Martina Bielaszewska

..stx2c-positive STEC isolates can cause HUS, but the presence of stx2d or stx2e may predict a milder disease with a minimal risk of HUS...

..The suggested occurrence of this process in the human intestine has diagnostic, clinical, epidemiological, and evolutionary implications...

..The presence of proteolytically active EspP in EHEC serogroups O157, O26, O111, and O145, which are bona fide human pathogens, suggests that EspP might play a role as an EHEC virulence factor...

..These findings indicate close relatedness between these pathotypes and provide a basis for their clinical laboratory diagnosis...

..The variability of PFGE patterns for the progeny of a single colony must be considered when interpreting PFGE patterns in SF EHEC O157-associated outbreaks...

..Spontaneous deletions affecting Tel(R) OIs contribute to EHEC O157 genome plasticity and might impair virulence and/or fitness...

..These data support a close relatedness between aEPEC O26 and EHEC O26 and have evolutionary implications. The presence of OI-122 in aEPEC O26 might contribute to their pathogenic potential...

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..5%) of 86 sorbitol-fermenting (SF) EHEC O157:NM strains had Te MICs of </=4 microg/ml, did not grow on Te-containing media, and lacked ter genes. Optimal detection of SF EHEC O157:NM strains requires Te-independent strategies...

..Our data demonstrate that CDT-V causes irreversible damage to human endothelial cells and thus may contribute to the pathogenesis of STEC-mediated diseases...

..However, the frequency of stx-negative/eae-positive E. coli in stools of HUS patients and the clinical significance of such strains are unknown...

..We investigated the prevalence of Stx2d(activatable) among Stx-producing E. coli (STEC) isolated from humans and the association between production of this Stx and the clinical outcome of infection...

..coli vacuolating toxins. Through its microvascular endothelium-injuring potential combined with the ability to induce interleukin 6 release from these cells EHEC-Vac might contribute to the pathogenesis of HUS...

..The reasons for the convergence of pathogenic EHEC strains on a suite of virulence loci remain unknown...

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..cdt is either chromosomal and homologous to cdt-V (serotypes O73:H18, O91:H21, and O113:H21) or plasmidborne and identical to cdt-III (serotype O153:H18). Among eae-negative STEC, cdt was associated with disease (P = 0.003)...

..coli and cause diarrhea worldwide. However, it is unknown whether there are bacterial lineage-specific human disease phenotypes. We compared stx-/EAF- AEEC recovered from patients (mostly children) with bloody and nonbloody diarrhea...

..The divergence within EHEC O111 makes it possible to subtype these emerging pathogens in the laboratory thereby providing a basis for further investigations into their ecological niches and survival capabilities...

..We identified 10 specific sequence types (ST) and 4 distinct clonal groups. ST442 was significantly associated with hemolytic uremic syndrome...

..The ability to recycle stx(2), a critical virulence trait, makes SF E. coli O157:NM strains ephemeral EHEC that can exist as stx-negative variants during certain phases of their life cycle...

..coli O157-infected patients. It is unknown if loss of the stx gene during the early stage of an enterohemorrhagic E. coli infection prevents HUS, or if absence of the stx gene from E. coli O157 reduces or ablates virulence...

..We analysed virulence profiles and relevant phenotypes of outbreak isolates recovered in our laboratory...

..We propose two possible evolutionary scenarios for eibG in STEC: a clonal development of eibG in strains with the same phylogenetic background or horizontal transfer of eibG between phylogenetically unrelated STEC strains...

..coli O55:H7, the proposed progenitor of EHEC O157, we hypothesize that EHEC O157:H7 diverged from the evolutionary pathway at an early stage and then acquired the O islands carrying the ure gene cluster...

..CDT-V was expressed in all but two cdt-V+ strains and was lethal to cultured endothelial cells. Subtyping schemes should include cdt-V as a marker to differentiate E. coli O157:H7 even within the same phage type...

..coli O157:NM strains is induced under conditions resembling those of the natural site of infection and that Sfp fimbriae may contribute to the adherence of the organisms to human intestinal epithelium...

