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Rivas M, Pichel M, Colonna M, Casanello AL, Alconcher LF, Galavotti J, Principi I, Araujo SP, Ramírez FB, González G, Pianciola LA, Mazzeo M, Suarez Á, Oderiz S, Ghezzi LFR, Arrigo DJ, Paladini JH, Baroni MR, Pérez S, Tamborini A, Chinen I, Miliwebsky ES, Goldbaum F, Muñoz L, Spatz L, Sanguineti S. Surveillance of Shiga toxin-producing Escherichia coli associated bloody diarrhea in Argentina. Rev Argent Microbiol 2023; 55:345-354. [PMID: 37301652 DOI: 10.1016/j.ram.2023.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 12/12/2022] [Accepted: 03/27/2023] [Indexed: 06/12/2023] Open
Abstract
In Argentina, hemolytic uremic syndrome (HUS) caused by Shiga toxin-producing Escherichia coli (STEC-HUS) infection is endemic, and reliable data about prevalence and risk factors have been available since 2000. However, information about STEC-associated bloody diarrhea (BD) is limited. A prospective study was performed during the period October 2018-June 2019 in seven tertiary-hospitals and 18 referral units from different regions, aiming to determine (i) the frequency of STEC-positive BD cases in 714 children aged 1-9 years of age and (ii) the rate of progression of bloody diarrhea to HUS. The number and regional distribution of STEC-HUS cases in the same hospitals and during the same period were also assessed. Twenty-nine (4.1%) of the BD patients were STEC-positive, as determined by the Shiga Toxin Quik Chek (STQC) test and/or the multiplex polymerase chain reaction (mPCR) assay. The highest frequencies were found in the Southern region (Neuquén, 8.7%; Bahía Blanca, 7.9%), in children between 12 and 23 month of age (8.8%), during summertime. Four (13.8%) cases progressed to HUS, three to nine days after diarrhea onset. Twenty-seven STEC-HUS in children under 5 years of age (77.8%) were enrolled, 51.9% were female; 44% were Stx-positive by STQC and all by mPCR. The most common serotypes were O157:H7 and O145:H28 and the prevalent genotypes, both among BD and HUS cases, were stx2a-only or -associated. Considering the endemic behavior of HUS and its high incidence, these data show that the rate of STEC-positive cases is low among BD patients. However, the early recognition of STEC-positive cases is important for patient monitoring and initiation of supportive treatment.
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Affiliation(s)
- Marta Rivas
- Inmunova S.A., Av. 25 de Mayo 1021, San Martín, 1650 Buenos Aires, Argentina.
| | - Mariana Pichel
- Inmunova S.A., Av. 25 de Mayo 1021, San Martín, 1650 Buenos Aires, Argentina
| | - Mariana Colonna
- Inmunova S.A., Av. 25 de Mayo 1021, San Martín, 1650 Buenos Aires, Argentina
| | | | - Laura F Alconcher
- Hospital Interzonal "Dr. José Penna", Av. Laínez 2401, B8000 Bahía Blanca, Buenos Aires, Argentina
| | - Jimena Galavotti
- Hospital Interzonal "Dr. José Penna", Av. Laínez 2401, B8000 Bahía Blanca, Buenos Aires, Argentina
| | - Iliana Principi
- Hospital de Niños "Dr. Humberto Notti", Av. Bandera de los Andes 2603, M5521 Guaymallén, Mendoza, Argentina
| | - Sofía Pérez Araujo
- Hospital de Niños "Dr. Humberto Notti", Av. Bandera de los Andes 2603, M5521 Guaymallén, Mendoza, Argentina
| | - Flavia B Ramírez
- Hospital Provincial Neuquén Dr. Castro Rendón, Buenos Aires 450, Q8300 Neuquén, Argentina
| | - Gladys González
- Hospital Provincial Neuquén Dr. Castro Rendón, Buenos Aires 450, Q8300 Neuquén, Argentina
| | - Luis A Pianciola
- Laboratorio Central, Gregorio Martínez 65, Q8300 Neuquén, Argentina
| | - Melina Mazzeo
- Laboratorio Central, Gregorio Martínez 65, Q8300 Neuquén, Argentina
| | - Ángela Suarez
- Hospital De Niños "Sor María Ludovica", Calle 14 1631 entre 65 y 66, B1904CSI La Plata, Buenos Aires, Argentina
| | - Sebastián Oderiz
- Hospital De Niños "Sor María Ludovica", Calle 14 1631 entre 65 y 66, B1904CSI La Plata, Buenos Aires, Argentina
| | - Lidia F R Ghezzi
- Hospital Italiano de Buenos Aires, Tte. Gral. Juan Domingo Perón 4190, C1199AB, Buenos Aires, Argentina
| | - Diego J Arrigo
- Hospital Italiano de Buenos Aires, Tte. Gral. Juan Domingo Perón 4190, C1199AB, Buenos Aires, Argentina
| | - José H Paladini
- Hospital Dr. Orlando Alassia, Mendoza 4151, 3000 Santa Fe, Argentina
| | - María R Baroni
- Hospital Dr. Orlando Alassia, Mendoza 4151, 3000 Santa Fe, Argentina
| | - Susana Pérez
- Hospital "Dr. Lucio Molas", Raúl B. Díaz Pilcomayo, 6300 Santa Rosa, La Pampa, Argentina
| | - Ana Tamborini
- Hospital "Dr. Lucio Molas", Raúl B. Díaz Pilcomayo, 6300 Santa Rosa, La Pampa, Argentina
| | - Isabel Chinen
- Servicio Fisiopatogenia, Instituto Nacional de Enfermedades Infecciosas, ANLIS "Dr. Carlos G. Malbrán", Av. Vélez Sarsfield 563, 1281 Buenos Aires, Argentina
| | - Elizabeth S Miliwebsky
- Servicio Fisiopatogenia, Instituto Nacional de Enfermedades Infecciosas, ANLIS "Dr. Carlos G. Malbrán", Av. Vélez Sarsfield 563, 1281 Buenos Aires, Argentina
| | - Fernando Goldbaum
- Inmunova S.A., Av. 25 de Mayo 1021, San Martín, 1650 Buenos Aires, Argentina
| | - Luciana Muñoz
- Inmunova S.A., Av. 25 de Mayo 1021, San Martín, 1650 Buenos Aires, Argentina
| | - Linus Spatz
- Inmunova S.A., Av. 25 de Mayo 1021, San Martín, 1650 Buenos Aires, Argentina
| | - Santiago Sanguineti
- Inmunova S.A., Av. 25 de Mayo 1021, San Martín, 1650 Buenos Aires, Argentina
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Matussek A, Mernelius S, Chromek M, Zhang J, Frykman A, Hansson S, Georgieva V, Xiong Y, Bai X. Genome-wide association study of hemolytic uremic syndrome causing Shiga toxin-producing Escherichia coli from Sweden, 1994-2018. Eur J Clin Microbiol Infect Dis 2023; 42:771-779. [PMID: 37103716 PMCID: PMC10172287 DOI: 10.1007/s10096-023-04600-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 04/11/2023] [Indexed: 04/28/2023]
Abstract
Shiga toxin-producing Escherichia coli (STEC) infection can cause clinical manifestations ranging from diarrhea to potentially fatal hemolytic uremic syndrome (HUS). This study is aimed at identifying STEC genetic factors associated with the development of HUS in Sweden. A total of 238 STEC genomes from STEC-infected patients with and without HUS between 1994 and 2018 in Sweden were included in this study. Serotypes, Shiga toxin gene (stx) subtypes, and virulence genes were characterized in correlation to clinical symptoms (HUS and non-HUS), and pan-genome wide association study was performed. Sixty-five strains belonged to O157:H7, and 173 belonged to non-O157 serotypes. Our study revealed that strains of O157:H7 serotype especially clade 8 were most commonly found in patients with HUS in Sweden. stx2a and stx2a + stx2c subtypes were significantly associated with HUS. Other virulence factors associated with HUS mainly included intimin (eae) and its receptor (tir), adhesion factors, toxins, and secretion system proteins. Pangenome wide-association study identified numbers of accessory genes significantly overrepresented in HUS-STEC strains, including genes encoding outer membrane proteins, transcriptional regulators, phage-related proteins, and numerous genes related to hypothetical proteins. Whole-genome phylogeny and multiple correspondence analysis of pangenomes could not differentiate HUS-STEC from non-HUS-STEC strains. In O157:H7 cluster, strains from HUS patients clustered closely; however, no significant difference in virulence genes was found in O157 strains from patients with and without HUS. These results suggest that STEC strains from different phylogenetic backgrounds may independently acquire genes determining their pathogenicity and confirm that other non-bacterial factors and/or bacteria-host interaction may affect STEC pathogenesis.
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Affiliation(s)
- Andreas Matussek
- Department of Microbiology, Division of Laboratory Medicine, Oslo University Hospital, Oslo, Norway
- Department of Microbiology, Division of Laboratory Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- Laboratory Medicine, Department of Clinical and Experimental Medicine, Jönköping Region County, Linköping University, Jönköping, Sweden
| | - Sara Mernelius
- Laboratory Medicine, Department of Clinical and Experimental Medicine, Jönköping Region County, Linköping University, Jönköping, Sweden
- Department of Laboratory Medicine, Jönköping, Sweden
| | - Milan Chromek
- Division of Pediatrics, Department of Clinical Science, Intervention and Technology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Ji Zhang
- Fonterra Research and Development Centre, Dairy Farm Road, Palmerston North, New Zealand
| | - Anne Frykman
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Sverker Hansson
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Valya Georgieva
- Division of Pediatrics, Department of Clinical Science, Intervention and Technology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Yanwen Xiong
- State Key Laboratory of Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, National Institute for Communicable Disease Control and Prevention, Beijing, China
| | - Xiangning Bai
- Department of Microbiology, Division of Laboratory Medicine, Oslo University Hospital, Oslo, Norway.
- Department of Microbiology, Division of Laboratory Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden.
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3
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Detection of Escherichia coli O157:H7 in imported meat products from Saudi Arabian ports in 2017. Sci Rep 2023; 13:4222. [PMID: 36918659 PMCID: PMC10015049 DOI: 10.1038/s41598-023-30486-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 02/24/2023] [Indexed: 03/16/2023] Open
Abstract
Escherichia coli O157:H7 is a foodborne pathogen, which causes various health conditions in humans, including fatigue, nausea, bloody diarrhoea and in some cases, even death. In 2017, 15.71% of the total imported food products in Saudi Arabia (SA) were meat-based. India and Brazil are two of the top five countries from where SA imports meat. According to the Saudi Food and Drug Authority, in 2017, at least 562, 280, and 50 samples of imported beef, chicken and sheep meat, respectively, were tested for the presence of E. coli O157:H7. Amongst these, E. coli O157:H7 was detected in respectively 6.80% and 2.20% of the tested beef meat samples imported from India and Brazil as well as in respectively 6.96% and 3.57% of the tested chicken samples imported from Brazil and Ukraine. Moreover, the pathogen was detected in 2.13% of the tested sheep meat samples imported from India. The present report provides evidence that imported meat can serve as the carrier of E. coli O157:H7, which may lead to epidemics within the Kingdom of Saudi Arabia.
