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Hirai S, Yokoyama E, Shiwa Y, Ishige T, Ando N, Shimizu T, Murakami S. Clarification of relationship between single-nucleotide polymorphism panels of Shiga toxin-producing Escherichia coli O157:H7/H- strains. J Vet Med Sci 2022; 84:1399-1405. [PMID: 35989264 PMCID: PMC9586023 DOI: 10.1292/jvms.22-0242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Eighty strains of enterohemorrhagic Escherichia coli O157:H7/H- were
analyzed by three single-nucleotide polymorphism (SNP) panels using whole-genome
sequencing data. The partial concordance of SNP types among the different SNP panels was
observed on minimum spanning trees reconstructed with SNP data. As for lineage I/II
strains, some of the clade 7 strains belonged to one unique SNP type as determined by
three panels, suggesting that clade 7 should be divided into at least two genotypes,
namely, the unique type and the rest. In addition, clade 8 contained two unique genotypes,
which was consistent with the previous prediction. Similarly, for lineage II, clade 12
should be divided into three genotype strains. In contrast, many strains of several clades
belonging to lineage I were clustered into the same node on each minimum spanning tree
upon testing with the three SNP panels. Previous studies reported that lineage I diverged
more recently than lineages I/II and II. Such low diversity in lineage I in this study may
have arisen because this lineage has not accumulated SNPs because of its relatively recent
divergence. Based on the concordance observed in this study, some of the previously
published O157 genotype distribution data were successfully interpreted to clarify the
clade distribution, which was well supported by previous literature.
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Affiliation(s)
- Shinichiro Hirai
- Center for Emergency Preparedness and Response, National Institute of Infectious Diseases
| | - Eiji Yokoyama
- Center for Emergency Preparedness and Response, National Institute of Infectious Diseases.,Division of Bacteriology, Chiba Prefectural Institute of Public Health
| | - Yuh Shiwa
- NODAI Genome Research Center, Tokyo University of Agriculture.,Department of Molecular Microbiology, Faculty of Life Sciences, Tokyo University of Agriculture
| | - Taichiro Ishige
- NODAI Genome Research Center, Tokyo University of Agriculture
| | - Naoshi Ando
- Division of Bacteriology, Chiba Prefectural Institute of Public Health
| | - Takeshi Shimizu
- Department of Molecular Infectiology, Graduate School of Medicine, Chiba University
| | - Satoshi Murakami
- Laboratory of Animal Health, Department of Animal Science, Tokyo University of Agriculture
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2
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Eppinger M, Almería S, Allué-Guardia A, Bagi LK, Kalalah AA, Gurtler JB, Fratamico PM. Genome Sequence Analysis and Characterization of Shiga Toxin 2 Production by Escherichia coli O157:H7 Strains Associated With a Laboratory Infection. Front Cell Infect Microbiol 2022; 12:888568. [PMID: 35770066 PMCID: PMC9234449 DOI: 10.3389/fcimb.2022.888568] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 05/03/2022] [Indexed: 11/21/2022] Open
Abstract
A laboratory-acquired E. coli O157:H7 infection with associated severe sequelae including hemolytic uremic syndrome occurred in an individual working in the laboratory with a mixture of nalidixic acid-resistant (NalR) O157:H7 mutant strains in a soil-biochar blend. The patient was hospitalized and treated with an intravenous combination of metronidazole and levofloxacin. The present study investigated the source of this severe laboratory acquired infection and further examined the influence of the antibiotics used during treatment on the expression and production of Shiga toxin. Genomes of two Stx2a-and eae-positive O157:H7 strains isolated from the patient's stool were sequenced along with two pairs of the wt strains and their derived NalR mutants used in the laboratory experiments. High-resolution SNP typing determined the strains' individual genetic relatedness and unambiguously identified the two laboratory-derived NalR mutant strains as the source of the researcher's life-threatening disease, rather than a conceivable ingestion of unrelated O157:H7 isolates circulating at the same time. It was further confirmed that in sublethal doses, the antibiotics increased toxin expression and production. Our results support a simultaneous co-infection with clinical strains in the laboratory, which were the causative agents of previous O157:H7 outbreaks, and further that the administration of antibiotics may have impacted the outcome of the infection.
