Dataset Information

Genomic analysis of Shiga toxin-producing Escherichia coli O157:H7 from cattle and pork-production related environments.

ABSTRACT: Three E. coli O157:H7 outbreaks have been attributed to contaminated pork in Alberta, Canada, recently. This study investigates the phylogenetic relatedness of E. coli O157:H7 from pigs, cattle, and pork-production environments for source attribution. Limited strain diversity was observed using five conventional subtyping methods, with most or all strains being in one subgroup. Whole-genome single nucleotide polymorphism analysis confirmed the recent ancestry of the isolates from all three sources. Most environmental isolates clustered closer with pig isolates than cattle isolates. Also, a direct link was observed between 2018-outbreak environmental isolates and isolates collected from a pig farm in 2018. The majority of pig isolates harbor only one Shiga toxin gene, stx_2a, while 70% (35/50) of the cattle isolates have both stx_1a and stx_2a. The results show some E. coli O157:H7 strains could establish persistence on pig farms and as such, pigs can be a significant source of the organism.

SUBMITTER: Zhang P

PROVIDER: S-EPMC8249597 | biostudies-literature | 2021 Jul

REPOSITORIES: biostudies-literature

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Genomic analysis of Shiga toxin-producing Escherichia coli O157:H7 from cattle and pork-production related environments.

Zhang Peipei P Essendoubi Saida S Keenliside Julia J Reuter Tim T Stanford Kim K King Robin R Lu Patricia P Yang Xianqin X

NPJ science of food 20210701 1

Three E. coli O157:H7 outbreaks have been attributed to contaminated pork in Alberta, Canada, recently. This study investigates the phylogenetic relatedness of E. coli O157:H7 from pigs, cattle, and pork-production environments for source attribution. Limited strain diversity was observed using five conventional subtyping methods, with most or all strains being in one subgroup. Whole-genome single nucleotide polymorphism analysis confirmed the recent ancestry of the isolates from all three sourc ...[more]

PMID: 34210979

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Project description:Cattle are the main reservoir of Enterohemorrhagic Escherichia coli (EHEC), with O157:H7 the distinctive serotype. EHEC is the main causative agent of a severe systemic disease, Hemolytic Uremic Syndrome (HUS). Argentina has the highest pediatric HUS incidence worldwide with 12-14 cases per 100,000 children. Herein, we assessed the genomes of EHEC O157:H7 isolates recovered from cattle in the humid Pampas of Argentina. According to phylogenetic studies, EHEC O157 can be divided into clades. Clade 8 strains that were classified as hypervirulent. Most of the strains of this clade have a Shiga toxin stx2a-stx2c genotype. To better understand the molecular bases related to virulence, pathogenicity and evolution of EHEC O157:H7, we performed a comparative genomic analysis of these isolates through whole genome sequencing. The isolates classified as clade 8 (four strains) and clade 6 (four strains) contained 13 to 16 lambdoid prophages per genome, and the observed variability of prophages was analysed. An inter strain comparison show that while some prophages are highly related and can be grouped into families, other are unique. Prophages encoding for stx2a were highly diverse, while those encoding for stx2c were conserved. A cluster of genes exclusively found in clade 8 contained 13 genes that mostly encoded for DNA binding proteins. In the studied strains, polymorphisms in Q antiterminator, the Q-stx2A intergenic region and the O and P γ alleles of prophage replication proteins are associated with different levels of Stx2a production. As expected, all strains had the pO157 plasmid that was highly conserved, although one strain displayed a transposon interruption in the protease EspP gene. This genomic analysis may contribute to the understanding of the genetic basis of the hypervirulence of EHEC O157:H7 strains circulating in Argentine cattle. This work aligns with other studies of O157 strain variation in other populations that shows key differences in Stx2a-encoding prophages.