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Miyata T, Taniguchi I, Nakamura K, Gotoh Y, Yoshimura D, Itoh T, Hirai S, Yokoyama E, Ohnishi M, Iyoda S, Ogura Y, Hayashi T. Alteration of a Shiga toxin-encoding phage associated with a change in toxin production level and disease severity in Escherichia coli. Microb Genom 2023; 9:mgen000935. [PMID: 36821793 PMCID: PMC9997748 DOI: 10.1099/mgen.0.000935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
Abstract
Among the nine clades of Shiga toxin (Stx)-producing Escherichia coli O157:H7, clade 8 is thought to be highly pathogenic, as it causes severe disease more often than other clades. Two subclades have been proposed, but there are conflicting reports on intersubclade differences in Stx2 levels, although Stx2 production is a risk factor for severe disease development. The global population structure of clade 8 has also yet to be fully elucidated. Here, we present genome analyses of a global clade 8 strain set (n=510), including 147 Japanese strains sequenced in this study. The complete genome sequences of 18 of the 147 strains were determined to perform detailed clade-wide genome analyses together with 17 publicly available closed genomes. Intraclade variations in Stx2 production level and disease severity were also re-evaluated within the phylogenetic context. Based on phylogenomic analysis, clade 8 was divided into four lineages corresponding to the previously proposed SNP genotypes (SGs): SG8_30, SG8_31A, SG8_31B and SG8_32. SG8_30 and the common ancestor of the other SGs were first separated, with SG8_31A and SG8_31B emerging from the latter and SG8_32 emerging from SG8_31B. Comparison of 35 closed genomes revealed the overall structure of chromosomes and pO157 virulence plasmids and the prophage contents to be well conserved. However, Stx2a phages exhibit notable genomic diversity, even though all are integrated into the argW locus, indicating that subtype changes in Stx2a phage occurred from the γ subtype to its variant (γ_v1) in SG8_31A and from γ to δ in SG8_31B and SG8_32 via replacement of parts or almost entire phage genomes, respectively. We further show that SG8_30 strains (all carrying γ Stx2a phages) produce significantly higher levels of Stx2 and cause severe disease more frequently than SG8_32 strains (all carrying δ Stx2a phages). Clear conclusions on SG8_31A and SG8_31B cannot be made due to the small number of strains available, but as SG8_31A (carrying γ_v1 Stx2a phages) contains strains that produce much more Stx2 than SG8_30 strains, attention should also be paid to this SG.
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Affiliation(s)
- Tatsuya Miyata
- Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.,Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Itsuki Taniguchi
- Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Keiji Nakamura
- Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Yasuhiro Gotoh
- Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Dai Yoshimura
- School of Life Science and Technology, Tokyo Institute of Technology, Meguro, Tokyo 152-8550, Japan
| | - Takehiko Itoh
- School of Life Science and Technology, Tokyo Institute of Technology, Meguro, Tokyo 152-8550, Japan
| | - Shinichiro Hirai
- Division of Bacteriology, Chiba Prefectural Institute of Public Health, Chiba 260-8715, Japan.,Center for Emergency Preparedness and Response, National Institute of Infectious Diseases, Musashi-Murayama, Tokyo 208-0011, Japan
| | - Eiji Yokoyama
- Division of Bacteriology, Chiba Prefectural Institute of Public Health, Chiba 260-8715, Japan
| | - Makoto Ohnishi
- Department of Bacteriology I, National Institute of Infectious Diseases, Shinjuku, Tokyo 162-8640, Japan
| | - Sunao Iyoda
- Department of Bacteriology I, National Institute of Infectious Diseases, Shinjuku, Tokyo 162-8640, Japan
| | - Yoshitoshi Ogura
- Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.,Division of Microbiology, Department of Infectious Medicine, Kurume University School of Medicine, Kurume, Fukuoka 830-0011, Japan
| | - Tetsuya Hayashi
- Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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5
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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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Comparative Genomics of Shiga Toxin-Producing Escherichia coli Strains Isolated from Pediatric Patients with and without Hemolytic Uremic Syndrome from 2000 to 2016 in Finland. Microbiol Spectr 2022; 10:e0066022. [PMID: 35730965 PMCID: PMC9430701 DOI: 10.1128/spectrum.00660-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) infection can cause mild to severe illness, such as nonbloody or bloody diarrhea, and the fatal hemolytic uremic syndrome (HUS). The molecular mechanism underlying the variable pathogenicity of STEC infection is not fully defined so far. Here, we performed a comparative genomics study on a large collection of clinical STEC strains collected from STEC-infected pediatric patients with and without HUS in Finland over a 16-year period, aiming to identify the bacterial genetic factors that can predict the risk to cause HUS and poor renal outcome. Of 240 STEC strains included in this study, 52 (21.7%) were from pediatric patients with HUS. Serotype O157:H7 was the main cause of HUS, and Shiga toxin gene subtype stx2a was significantly associated with HUS. Comparative genomics and pangenome-wide association studies identified a number of virulence and accessory genes overrepresented in HUS-associated STEC compared to non-HUS STEC strains, including genes encoding cytolethal distending toxins, type III secretion system effectors, adherence factors, etc. No virulence or accessory gene was significantly associated with risk factors for poor renal outcome among HUS patients assessed in this study, including need for and duration of dialysis, presence and duration of anuria, and leukocyte counts. Whole-genome phylogeny and multiple-correspondence analysis of pangenomes could not separate HUS STEC from non-HUS STEC strains, suggesting that STEC strains with diverse genetic backgrounds may independently acquire genetic elements that determine their varied pathogenicity. Our findings indicate that nonbacterial factors, i.e., characteristics of the host immunity, might affect STEC virulence and clinical outcomes. IMPORTANCE Shiga toxin-producing Escherichia coli (STEC) is a serious public health burden worldwide which causes outbreaks of gastrointestinal diseases and the fatal hemolytic uremic syndrome (HUS) characterized by the triad of mechanical hemolytic anemia, thrombocytopenia, and acute renal failure. Understanding the mechanism underlying the disease severity and patient outcome is of high importance. Using comparative genomics on a large collection of clinical STEC strains from STEC-infected patients with and without HUS, our study provides a reference of STEC genetic factors/variants that can be used as predictors of the development of HUS, which will aid risk assessment at the early stage of STEC infection. Additionally, our findings suggest that nonbacterial factors may play a primary role in the renal outcome in STEC-infected patients with HUS; further studies are needed to validate this.
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Allué-Guardia A, Koenig SSK, Martinez RA, Rodriguez AL, Bosilevac JM, Feng† P, Eppinger M. Pathogenomes and variations in Shiga toxin production among geographically distinct clones of Escherichia coli O113:H21. Microb Genom 2022; 8. [PMID: 35394418 PMCID: PMC9453080 DOI: 10.1099/mgen.0.000796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Infections with globally disseminated Shiga toxin-producing Escherichia coli (STEC) of the O113:H21 serotype can progress to severe clinical complications, such as hemolytic uremic syndrome (HUS). Two phylogeographically distinct clonal complexes have been established by multi locus sequence typing (MLST). Infections with ST-820 isolates circulating exclusively in Australia have caused severe human disease, such as HUS. Conversely, ST-223 isolates prevalent in the US and outside Australia seem to rarely cause severe human disease but are frequent contaminants. Following a genomic epidemiology approach, we wanted to gain insights into the underlying cause for this disparity. We examined the plasticity in the genome make-up and Shiga toxin production in a collection of 20 ST-820 and ST-223 strains isolated from produce, the bovine reservoir, and clinical cases. STEC are notorious for assembly into fragmented draft sequences when using short-read sequencing technologies due to the extensive and partly homologous phage complement. The application of long-read technology (LRT) sequencing yielded closed reference chromosomes and plasmids for two representative ST-820 and ST-223 strains. The established high-resolution framework, based on whole genome alignments, single nucleotide polymorphism (SNP)-typing and MLST, includes the chromosomes and plasmids of other publicly available O113:H21 sequences and allowed us to refine the phylogeographical boundaries of ST-820 and ST-223 complex isolates and to further identify a historic non-shigatoxigenic strain from Mexico as a quasi-intermediate. Plasmid comparison revealed strong correlations between the strains' featured pO113 plasmid genotypes and chromosomally inferred ST, which suggests coevolution of the chromosome and virulence plasmids. Our pathogenicity assessment revealed statistically significant differences in the Stx2a-production capabilities of ST-820 as compared to ST-223 strains under RecA-induced Stx phage mobilization, a condition that mimics Stx-phage induction. These observations suggest that ST-820 strains may confer an increased pathogenic potential in line with the strain-associated epidemiological metadata. Still, some of the tested ST-223 cultures sourced from contaminated produce or the bovine reservoir also produced Stx at levels comparable to those of ST-820 isolates, which calls for awareness and for continued surveillance of this lineage.
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Affiliation(s)
- Anna Allué-Guardia
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, USA
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, USA
| | - Sara S. K. Koenig
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, USA
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, USA
| | - Ricardo A. Martinez
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, USA
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, USA
| | - Armando L. Rodriguez
- University of Texas at San Antonio, Research Computing Support Group, San Antonio, TX, USA
| | - Joseph M. Bosilevac
- U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), Roman L. Hruska U.S. Meat Animal Research Center, Clay Center, NE, USA
| | - Peter Feng†
- U.S. Food and Drug Administration (FDA), College Park, MD, USA
| | - Mark Eppinger
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, USA
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, USA
- *Correspondence: Mark Eppinger,
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8
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AB 5 Enterotoxin-Mediated Pathogenesis: Perspectives Gleaned from Shiga Toxins. Toxins (Basel) 2022; 14:toxins14010062. [PMID: 35051039 PMCID: PMC8779504 DOI: 10.3390/toxins14010062] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/12/2022] [Accepted: 01/12/2022] [Indexed: 02/01/2023] Open
Abstract
Foodborne diseases affect an estimated 600 million people worldwide annually, with the majority of these illnesses caused by Norovirus, Vibrio, Listeria, Campylobacter, Salmonella, and Escherichia coli. To elicit infections in humans, bacterial pathogens express a combination of virulence factors and toxins. AB5 toxins are an example of such toxins that can cause various clinical manifestations, including dehydration, diarrhea, kidney damage, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Treatment of most bacterial foodborne illnesses consists of fluid replacement and antibiotics. However, antibiotics are not recommended for infections caused by Shiga toxin-producing E. coli (STEC) because of the increased risk of HUS development, although there are conflicting views and results in this regard. Lack of effective treatment strategies for STEC infections pose a public health threat during outbreaks; therefore, the debate on antibiotic use for STEC infections could be further explored, along with investigations into antibiotic alternatives. The overall goal of this review is to provide a succinct summary on the mechanisms of action and the pathogenesis of AB5 and related toxins, as expressed by bacterial foodborne pathogens, with a primary focus on Shiga toxins (Stx). The role of Stx in human STEC disease, detection methodologies, and available treatment options are also briefly discussed.
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Fitzgerald SF, Lupolova N, Shaaban S, Dallman TJ, Greig D, Allison L, Tongue SC, Evans J, Henry MK, McNeilly TN, Bono JL, Gally DL. Genome structural variation in Escherichia coli O157:H7. Microb Genom 2021; 7. [PMID: 34751643 PMCID: PMC8743559 DOI: 10.1099/mgen.0.000682] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The human zoonotic pathogen Escherichia coli O157:H7 is defined by its extensive prophage repertoire including those that encode Shiga toxin, the factor responsible for inducing life-threatening pathology in humans. As well as introducing genes that can contribute to the virulence of a strain, prophage can enable the generation of large-chromosomal rearrangements (LCRs) by homologous recombination. This work examines the types and frequencies of LCRs across the major lineages of the O157:H7 serotype. We demonstrate that LCRs are a major source of genomic variation across all lineages of E. coli O157:H7 and by using both optical mapping and Oxford Nanopore long-read sequencing prove that LCRs are generated in laboratory cultures started from a single colony and that these variants can be recovered from colonized cattle. LCRs are biased towards the terminus region of the genome and are bounded by specific prophages that share large regions of sequence homology associated with the recombinational activity. RNA transcriptional profiling and phenotyping of specific structural variants indicated that important virulence phenotypes such as Shiga-toxin production, type-3 secretion and motility can be affected by LCRs. In summary, E. coli O157:H7 has acquired multiple prophage regions over time that act to continually produce structural variants of the genome. These findings raise important questions about the significance of this prophage-mediated genome contingency to enhance adaptability between environments.