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Affiliation(s)
- Mark Eppinger
- Department of Molecular Microbiology and Immunology (MMI), University of Texas at San Antonio, San Antonio, TX, United States.,South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, United States
| | - Sonia Almería
- United States (US) Department of Agriculture (USDA), Agricultural Research Service (ARS), Eastern Regional Research Center, Wyndmoor, PA, United States
| | - Anna Allué-Guardia
- Department of Molecular Microbiology and Immunology (MMI), University of Texas at San Antonio, San Antonio, TX, United States
| | - Lori K Bagi
- United States (US) Department of Agriculture (USDA), Agricultural Research Service (ARS), Eastern Regional Research Center, Wyndmoor, PA, United States
| | - Anwar A Kalalah
- Department of Molecular Microbiology and Immunology (MMI), University of Texas at San Antonio, San Antonio, TX, United States.,South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, United States
| | - Joshua B Gurtler
- United States (US) Department of Agriculture (USDA), Agricultural Research Service (ARS), Eastern Regional Research Center, Wyndmoor, PA, United States
| | - Pina M Fratamico
- United States (US) Department of Agriculture (USDA), Agricultural Research Service (ARS), Eastern Regional Research Center, Wyndmoor, PA, United States
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3
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Repeated Oral Vaccination of Cattle with Shiga Toxin-Negative Escherichia coli O157:H7 Reduces Carriage of Wild-Type E. coli O157:H7 after Challenge. Appl Environ Microbiol 2021; 87:AEM.02183-20. [PMID: 33158889 DOI: 10.1128/aem.02183-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 10/28/2020] [Indexed: 12/31/2022] Open
Abstract
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.
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Tarr GAM, Stokowski T, Shringi S, Tarr PI, Freedman SB, Oltean HN, Rabinowitz PM, Chui L. Contribution and Interaction of Shiga Toxin Genes to Escherichia coli O157:H7 Virulence. Toxins (Basel) 2019; 11:toxins11100607. [PMID: 31635282 PMCID: PMC6832461 DOI: 10.3390/toxins11100607] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 10/14/2019] [Accepted: 10/16/2019] [Indexed: 01/17/2023] Open
Abstract
Escherichia coli O157:H7 is the predominant cause of diarrhea-associated hemolytic uremic syndrome (HUS) worldwide. Its cardinal virulence traits are Shiga toxins, which are encoded by stx genes, the most common of which are stx1a, stx2a, and stx2c. The toxins these genes encode differ in their in vitro and experimental phenotypes, but the human population-level impact of these differences is poorly understood. Using Shiga toxin-encoding bacteriophage insertion typing and real-time polymerase chain reaction, we genotyped isolates from 936 E. coli O157:H7 cases and verified HUS status via chart review. We compared the HUS risk between isolates with stx2a and those with stx2a and another gene and estimated additive interaction of the stx genes. Adjusted for age and symptoms, the HUS incidence of E. coli O157:H7 containing stx2a alone was 4.4% greater (95% confidence interval (CI) −0.3%, 9.1%) than when it occurred with stx1a. When stx1a and stx2a occur together, the risk of HUS was 27.1% lower (95% CI −87.8%, −2.3%) than would be expected if interaction were not present. At the population level, temporal or geographic shifts toward these genotypes should be monitored, and stx genotype may be an important consideration in clinically predicting HUS among E. coli O157:H7 cases.
