- Attack of the clones: whole genome-based characterization of two closely related. - enterohemorrhagic Escherichia coli O26 epidemic lineages. - Background: Enterohemorrhagic Escherichia coli (EHEC) O26:H11/H. - Here, we investigated the population structure of EHEC O26 isolated from patients in several European countries using whole genome sequencing, with emphasis on a detailed analysis of strains of the highly virulent new European clone (nEC) which has spread since 1990s.. - The evolutionary divergence of the early nEC and late nEC is marked by the presence of 59 and 70 lineage-specific SNPs (synapomorphic mutations) in the genomes of the respective lineages. - Most of the late nEC strains harbor one of two major types of Shiga toxin 2a (Stx2a)- encoding prophages. - Conclusions: Using SNP-level analyses, we provide the evidence of the evolutionary split of EHEC O26:H11/H − nEC into two distinct lineages, and a recent replacement of the early nEC by the late nEC in Germany and the Czech Republic. - Keywords: Shiga toxin, O26, Enterohemorrhagic Escherichia coli (EHEC), New European clone. - 6 Department of Medical Microbiology, 2nd Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic Full list of author information is available at the end of the article. - 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0. - Enterohemorrhagic Escherichia coli (EHEC) O26:H11/. - The presence of stx 2a and/or production of Stx2a alone is a predictor for a severe disease including progression of the infection to HUS [31]. - To put these data into a global context, the genomic sequences of the Czech isolates were compared with those of EHEC O26 isolated in other European countries and with E. - Five of the six ST21 strains harbored stx 2a only, and one contained stx 1a only. - Nine of the ten ST29 EHEC O26 Czech strains corresponded to the new European clone (nEC) as defined in [31], i.e., they contained stx 2a as the sole stx gene and the plasmid virulence gene profile EHEC-- hlyA+, katP-, espP-, and etpD+ (Additional file 1: Table S1). - This is, to the best of our knowledge, the first report of stx 1c genotype in strains of the nEC. - To gain a more detailed insight into the population structure of the nEC, we performed add- itional WGS of a collection of European nEC isolates in- cluding 16 strains originating from Germany (n = 11), Italy (n = 3), and Austria (n = 2). - Strikingly, the phylo- genetic analysis demonstrated that strains of the nEC (syn. - among a large, representative collection of European ST29 strains isolated between 1996 and 2012 in the original de- scription of the nEC [31]. - Retrospectively, we noted tenta- tive differences between the two ST29 PFGE clusters with respect to the distribution of isolation dates of the corre- sponding strains. - In contrast, strains of the PFGE cluster C started to emerge, with a single exception, since 2004 [31]. - Evolution, diversification and spread of the nEC. - To infer which genetic events underlied the evolutionary establishment of the nEC and its subsequent split into the “early” and “late” lineages, we sought mutations characteristic for particular lineages, i.e., SNPs absent in other E. - The sets of synapomorphic mutations detected by this approach (Additional file 4: Table S2) provide an unambiguous genetic definition of the par- ticular nEC lineages. - Despite the limited numbers of isolates, a trend of the early nEC decline with a concomitant in- crease in the late nEC proportion was observed in both countries (Fig. - The emergence of the late nEC in Germany (regu- larly isolated since 2004) preceded its first occurrence in the Czech Republic (2013) by nine years (Fig. - Late nEC. - coli O26 nEC (ST29C2). - the high level of homology was confirmed by re-mapping of the se- quencing reads to the O157:H7 prophage reference (Fig.. - To determine whether or not the A273 → T273 mutation in Stx2a A subunit encoded by the type II stx 2a -prophages influenced the toxicity of the resulting Stx2a protein, we compared the amounts, Vero cell cytotoxicity titers, and specific activities (CD 50 /ng toxin) of Stx2a produced by nEC strains harboring the type II prophages with those of strains harboring the type I or other stx 2a -converting