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

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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Presence and Characterization of Shiga Toxin-Producing Escherichia coli and Other Potentially Diarrheagenic E. coli Strains in Retail Meats

Applied and Environmental Microbiology ◽

10.1128/aem.01968-09 ◽

2010 ◽

Vol 76 (6) ◽

pp. 1709-1717 ◽

Cited By ~ 39

Author(s):

Xiaodong Xia ◽

Jianghong Meng ◽

Patrick F. McDermott ◽

Sherry Ayers ◽

Karen Blickenstaff ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Ground Beef ◽

Vero Cells ◽

E Coli ◽

Retail Meats ◽

Retail Meat ◽

Human Infections ◽

Shiga Toxin Genes

ABSTRACT To determine the presence of Shiga toxin-producing Escherichia coli (STEC) and other potentially diarrheagenic E. coli strains in retail meats, 7,258 E. coli isolates collected by the U.S. National Antimicrobial Resistance Monitoring System (NARMS) retail meat program from 2002 to 2007 were screened for Shiga toxin genes. In addition, 1,275 of the E. coli isolates recovered in 2006 were examined for virulence genes specific for other diarrheagenic E. coli strains. Seventeen isolates (16 from ground beef and 1 from a pork chop) were positive for stx genes, including 5 positive for both stx 1 and stx 2, 2 positive for stx 1, and 10 positive for stx 2. The 17 STEC strains belonged to 10 serotypes: O83:H8, O8:H16, O15:H16, O15:H17, O88:H38, ONT:H51, ONT:H2, ONT:H10, ONT:H7, and ONT:H46. None of the STEC isolates contained eae, whereas seven carried enterohemorrhagic E. coli (EHEC) hlyA. All except one STEC isolate exhibited toxic effects on Vero cells. DNA sequence analysis showed that the stx 2 genes from five STEC isolates encoded mucus-activatable Stx2d. Subtyping of the 17 STEC isolates by pulsed-field gel electrophoresis (PFGE) yielded 14 distinct restriction patterns. Among the 1,275 isolates from 2006, 11 atypical enteropathogenic E. coli (EPEC) isolates were identified in addition to 3 STEC isolates. This study demonstrated that retail meats, mainly ground beef, were contaminated with diverse STEC strains. The presence of atypical EPEC strains in retail meat is also of concern due to their potential to cause human infections.

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Escherichia Coli O157:H7: Distribution, molecular characterization, antimicrobial resistance patterns and source of contamination of sheep and goat carcasses at an export Abattoir, Mojdo, Ethiopia

10.21203/rs.2.9605/v1 ◽

2019 ◽

Author(s):

Solomon Abreham ◽

Akafete Teklu ◽

Eric Cox ◽

Tesfaye Sisay Tessema

Keyword(s):

Escherichia Coli ◽

Molecular Characterization ◽

Latex Agglutination ◽

Human Infection ◽

Escherichia Coli O157 ◽

Systematic Random Sampling ◽

E Coli ◽

Source Of Infection ◽

Resistance Patterns

Abstract Background: Cattle have been identified as a major reservoir of E. coli O157:H7 for human infection; the ecology of the organism in sheep and goats is less understood. This study was carried out to determine prevalence, source of infection, antibiotic resistance and molecular characterization of Escherichia coli O157: H7 isolated from sheep and goat. Methods: Systematic random sampling was carried out at Modjo export abattoir, Ethiopia, from November 2012 to April 2013 to collect 408 samples from 72 sheep and 32 goats. Samples collected were skin swabs, fecal samples, intestinal mucosal swabs and the inside and outside part of carcasses as well as carcass in contacts such as workers hands, knife, hook and carcass washing water. Then, samples were processed following standard bacteriological procedures. Non-Sorbitol fermenting colonies were tested on latex agglutination test and the positives are subjected to PCR for detection of attaching and effacing genes (eae) and shiga toxin producing genes (stx 1 and stx 2). All E. coli O157:H7 isolates were checked for their susceptibility pattern towards 15 selected antibiotics. Results: E. coli O157:H7 were detected in only 20/408 samples (4.9%). Among these 20 positive samples, 70% (14/20), 25% (5/20) and 5% (1/20) were from sheep, goats and knife samples, respectively. No significant associations were found between carcasses and the assumed sources of contaminations. Of all the 20 isolates virulent genes were found in 10 (50%) of them; 3 (15%) with only the eaeA gene and 7(35%) expressing eaeA and stx 2 genes. All the isolates were susceptible to Norfloxacin (NOR) (100%). Conclusions: The presence of virulent genes shows E. coli O157:H7 is a potential source of human infection in Ethiopia.

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Escherichia Coli O157:H7: Distribution, molecular characterization, antimicrobial resistance patterns and source of contamination of sheep and goat carcasses at an export Abattoir, Mojdo, Ethiopia

10.21203/rs.2.9605/v2 ◽

2019 ◽

Author(s):

Solomon Abreham ◽

Akafete Teklu ◽

Eric Cox ◽

Tesfaye Sisay Tessema

Keyword(s):

Escherichia Coli ◽

Molecular Characterization ◽

Latex Agglutination ◽

Human Infection ◽

Escherichia Coli O157 ◽

Systematic Random Sampling ◽

E Coli ◽

Source Of Infection ◽

Resistance Patterns

Abstract Background: Cattle have been identified as a major reservoir of E. coli O157:H7 for human infection; the ecology of the organism in sheep and goats is less understood. This study was carried out to determine prevalence, source of infection, antibiotic resistance and molecular characterization of Escherichia coli O157: H7 isolated from sheep and goat. Methods: Systematic random sampling was carried out at Modjo export abattoir, Ethiopia, from November 2012 to April 2013 to collect 408 samples from 72 sheep and 32 goats. Samples collected were skin swabs, fecal samples, intestinal mucosal swabs and the inside and outside part of carcasses as well as carcass in contacts such as workers hands, knife, hook and carcass washing water. Then, samples were processed following standard bacteriological procedures. Non-Sorbitol fermenting colonies were tested on latex agglutination test and the positives are subjected to PCR for detection of attaching and effacing genes (eae) and shiga toxin producing genes (stx 1 and stx 2). All E. coli O157:H7 isolates were checked for their susceptibility pattern towards 15 selected antibiotics. Results: E. coli O157:H7 were detected in only 20/408 samples (4.9%). Among these 20 positive samples, 70% (14/20), 25% (5/20) and 5% (1/20) were from sheep, goats and knife samples, respectively. No significant associations were found between carcasses and the assumed sources of contaminations. Of all the 20 isolates virulent genes were found in 10 (50%) of them; 3 (15%) with only the eaeA gene and 7(35%) expressing eaeA and stx 2 genes. All the isolates were susceptible to Norfloxacin (NOR) (100%). Conclusions: The presence of virulent genes shows E. coli O157:H7 is a potential source of human infection in Ethiopia.

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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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