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Affiliation(s)
- Gillian A M Tarr
- Department of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, AB T3B 6A8, Canada.
| | - Taryn Stokowski
- Department of Laboratory Medicine and Pathology, University of Alberta and Alberta Public Labs, Edmonton, AB T6G 2J2, Canada.
| | - Smriti Shringi
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99163, USA.
| | - Phillip I Tarr
- Division of Gastroenterology, Hepatology, and Nutrition, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Stephen B Freedman
- Department of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, AB T3B 6A8, Canada.
| | - Hanna N Oltean
- Washington State Department of Health, Shoreline, WA 98155, USA.
| | - Peter M Rabinowitz
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195, USA.
| | - Linda Chui
- Department of Laboratory Medicine and Pathology, University of Alberta and Alberta Public Labs, Edmonton, AB T6G 2J2, Canada.
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Sharma VK, Akavaram S, Schaut RG, Bayles DO. Comparative genomics reveals structural and functional features specific to the genome of a foodborne Escherichia coli O157:H7. BMC Genomics 2019; 20:196. [PMID: 30849935 PMCID: PMC6408774 DOI: 10.1186/s12864-019-5568-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 02/25/2019] [Indexed: 01/09/2023] Open
Abstract
Background Escherichia coli O157:H7 (O157) has been linked to numerous foodborne disease outbreaks. The ability to rapidly sequence and analyze genomes is important for understanding epidemiology, virulence, survival, and evolution of outbreak strains. In the current study, we performed comparative genomics to determine structural and functional features of the genome of a foodborne O157 isolate NADC 6564 and infer its evolutionary relationship to other O157 strains. Results The chromosome of NADC 6564 contained 5466 kb compared to reference strains Sakai (5498 kb) and EDL933 (5547 kb) and shared 41 of its 43 Linear Conserved Blocks (LCB) with the reference strains. However, 18 of 41 LCB had inverse orientation in NADC 6564 compared to the reference strains. NADC 6564 shared 18 of 19 bacteriophages with reference strains except that the chromosomal positioning of some of the phages differed among these strains. The additional phage (P19) of NADC 6564 was located on a 39-kb insertion element (IE) encoding several hypothetical proteins, an integrase, transposases, transcriptional regulators, an adhesin, and a phosphoethanolamine transferase (PEA). The complete homologs of the 39-kb IE were found in E. coli PCN061 of porcine origin. The IE-encoded PEA showed low homology (32–33%) to four other PEA in NADC 6564 and PEA linked to mobilizable colistin resistance in E. coli but was highly homologous (95%) to a PEA of uropathogenic, avian pathogenic, and enteroaggregative E. coli. NADC 6564 showed slightly higher minimum inhibitory concentration of colistin compared to the reference strains. The 39-kb IE also contained dndBCDE and dptFGH operons encoding DNA S-modification and a restriction pathway, linked to oxidative stress tolerance and self-defense against foreign DNA, respectively. Evolutionary tree analysis grouped NADC 6564 with lineage I O157 strains. Conclusions These results indicated that differential phage counts and different chromosomal positioning of many bacteriophages and genomic islands might have resulted in recombination events causing altered chromosomal organization in NADC 6564. Evolutionary analysis grouped NADC 6564 with lineage I strains and suggested its earlier divergence from these strains. The ability to perform S-DNA modification might affect tolerance of NADC 6564 to various stressors. Electronic supplementary material The online version of this article (10.1186/s12864-019-5568-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Vijay K Sharma
- Food Safety and Enteric Pathogens Research Unit, USDA, ARS, National Animal Disease Center, 1920 Dayton Avenue, P.O. Box 70, Ames, IA, 50010, USA.