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Affiliation(s)
- Stephen F Fitzgerald
- Division of Infection and Immunity, The Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Nadejda Lupolova
- Division of Infection and Immunity, The Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Sharif Shaaban
- Division of Infection and Immunity, The Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Timothy J Dallman
- Gastrointestinal Bacterial Reference Unit, 61 Colindale Avenue, Public Health England, NW9 5EQ London, UK
| | - David Greig
- Gastrointestinal Bacterial Reference Unit, 61 Colindale Avenue, Public Health England, NW9 5EQ London, UK
| | - Lesley Allison
- Scottish E. coli O157/VTEC Reference Laboratory, Department of Laboratory Medicine, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh EH16 4SA, UK
| | - Sue C Tongue
- Epidemiology Research Unit (Inverness), Department of Veterinary and Animal Science, Northern Faculty, Scotland's Rural College (SRUC), Scotland, IV2 5NA, UK
| | - Judith Evans
- Epidemiology Research Unit (Inverness), Department of Veterinary and Animal Science, Northern Faculty, Scotland's Rural College (SRUC), Scotland, IV2 5NA, UK
| | - Madeleine K Henry
- Epidemiology Research Unit (Inverness), Department of Veterinary and Animal Science, Northern Faculty, Scotland's Rural College (SRUC), Scotland, IV2 5NA, UK
| | - Tom N McNeilly
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 OPZ, UK
| | - James L Bono
- United States Department of Agriculture, Agricultural Research Service, US Meat Animal Research Center, Clay Center, Nebraska, USA
| | - David L Gally
- Division of Infection and Immunity, The Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
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10
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Hua Y, Chromek M, Frykman A, Jernberg C, Georgieva V, Hansson S, Zhang J, Marits AK, Wan C, Matussek A, Bai X. Whole-genome characterization of hemolytic uremic syndrome-causing Shiga toxin-producing Escherichia coli in Sweden. Virulence 2021; 12:1296-1305. [PMID: 33939581 PMCID: PMC8096335 DOI: 10.1080/21505594.2021.1922010] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Shiga toxin-producing Escherichia coli, a foodborne bacterial pathogen, has been linked to a broad spectrum of clinical outcomes ranging from asymptomatic carriage to fatal hemolytic uremic syndrome (HUS). Here, we collected clinical data and STEC strains from HUS patients from 1994 through 2018, whole-genome sequencing was performed to molecularly characterize HUS-associated STEC strains, statistical analysis was conducted to identify bacterial genetic factors associated with severe outcomes in HUS patients. O157:H7 was the most predominant serotype (57%) among 54 HUS-associated STEC strains, followed by O121:H19 (19%) and O26:H11 (7%). Notably, some non-predominant serotypes such as O59:H17 (2%) and O109:H21 (2%) also caused HUS. All O157:H7 strains with one exception belonged to clade 8. During follow-up at a median of 4 years, 41% of the patients had renal sequelae. Fifty-nine virulence genes were found to be statistically associated with severe renal sequelae, these genes encoded type II and type III secretion system effectors, chaperones, and other factors. Notably, virulence genes associated with severe clinical outcomes were significantly more prevalent in O157:H7 strains. In contrast, genes related to mild symptoms were evenly distributed across all serotypes. The whole-genome phylogeny indicated high genomic diversity among HUS-STEC strains. No distinct cluster was found between HUS and non-HUS STEC strains. The current study showed that O157:H7 remains the main cause of STEC-associated HUS, despite the rising importance of other non-O157 serotypes. Besides, O157:H7 is associated with severe renal sequelae in the follow-up, which could be a risk factor for long-term prognosis in HUS patients.
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Affiliation(s)
- Ying Hua
- Department of Microbiology, School of Public Health, Southern Medical University, Guangzhou, China.,Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Milan Chromek
- Division of Pediatrics, Department of Clinical Science, Intervention and Technology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Anne Frykman
- Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Gothenburg, Sweden.,Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | | | - Valya Georgieva
- Division of Pediatrics, Department of Clinical Science, Intervention and Technology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Sverker Hansson
- Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Gothenburg, Sweden.,Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Ji Zhang
- Molecular Epidemiology and Public Health Laboratory, School of Veterinary Sciences, Massey University, Palmerston North, New Zealand
| | - Ann Katrine Marits
- Division of Pediatrics, Department of Clinical Science, Intervention and Technology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Chengsong Wan
- Department of Microbiology, School of Public Health, Southern Medical University, Guangzhou, China
| | - Andreas Matussek
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden.,Laboratory Medicine, Jönköping Region County, Department of Clinical and Experimental Medicine, Linköping University, Jönköping, Sweden.,Oslo University Hospital, Oslo, Norway.,Division of Laboratory Medicine, Institute of Clinical Medicine, University of Oslo, Norway
| | - Xiangning Bai
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden.,Division of Infectious Diseases, Department of Medicine Huddinge, Karolinska Institutet, Huddinge, Sweden.,State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
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11
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Identification, Shiga toxin subtypes and prevalence of minor serogroups of Shiga toxin-producing Escherichia coli in feedlot cattle feces. Sci Rep 2021; 11:8601. [PMID: 33883564 PMCID: PMC8060326 DOI: 10.1038/s41598-021-87544-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 03/23/2021] [Indexed: 01/12/2023] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens that cause illnesses in humans ranging from mild to hemorrhagic enteritis with complications of hemolytic uremic syndrome and even death. Cattle are a major reservoir of STEC, which reside in the hindgut and are shed in the feces, a major source of food and water contaminations. Seven serogroups, O26, O45, O103, O111, O121, O145 and O157, called ‘top-7’, are responsible for the majority of human STEC infections in North America. Additionally, 151 serogroups of E. coli are known to carry Shiga toxin genes (stx). Not much is known about fecal shedding and prevalence and virulence potential of STEC other than the top-7. Our primary objectives were to identify serogroups of STEC strains, other than the top-7, isolated from cattle feces and subtype stx genes to assess their virulence potential. Additional objective was to develop and validate a novel multiplex PCR assay to detect and determine prevalence of six serogroups, O2, O74, O109, O131, O168, and O171, in cattle feces. A total of 351 strains, positive for stx gene and negative for the top-7 serogroups, isolated from feedlot cattle feces were used in the study. Of the 351 strains, 291 belonged to 16 serogroups and 60 could not be serogrouped. Among the 351 strains, 63 (17.9%) carried stx1 gene and 300 (82.1%) carried stx2, including 12 strains positive for both. The majority of the stx1 and stx2 were of stx1a (47/63; 74.6%) and stx2a subtypes (234/300; 78%), respectively, which are often associated with human infections. A novel multiplex PCR assay developed and validated to detect six serogroups, O2, O74, O109, O131, O168, and O171, which accounted for 86.9% of the STEC strains identified, was utilized to determine their prevalence in fecal samples (n = 576) collected from a commercial feedlot. Four serogroups, O2, O109, O168, and O171 were identified as the dominant serogroups prevalent in cattle feces. In conclusion, cattle shed in the feces a number of STEC serogroups, other than the top-7, and the majority of the strains isolated possessed stx2, particularly of the subtype 2a, suggesting their potential risk to cause human infections.
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12
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Differential Outcome between BALB/c and C57BL/6 Mice after Escherichia coli O157:H7 Infection Is Associated with a Dissimilar Tolerance Mechanism. Infect Immun 2021; 89:IAI.00031-21. [PMID: 33619029 DOI: 10.1128/iai.00031-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 02/01/2021] [Indexed: 01/19/2023] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) infections can result in a wide range of clinical presentations despite that EHEC strains belong to the O157:H7 serotype, one of the most pathogenic forms. Although pathogen virulence influences disease outcome, we emphasize the concept of host-pathogen interactions, which involve resistance or tolerance mechanisms in the host that determine total host fitness and bacterial virulence. Taking advantage of the genetic differences between mouse strains, we analyzed the clinical progression in C57BL/6 and BALB/c weaned mice infected with an E. coli O157:H7 strain. We carefully analyzed colonization with several bacterial doses, clinical parameters, intestinal histology, and the integrity of the intestinal barrier, as well as local and systemic levels of antibodies to pathogenic factors. We demonstrated that although both strains had comparable susceptibility to Shiga toxin (Stx) and the intestinal bacterial burden was similar, C57BL/6 showed increased intestinal damage, alteration of the integrity of the intestinal barrier, and impaired renal function that resulted in increased mortality. The increased survival rate in the BALB/c strain was associated with an early specific antibody response as part of a tolerance mechanism.
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13
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Lupolova N, Chalka A, Gally DL. Predicting Host Association for Shiga Toxin-Producing E. coli Serogroups by Machine Learning. Methods Mol Biol 2021; 2291:99-117. [PMID: 33704750 DOI: 10.1007/978-1-0716-1339-9_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Escherichia coli is a species of bacteria that can be present in a wide variety of mammalian hosts and potentially soil environments. E. coli has an open genome and can show considerable diversity in gene content between isolates. It is a reasonable assumption that gene content reflects evolution of strains in particular host environments and therefore can be used to predict the host most likely to be the source of an isolate. An extrapolation of this argument is that strains may also have gene content that favors success in multiple hosts and so the possibility of successful transmission from one host to another, for example, from cattle to human, can also be predicted based on gene content. In this methods chapter, we consider the issue of Shiga toxin (Stx)-producing E. coli (STEC) strains that are present in ruminants as the main host reservoir and for which we know that a subset causes life-threatening infections in humans. We show how the genome sequences of E. coli isolated from both cattle and humans can be used to build a classifier to predict human and cattle host association and how this can be applied to score key STEC serotypes known to be associated with human infection. With the example dataset used, serogroups O157, O26, and O111 show the highest, and O103 and O145 the lowest, predictions for human association. The long-term ambition is to combine such machine learning predictions with phylogeny to predict the zoonotic threat of an isolate based on its whole genome sequence (WGS).
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Affiliation(s)
- Nadejda Lupolova
- Division of Infection and Immunity, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
| | - Antonia Chalka
- Division of Infection and Immunity, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
| | - David L Gally
- Division of Infection and Immunity, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK.
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14
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Lee MS, Yoon JW, Tesh VL. Editorial: Recent Advances in Understanding the Pathogenesis of Shiga Toxin-Producing Shigella and Escherichia coli. Front Cell Infect Microbiol 2020; 10:620703. [PMID: 33324585 PMCID: PMC7726016 DOI: 10.3389/fcimb.2020.620703] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 11/06/2020] [Indexed: 12/17/2022] Open
Affiliation(s)
- Moo-Seung Lee
- Environmental Diseases Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.,Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, South Korea
| | - Jang Won Yoon
- College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon, South Korea
| | - Vernon L Tesh
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, College of Medicine, Bryan, TX, United States
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15
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Kawase J, Hirai S, Yokoyama E, Hayashi F, Kurosaki M, Kawakami Y, Fukuma A, Sakai T, Kotani M, Asakura H. Phylogeny, Prevalence, and Shiga Toxin (Stx) Production of Clinical Escherichia coli O157 Clade 2 Strains Isolated in Shimane Prefecture, Japan. Curr Microbiol 2020; 78:265-273. [PMID: 33095293 DOI: 10.1007/s00284-020-02252-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 10/12/2020] [Indexed: 10/23/2022]
Abstract
This study investigated the genetic and pathogenic variation of the subgroups of clade 2 strains of Shiga toxin (Stx)-producing Escherichia coli (STEC) O157. A total of 111 strains of STEC O157 isolated in Shimane prefecture, Japan, were classified in clade 2 (n = 39), clade 3 (n = 16), clade 4/5 (n = 3), clade 7 (n = 14), clade 8 (n = 17), and clade 12 (n = 22) by single-nucleotide polymorphism analysis and lineage-specific polymorphism assay-6. These results showed a distinct difference from our previous study in which clade 3 strains were the most prevalent strains in three other prefectures in Japan, indicating that the clade distribution of O157 strains was different in different geographic areas in Japan. Phylogenetic analysis using insertion sequence (IS) 629 distribution data showed that clade 2 strains formed two clusters, designated 2a and 2b. Stx2 production by cluster 2b strains was significantly higher than by cluster 2a strains (P < 0.01). In addition, population genetic analysis of the clade 2 strains showed significant linkage disequilibrium in the IS629 distribution of the strains in clusters 2a and 2b (P < 0.05). The ΦPT values calculated using the IS629 distribution data indicated that strains in clusters 2a and 2b were genetically different (P < 0.001). Cluster 2b strains are a highly pathogenic phylogenetic group and their geographic spread may be a serious public health concern.
