Toxin Producing E. coli from Retail Meat and Humans

Zagazig Veterinary Journal ◽

10.21608/zvjz.2017.7950 ◽

2017 ◽

Vol 45 (3) ◽

pp. 250-261 ◽

Cited By ~ 1

Author(s):

Heba Ahmed ◽

Ewan MacLeod ◽

Rasha El Bayomi ◽

Rasha Mohsen ◽

Arwa Nassar

Keyword(s):

Escherichia Coli ◽

Molecular Characterization ◽

Shiga Toxin ◽

Escherichia Coli O157 ◽

E Coli ◽

Retail Meat

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

Epidemiology and Infection ◽

10.1017/s0950268801006689 ◽

2002 ◽

Vol 128 (3) ◽

pp. 357-362 ◽

Cited By ~ 17

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.

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Prevalence of shiga toxin-producing Escherichia coli O157, O26 and O111 in milk, meat and faeces of cattle, sheep and pigs slaughtered in Benin

Journal of Applied Biosciences ◽

10.35759/jabs.152.6 ◽

2020 ◽

Vol 152 ◽

pp. 15667-15675

Author(s):

Chakirath Folakè Arikè Salifou ◽

Cyrille Boko ◽

Isidore Houaga ◽

Raoul Agossa ◽

Isabelle Ogbankotan ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Virulence Genes ◽

Animal Origin ◽

Escherichia Coli O157 ◽

E Coli ◽

Milk Samples ◽

Food Of Animal Origin ◽

Cattle Faeces ◽

Risk Assessment And Management

Objectives: The study aimed to search for E. coli O157 and non-O157 in milk, meat and faeces of cattle, sheep and pigs slaughtered in Cotonou. Methodology and Results: One hundred and Seventy-Five (175) samples including 25 meat, 25 faeces per species and 25 milk from cattle were analysed for E. coli O157; O26 and O111 and the virulence genes were identified by PCR. The SAS software (1998) and the bilateral Z test were used to calculate and compare the identification frequencies. E. coli O157 was identified in 4% of cattle faeces, 4% of sheep faeces, and 20% of beef and, in 20% of milk samples. E. coli O26 was identified in 12% of cattle faeces and, in 8% of beef samples. E. coli O111 was identified at frequencies of 8%, and 12% in faeces of sheep and pigs, respectively. The eae gene was detected in 4% of beef, ovine meat, milk, pig faeces and in sheep faeces. stx1 was detected in 8% of milk, and in 4% of bovine and sheep faeces. The strains possessing the gene were all of E. coli O157 with the exception of one from pig faeces identified as O111. Conclusions and application of findings: The presence of these serogroups of E. coli with virulence genes poses a real food safety problem in Benin. This study findings must be taken into account for risk assessment and management related to the consumption of food of animal origin. Keywords: Benin, E. coli O157, O26, O111, faeces, meat, milk

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Simultaneous Enrichment of Shiga Toxin–Producing Escherichia coli O157 and O26 and Salmonella in Food Samples Using Universal Preenrichment Broth

Journal of Food Protection ◽

10.4315/0362-028x-72.10.2065 ◽

2009 ◽

Vol 72 (10) ◽

pp. 2065-2070 ◽

Cited By ~ 8

Author(s):

MASASHI KANKI ◽

KAZUKO SETO ◽

JUNKO SAKATA ◽

TETSUYA HARADA ◽

YUKO KUMEDA

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Food Samples ◽

Escherichia Coli O157 ◽

E Coli ◽

Significant Difference ◽

Peptone Water ◽

Radish Sprouts ◽

Pork Samples ◽

Better Than

Universal preenrichment broth (UPB) was compared with modified Escherichia coli broth with novobiocin (mEC+n) for enrichment of Shiga toxin–producing E. coli O157 and O26, and with buffered peptone water (BPW) for preenrichment of Salmonella enterica. Ten strains each of the three pathogens were inoculated into beef and radish sprouts following thermal, freezing, or no treatment. With regard to O157 and O26, UPB incubated at 42°C recovered significantly more cells from inoculated beef than UPB at 35°C and from radish sprout samples than UPB at 35°C and mEC+n. With regard to Salmonella, UPB incubated at 42°C was as effective as UPB at 35°C and BPW at recovering cells from beef and radish sprout samples. No significant difference was noted between the effectiveness of UPB at 42°C and UPB at 35°C or BPW in the recovery of Salmonella from 205 naturally contaminated poultry samples. By using UPB at 42°C, one O157:H7 strain was isolated from the mixed offal of 53 beef samples, 6 cattle offal samples, and 50 pork samples all contaminated naturally, with no pathogen inoculation. The present study found that UPB incubated at 42°C was as effective as, or better than, mEC+n for enrichment of O157 and O26 and comparable to BPW for preenrichment of Salmonella. These findings suggest that a great deal of labor, time, samples, and space may be saved if O157, O26, and Salmonella are enriched simultaneously with UPB at 42°C.

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

Veterinární Medicína ◽

10.17221/5819-vetmed ◽

2012 ◽

Vol 47 (No. 6) ◽

pp. 149-158 ◽

Cited By ~ 15

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.