| | - Suryatej Akavaram
- Food Safety and Enteric Pathogens Research Unit, USDA, ARS, National Animal Disease Center, 1920 Dayton Avenue, P.O. Box 70, Ames, IA, 50010, USA
| | - Robert G Schaut
- Food Safety and Enteric Pathogens Research Unit, USDA, ARS, National Animal Disease Center, 1920 Dayton Avenue, P.O. Box 70, Ames, IA, 50010, USA.,Oak Ridge Institute for Science and Education (ORISE), ARS Research Participation Program, MS 36, P.O. Box 117, Oak Ridge, TN, 37831, USA
| | - Darrell O Bayles
- Infectious Bacterial Diseases Research Unit, National Animal Disease Center, ARS-USDA, Ames, Iowa, USA
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Tarr GAM, Shringi S, Oltean HN, Mayer J, Rabinowitz P, Wakefield J, Tarr PI, Besser TE, Phipps AI. Importance of case age in the purported association between phylogenetics and hemolytic uremic syndrome in Escherichia coli O157:H7 infections. Epidemiol Infect 2018; 146:1550-1555. [PMID: 29914582 PMCID: PMC6092231 DOI: 10.1017/s0950268818001632] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 02/13/2018] [Accepted: 05/18/2018] [Indexed: 11/05/2022] Open
Abstract
Escherichia coli O157:H7 is the largest cause of hemolytic uremic syndrome (HUS). Previous studies proposed that HUS risk varies across the E. coli O157:H7 phylogenetic tree (hypervirulent clade 8), but the role of age in the association is unknown. We determined phylogenetic lineage of E. coli O157:H7 isolates from 1160 culture-confirmed E. coli O157:H7 cases reported in Washington State, 2004-2015. Using generalised estimating equations, we tested the association between phylogenetic lineage and HUS. Age was evaluated as an effect modifier. Among 1082 E. coli O157:H7 cases with both phylogenetic lineage and HUS status (HUS n = 76), stratified analysis suggested effect modification by age. Lineages IIa and IIb, relative to Ib, did not appear associated with HUS in children 0-9-years-old. For cases 10-59-years-old, lineages IIa and IIb appeared to confer increased risk of HUS, relative to lineage Ib. The association reversed in ⩾60-year-olds. Results were similar for clade 8. Phylogenetic lineage appears to be associated with HUS risk only among those ⩾10-years-old. Among children <10, the age group most frequently affected, lineage does not explain progression to HUS. However, lineage frequency varied across age groups, suggesting differences in exposure and/or early disease manifestation.
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Affiliation(s)
- G. A. M. Tarr
- Department of Pediatrics, University of Calgary Cumming School of Medicine, Calgary, Alberta, CA
| | - S. Shringi
- Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - H. N. Oltean
- Washington State Department of Health, Shoreline, Washington, USA
| | - J. Mayer
- Department of Epidemiology, University of Washington, Seattle, Washington, USA
- Department of Geography, University of Washington, Seattle, Washington, USA
| | - P. Rabinowitz
- Department of Environmental and Occupational Health Sciences and Center for One Health Research, University of Washington, Seattle, Washington, USA
| | - J. Wakefield
- Departments of Biostatistics and Statistics, University of Washington, Seattle, Washington, USA
| | - P. I. Tarr
- Department of Pediatrics, Washington University in St. Louis School of Medicine, St. Louis, Missouri, USA
| | - T. E. Besser
- Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - A. I. Phipps
- Department of Epidemiology, University of Washington, Seattle, Washington, USA
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7
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Tarr GAM, Shringi S, Phipps AI, Besser TE, Mayer J, Oltean HN, Wakefield J, Tarr PI, Rabinowitz P. Geogenomic Segregation and Temporal Trends of Human Pathogenic Escherichia coli O157:H7, Washington, USA, 2005-2014 1. Emerg Infect Dis 2018; 24:32-39. [PMID: 29260688 PMCID: PMC5749469 DOI: 10.3201/eid2401.170851] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The often-noted and persistent increased incidence of Escherichia
coli O157:H7 infections in rural areas is not well understood. We
used a cohort of E. coli O157:H7 cases reported in Washington,
USA, during 2005–2014, along with phylogenomic characterization of the
infecting isolates, to identify geographic segregation of and temporal trends in
specific phylogenetic lineages of E. coli O157:H7. Kernel
estimation and generalized additive models demonstrated that pathogen lineages
were spatially segregated during the period of analysis and identified a focus
of segregation spanning multiple, predominantly rural, counties for each of the
main clinical lineages, Ib, IIa, and IIb. These results suggest the existence of
local reservoirs from which humans are infected. We also noted a secular
increase in the proportion of lineage IIa and IIb isolates. Spatial segregation
by phylogenetic lineage offers the potential to identify local reservoirs and
intervene to prevent continued transmission.
