Putative roles of the CNF2 and CDTIII toxins in experimental infections with necrotoxigenic Escherichia coli type 2 (NTEC2) strains in calves

Bost, Sigrid Van; Roels, Stefan; Oswald, Éric; Mainil, Jacques

doi:10.1016/j.micinf.2003.08.005

Cited by 8 publications

(10 citation statements)

References 21 publications

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“…Clone I and II were closely related with 90% identity on their PFGE patterns and included 11 ONT and 2 ONT and 1 O101 isolates respectively. Clone III included 3 ONT isolates, one of them carrying the enterotoxigenic E. coli characteristic genes LT - I and ST - I , clone IV included a single O15 isolate and clone V included 2 ONT isolates, which were found to carry the typical bovine necrotoxigenic E. coli genes cnf2 and cdtIII [ 33 , 34 ]. The PCR product obtained with F17-A common primers on one E. coli isolate of the most prevalent clone (clone I) was sequenced and compared to the F17-A variants sequences by ClustalX2 software alignment.…”

Section: Resultsmentioning

confidence: 99%

Identification and detection of three new F17 fimbrial variants in Escherichia coli strains isolated from cattle

Bihannic

Ghanbarpour

Auvray³

et al. 2014

Vet Res

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F17 fimbriae are produced by pathogenic Escherichia coli involved in diarrhea and septicemia outbreaks in calves and lambs. These proteins result from the expression of four different clustered genes, namely f17A, f17D, f17C and f17G, encoding a pilin protein, a periplasmic protein, an anchor protein and an adhesin protein, respectively. Several variants of f17A and f17G genes have been reported and found genetically associated with typical virulence factors of bovine pathogenic E. coli strains. In this study, a new F17e-A variant, closely related to F17b-A, was identified from a collection of 58 E. coli isolates from diarrheic calves in Iran. While highly prevalent in Iranian F17-producing clinical isolates from calves, this variant was rare among E. coli from a French healthy adult bovine population, suggesting a possible association with virulence. The f17Ae gene was also found in the genome of the Shiga-like toxin variant Stx1d–producing bovine E. coli strain MHI813, and belonged to a gene cluster also encoding a new F17-G3 variant, which greatly differed from F17-G1 and F17-G2. This gene cluster was located on a pathogenicity island integrated in the tRNA pheV gene. The gene coding for a third new F17f-A variant corresponding to a combination of F17c-A and F17d-A was also identified on the pVir68 plasmid in the bovine pathogenic E. coli strain 6.0900. In conclusion, we identified three new F17-A and F17-G variants in cattle E. coli, which may also have significant impact on the development of new diagnostics and vaccination tools.

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Section: Resultsmentioning

confidence: 99%

Identification and detection of three new F17 fimbrial variants in Escherichia coli strains isolated from cattle

Bihannic

Ghanbarpour

Auvray³

et al. 2014

Vet Res

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“…Once in the host cell nucleus, CdtB induces DNA double-strand breaks in both proliferating and nonproliferating cells (13,15,26). Although pathogenic roles of CDT have been shown for chronic infection in mouse models (12,39), CDT has not played a significant role in acute infection models tested to date (25,40,48,49). Nevertheless, CDT appears to be a virulence factor; accordingly, studying its spread is important.…”

Section: Five Types Of Cytolethal Distending Toxin (Cdt-i To Cdt-v) Hmentioning

confidence: 99%

Cytolethal Distending Toxin Type I and Type IV Genes Are Framed with Lambdoid Prophage Genes in Extraintestinal Pathogenic Escherichia coli