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Affiliation(s)
- Jun Kawase
- Division of Bacteriology, Shimane Prefectural Institute of Public Health and Environmental Science, 582 Nishihamasada, Matsue City, Shimane, 690-0122, Japan.
| | - Shinichiro Hirai
- Infectious Disease Surveillance Center, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama City, Tokyo, 208-0011, Japan
| | - Eiji Yokoyama
- Division of Bacteriology, Chiba Prefectural Institute of Public Health, 666-2 Nitona, Chuo, Chiba City, Chiba, 260-8715, Japan
| | - Fumi Hayashi
- Division of Bacteriology, Shimane Prefectural Institute of Public Health and Environmental Science, 582 Nishihamasada, Matsue City, Shimane, 690-0122, Japan
| | - Morito Kurosaki
- Division of Bacteriology, Shimane Prefectural Institute of Public Health and Environmental Science, 582 Nishihamasada, Matsue City, Shimane, 690-0122, Japan
| | - Yuta Kawakami
- Division of Bacteriology, Shimane Prefectural Institute of Public Health and Environmental Science, 582 Nishihamasada, Matsue City, Shimane, 690-0122, Japan
| | - Aiko Fukuma
- Division of Bacteriology, Shimane Prefectural Institute of Public Health and Environmental Science, 582 Nishihamasada, Matsue City, Shimane, 690-0122, Japan
| | - Tomotake Sakai
- Division of Bacteriology, Shimane Prefectural Institute of Public Health and Environmental Science, 582 Nishihamasada, Matsue City, Shimane, 690-0122, Japan
| | - Mayuko Kotani
- Division of Bacteriology, Shimane Prefectural Institute of Public Health and Environmental Science, 582 Nishihamasada, Matsue City, Shimane, 690-0122, Japan
| | - Hiroshi Asakura
- Division of Biomedical Food Research, National Institute of Health Sciences, Tonomachi 3-25-26, Kawasaki-ku, Kawasaki City, Kanagawa, 210-9501, Japan
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16
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Greig DR, Mikhail AFW, Dallman TJ, Jenkins C. Analysis Shiga Toxin-Encoding Bacteriophage in a Rare Strain of Shiga Toxin-Producing Escherichia coli O157:H7 stx2a/stx2c. Front Microbiol 2020; 11:577658. [PMID: 33193199 PMCID: PMC7609406 DOI: 10.3389/fmicb.2020.577658] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/09/2020] [Indexed: 02/05/2023] Open
Abstract
In December 2015, six cases of Shiga toxin (Stx)-producing Escherichia coli (STEC) O157:H7 stx2a/stx2c phage type (PT) 24 were identified by the national gastrointestinal disease surveillance system at Public Health England (PHE). Frozen grated coconut imported from India was implicated as the vehicle of infection. Short and long read sequencing data were interrogated for genomic markers to provide evidence that the outbreak strain was from an imported source. The outbreak strain belonged to a sub-lineage (IIa) rare in domestically acquired infection in the United Kingdom, and indicative of an imported strain. Phylogenetic analysis identified the most closely related isolates to the outbreak strain were from cases reporting recent travel not to India, but to Uganda. Phylo-geographical signals based on travel data may be confounded by the failure of local and/or global monitoring systems to capture the full diversity of strains in a given country. This may be due to low prevalence strains circulating in-country under the surveillance radar, or a recent importation event involving the migration of animals and/or people. Comparison of stx2a-encoding prophage harbored by the outbreak strain with publicly available stx2a-encoding prophage sequences revealed that it was most closely related to stx2a-encoding prophage acquired by STEC O157:H7 that caused the first outbreak of STEC-hemolytic uremic syndrome (HUS) in England in 1982–83. Animal and people migration events may facilitate the transfer of stx2a-encoding prophage from indigenous STEC O157:H7 to recently imported strains, or vice versa. Monitoring the global transmission of STEC O157:H7 and tracking the exchange of stx2a-encoding phage between imported and indigenous strains may provide an early warning of emerging threats to public health.
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Affiliation(s)
- David R Greig
- National Infection Service, Public Health England, London, United Kingdom.,Division of Infection and Immunity, The Royal (Dick) School of Veterinary Studies, The Roslin Institute, The University of Edinburgh, Easter Bush, United Kingdom
| | - Amy F W Mikhail
- National Infection Service, Public Health England, London, United Kingdom
| | - Timothy J Dallman
- National Infection Service, Public Health England, London, United Kingdom.,Division of Infection and Immunity, The Royal (Dick) School of Veterinary Studies, The Roslin Institute, The University of Edinburgh, Easter Bush, United Kingdom
| | - Claire Jenkins
- National Infection Service, Public Health England, London, United Kingdom
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17
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Abstract
Escherichia coli is a commensal of the vertebrate gut that is increasingly involved in various intestinal and extra-intestinal infections as an opportunistic pathogen. Numerous pathotypes that represent groups of strains with specific pathogenic characteristics have been described based on heterogeneous and complex criteria. The democratization of whole-genome sequencing has led to an accumulation of genomic data that render possible a population phylogenomic approach to the emergence of virulence. Few lineages are responsible for the pathologies compared with the diversity of commensal strains. These lineages emerged multiple times during E. coli evolution, mainly by acquiring virulence genes located on mobile elements, but in a specific chromosomal phylogenetic background. This repeated emergence of stable and cosmopolitan lineages argues for an optimization of strain fitness through epistatic interactions between the virulence determinants and the remaining genome.
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18
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Teng L, Lee S, Park D, Jeong KC. Genetic and Functional Analyses of Virulence Potential of an Escherichia coli O157:H7 Strain Isolated From Super-Shedder Cattle. Front Cell Infect Microbiol 2020; 10:271. [PMID: 32582570 PMCID: PMC7289925 DOI: 10.3389/fcimb.2020.00271] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 05/07/2020] [Indexed: 12/19/2022] Open
Abstract
Shiga toxin (Stx)-producing Escherichia coli (STEC) O157:H7 is an enteric pathogen that causes life-threatening disease in humans, with cattle being major natural reservoirs. A group of STEC O157:H7 with a dramatic combination of high virulence potentials and super-shedder bovine origin have been isolated. Here, an STEC O157:H7 isolate, JEONG-1266, was analyzed by comparative genomics, stx genotyping, and phenotypic analyses. The phylogenetic typing and whole-genome comparison consistently showed that JEONG-1266 is genetically close to EC4115 (one of 2006 Spinach outbreak isolates) and SS17 (an isolate from super-shedder cattle) strains, all of which belong to lineage I/II and Clade 8. Both lineage I/II and Clade 8 are known to be mostly associated with clinical strains with high virulence and severe clinical symptoms. Further, JEONG-1266, like EC4115 and SS17, harbors stx2a/stx2c genes, and carries Stx-encoding prophages, specifically the φstx2a-γ subtype. Possession of the φstx2a-γ subtype of Stx-encoding prophages and production of Stx2a have been shown to be a key signature associated with hypervirulent STEC O157:H7 strains. In silico virulence typing elucidated JEONG-1266, EC4115, and SS17 shared a highly conserved profile of key virulence genes at the nucleotide sequence level. Consistently, phenotypic data showed that JEONG-1266 expressed a high level of Stx2 toxins and had the full capacity of adhesion in vitro. Taken together, our study suggests that JEONG-1266 may represent an emerging STEC O157:H7 group, which are hypervirulent strains that originate from super-shedders, that can be a threat to food safety and public health.
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Affiliation(s)
- Lin Teng
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States.,Department of Animal Sciences, University of Florida, Gainesville, FL, United States
| | - Shinyoung Lee
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States.,Department of Animal Sciences, University of Florida, Gainesville, FL, United States
| | - Dongjin Park
- Food Science and Technology Department, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Kwangcheol Casey Jeong
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States.,Department of Animal Sciences, University of Florida, Gainesville, FL, United States
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19
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Analysis of virulence potential of Escherichia coli O145 isolated from cattle feces and hide samples based on whole genome sequencing. PLoS One 2019; 14:e0225057. [PMID: 31774847 PMCID: PMC6881001 DOI: 10.1371/journal.pone.0225057] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 10/28/2019] [Indexed: 12/29/2022] Open
Abstract
Escherichia coli O145 serogroup is one of the big six non-O157 Shiga toxin producing E. coli (STEC) that causes foodborne illnesses in the United States and other countries. Cattle are a major reservoir of STEC, which harbor them in their hindgut and shed in the feces. Cattle feces is the main source of hide and subsequent carcass contaminations during harvest leading to foodborne illnesses in humans. The objective of our study was to determine the virulence potential of STEC O145 strains isolated from cattle feces and hide samples. A total of 71 STEC O145 strains isolated from cattle feces (n = 16), hide (n = 53), and human clinical samples (n = 2) were used in the study. The strains were subjected to whole genome sequencing using Illumina MiSeq platform. The average draft genome size of the fecal, hide, and human clinical strains were 5.41, 5.28, and 5.29 Mb, respectively. The average number of genes associated with mobile genetic elements was 260, 238, and 259, in cattle fecal, hide, and human clinical strains, respectively. All strains belonged to O145:H28 serotype and carried eae subtype γ. Shiga toxin 1a was the most common Shiga toxin gene subtype among the strains, followed by stx2a and stx2c. The strains also carried genes encoding type III secretory system proteins, nle, and plasmid-encoded virulence genes. Phylogenetic analysis revealed clustering of cattle fecal strains separately from hide strains, and the human clinical strains were more closely related to the hide strains. All the strains belonged to sequence type (ST)-32. The virulence gene profile of STEC O145 strains isolated from cattle sources was similar to that of human clinical strains and were phylogenetically closely related to human clinical strains. The genetic analysis suggests the potential of cattle STEC O145 strains to cause human illnesses. Inclusion of more strains from cattle and their environment in the analysis will help in further elucidation of the genetic diversity and virulence potential of cattle O145 strains.
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20
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Lisboa LF, Szelewicki J, Lin A, Latonas S, Li V, Zhi S, Parsons BD, Berenger B, Fathima S, Chui L. Epidemiology of Shiga Toxin-Producing Escherichia coli O157 in the Province of Alberta, Canada, 2009-2016. Toxins (Basel) 2019; 11:toxins11100613. [PMID: 31652648 PMCID: PMC6832344 DOI: 10.3390/toxins11100613] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/16/2019] [Accepted: 10/19/2019] [Indexed: 11/19/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) infections are the product of the interaction between bacteria, phages, animals, humans, and the environment. In the late 1980s, Alberta had one of the highest incidences of STEC infections in North America. Herein, we revisit and contextualize the epidemiology of STEC O157 human infections in Alberta for the period 2009–2016. STEC O157 infections were concentrated in large urban centers, but also in rural areas with high cattle density. Hospitalization was often required when the Shiga toxin genotype stx2a stx2c was involved, however, only those aged 60 years or older and infection during spring months (April to June) independently predicted that need. Since the late 1980s, the rate of STEC O157-associated hemolytic uremic syndrome (HUS) in Alberta has remained unchanged at 5.1%, despite a marked drop in the overall incidence of the infection. While Shiga toxin genotypes stx1a stx2c and stx2a stx2c seemed associated with HUS, only those aged under 10 years and infection during spring months were independently predictive of that complication. The complexity of the current epidemiology of STEC O157 in Alberta highlights the need for a One Health approach for further progress to be made in mitigating STEC morbidity.