pro- phages. - titers, and Stx2a specific activities between strains of the late nEC and early nEC did not reveal any differences in these characteristics within the ST29 nEC group (Fig. - coli O26:H11/. - Given the genetic distinctness of the early and late nEC, their expan- sions are likely to have occurred independently. - Thus, reservoirs and possible ways of the worldwide spread of E. - coli O26 nEC in general and of the. - This is particularly important because of the increasing fre- quency of the late nEC strains as causes of human diseases in some European countries during last years (Fig. - coli O26 isolates from cattle and other animals, using the sen/ent SNP-based PCR developed in this study, combined with plasmid gene profiling might be a useful and simple tool for identification of strains of the early and late nEC.. - Altogether, the emergence of the late nEC both throughout and outside Europe supports a continuous evolution of E.. - evolution of the highly virulent, Stx2a-producing EHEC O104:H4 outbreak strain. - however, this hy- pothesis needs to be confirmed by complete sequence analyses of the bovine phages.. - coli O26 population.. - This mutation does not affect the potency of the toxin as demonstrated by its specific activity for Vero cells, which is similar to that of strains harboring type I prophages (Fig. - However, the localization of the mutation suggests a possible connection with Stx2a maturation. - Using genome-wide SNP-based analysis, this study pre- sents the evidence of the split of the EHEC O26:H11/H − nEC, which emerged in Germany in the 1990s and has spread throughout Europe [31], into two cryptic, yet dis- tinct clones (early nEC and late nEC, Fig. - The fact that strains of the early nEC and late nEC are indistinguish- able by this approach (Fig. - This will, in turn, enable further investigations of the geographic dis- tribution of these pathogens, their clinical significance, and the epidemiology of human infections they cause.. - ST29 late nEC. - coli O26 [9, 38]. - late nEC: ED676, St. - Late nEC-discriminating PCR. - Stx1a and Stx2a titers were expressed as reciprocals of the supernatants´ dilutions that produced a clear agglu- tination of latex particles sensitized with anti-Stx1a and anti-Stx2a antibody, respectively. - Cytotoxicity titers were expressed as recipro- cal values of the sample dilutions that killed 50% of cells (CD 50. - coli O26 isolates. - Representative gel image which demonstrates the performance of the sen/ent SNP-specific PCR in differentiating early- and late nEC strains is included. - This study was supported by the Grant Agency of the Charles University (194215) and by the Ministry of Health of the Czech Republic (funding project Conceptual development of research organization “ The National Institute of Public Health - NIPH 75010330. - PD and JN acknowledge financial support from Czech Health Research Council of Ministry of Health of the Czech Republic, grant no. - The funders had no role in the design of the study and collection, analysis, and interpretation of data and in writing the manuscript.. - The use of the Czech isolates was approved by the Ethical Committee of the University Hospital Motol, Prague, Czech Republic. - The isolates from Germany and other countries available in the collection of the Institute of Hygiene, University of Münster, were used in accordance with guidelines approved by the Ethical Committee of the Medical Faculty of the University of Münster and of the Ärztekammer Westfalen-Lippe. - The informed consent of the participants was not required because the data were analyzed anonymously.. - The epidemiology, microbiology and clinical impact of Shiga toxin-producing Escherichia coli in England, 2009-2012. - Public health microbiology of Shiga toxin- producing Escherichia coli. - Surveillance of hemolytic uremic syndrome in children less than 15 years of age, a system to monitor O157 and non-O157 Shiga toxin-producing Escherichia coli infections in France, 1996-2006. - Clinical course and the role of Shiga toxin-producing Escherichia coli infection in the hemolytic-uremic syndrome in pediatric patients in Germany and Austria: a prospective study. - Increased recognition of non-O157 Shiga toxin-producing