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8
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Pianciola L, Rivas M. Genotypic Features of Clinical and Bovine Escherichia coli O157 Strains Isolated in Countries with Different Associated-Disease Incidences. Microorganisms 2018; 6:microorganisms6020036. [PMID: 29702577 PMCID: PMC6027531 DOI: 10.3390/microorganisms6020036] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 04/20/2018] [Accepted: 04/25/2018] [Indexed: 01/19/2023] Open
Abstract
There is great geographical variation in the frequency of Escherichia coli O157 infections that correlates with important differences in the bovine reservoir of each country. Our group carried out a broad molecular characterization of human and bovine E. coli O157 strains circulating in Argentina using different methodologies. Our data allows us to conclude that in Argentina, a high homogeneity is observed in both cattle and human strains, with almost exclusive circulation of strains belonging to the hypervirulent clade 8 described by Manning. The aim of this review was to compare the genetic background of E. coli O157 strains isolated in countries that have conducted similar studies, to try to correlate specific O157 genotypes with the incidence and severity of E. coli O157 associated diseases. The characteristics of the strains that cause disease in humans reflect the predominant genotypes in cattle in each of the countries analyzed. The main features clearly linked to high incidence or severity of E. coli O157 infections are lineage-specific polymorphism assay-6 lineage I/II, clade 8 strains and probably, clade 6 strains, the stx2a/stx2c genotype, the presence of q933 and q21 simultaneously, and putative virulence factor EC_3286. In countries with an absence of these features in O157 strains, the overall incidence of O157 disease is low. Argentina, where these characteristics are detected in most strains, shows the highest incidence of hemolytic uremic syndrome (HUS) worldwide.
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Affiliation(s)
- Luis Pianciola
- Laboratorio Central, Subsecretaría de Salud de Neuquén, Gregorio Martínez 65, Neuquén 8300, Argentina.
| | - Marta Rivas
- Servicio Fisiopatogenia, INEI-ANLIS "Carlos G. Malbrán", Av. Vélez Sarsfield 563, Buenos Aires 1281, Argentina.
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Affiliation(s)
- Bente Olesen
- Department of Clinical Microbiology, Herlev and Gentofte Hospital, University of Copenhagen, Denmark
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10
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Yokoyama E, Hirai S, Ishige T, Murakami S. Application of whole genome sequence data in analyzing the molecular epidemiology of Shiga toxin-producing Escherichia coli O157:H7/H. Int J Food Microbiol 2017; 264:39-45. [PMID: 29107195 DOI: 10.1016/j.ijfoodmicro.2017.10.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 06/28/2017] [Accepted: 10/16/2017] [Indexed: 10/18/2022]
Abstract
Seventeen clusters of Shiga toxin-producing Escherichia coli O157:H7/- (O157) strains, determined by cluster analysis of pulsed-field gel electrophoresis patterns, were analyzed using whole genome sequence (WGS) data to investigate this pathogen's molecular epidemiology. The 17 clusters included 136 strains containing strains from nine outbreaks, with each outbreak caused by a single source contaminated with the organism, as shown by epidemiological contact surveys. WGS data of these strains were used to identify single nucleotide polymorphisms (SNPs) by two methods: short read data were directly mapped to a reference genome (mapping derived SNPs) and common SNPs between the mapping derived SNPs and SNPs in assembled data of short read data (common SNPs). Among both SNPs, those that were detected in genes with a gap were excluded to remove ambiguous SNPs from further analysis. The effectiveness of both SNPs was investigated among all the concatenated SNPs that were detected (whole SNP set); SNPs were divided into three categories based on the genes in which they were located (i.e., backbone SNP set, O-island SNP set, and mobile element SNP set); and SNPs in non-coding regions (intergenic region SNP set). When SNPs from strains isolated from the nine single source derived outbreaks were analyzed using an unweighted pair group method with arithmetic mean tree (UPGMA) and a minimum spanning tree (MST), the maximum pair-wise distances of the backbone SNP set of the mapping derived SNPs were significantly smaller than those of the whole and intergenic region SNP set on both UPGMAs and MSTs. This significant difference was also observed when the backbone SNP set of the common SNPs were examined (Steel-Dwass test, P≤0.01). When the maximum pair-wise distances were compared between the mapping derived and common SNPs, significant differences were observed in those of the whole, mobile element, and intergenic region SNP set (Wilcoxon signed rank test, P≤0.01). When all the strains included in one complex on an MST or one cluster on a UPGMA were designated as the same genotype, the values of the Hunter-Gaston Discriminatory Power Index for the backbone SNP set of the mapping derived and common SNPs were higher than those of other SNP sets. In contrast, the mobile element SNP set could not robustly subdivide lineage I strains of tested O157 strains using both the mapping derived and common SNPs. These results suggested that the backbone SNP set were the most effective for analysis of WGS data for O157 in enabling an appropriation of its molecular epidemiology.