et al. 2009

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Five types of cytolethal distending toxin (CDT-I to CDT-V) have been identified in Escherichia coli.In the present study we cloned and sequenced the cdt-IV operon and flanking region from a porcine extraintestinal pathogenic E. coli (ExPEC) strain belonging to serogroup O75. We confirmed that similar to other CDTs, CDT-IV induced phosphorylation of host histone H2AX, a sensitive marker of DNA double-strand breaks, and blocked the HeLa cell cycle at the G 2 -M transition. The cdt-IV genes were framed by lambdoid prophage genes. We cloned and sequenced the cdt-I operon and flanking regions from a human ExPEC O18:K1:H7 strain and observed that cdt-I genes were also flanked by lambdoid prophage genes. PCR studies indicated that a gene coding for a putative protease was always associated with the cdtC-IV gene but was not associated with cdtC genes in strains producing CDT-I, CDT-III, and CDT-V. Our results suggest that the cdt-I and cdt-IV genes might have been acquired from a common ancestor by phage transduction and evolved in their bacterial hosts. The lysogenic bacteriophages have the potential to carry nonessential "cargo" genes or "morons" and therefore play a crucial role in the generation of genetic diversity within ExPEC.Cytolethal distending toxins (CDTs) were the first bacterial toxins that block the eukaryotic cell cycle that were described, and they suppress cell proliferation and eventually lead to cell death. CDTs represent an emerging toxin family, which was initially described for Escherichia coli but is actually widely distributed among a variety of pathogenic bacteria, including Shigella dysenteriae, Salmonella enterica serovar Typhi, Campylobacter spp., Helicobacter spp., Aggregatibacter (formerly Actinobacillus) actinomycetemcomitans, and Haemophilus ducreyi (31,34).A CDT is a tripartite holotoxin (28) in which CdtB is the active subunit and CdtA and CdtC form a heterodimeric subunit apparatus required for delivery of CdtB into the cell (8,23,24). The toxin of S. enterica serovar Typhi is an exception. This organism does not encode CdtA or CdtC; instead, the enzymatic CdtB is delivered directly into host cells by a bacterial internalization pathway (14). Nuclear entry of CdtB, which relies on an atypical nuclear localization signal, is crucial for the cytotoxic activity (25,27,29). CdtB has DNase I-like activity (10,15,23). Once in the host cell nucleus, CdtB induces DNA double-strand breaks in both proliferating and nonproliferating cells (13,15,26). Although pathogenic roles of CDT have been shown for chronic infection in mouse models (12, 39), CDT has not played a significant role in acute infection models tested to date (25,40,48,49). Nevertheless, CDT appears to be a virulence factor; accordingly, studying its spread is important.So far, five different CDTs have been reported for E. coli, and they were designated in order of publication. CDT-I (44) and CDT-II (38) were identified in enteropathogenic E. coli (EPEC) serotype O86:H34 and O128:NM strains, respectively. CDT-III was cloned from an...

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“…Plasmids are important vectors for transmitting virulence factors, such as toxins and adhesins (De Rycke et al, 1999), among E. coli associated with intestinal and extraintestinal illnesses in humans and animals, and it may be that the possession of these virulence plasmids is what distinguishes pathogen from commensal (Van Bost et al, 2003). As enterohemorrhagic E. coli is an amalgam, representing essential combination of virulence genes of diverse bacterial origins (Boerlin 1999), these two new genes-hlyF and orf2-may represent the emergence of new virulence factors among pathogenic E. coli strains.…”

Section: Resultsmentioning

confidence: 99%

Detection of a Novel Virulence Gene and a Salmonella Virulence Homologue Among Escherichia coli Isolated from Broiler Chickens

Morales

Lee

Hofacre

et al. 2004

Foodborne Pathogens and Disease

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Despite the diversity of Escherichia coli pathotypes, there are many virulence genes common to isolates from food animals and humans, suggesting that opportunity exists for genetic exchange between human and animal isolates to create the next emerging, foodborne pathogen. Hemolytic activity in E. coli has been attributed to hemolysin genes found in either uropathogenic or enterohemorrhagic E. coli. These E. coli hemolysins are classified as RTX toxins due to a repetitive toxin domain and similar gene organization, sequence homology, and mechanism of action and presence in animal and human E. coli isolates. Certain hemolytic animal isolates, however, lack these E. coli hemolysin genes. Recently, we identified a hemolysin from E. coli, isolated from poultry, with significant homology to the K12 "silent" hemolysin gene she. This gene was present only in one of four hemolytic, avian E. coli isolates examined, suggesting that the other three E. coli contain a gene distinct from the RTX toxin genes, hlyA and the she homolog, hlyE. A phagemid library was made from chicken E. coli isolate 963726, which was negative for hemolysin gene hlyA and hlyE. A hemolytic clone was identified from this library, which contained a 3.3-kb Sau3A DNA insert. The nucleotide sequences of this DNA insert revealed two, open reading frames (ORF). The first ORF encoded for a 40-Kdal protein with no significant homology to known hemolysins reported in the Gen- Bank DNA/Protein database. The second ORF specified a 26-Kdal protein with significant homology to a Salmonella regulatory gene mig-14 that had a broad distribution among the pathogenic, animal E. coli isolates. Deletion of the second orf did not abrogate hemolysis, indicating that the first ORF encoded the hemolysin. This new bacterial gene designated hlyF represents a new class of hemolysin.

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Putative roles of the CNF2 and CDTIII toxins in experimental infections with necrotoxigenic Escherichia coli type 2 (NTEC2) strains in calves

Cited by 8 publications

References 21 publications

Identification and detection of three new F17 fimbrial variants in Escherichia coli strains isolated from cattle

Identification and detection of three new F17 fimbrial variants in Escherichia coli strains isolated from cattle

Cytolethal Distending Toxin Type I and Type IV Genes Are Framed with Lambdoid Prophage Genes in Extraintestinal Pathogenic Escherichia coli

Detection of a Novel Virulence Gene and a Salmonella Virulence Homologue Among Escherichia coli Isolated from Broiler Chickens

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