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Affiliation(s)
- Luiz F Lisboa
- Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R3, Canada.
| | - Jonas Szelewicki
- Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R3, Canada.
| | - Alex Lin
- Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R3, Canada.
| | - Sarah Latonas
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R3, Canada.
| | - Vincent Li
- Provincial Laboratory for Public Health, Alberta Public Laboratories, Edmonton, AB T6G 2B7, Canada.
| | - Shuai Zhi
- Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R3, Canada.
| | - Brendon D Parsons
- Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R3, Canada.
| | - Byron Berenger
- Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R3, Canada.
| | - Sumana Fathima
- The Ministry of Health, Government of Alberta, Edmonton, AB T5J 1S6, Canada.
| | - Linda Chui
- Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R3, Canada.
- Provincial Laboratory for Public Health, Alberta Public Laboratories, Edmonton, AB T6G 2B7, Canada.
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21
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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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Effective Surveillance Using Multilocus Variable-Number Tandem-Repeat Analysis and Whole-Genome Sequencing for Enterohemorrhagic Escherichia coli O157. Appl Environ Microbiol 2019; 85:AEM.00728-19. [PMID: 31227555 DOI: 10.1128/aem.00728-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 06/13/2019] [Indexed: 01/06/2023] Open
Abstract
Due to the potential of enterohemorrhagic Escherichia coli (EHEC) serogroup O157 to cause large food borne outbreaks, national and international surveillance is necessary. For developing an effective method of molecular surveillance, a conventional method, multilocus variable-number tandem-repeat analysis (MLVA), and whole-genome sequencing (WGS) analysis were compared. WGS of 369 isolates of EHEC O157 belonging to 7 major MLVA types and their relatives were subjected to comprehensive in silico typing, core genome single nucleotide polymorphism (cgSNP), and core genome multilocus sequence typing (cgMLST) analyses. The typing resolution was the highest in cgSNP analysis. However, determination of the sequence of the mismatch repair protein gene mutS is necessary because spontaneous deletion of the gene could lead to a hypermutator phenotype. MLVA had sufficient typing resolution for a short-term outbreak investigation and had advantages in rapidity and high throughput. cgMLST showed less typing resolution than cgSNP, but it is less time-consuming and does not require as much computer power. Therefore, cgMLST is suitable for comparisons using large data sets (e.g., international comparison using public databases). In conclusion, screening using MLVA followed by cgMLST and cgSNP analyses would provide the highest typing resolution and improve the accuracy and cost-effectiveness of EHEC O157 surveillance.IMPORTANCE Intensive surveillance for enterohemorrhagic Escherichia coli (EHEC) serogroup O157 is important to detect outbreaks and to prevent the spread of the bacterium. Recent advances in sequencing technology made molecular surveillance using whole-genome sequence (WGS) realistic. To develop rapid, high-throughput, and cost-effective typing methods for real-time surveillance, typing resolution of WGS and a conventional typing method, multilocus variable-number tandem-repeat analysis (MLVA), was evaluated. Nation-level systematic comparison of MLVA, core genome single nucleotide polymorphism (cgSNP), and core genome multilocus sequence typing (cgMLST) indicated that a combination of WGS and MLVA is a realistic approach to improve EHEC O157 surveillance.
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23
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Virulence Characteristics and Antimicrobial Resistance Profiles of Shiga Toxin-Producing Escherichia coli Isolates from Humans in South Africa: 2006-2013. Toxins (Basel) 2019; 11:toxins11070424. [PMID: 31331115 PMCID: PMC6669688 DOI: 10.3390/toxins11070424] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Revised: 07/01/2019] [Accepted: 07/03/2019] [Indexed: 01/11/2023] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) isolates (N = 38) that were incriminated in human disease from 2006 to 2013 in South Africa were characterized by serotype, virulence-associated genes, antimicrobial resistance and pulsed-field gel electrophoresis (PFGE). The isolates belonged to 11 O:H serotypes. STEC O26:H11 (24%) was the most frequent serotype associated with human disease, followed by O111:H8 (16%), O157:H7 (13%) and O117:H7 (13%). The majority of isolates were positive for key virulence-associated genes including stx1 (84%), eaeA (61%), ehxA (68.4%) and espP (55%), but lacked stx2 (29%), katP (42%), etpD (16%), saa (16%) and subA (3%). stx2 positive isolates carried stx2c (26%) and/or stx2d (26%) subtypes. All pathogenicity island encoded virulence marker genes were detected in all (100%) isolates except nleA (47%), nleC (84%) and nleD (76%). Multidrug resistance was observed in 89% of isolates. PFGE revealed 34 profiles with eight distinct clusters that shared ≥80% intra-serotype similarity, regardless of the year of isolation. In conclusion, STEC isolates that were implicated in human disease between 2006 and 2013 in South Africa were mainly non-O157 strains which possessed virulence genes and markers commonly associated with STEC strains that have been incriminated in mild to severe human disease worldwide. Improved STEC monitoring and surveillance programs are needed in South Africa to control and prevent STEC disease in humans.
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24
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Ingle DJ, Gonçalves da Silva A, Valcanis M, Ballard SA, Seemann T, Jennison AV, Bastian I, Wise R, Kirk MD, Howden BP, Williamson DA. Emergence and divergence of major lineages of Shiga-toxin-producing Escherichia coli in Australia. Microb Genom 2019; 5. [PMID: 31107203 PMCID: PMC6562248 DOI: 10.1099/mgen.0.000268] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Shiga-toxin-producing Escherichia coli (STEC) infection is an important global cause of foodborne disease. To date however, genomics-based studies of STEC have been predominately focused upon STEC collected in the Northern Hemisphere. Here, we demonstrate the population structure of 485 STEC isolates in Australia, and show that several clonal groups (CGs) common to Australia were infrequently detected in a representative selection of contemporary STEC genomes from around the globe. Further, phylogenetic analysis demonstrated that lineage II of the global O157:H7 STEC was most prevalent in Australia, and was characterized by a frameshift mutation in flgF, resulting in the H-non-motile phenotype. Strong concordance between in silico and phenotypic serotyping was observed, along with concordance between in silico and conventional detection of stx genes. These data represent the most comprehensive STEC analysis from the Southern Hemisphere, and provide a framework for future national genomics-based surveillance of STEC in Australia.
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Affiliation(s)
- Danielle J. Ingle
- Microbiological Diagnostic Unit Public Health Laboratory at the University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- National Centre for Epidemiology and Population Health, The Australian National University, Canberra, Australia
| | - Anders Gonçalves da Silva
- Microbiological Diagnostic Unit Public Health Laboratory at the University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Mary Valcanis
- Microbiological Diagnostic Unit Public Health Laboratory at the University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Susan A. Ballard
- Microbiological Diagnostic Unit Public Health Laboratory at the University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Torsten Seemann
- Microbiological Diagnostic Unit Public Health Laboratory at the University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- Melbourne Bioinformatics Group, Victoria, Australia
| | - Amy V. Jennison
- Public Health Microbiology, Forensic and Scientific Services, Queensland Department of Health, Queensland, Australia
| | | | - Rolf Wise
- SA Pathology, South Australia, Australia
| | - Martyn D. Kirk
- National Centre for Epidemiology and Population Health, The Australian National University, Canberra, Australia
| | - Benjamin P. Howden
- Microbiological Diagnostic Unit Public Health Laboratory at the University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- Doherty Applied Microbial Genomics, Department Microbiology and Immunology, The University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Deborah A. Williamson
- Microbiological Diagnostic Unit Public Health Laboratory at the University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- *Correspondence: Deborah A. Williamson,
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25
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Response to Questions Posed by the Food and Drug Administration Regarding Virulence Factors and Attributes that Define Foodborne Shiga Toxin-Producing Escherichia coli (STEC) as Severe Human Pathogens †. J Food Prot 2019; 82:724-767. [PMID: 30969806 DOI: 10.4315/0362-028x.jfp-18-479] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
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- NACMCF Executive Secretariat, * U.S. Department of Agriculture, Food Safety and Inspection Service, Office of Public Health Science, PP3, 9-178, 1400 Independence Avenue S.W., Washington, D.C. 20250-3700, USA
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26
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Modulation of Enterohaemorrhagic Escherichia coli Survival and Virulence in the Human Gastrointestinal Tract. Microorganisms 2018; 6:microorganisms6040115. [PMID: 30463258 PMCID: PMC6313751 DOI: 10.3390/microorganisms6040115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 11/16/2018] [Accepted: 11/18/2018] [Indexed: 01/05/2023] Open
Abstract
Enterohaemorrhagic Escherichia coli (EHEC) is a major foodborne pathogen responsible for human diseases ranging from diarrhoea to life-threatening complications. Survival of the pathogen and modulation of virulence gene expression along the human gastrointestinal tract (GIT) are key features in bacterial pathogenesis, but remain poorly described, due to a paucity of relevant model systems. This review will provide an overview of the in vitro and in vivo studies investigating the effect of abiotic (e.g., gastric acid, bile, low oxygen concentration or fluid shear) and biotic (e.g., gut microbiota, short chain fatty acids or host hormones) parameters of the human gut on EHEC survival and/or virulence (especially in relation with motility, adhesion and toxin production). Despite their relevance, these studies display important limitations considering the complexity of the human digestive environment. These include the evaluation of only one single digestive parameter at a time, lack of dynamic flux and compartmentalization, and the absence of a complex human gut microbiota. In a last part of the review, we will discuss how dynamic multi-compartmental in vitro models of the human gut represent a novel platform for elucidating spatial and temporal modulation of EHEC survival and virulence along the GIT, and provide new insights into EHEC pathogenesis.
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27
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Rahman M, Nabi A, Asadulghani M, Faruque SM, Islam MA. Toxigenic properties and stx phage characterization of Escherichia coli O157 isolated from animal sources in a developing country setting. BMC Microbiol 2018; 18:98. [PMID: 30170562 PMCID: PMC6119239 DOI: 10.1186/s12866-018-1235-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 08/16/2018] [Indexed: 12/21/2022] Open
Abstract
Background In many Asian countries including Bangladesh E. coli O157 are prevalent in animal reservoirs and in the food chain, but the incidence of human infection due to E. coli O157 is rare. One of the reasons could be inability of the organism from animal origin to produce sufficient amount of Shiga toxin (Stx), which is the main virulence factor associated with the severe sequelae of infection. This study aimed to fill out this knowledge gap by investigating the toxigenic properties and characteristics of stx phage of E. coli O157 isolated from animal sources in Bangladesh. Results We analysed 47 stx2 positive E. coli O157 of food/animal origin for stx2 gene variants, Shiga toxin production, presence of other virulence genes, stx phage insertion sites, presence of genes associated with functionality of stx phages (Q933 and Q21) and stx2 upstream region. Of the 47 isolates, 46 were positive for both stx2a and stx2d while the remaining isolate was positive for stx2d only. Reverse Passive Latex Agglutination assay (RPLA) showed that 42/47 isolates produced little or no toxin, while 5 isolates produced a high titre of toxin (64 to 128). 39/47 isolates were positive for the Toxin Non-Producing (TNP) specific regions in the stx2 promoter. Additionally, all isolates were negative for antiterminator Q933while a majority of isolates were positive for Q21 gene suggesting the presence of defective stx phage. Of the yehV and wrbA phage insertion sites, yehV was found occupied in 11 isolates while wrbA site was intact in all the isolates. None of the isolates was positive for the virulence gene, cdt but all were positive for hlyA, katP, etpD and eae genes. Isolates that produced high titre Stx (n = 5) produced complete phage particles capable of infecting multiple bacterial hosts. One of these phages was shown to produce stable lysogens in host strains rendering the Stx2 producing ability. Conclusion Despite low frequency in the tested isolates, E. coli O157 isolates in Bangladesh carry inducible stx phages and have the capacity to produce Stx2, indicating a potential risk of E. coli O157 infection in humans.