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Affiliation(s)
- Eiji Yokoyama
- Division of Bacteriology, Chiba Prefectural Institute of Public Health, 666-2 Nitona, Chuo, Chiba City, Chiba 260-8715, Japan.
| | - Shinichiro Hirai
- Division of Bacteriology, Chiba Prefectural Institute of Public Health, 666-2 Nitona, Chuo, Chiba City, Chiba 260-8715, Japan
| | - Taichiro Ishige
- Genome Research Center, NODAI Research Institute, Tokyo University of Agriculture, 1-1-1, Sakuragaoka, Setagaya, Tokyo 256-0054, Japan
| | - Satoshi Murakami
- Laboratory of Animal Hygiene, Department of Animal Science, Tokyo University of Agriculture, 1737, Funako, Atsugi, Kanagawa 243-0034, Japan
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Abstract
This introductory article provides an overview of preharvest food safety activities and initiatives for the past 15 years. The section on traditional areas of preharvest food safety focuses on significant scientific advancements that are a culmination of collaborative efforts (both public health and agriculture) and significant research results. The highlighted advancements provide the foundation for exploring future preharvest areas and for improving and focusing on more specific intervention/control/prevention strategies. Examples include Escherichia coli and cattle, Salmonella and Campylobacter in poultry, and interventions and prevention and control programs. The section on "nontraditional" preharvest food safety areas brings attention to potential emerging food safety issues and to future food safety research directions. These include organic production, the FDA's Produce Rule (water and manure), genomic sequencing, antimicrobial resistance, and performance metrics. The concluding section emphasizes important themes such as strategic planning, coordination, epidemiology, and the need for understanding food safety production as a continuum. Food safety research, whether at the pre- or postharvest level, will continue to be a fascinating complex web of foodborne pathogens, risk factors, and scientific and policy interactions. Food safety priorities and research must continue to evolve with emerging global issues, emerging technologies, and methods but remain grounded in a multidisciplinary, collaborative, and systematic approach.