..The toxicity of EHEC-Hly to microvascular endothelial cells plausibly contributes to the virulence of the stx-negative E. coli O26 strains and to the pathogenesis of HUS...

..coli, hamper the laboratory diagnosis of these strains. Our data demonstrate that pigeons may be a reservoir of Stx2f-producing E. coli strains associated with human disease...

..This mosaic island is absent from strain EDL933. PCR targeting the SRL-related sequence is a useful tool to distinguish SF EHEC O157:H(-) from EHEC O157:H7...

..To investigate genetic changes in EHEC during the course of human infection, we analyzed consecutive stool samples and shed isolates from patients with HUS, focusing on the genes encoding Shiga toxin (stx) and intimin (eae)...

..None of the other stool samples was positive by the sfpA PCR; 59 of these stool samples contained EHEC O157:H7. The sfpA gene can be recommended as a target for screening for SF E. coli O157:H-...

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..These isolates produced significantly less stx mRNA than Stx2d, Stx2e, Stx2c, or Stx2 secretors did. Standard screening procedures miss a significant subset of E. coli harboring stx(2) variants...

..Interference between effector molecules might be an additional way to regulate virulence functions and increases the complexity of monomolecular phenotypes...

..1% of these strains clustered in 5 STs. From all STs and serotypes identified, we established a reference panel of EHEC associated with HUS (HUSEC collection)...

..Our data demonstrate that E. coli isolates producing Shiga toxin 2e have imported specific virulence and fitness determinants which allow them to adapt to the specific hosts in which they cause various forms of disease...

..The phenotypic and molecular characteristics determined in this study allow the subtyping of Stx1c-producing STEC in epidemiological and clinical studies...

..These findings have implications in the pathogenesis of HUS, and suggest the existence of yet to be delineated Stx type-specific mechanisms of endothelial cell injury beyond inhibition of protein biosynthesis...

..This deficiency, resulting in the accumulation of Gb3Cer in EA.hy 926 cells, represents the most prominent molecular reason that underlies the different Stx1 sensitivities of HBMECs and EA.hy 926 endothelial cells...

..coli O55:H7 ancestor than STEC O157:H7. Our data demonstrate the presence of a potential virulence gene in SF STEC O157:H- that is only rudimentarily present in STEC O157:H7...

..Specific MLVA profiles with an evolutionary persistence were identified, particularly within sorbitol-fermenting EHEC O157:H-.These pathogens belonged to the same MLVA cluster. Our findings indicate successful persistence of this clone...

..The procedures developed in this study now allow the determination of the frequency of STEC strains harboring stx(1c) among clinical STEC isolates and their association with human disease in prospective studies...

..It is therefore suitable for use by clinical microbiological laboratories to improve the toxin detection in clinical samples...

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..Based on current data, cytolethal distending toxin, EHEC haemolysin, and subtilase cytotoxin might be such candidates...

..coli pathotypes have been addressed and the results have been directly applied for the improvement of diagnostic methods...

..The intensive study of human enteric factors that induce or modulate pathogen chromosome instability could provide important information about host-microbial interactions...

..The mechanisms underlying these functional variations in EspP subtypes are, however, unknown...

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..This review will focus on the microbiology, epidemiology, and pathophysiology of EHEC-associated diseases, and illustrate future challenges and opportunities for their control...

..The heterogeneity of EHEC O145 strains at the chromosomal and plasmid level, in particular the high diversity in PFGE patterns, provides a basis for molecular subtyping of these pathogens...

..Our findings provide a general concept for stabilization of RTX toxins and open new insights into the biology of these important virulence factors...

..In conclusion, rapid next-generation technologies facilitated prospective whole genome characterization in the early stages of an outbreak...

..Our data demonstrate that cdt, encoding a potential virulence factor, is present in the EHEC O157 complex and suggest that cdt may have been acquired by phage transduction...

..033). Non-O157:H7 STEC are more heterogeneous and cause bloody diarrhea less frequently than do E. coli O157:H7. Bloody diarrhea cannot be attributed simply to the stx genotype of the infecting organism...