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Affiliation(s)
- Mahdia Rahman
- Enteric and Food Microbiology Laboratory, Laboratory Sciences and Services Division (LSSD), International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Mohakhali, Dhaka, 1212, Bangladesh
| | - Ashikun Nabi
- Enteric and Food Microbiology Laboratory, Laboratory Sciences and Services Division (LSSD), International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Mohakhali, Dhaka, 1212, Bangladesh.,Present Address: Department of Biology, University of Vermont, Burlington, VT, 05405, USA
| | - Md Asadulghani
- Enteric and Food Microbiology Laboratory, Laboratory Sciences and Services Division (LSSD), International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Mohakhali, Dhaka, 1212, Bangladesh
| | - Shah M Faruque
- Enteric and Food Microbiology Laboratory, Laboratory Sciences and Services Division (LSSD), International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Mohakhali, Dhaka, 1212, Bangladesh.,Present Address: Department of Mathematics and Natural Sciences, BRAC University, Mohakhali, Dhaka, 1212, Bangladesh
| | - Mohammad Aminul Islam
- Enteric and Food Microbiology Laboratory, Laboratory Sciences and Services Division (LSSD), International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Mohakhali, Dhaka, 1212, Bangladesh.
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28
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Oprea M, Ciontea AS, Militaru M, Dinu S, Cristea D, Usein CR. Molecular Typing of Escherichia coli O157 Isolates from Romanian Human Cases. Jpn J Infect Dis 2018; 71:455-461. [PMID: 30068889 DOI: 10.7883/yoken.jjid.2018.129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Verocytotoxin-producing Escherichia coli (VTEC) of serogroup O157 are among the most important causes of severe cases of foodborne disease and outbreaks worldwide. As little is known about the characteristic of these strains in Romania, we aimed to provide reference information on the virulence gene content, phylogenetic background, and genetic diversity of 7 autochthonous O157 strains collected during 2016 and 2017 from epidemiologically non-related cases. These strains were typed by a combination of phenotypic and molecular methods routinely used by the national reference laboratory. Additionally, 4 of them were subjected to whole-genome sequencing (WGS), and public web-based tools were used to extract information on virulence gene profiles, multilocus sequence types (MLST), and single nucleotide polymorphism (SNP)-based phylogenetic relatedness. Molecular typing provided evidence of the circulation of a polyclonal population while distinguishing a cluster of non-sorbitol-fermenting, glucuronidase-negative, phylogenetic group E, MLST 1804 strains, representing lineage II and clade 7, which harbored vtx2c, eae-gamma, and ehxA genes. A good correlation between the routine typing methods and WGS data was observed. However, SNP-based genotyping provided a higher resolution in depicting the relationships between the O157:H7 strains than that provided by Pulse-field gel electrophoresis. This study should be a catalyst for improved laboratory-based surveillance of autochthonous VTEC.
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Affiliation(s)
- Mihaela Oprea
- Cantacuzino National Medico-Military Institute for Research and Development.,The Research Institute of the University of Bucharest
| | | | - Mădălina Militaru
- Cantacuzino National Medico-Military Institute for Research and Development
| | - Sorin Dinu
- Cantacuzino National Medico-Military Institute for Research and Development
| | - Daniela Cristea
- Cantacuzino National Medico-Military Institute for Research and Development
| | - Codruţa-Romaniţa Usein
- Cantacuzino National Medico-Military Institute for Research and Development.,Carol Davila University of Medicine and Pharmacy
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29
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Salinas Ibáñez ÁG, Lucero Estrada C, Favier GI, Vega AE, Stagnitta PV, Mattar MA, Zolezzi G, Carbonari C, Miliwebsky E, Cortiñas TI, Escudero ME. Characterization of Shiga-toxin producingEscherichia coliisolated from meat products sold in San Luis, Argentina. J Food Saf 2018. [DOI: 10.1111/jfs.12488] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Cecilia Lucero Estrada
- Microbiologia Area, National University of San Luis; San Luis Argentina
- Multidisciplinary Institute of Biological Researches, National Council of Scientific and Technological Researches (IMIBIO-CONICET); San Luis Argentina
| | | | - Alba Edith Vega
- Microbiologia Area, National University of San Luis; San Luis Argentina
| | | | - María Aída Mattar
- Microbiologia Area, National University of San Luis; San Luis Argentina
| | - Gisela Zolezzi
- STEC National Reference Laboratory at the ANLIS-INEI “Dr. Carlos G. Malbran” Institute; Ciudad Autónoma de Buenos Aires; Argentina
| | - Carolina Carbonari
- STEC National Reference Laboratory at the ANLIS-INEI “Dr. Carlos G. Malbran” Institute; Ciudad Autónoma de Buenos Aires; Argentina
| | - Elizabeth Miliwebsky
- STEC National Reference Laboratory at the ANLIS-INEI “Dr. Carlos G. Malbran” Institute; Ciudad Autónoma de Buenos Aires; Argentina
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30
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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 DOI: 10.1017/s0950268818001632] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [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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31
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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: 14] [Impact Index Per Article: 2.3] [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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32
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Shridhar PB, Patel IR, Gangiredla J, Noll LW, Shi X, Bai J, Elkins CA, Strockbine NA, Nagaraja TG. Genetic Analysis of Virulence Potential of Escherichia coli O104 Serotypes Isolated From Cattle Feces Using Whole Genome Sequencing. Front Microbiol 2018; 9:341. [PMID: 29545780 PMCID: PMC5838399 DOI: 10.3389/fmicb.2018.00341] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 02/12/2018] [Indexed: 11/13/2022] Open
Abstract
Escherichia coli O104:H4, a Shiga toxin-producing hybrid pathotype that was implicated in a major foodborne outbreak in Germany in 2011, has not been detected in cattle. However, serotypes of O104, other than O104:H4, have been isolated from cattle feces, with O104:H7 being the most predominant. In this study, we investigated, based on whole genome sequence analyses, the virulence potential of E. coli O104 strains isolated from cattle feces, since cattle are asymptomatic carriers of E. coli O104. The genomes of ten bovine E. coli O104 strains (six O104:H7, one O104:H8, one O104:H12, and two O104:H23) and five O104:H7 isolated from human clinical cases were sequenced. Of all the bovine O104 serotypes (H7, H8, H12, and H23) that were included in the study, only E. coli O104:H7 serotype possessed Shiga toxins. Four of the six bovine O104:H7 strains and one of the five human strains carried stx1c. Three human O104 strains carried stx2, two were of subtype 2a, and one was 2d. Genomes of stx carrying bovine O104:H7 strains were larger than the stx-negative strains of O104:H7 or other serotypes. The genome sizes were proportional to the number of genes carried on the mobile genetic elements (phages, prophages, transposable elements and plasmids). Both bovine and human strains were negative for intimin and other genes associated with the type III secretory system and non-LEE encoded effectors. Plasmid-encoded virulence genes (ehxA, epeA, espP, katP) were also present in bovine and human strains. All O104 strains were negative for antimicrobial resistance genes, except one human strain. Phylogenetic analysis indicated that bovine E. coli O104 strains carrying the same flagellar antigen clustered together and STEC strains clustered separately from non-STEC strains. One of the human O104:H7 strains was phylogenetically closely related to and belonged to the same sequence type (ST-1817) as the bovine O104:H7 STEC strains. This suggests that the bovine feces could be a source of human illness caused by E. coli O104:H7 serotype. Because bovine O104:H7 strains carried virulence genes similar to human clinical strains and one of the human clinical strains was phylogenetically related to bovine strains, the serotype has the potential to be a diarrheagenic pathogen in humans.
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Affiliation(s)
- Pragathi B Shridhar
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS, United States
| | - Isha R Patel
- Division of Molecular Biology, Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Laurel, MD, United States
| | - Jayanthi Gangiredla
- Division of Molecular Biology, Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Laurel, MD, United States
| | - Lance W Noll
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS, United States
| | - Xiaorong Shi
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS, United States
| | - Jianfa Bai
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS, United States.,Veterinary Diagnostic Laboratory, Kansas State University, Manhattan, KS, United States
| | - Christopher A Elkins
- Division of Molecular Biology, Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Laurel, MD, United States
| | - Nancy A Strockbine
- Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - T G Nagaraja
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS, United States
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33
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Enterohemorrhagic Escherichia coli O157 subclade 8b strains in Chiba Prefecture, Japan, produced larger amounts of Shiga toxin 2 than strains in subclade 8a and other clades. PLoS One 2018; 13:e0191834. [PMID: 29381715 PMCID: PMC5790261 DOI: 10.1371/journal.pone.0191834] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 01/11/2018] [Indexed: 11/19/2022] Open
Abstract
Enterohemorrhagic Escherichia coli O157 (O157) strains can be classified into clades (one of several phylogenetic groups) by single nucleotide polymorphisms (SNPs): these are clade 1, clade 2, clade 3, descendant and ancestral clades 4/5, clade 6, clade 7, clade 8, clade 9, and clade 12. Some recent studies showed that some O157 strains in clade 8 produced a larger amount of Shiga toxin (Stx) 2 than other strains. In this study, 1121 epidemiologically unlinked strains of O157 isolated in Chiba Prefecture, Japan were classified into clades during 1996–2014. Clade 8 strains were further classified into subclade 8a (67 strains) and subclade 8b (48 strains) using SNP analysis. In the absence of mitomycin C (MMC), subclade 8a strains in this study produced significantly greater amounts of Stx2 than subclade 8b strains. However, in the presence of MMC, the levels of Stx2 production in subclade 8b strains were significantly greater than subclade 8a strains. On the other hand, a recent study reported that the Stx2 production level in O157 strains was determined mainly by the subtypes of Stx2a phage (ϕStx2_α, β, γ, δ, ε, and ζ). Using O157 strains in this study, the Stx2a phages were classified into these subtypes. In this study, all strains of subclades 8a and 8b carried ϕStx2a_γ and ϕStx2a_δ, respectively. Some strains in clade 6 also carried ϕStx2a_δ. In the presence of MMC, subclade 8b strains produced significantly greater amounts of Stx2 than clade 6 strains carrying ϕStx2_δ. In this study, we propose that Stx2 production in subclade 8b strains in the presence of MMC might be enhanced due to genetic factors other than ϕStx2_δ.
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Worley JN, Flores KA, Yang X, Chase JA, Cao G, Tang S, Meng J, Atwill ER. Prevalence and Genomic Characterization of Escherichia coli O157:H7 in Cow-Calf Herds throughout California. Appl Environ Microbiol 2017; 83:e00734-17. [PMID: 28550057 PMCID: PMC5541215 DOI: 10.1128/aem.00734-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 05/17/2017] [Indexed: 01/12/2023] Open
Abstract
Escherichia coli serotype O157:H7 is a zoonotic food- and waterborne bacterial pathogen that causes a high hospitalization rate and can cause life-threatening complications. Increasingly, E. coli O157:H7 infections appear to originate from fresh produce. Ruminants, such as cattle, are a prominent reservoir of E. coli O157:H7 in the United States. California is one of the most agriculturally productive regions in the world for fresh produce, beef, and milk. The close proximity of fresh produce and cattle presents food safety challenges on a uniquely large scale. We performed a survey of E. coli O157:H7 on 20 farms in California to observe the regional diversity and prevalence of E. coli O157:H7. Isolates were obtained from enrichment cultures of cow feces. Some farms were sampled on two dates. Genomes from isolates were sequenced to determine their relatedness and pathogenic potential. E. coli O157:H7 was isolated from approximately half of the farms. The point prevalence of E. coli O157:H7 on farms was highly variable, ranging from zero to nearly 90%. Within farms, generally one or a few lineages were found, even when the rate of isolation was high. On farms with high isolation rates, a single clonal lineage accounted for most of the isolates. Farms that were visited months after the first visit might have had the same lineages of E. coli O157:H7. Strains of E. coli O157:H7 may be persistent for months on farms.IMPORTANCE This survey of 20 cow-calf operations from different regions of California provides an in depth look at resident Escherichia coli O157:H7 populations at the molecular level. E. coli O157:H7 is found to have a highly variable prevalence, and with whole-genome sequencing, high prevalences in herds were found to be due to a single lineage shed from multiple cows. Few repeat lineages were found between farms in this area; therefore, we predict that E. coli O157:H7 has significant diversity in this area beyond what is detected in this survey. All isolates from this study were found to have pathogenic potential based on the presence of key virulence gene sequences. This represents a novel insight into pathogen diversity within a single subtype and will inform future attempts to survey regional pathogen populations.