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12
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Sheng H, Shringi S, Baker KNK, Minnich SA, Hovde CJ, Besser TE. Standardized Escherichia coli O157:H7 Exposure Studies in Cattle Provide Evidence that Bovine Factors Do Not Drive Increased Summertime Colonization. Appl Environ Microbiol 2016; 82:964-71. [PMID: 26607594 PMCID: PMC4725274 DOI: 10.1128/aem.02839-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 11/17/2015] [Indexed: 12/11/2022] Open
Abstract
The increased summertime prevalence of cattle carriage of enterohemorrhagic Shiga toxin-producing Escherichia coli O157:H7 (STEC O157) is associated with the increased summertime incidence of human infection. The mechanism driving the seasonality of STEC O157 carriage among cattle is unknown. We conducted experimental challenge trials to distinguish whether factors extrinsic or intrinsic to cattle underlie the seasonality of STEC O157 colonization. Holstein steers (n = 20) exposed to ambient environmental conditions were challenged with a standardized pool of STEC O157 strains four times at 6-month intervals. The densities and durations of rectoanal junction mucosa (RAJ) colonization with STEC O157 were compared by season (winter versus summer), dose (10(9) CFU versus 10(7) CFU), and route of challenge (oral versus rectal). Following summer challenges, the RAJ STEC O157 colonization density was significantly lower (P = 0.016) and the duration was shorter (P = 0.052) than for winter challenges, a seasonal pattern opposite to that observed naturally. Colonization was unaffected by the challenge route, indicating that passage through the gastrointestinal microbiome did not significantly affect the infectious dose to the RAJ. A 2-log reduction of the challenge doses in the second-year trials was accompanied by similarly reduced RAJ colonization in both seasons (P < 0.001). These results refute the hypothesis that cattle are predisposed to STEC O157 colonization during the summer months, either due to intrinsic factors or indirectly due to gastrointestinal tract microbiome effects. Instead, the data support the hypothesis that the increased summertime STEC O157 colonization results from increased seasonal oral exposure to this pathogen.
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Affiliation(s)
- Haiqing Sheng
- Bi-state School of Food Science, University of Idaho, Moscow, Idaho, USA
| | - Smriti Shringi
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Katherine N K Baker
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Scott A Minnich
- Bi-state School of Food Science, University of Idaho, Moscow, Idaho, USA
| | - Carolyn J Hovde
- Bi-state School of Food Science, University of Idaho, Moscow, Idaho, USA
| | - Thomas E Besser
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
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Whole Genome Sequencing demonstrates that Geographic Variation of Escherichia coli O157 Genotypes Dominates Host Association. Sci Rep 2015; 5:14145. [PMID: 26442781 PMCID: PMC4595763 DOI: 10.1038/srep14145] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 08/19/2015] [Indexed: 02/04/2023] Open
Abstract
Genetic variation in an infectious disease pathogen can be driven by ecological niche dissimilarities arising from different host species and different geographical locations. Whole genome sequencing was used to compare E. coli O157 isolates from host reservoirs (cattle and sheep) from Scotland and to compare genetic variation of isolates (human, animal, environmental/food) obtained from Scotland, New Zealand, Netherlands, Canada and the USA. Nei’s genetic distance calculated from core genome single nucleotide polymorphisms (SNPs) demonstrated that the animal isolates were from the same population. Investigation of the Shiga toxin bacteriophage and their insertion sites (SBI typing) revealed that cattle and sheep isolates had statistically indistinguishable rarefaction profiles, diversity and genotypes. In contrast, isolates from different countries exhibited significant differences in Nei’s genetic distance and SBI typing. Hence, after successful international transmission, which has occurred on multiple occasions, local genetic variation occurs, resulting in a global patchwork of continental and trans-continental phylogeographic clades. These findings are important for three reasons: first, understanding transmission and evolution of infectious diseases associated with multiple host reservoirs and multi-geographic locations; second, highlighting the relevance of the sheep reservoir when considering farm based interventions; and third, improving our understanding of why human disease incidence varies across the world.
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Geographically distinct Escherichia coli O157 isolates differ by lineage, Shiga toxin genotype, and total shiga toxin production. J Clin Microbiol 2014; 53:579-86. [PMID: 25502531 DOI: 10.1128/jcm.01532-14] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
While the differential association of Escherichia coli O157 genotypes with animal and human hosts has recently been well documented, little is known about their distribution between countries and how this might affect regional disease rates. Here, we used a 48-plex single nucleotide polymorphism (SNP) assay to segregate 148 E. coli O157 isolates from Australia, Argentina, and the United States into 11 SNP lineages. We also investigated the relationship between SNP lineages, Shiga toxin (Stx) gene profiles, and total Stx production. E. coli O157 isolates clearly segregated into SNP lineages that were differentially associated with each country. Of the 11 SNP lineages, seven were detected among isolates from a single country, two were detected among isolates from all three countries, and another two were detected only among U.S. and Argentinean isolates. A number of Australian (30%) and Argentinean (14%) isolates were associated with novel, previously undescribed SNP lineages that were unique to each country. Isolates within SNP lineages that were strongly associated with the carriage of stx2a produced comparatively more Stx on average than did those lacking the stx2a subtype. Furthermore, the proportion of isolates in stx2a-associated SNP lineages was significantly higher in Argentina and the United States than Australia (P < 0.05). This study provides evidence for the geographic divergence of E. coli O157 and for a prominent role of stx2a in total Stx production. These results also highlight the need for more comprehensive studies of the global distribution of E. coli O157 lineages and the impacts of regionally predominant E. coli O157 lineages on the prevalence and severity of disease.