Escherichia coli infections in the United States during epidemiologic features and comparison with E coli O157 infections. - Characteristics of O157 versus non-O157 Shiga toxin-producing Escherichia coli infections in Minnesota, 2000-2006. - Identification of a new virulent clade in enterohemorrhagic Escherichia coli O26:H11/H- sequence type 29.. - Enterohaemorrhagic Escherichia coli in human medicine. - Enterohemorrhagic Escherichia coli as causes of hemolytic uremic syndrome in the Czech Republic. - Highly virulent Escherichia coli O26 Scotland. - Characterization and epidemiologic subtyping of Shiga toxin-producing Escherichia coli strains isolated from hemolytic uremic syndrome and diarrhea cases in Argentina. - Genome sequence for Shiga toxin-producing Escherichia coli O26:H11, associated with a cluster of hemolytic-uremic syndrome cases in South Africa, 2017. - Shiga toxin-producing Escherichia coli infections associated with hemolytic uremic syndrome, Italy . - Enterohemorrhagic Escherichia coli O26:H11- associated hemolytic uremic syndrome: bacteriology and clinical presentation. - The utility and public health implications of PCR and whole genome sequencing for the detection and investigation of an outbreak of Shiga toxin- producing Escherichia coli serogroup O26:H11. - producing Escherichia coli O26:H11 in southern Italy summer 2013. - Case finding using syndromic surveillance data during an outbreak of Shiga toxin-producing Escherichia coli O26 infections, Oregon 2015. - Outbreaks of non-O157 Shiga toxin-producing Escherichia coli infection: USA. - Cluster of hemolytic-uremic syndrome caused by Shiga toxin- producing Escherichia coli O26:H11. - Real-time genomic investigation underlying the public health response to a Shiga toxin-producing Escherichia coli O26:H11 outbreak in a nursery. - A case of haemolytic uraemic syndrome (HUS) revealed an outbreak of Shiga toxin-2-producing Escherichia coli O26:. - Community-wide outbreaks of haemolytic uraemic syndrome associated with Shiga toxin- producing Escherichia coli O26 in Italy and Romania: a new challenge for the European Union. - A multistate outbreak of Shiga toxin- producing Escherichia coli O26:H11 infections in Germany detected by molecular subtyping surveillance. - Enterohemorrhagic Escherichia coli O26:H11/H-: a new virulent clone emerges in Europe. - Analysis of collection of hemolytic uremic syndrome-associated enterohemorrhagic Escherichia coli. - Molecular characteristics and epidemiological significance of Shiga toxin- producing Escherichia coli O26 strains. - Draft genome sequences of human-pathogenic Escherichia coli O26:H11 strains carrying the stx2 gene only and circulating in France. - Whole-genome characterization and strain comparison of VT2f-producing Escherichia coli causing hemolytic uremic syndrome. - Evolution of enterohemorrhagic Escherichia coli O26 based on single-nucleotide polymorphisms. - a major contributor to Escherichia coli stx2-positive O26:H11 strains intra-serotype diversity. - Population structure of Escherichia coli O26 : H11 with recent and repeated stx2 acquisition in multiple lineages. - enterohemorrhagic Escherichia coli serotypes and the German E. - characterization of the German enterohemorrhagic Escherichia coli O104:H4 outbreak by rapid next generation sequencing technology. - Genome sequence of enterohaemorrhagic Escherichia coli O157:H7. - The Shiga toxin 2 production level in enterohemorrhagic Escherichia coli O157:H7 is correlated with the subtypes of toxin-encoding phage. - Hemolytic-uremic syndrome associated with enterohemorrhagic Escherichia coli O26:H infection and consumption of unpasteurized cow's milk. - Detection of the emerging Shiga toxin- producing Escherichia coli O26:H11/H- sequence type 29 (ST29) clone in human patients and healthy cattle in Switzerland. - Shiga toxin-producing Escherichia coli strains from cattle as a source of the Stx2a bacteriophages present in enteroaggregative Escherichia coli O104:H4 strains. - Genome sequences of 11 Shiga toxin- producing Escherichia coli strains. - Comparative genomics reveal the mechanism of the parallel evolution of O157 and non-O157 enterohemorrhagic Escherichia coli
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