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Affiliation(s)
- Jay N Worley
- Joint Institute for Food Safety and Applied Nutrition, University of Maryland, College Park, Maryland, USA
| | - Kristopher A Flores
- Western Center for Food Safety, University of California, Davis, Davis, California, USA
| | - Xun Yang
- Department of Nutrition and Food Science, University of Maryland, College Park, Maryland, USA
| | - Jennifer A Chase
- Western Center for Food Safety, University of California, Davis, Davis, California, USA
| | - Guojie Cao
- Joint Institute for Food Safety and Applied Nutrition, University of Maryland, College Park, Maryland, USA
| | - Shuai Tang
- Department of Nutrition and Food Science, University of Maryland, College Park, Maryland, USA
| | - Jianghong Meng
- Joint Institute for Food Safety and Applied Nutrition, University of Maryland, College Park, Maryland, USA
| | - Edward R Atwill
- Western Center for Food Safety, University of California, Davis, Davis, California, USA
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Shridhar PB, Siepker C, Noll LW, Shi X, Nagaraja TG, Bai J. Shiga Toxin Subtypes of Non-O157 Escherichia coli Serogroups Isolated from Cattle Feces. Front Cell Infect Microbiol 2017; 7:121. [PMID: 28443248 PMCID: PMC5386980 DOI: 10.3389/fcimb.2017.00121] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 03/24/2017] [Indexed: 11/13/2022] Open
Abstract
Shiga toxin producing Escherichia coli (STEC) are important foodborne pathogens responsible for human illnesses. Cattle are a major reservoir that harbor the organism in the hindgut and shed in the feces. Shiga toxins (Stx) are the primary virulence factors associated with STEC illnesses. The two antigenically distinct Stx types, Stx1 and Stx2, encoded by stx1 and stx2 genes, share approximately 56% amino acid sequence identity. Genetic variants exist within Stx1 and Stx2 based on differences in amino acid composition and in cytotoxicity. The objective of our study was to identify the stx subtypes in strains of STEC serogroups, other than O157, isolated from cattle feces. Shiga toxin gene carrying E. coli strains (n = 192), spanning 27 serogroups originating from cattle (n = 170) and human (n = 22) sources, were utilized in the study. Shiga toxin genes were amplified by PCR, sequenced, and nucleotide sequences were translated into amino acid sequences using CLC main workbench software. Shiga toxin subtypes were identified based on the amino acid motifs that define each subtype. Shiga toxin genotypes were also identified at the nucleotide level by in silico restriction fragment length polymorphism (RFLP). Of the total 192 STEC strains, 93 (48.4%) were positive for stx1 only, 43 (22.4%) for stx2 only, and 56 (29.2%) for both stx1 and stx2. Among the 149 strains positive for stx1, 132 (88.6%) were stx1a and 17 (11.4%) were stx1c. Shiga toxin 1a was the most common subtype of stx1 among cattle (87.9%; 123/140) and human strains (100%; 9/9) of non-O157 serogroups. Of the total 99 strains positive for stx2, 79 were stx2a (79.8%), 11 (11.1%) were stx2c, 12 (12.1%) were stx2d. Of the 170 strains originating from cattle feces, 58 (34.1%) were stx2a subtype, 11 (6.5%) were stx2c subtype, and 11 were of subtype stx2d (6.5%). All but one of the human strains were positive for stx2a. Three strains of cattle origin were positive for both stx2a and stx2d. In conclusion, a number of non-O157 STEC serogroups harbored by cattle possess a wide variety of Shiga toxin subtypes, with stx1a and stx2a being the most predominant stx subtypes occurring individually or in combination. Cattle are a reservoir of a number of non-O157 STEC serogroups and information on the Shiga toxin subtypes is useful in assessing the potential risk as human pathogens.
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Affiliation(s)
- Pragathi B Shridhar
- Department of Diagnostic Medicine and Pathobiology, Kansas State UniversityManhattan, KS, USA
| | - Chris Siepker
- Department of Diagnostic Medicine and Pathobiology, Kansas State UniversityManhattan, KS, USA
| | - Lance W Noll
- Department of Diagnostic Medicine and Pathobiology, Kansas State UniversityManhattan, KS, USA
| | - Xiaorong Shi
- Department of Diagnostic Medicine and Pathobiology, Kansas State UniversityManhattan, KS, USA
| | - T G Nagaraja
- Department of Diagnostic Medicine and Pathobiology, Kansas State UniversityManhattan, KS, USA
| | - Jianfa Bai
- Department of Diagnostic Medicine and Pathobiology, Kansas State UniversityManhattan, KS, USA.,Veterinary Diagnostic Laboratory, Kansas State UniversityManhattan, KS, USA
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Identification of a New Virulent Clade in Enterohemorrhagic Escherichia coli O26:H11/H- Sequence Type 29. Sci Rep 2017; 7:43136. [PMID: 28230102 PMCID: PMC5322567 DOI: 10.1038/srep43136] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 01/19/2017] [Indexed: 01/04/2023] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O26 infections cause severe human diseases such as hemolytic uremic syndrome and encephalopathy, and is the predominant serogroup among non-O157 EHEC in many countries. Shiga toxin (Stx), which consists of two distinct types (Stx1 and Stx2), plays a central role in EHEC pathogenesis. The major stx gene type in EHEC O26 strains is stx1, although isolates with only stx2 have emerged in Japan since 2012 and have been reported in Europe. In this study, we selected 27 EHEC O26 strains isolated in Japan and identified a distinct genetic clade within sequence type (ST) 29, designated ST29C1, that carried only stx2 and had the plasmid gene profile ehxA+/katP−/espP+/etpD−. We showed that ST29C1 strains produced higher Stx2a levels, and greater virulence in Vero cells and in germ-free mice than other lineages. We also showed that ST29C1 was a distinct phylogenetic clade by SNP analysis using whole genome sequences and clearly differed from the major European EHEC O26 virulent clone, which was designated ST29C2 in this study. The combination of toxin production analysis, virulence analysis in Vero cells and germ-free mice, and phylogenetic analysis identified a newly emerging virulent EHEC clade.
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Sharapov UM, Wendel AM, Davis JP, Keene WE, Farrar J, Sodha S, Hyytia-Trees E, Leeper M, Gerner-Smidt P, Griffin PM, Braden C. Multistate Outbreak of Escherichia coli O157:H7 Infections Associated with Consumption of Fresh Spinach: United States, 2006. J Food Prot 2016; 79:2024-2030. [PMID: 28221950 DOI: 10.4315/0362-028x.jfp-15-556] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
During September to October, 2006, state and local health departments and the Centers for Disease Control and Prevention investigated a large, multistate outbreak of Escherichia coli O157:H7 infections. Case patients were interviewed regarding specific foods consumed and other possible exposures. E. coli O157:H7 strains isolated from human and food specimens were subtyped using pulsed-field gel electrophoresis and multiple-locus variable-number tandem repeat analyses (MLVA). Two hundred twenty-five cases (191 confirmed and 34 probable) were identified in 27 states; 116 (56%) case patients were hospitalized, 39 (19%) developed hemolytic uremic syndrome, and 5 (2%) died. Among 176 case patients from whom E. coli O157:H7 with the outbreak genotype (MLVA outbreak strain) was isolated and who provided details regarding spinach exposure, 161 (91%) reported fresh spinach consumption during the 10 days before illness began. Among 116 patients who provided spinach brand information, 106 (91%) consumed bagged brand A. E. coli O157:H7 strains were isolated from 13 bags of brand A spinach collected from patients' homes; isolates from 12 bags had the same MLVA pattern. Comprehensive epidemiologic and laboratory investigations associated this large multistate outbreak of E. coli O157:H7 infections with consumption of fresh bagged spinach. MLVA, as a supplement to pulsed-field gel electrophoresis genotyping of case patient isolates, was important to discern outbreak-related cases. This outbreak resulted in enhanced federal and industry guidance to improve the safety of leafy green vegetables and launched an independent collaborative approach to produce safety research in 2007.
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Affiliation(s)
- Umid M Sharapov
- Epidemic Intelligence Service, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, Georgia 30329.,Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, Georgia 30329
| | - Arthur M Wendel
- Epidemic Intelligence Service, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, Georgia 30329.,Wisconsin Division of Public Health, 1 West Wilson Street, P.O. Box 2659, Madison, Wisconsin 53703
| | - Jeffrey P Davis
- Wisconsin Division of Public Health, 1 West Wilson Street, P.O. Box 2659, Madison, Wisconsin 53703
| | - William E Keene
- Oregon Public Health Division, 800 N.E. Oregon Street, Portland, Oregon 97232
| | - Jeffrey Farrar
- California Department of Health Services, P.O. Box 997377, MS 0500, Sacramento, California 95899, USA
| | - Samir Sodha
- Epidemic Intelligence Service, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, Georgia 30329.,Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, Georgia 30329
| | - Eija Hyytia-Trees
- Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, Georgia 30329
| | - Molly Leeper
- Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, Georgia 30329
| | - Peter Gerner-Smidt
- Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, Georgia 30329
| | - Patricia M Griffin
- Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, Georgia 30329
| | - Chris Braden
- Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, Georgia 30329
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Amigo N, Zhang Q, Amadio A, Zhang Q, Silva WM, Cui B, Chen Z, Larzabal M, Bei J, Cataldi A. Overexpressed Proteins in Hypervirulent Clade 8 and Clade 6 Strains of Escherichia coli O157:H7 Compared to E. coli O157:H7 EDL933 Clade 3 Strain. PLoS One 2016; 11:e0166883. [PMID: 27880834 PMCID: PMC5120812 DOI: 10.1371/journal.pone.0166883] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Accepted: 11/04/2016] [Indexed: 11/19/2022] Open
Abstract
Escherichia coli O157:H7 is responsible for severe diarrhea and hemolytic uremic syndrome (HUS), and predominantly affects children under 5 years. The major virulence traits are Shiga toxins, necessary to develop HUS and the Type III Secretion System (T3SS) through which bacteria translocate effector proteins directly into the host cell. By SNPs typing, E. coli O157:H7 was separated into nine different clades. Clade 8 and clade 6 strains were more frequently associated with severe disease and HUS. In this study, we aimed to identify differentially expressed proteins in two strains of E. coli O157:H7 (clade 8 and clade 6), obtained from cattle and compared them with the well characterized reference EDL933 strain (clade 3). Clade 8 and clade 6 strains show enhanced pathogenicity in a mouse model and virulence-related properties. Proteins were extracted and analyzed using the TMT-6plex labeling strategy associated with two dimensional liquid chromatography and mass spectrometry in tandem. We detected 2241 proteins in the cell extract and 1787 proteins in the culture supernatants. Attention was focused on the proteins related to virulence, overexpressed in clade 6 and 8 strains compared to EDL933 strain. The proteins relevant overexpressed in clade 8 strain were the curli protein CsgC, a transcriptional activator (PchE), phage proteins, Stx2, FlgM and FlgD, a dienelactone hydrolase, CheW and CheY, and the SPATE protease EspP. For clade 6 strain, a high overexpression of phage proteins was detected, mostly from Stx2 encoding phage, including Stx2, flagellin and the protease TagA, EDL933_p0016, dienelactone hydrolase, and Haemolysin A, amongst others with unknown function. Some of these proteins were analyzed by RT-qPCR to corroborate the proteomic data. Clade 6 and clade 8 strains showed enhanced transcription of 10 out of 12 genes compared to EDL933. These results may provide new insights in E. coli O157:H7 mechanisms of pathogenesis.