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Jaros P, Cookson AL, Campbell DM, Duncan GE, Prattley D, Carter P, Besser TE, Shringi S, Hathaway S, Marshall JC, French NP. Geographic divergence of bovine and human Shiga toxin–producing Escherichia coli O157:H7 genotypes, New Zealand. Emerg Infect Dis 2014; 20:1980-9. [PMID: 25568924 PMCID: PMC4257794 DOI: 10.3201/eid2012.140281] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC)O157:H7 is a zoonotic pathogen of public health concern worldwide. To compare the local and large-scale geographic distributions of genotypes of STEC O157:H7 isolates obtained from various bovine and human sources during 2008–2011, we used pulsed-field gel electrophoresis and Shiga toxin–encoding bacteriophage insertion (SBI) typing. Using multivariate methods, we compared isolates from the North and South Islands of New Zealand with isolates from Australia and the United States. The STEC O157:H7 population structure differed substantially between the 2 islands and showed evidence of finer scale spatial structuring, which is consistent with highly localized transmission rather than disseminated foodborne outbreaks. The distribution of SBI types differed markedly among isolates from New Zealand, Australia, and the United States. Our findings also provide evidence for the historic introduction into New Zealand of a subset of globally circulating STEC O157:H7 strains that have continued to evolve and be transmitted locally between cattle and humans.
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Eppinger M, Cebula TA. Future perspectives, applications and challenges of genomic epidemiology studies for food-borne pathogens: A case study of Enterohemorrhagic Escherichia coli (EHEC) of the O157:H7 serotype. Gut Microbes 2014; 6:194-201. [PMID: 25483335 PMCID: PMC4615391 DOI: 10.4161/19490976.2014.969979] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The shiga-toxin (Stx)-producing human pathogen Escherichia coli serotype O157:H7 is a highly pathogenic subgroup of Stx-producing E. coli (STEC) with food-borne etiology and bovine reservoir. Each year in the U. S., approximately 100,000 patients are infected with enterohemorrhagic E. coli (EHEC) of the O157:H7 serotype. This food-borne pathogen is a global public health threat responsible for widespread outbreaks of human disease. Since its initial discovery in 1982, O157:H7 has rapidly become the dominant EHEC serotype in North America. Hospitalization rates among patients as high as 50% have been reported for severe outbreaks of human disease. Symptoms of disease can rapidly deteriorate and progress to life-threatening complications such as Hemolytic Uremic Syndrome (HUS), the leading cause of kidney failure in children, or Hemorrhagic Colitis. In depth understanding of the genomic diversity that exists among currently circulating EHEC populations has broad applications for improved molecular-guided biosurveillance, outbreak preparedness, diagnostic risk assessment, and development of alternative toxin-suppressing therapeutics.
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Affiliation(s)
- Mark Eppinger
- Department of Biology; The University of Texas at San Antonio; San Antonio, TX, USA,South Texas Center For Emerging Infectious Diseases; The University of Texas at San Antonio; San Antonio, TX, USA,Correspondence to: Mark Eppinger;
| | - Thomas A Cebula
- Department of Biology; Johns Hopkins University; Baltimore, MD, USA,CosmosID; Fairfax, VA, USA
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