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How Does Escherichia coli O157:H7 Testing in Meat Compare with What We Are Seeing Clinically?

Journal of Food Protection ◽

10.4315/0362-028x-63.6.819 ◽

2000 ◽

Vol 63 (6) ◽

pp. 819-821 ◽

Cited By ~ 26

Author(s):

DAVID W. K. ACHESON

Keyword(s):

United States ◽

Escherichia Coli ◽

Shiga Toxin ◽

Food Supply ◽

The United States ◽

Escherichia Coli O157 ◽

Current Policy ◽

E Coli ◽

Different Types ◽

Uremic Syndrome

Escherichia coli O157:H7 is but one of a group of Shiga toxin-producing E. coli (STEC) that cause both intestinal disease such as bloody and nonbloody diarrhea and serious complications like hemolytic uremic syndrome (HUS). While E. coli O157: H7 is the most renowned STEC, over 200 different types of STEC have been documented in meat and animals, at least 60 of which have been linked with human disease. A number of studies have suggested that non-O157 STEC are associated with clinical disease, and non-O157 STEC are present in the food supply. Non-O157 STEC, such as O111 have caused large outbreaks and HUS in the United States and other countries. The current policy in the United States is to examine ground beef for O157:H7 only, but restricting the focus to O157 will miss other important human STEC pathogens.

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Iha: a Novel Escherichia coli O157:H7 Adherence-Conferring Molecule Encoded on a Recently Acquired Chromosomal Island of Conserved Structure

Infection and Immunity ◽

10.1128/iai.68.3.1400-1407.2000 ◽

2000 ◽

Vol 68 (3) ◽

pp. 1400-1407 ◽

Cited By ~ 229

Author(s):

Phillip I. Tarr ◽

Sima S. Bilge ◽

James C. Vary ◽

Srdjan Jelacic ◽

Rebecca L. Habeeb ◽

...

Keyword(s):

Escherichia Coli ◽

Epithelial Cells ◽

Vibrio Cholerae ◽

Shiga Toxin ◽

Escherichia Coli O157 ◽

Chromosomal Gene ◽

Gene Encoding ◽

Tellurite Resistance ◽

E Coli ◽

Dna Library

ABSTRACT The mechanisms used by Shiga toxin (Stx)-producingEscherichia coli to adhere to epithelial cells are incompletely understood. Two cosmids from an E. coliO157:H7 DNA library contain an adherence-conferring chromosomal gene encoding a protein similar to iron-regulated gene A (IrgA) ofVibrio cholerae (M. B. Goldberg, S. A. Boyko, J. R. Butterton, J. A. Stoebner, S. M. Payne, and S. B. Calderwood, Mol. Microbiol. 6:2407–2418, 1992). We have termed the product of this gene the IrgA homologue adhesin (Iha), which is encoded by iha. Iha is 67 kDa in E. coliO157:H7 and 78 kDa in laboratory E. coli and is structurally unlike other known adhesins. DNA adjacent toiha contains tellurite resistance loci and is conserved in structure in distantly related pathogenic E. coli, but it is absent from nontoxigenic E. coli O55:H7, sorbitol-fermenting Stx-producing E. coli O157:H−, and laboratory E. coli. We have termed this region the tellurite resistance- and adherence-conferring island. We conclude that Iha is a novel bacterial adherence-conferring protein and is contained within an E. coli chromosomal island of conserved structure. Pathogenic E. coli O157:H7 has only recently acquired this island.

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Occurrence and Characterization of Escherichia coli O157 and Other Serotypes in Raw Meat Products in Morocco

Journal of Food Protection ◽

10.4315/0362-028x-71.10.2082 ◽

2008 ◽

Vol 71 (10) ◽

pp. 2082-2086 ◽

Cited By ~ 5

Author(s):

LUCIANO BENEDUCE ◽

GIUSEPPE SPANO ◽

ARI Q. NABI ◽

FRANCESCO LAMACCHIA ◽

SALVATORE MASSA ◽

...

Keyword(s):

Escherichia Coli ◽

Susceptibility Testing ◽

Meat Products ◽

Molecular Techniques ◽

Escherichia Coli O157 ◽

Raw Meat ◽

E Coli ◽

Meat Samples ◽

The City

In this study, 100 raw meat samples were collected from 15 local Moroccan butcheries in five different areas of the city of Rabat during a period of 4 months. Overall, 7 of 15 butcheries from three areas of the city yielded strains of Escherichia coli O157. Single isolates from 9 (9%) of 100 raw meat samples were biochemically and serologically confirmed as E. coli O157. Using molecular techniques, two strains were positive for the Shiga toxin, with two additional strains containing an attaching-effacing gene. All potentially virulent serotypes isolated from these meat samples showed distinct pulsed-field gel electrophoresis profiles. Based on antibiotic susceptibility testing, more than 70% of the isolates were resistant to ampicillin and clavulanic acid–amoxicillin. Moreover, one strain was resistant to more than three antibiotics. Our study represents the first survey of E. coli O157 and related serotypes in raw meat products in Morocco.

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