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Affiliation(s)
- Natalia Amigo
- Institute of Biotechnology, CICVyA, National Institute of Agricultural Technology. Hurlingham, Buenos Aires, Argentina
| | - Qi Zhang
- AGRO-Biological Gene Research Center, Guangdong `Academy of Agricultural Sciences (GDAAS), Guangzhou, China
| | - Ariel Amadio
- Rafaela Experimental Station, National Institute of Agricultural Technology. Rafaela, Santa Fe, Argentina
| | - Qunjie Zhang
- AGRO-Biological Gene Research Center, Guangdong `Academy of Agricultural Sciences (GDAAS), Guangzhou, China
| | - Wanderson M. Silva
- Institute of Biotechnology, CICVyA, National Institute of Agricultural Technology. Hurlingham, Buenos Aires, Argentina
| | - Baiyuan Cui
- AGRO-Biological Gene Research Center, Guangdong `Academy of Agricultural Sciences (GDAAS), Guangzhou, China
| | - Zhongjian Chen
- AGRO-Biological Gene Research Center, Guangdong `Academy of Agricultural Sciences (GDAAS), Guangzhou, China
| | - Mariano Larzabal
- Institute of Biotechnology, CICVyA, National Institute of Agricultural Technology. Hurlingham, Buenos Aires, Argentina
| | - Jinlong Bei
- AGRO-Biological Gene Research Center, Guangdong `Academy of Agricultural Sciences (GDAAS), Guangzhou, China
- * E-mail:
| | - Angel Cataldi
- Institute of Biotechnology, CICVyA, National Institute of Agricultural Technology. Hurlingham, Buenos Aires, Argentina
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Galli L, Brusa V, Singh P, Cataldi AA, Manning S, Peral-García P, Leotta GA. High prevalence of clade 8 Escherichia coli O157:H7 isolated from retail meat and butcher shop environment. INFECTION GENETICS AND EVOLUTION 2016; 45:1-5. [DOI: 10.1016/j.meegid.2016.08.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 08/02/2016] [Accepted: 08/04/2016] [Indexed: 12/16/2022]
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40
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Askari Badouei M. Escherichia coli O157: H7 in Iran: Time to Look Closer. INTERNATIONAL JOURNAL OF ENTERIC PATHOGENS 2016. [DOI: 10.17795/ijep37471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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The Shiga toxin 2 production level in enterohemorrhagic Escherichia coli O157:H7 is correlated with the subtypes of toxin-encoding phage. Sci Rep 2015; 5:16663. [PMID: 26567959 PMCID: PMC4645166 DOI: 10.1038/srep16663] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 10/19/2015] [Indexed: 01/21/2023] Open
Abstract
Enterohemorrhagic E. coli (EHEC) causes diarrhea and hemorrhagic colitis with life-threatening complications, such as hemolytic uremic syndrome. Their major virulence factor is Shiga toxin (Stx), which is encoded by bacteriophages. Of the two types of Stx, the production of Stx2, particularly that of Stx2a (a subtype of Stx2), is a major risk factor for severe EHEC infections, but the Stx2 production level is highly variable between strains. Here, we define four major and two minor subtypes of Stx2a-encoding phages according to their replication proteins. The subtypes are correlated with Stx2a titers produced by the host O157 strains, suggesting a critical role of the phage subtype in determining the Stx2a production level. We further show that one of the two subclades in the clade 8, a proposed hyper-virulent lineage of O157, carries the Stx2 phage subtype that confers the highest Stx2 production to the host strain. The presence of this subclade may explain the proposed high virulence potential of clade 8. These results provide novel insights into the variation in virulence among O157 strains and highlight the role of phage variation in determining the production level of the virulence factors that phages encode.
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Yin S, Rusconi B, Sanjar F, Goswami K, Xiaoli L, Eppinger M, Dudley EG. Escherichia coli O157:H7 strains harbor at least three distinct sequence types of Shiga toxin 2a-converting phages. BMC Genomics 2015; 16:733. [PMID: 26416807 PMCID: PMC4587872 DOI: 10.1186/s12864-015-1934-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/15/2015] [Indexed: 02/08/2023] Open
Abstract
Background Shiga toxin-producing Escherichia coli O157:H7 is a foodborne pathogen that causes severe human diseases including hemolytic uremic syndrome (HUS). The virulence factor that mediates HUS, Shiga toxin (Stx), is encoded within the genome of a lambdoid prophage. Although draft sequences are publicly available for a large number of E. coli O157:H7 strains, the high sequence similarity of stx-converting bacteriophages with other lambdoid prophages poses challenges to accurately assess the organization and plasticity among stx-converting phages due to assembly difficulties. Methods To further explore genome plasticity of stx-converting prophages, we enriched phage DNA from 45 ciprofloxacin-induced cultures for subsequent 454 pyrosequencing to facilitate assembly of the complete phage genomes. In total, 22 stx2a-converting phage genomes were closed. Results Comparison of the genomes distinguished nine distinct phage sequence types (PSTs) delineated by variation in obtained sequences, such as single nucleotide polymorphisms (SNPs) and insertion sequence element prevalence and location. These nine PSTs formed three distinct clusters, designated as PST1, PST2 and PST3. The PST2 cluster, identified in two clade 8 strains, was related to stx2a-converting phages previously identified in non-O157 Shiga-toxin producing E. coli (STEC) strains associated with a high incidence of HUS. The PST1 cluster contained phages related to those from E. coli O157:H7 strain Sakai (lineage I, clade 1), and PST3 contained a single phage that was distinct from the rest but most related to the phage from E. coli O157:H7 strain EC4115 (lineage I/II, clade 8). Five strains carried identical stx2a-converting phages (PST1-1) integrated at the same chromosomal locus, but these strains produced different levels of Stx2. Conclusion The stx2a-converting phages of E. coli O157:H7 can be categorized into at least three phage types. Diversification within a phage type is mainly driven by IS629 and by a small number of SNPs. Polymorphisms between phage genomes may help explain differences in Stx2a production between strains, however our data indicates that genes encoded external to the phage affect toxin production as well. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1934-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Shuang Yin
- Department of Food Science, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Brigida Rusconi
- Department of Biology and South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX, 78249, USA
| | - Fatemeh Sanjar
- Department of Biology and South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX, 78249, USA
| | - Kakolie Goswami
- Department of Food Science, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Lingzi Xiaoli
- Department of Food Science, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Mark Eppinger
- Department of Biology and South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX, 78249, USA
| | - Edward G Dudley
- Department of Food Science, The Pennsylvania State University, University Park, PA, 16802, USA. .,Center of Molecular Immunology and Infectious Disease, The Pennsylvania State University, University Park, PA, 16802, USA. .,427 Food Science Building, The Pennsylvania State University, University Park, PA, 16802, USA.
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Coculture of Escherichia coli O157:H7 with a Nonpathogenic E. coli Strain Increases Toxin Production and Virulence in a Germfree Mouse Model. Infect Immun 2015; 83:4185-93. [PMID: 26259815 DOI: 10.1128/iai.00663-15] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 08/05/2015] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli O157:H7 is a notorious foodborne pathogen due to its low infectious dose and the disease symptoms it causes, which include bloody diarrhea and severe abdominal cramps. In some cases, the disease progresses to hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS), due to the expression of one or more Shiga toxins (Stx). Isoforms of Stx, including Stx2a, are encoded within temperate prophages. In the presence of certain antibiotics, phage induction occurs, which also increases the expression of toxin genes. Additionally, increased Stx2 accumulation has been reported when O157:H7 was cocultured with phage-susceptible nonpathogenic E. coli. This study characterized an E. coli O157:H7 strain, designated PA2, that belongs to the hypervirulent clade 8 cluster. Stx2a levels after ciprofloxacin induction were lower for PA2 than for the prototypical outbreak strains Sakai and EDL933. However, during coculture with the nonpathogenic strain E. coli C600, PA2 produced Stx2a levels that were 2- to 12-fold higher than those observed during coculture with EDL933 and Sakai, respectively. Germfree mice cocolonized by PA2 and C600 showed greater kidney damage, increased Stx2a accumulation in feces, and more visible signs of disease than mice given PA2 or C600 alone. These data suggest one mechanism by which microorganisms associated with the colonic microbiota could enhance the virulence of E. coli O157:H7, particularly a subset of clade 8 strains.
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Reduced Toxicity of Shiga Toxin (Stx) Type 2c in Mice Compared to Stx2d Is Associated with Instability of Stx2c Holotoxin. Toxins (Basel) 2015; 7:2306-20. [PMID: 26110507 PMCID: PMC4488704 DOI: 10.3390/toxins7062306] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 05/28/2015] [Accepted: 06/16/2015] [Indexed: 11/28/2022] Open
Abstract
Shiga toxin (Stx) is an AB5 ribotoxin made by Stx-producing Escherichia coli (STEC). These organisms cause diarrhea, hemorrhagic colitis and the hemolytic uremic syndrome. STEC make two types of Stxs, Stx1 and/or Stx2. Stx2 has one prototype (a) and six subtypes (b–g), but only STEC that make Stx2a, and/or Stx2c, or Stx2d are associated with severe disease. However, Stx2c is about 10-fold less toxic than Stx2d in vivo despite only two amino acid differences in the A subunit at positions 291 and 297. We made mutations at these two sites to create intermediate toxins between Stx2c and Stx2d, and determined the 50% cytotoxic dose on Vero cells before and after heat treatment, and the 50% lethal dose in mice of the toxins. We found that serine 291 was associated with increased toxicity in vivo and that either amino acid change from that in Stx2c to that in Stx2d increased heat stability. We also assessed the secondary structure of Stx2c and Stx2d by circular dichroism (CD) spectroscopy. The CD studies suggest that Stx2c has a less-ordered secondary structure than Stx2d. We conclude that both amino acids at positions 291 and 297 in Stx2c contribute to its decreased stability and in vivo toxicity compared to Stx2d.
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Kameyama M, Tominaga K, Yabata J, Nomura Y. Distribution of IS629 and stx genotypes among enterohemorrhagic Escherichia coli O157 isolates in Yamaguchi Prefecture, Japan, 2004-2013. J Vet Med Sci 2015; 77:1437-41. [PMID: 26050840 PMCID: PMC4667661 DOI: 10.1292/jvms.15-0166] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Patterns of insertion sequence (IS)629, norV
genotype, and Shiga toxin (Stx) genotype distribution were investigated amongst 203
enterohemorrhagic Escherichia coli O157 isolates collected in Yamaguchi
Prefecture, Japan, between 2004 and 2013. A total of 114 IS629 patterns
were identified; these were divided into eight IS groups (A–H). Ninety isolates carried an
intact norV gene, whereas 113 isolates carried a norV
with a 204-bp deletion. Other than one isolate from IS group G, all isolates with an
intact norV belonged to groups A–F, whereas isolates with a mutant
norV belonged to IS groups G and H. Seven stx
genotypes were identified, and of those, stx1a/stx2a was
predominant (n=105), followed by stx2c (n=32) and stx2a
(n=27). The stx1a/stx2a genotype was associated with the
mutant norV isolates, whereas isolates with an intact
norV had the stx2c genotype. Therefore, certain
combinations of IS type and stx genotype appear to be more frequent among
O157 clades which may be useful for detection of predominant subtypes in the interest of
public health.
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Affiliation(s)
- Mitsuhiro Kameyama
- Department of Health Science, Yamaguchi Prefectural Institute of Public Health and Environment, 2-5-67 Aoi, Yamaguchi 753-0821, Japan
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