Project description:BackgroundShiga toxin-producing Escherichia coli O157:H7 (STEC O157:H7) is a zoonotic pathogen that causes diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome worldwide. This study aimed to determine the prevalence, antibiotic susceptibility, and associated risk factors of STEC O157:H7 among diarrheic patients and their cattle.MethodsA cross-sectional study was conducted among diarrheic patients and their cattle in Amhara National Regional State, Ethiopia from December- 2020 to June- 2022. A total of 1,149 diarrheic patients and 229 cattle were included in the study. STEC O157:H7 detection was done using culture, latex agglutination test, and polymerase chain reaction on diarrheic stool samples and recto-anal mucosal swabs of cattle. Antibiotic susceptibility tests were performed using disk diffusion techniques. Risk factors association were identified using binary and multivariable logistic regression analysis.ResultsThe overall prevalence of STEC O157:H7 in diarrheic patients and their cattle was 11.1% (128/1149) and 14.4% (33/229) respectively. High percentage of the study subjects were found in under-five children (34.5%). Age less than 5 (AOR: 4.02, 95%CI:1.608-10.058,P = 0.003), and greater than 64 years old (AOR:3.36, 95% CI:1.254-8.986, P = 0.016), presence of diarrheic patient in the house (AOR:2.11, 95%CI:1.309-3.390, P = 0.002), availability of cattle in the house (AOR:2.52, 95%CI:1.261-5.049, P = 0.009), and habit of consuming raw foods (AOR:4.35, 95%CI:2.645-7.148, P = 0.000) were risk factors. Antibiotic resistance was shown in 109(85.2%), and 31(93.9%) isolates from diarrheic patients and their cattle respectively. The highest levels of antibiotic resistance were found to tetracycline (54.7%, 69.7%) in diarrheic patients and their cattle respectively. Multiple drug resistance was also observed among 56(43.8%) and 11(33.3%) isolates in diarrheic patients and their cattle respectively.ConclusionOur study showed high prevalence of STEC O157:H7 in diarrheic patients and their cattle. Therefore, health education should be given to the community on how to care for animals, proper sanitation, and the impact of raw food consumption.

Project description:Subcutaneous vaccination of cattle for enterohemorrhagic Escherichia coli O157:H7 reduces the magnitude and duration of fecal shedding, but the often-required, repeated cattle restraint can increase costs, deterring adoption by producers. In contrast, live oral vaccines may be repeatedly administered in feed, without animal restraint. We investigated whether oral immunization with live stx-negative LEE+E. coli O157:H7 reduced rectoanal junction (RAJ) colonization by wild-type (WT) E. coli O157:H7 strains after challenge. Two groups of cattle were orally dosed twice weekly for 6 weeks with 3 × 109 CFU of a pool of three stx-negative LEE+E. coli O157:H7 strains (vaccine group) or three stx-negative LEE- non-O157:H7 E. coli strains (control group). Three weeks following the final oral dose, animals in both groups were orally challenged with a cocktail of four stx+ LEE+E. coli O157:H7 WT strains. Subsequently, WT strains at the RAJ were enumerated weekly for 4 weeks. Serum antibodies against type III secretion protein (TTSP), the translocated intimin receptor (Tir), and EspA were determined by enzyme-linked immunosorbent assay (ELISA) at day 0 (preimmunization), day 61 (postimmunization, prechallenge), and day 89 (postchallenge). Vaccine group cattle had lower numbers of WT strains at the RAJ than control group cattle on postchallenge days 3 and 7 (P ≤ 0.05). Also, vaccine group cattle shed WT strains for a shorter duration than control group cattle. All cattle seroconverted to TTSP, Tir, and EspA, either following immunization (vaccine group) or following challenge (control group). Increased antibody titers against Tir and TTSP postimmunization were associated with decreased numbers of WT E. coli O157:H7 organisms at the RAJ.IMPORTANCE The bacterium E. coli O157:H7 causes foodborne disease in humans that can lead to bloody diarrhea, kidney failure, vascular damage, and death. Healthy cattle are the main source of this human pathogen. Reducing E. coli O157:H7 in cattle will reduce human disease. Using a randomized comparison, a bovine vaccine to reduce carriage of the human pathogen was tested. A detoxified E. coli O157:H7 strain, missing genes that cause disease, was fed to cattle as an oral vaccine to reduce carriage of pathogenic E. coli O157:H7. After vaccination, the cattle were challenged with disease-causing E. coli O157:H7. The vaccinated cattle had decreased E. coli O157:H7 during the first 7 days postchallenge and shed the bacteria for a shorter duration than the nonvaccinated control cattle. The results support optimization of the approach to cattle vaccination that would reduce human disease.

Dataset Information

Genomic analysis of Shiga toxin-producing Escherichia coli O157:H7 from cattle and pork-production related environments.

Publications

Genomic analysis of Shiga toxin-producing Escherichia coli O157:H7 from cattle and pork-production related environments.

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