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Brachmann AO, Garcie C, Wu V, Martin P, Ueoka R, Oswald E, Piel J. Colibactin biosynthesis and biological activity depend on the rare aminomalonyl polyketide precursor. Chem Commun (Camb) 2016; 51:13138-41. [PMID: 26191546 DOI: 10.1039/c5cc02718g] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The as-yet unidentified E. coli metabolite colibactin induces DNA damage in eukaryotic cells and promotes tumorigenesis. Its wide distribution in pathogenic and probiotic strains has raised great interest in its structure and biosynthesis. Here we show that colibactin formation involves a rare aminomalonyl unit used as a building block.
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Rojo-Bezares B, Cavalié L, Dubois D, Oswald E, Torres C, Sáenz Y. Characterization of carbapenem resistance mechanisms and integrons in Pseudomonas aeruginosa strains from blood samples in a French hospital. J Med Microbiol 2016; 65:311-319. [DOI: 10.1099/jmm.0.000225] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Nakayama-Imaohji H, Hirota K, Yamasaki H, Yoneda S, Nariya H, Suzuki M, Secher T, Miyake Y, Oswald E, Hayashi T, Kuwahara T. DNA Inversion Regulates Outer Membrane Vesicle Production in Bacteroides fragilis. PLoS One 2016; 11:e0148887. [PMID: 26859882 PMCID: PMC4747536 DOI: 10.1371/journal.pone.0148887] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 01/25/2016] [Indexed: 02/06/2023] Open
Abstract
Phase changes in Bacteroides fragilis, a member of the human colonic microbiota, mediate variations in a vast array of cell surface molecules, such as capsular polysaccharides and outer membrane proteins through DNA inversion. The results of the present study show that outer membrane vesicle (OMV) formation in this anaerobe is also controlled by DNA inversions at two distantly localized promoters, IVp-I and IVp-II that are associated with extracellular polysaccharide biosynthesis and the expression of outer membrane proteins. These promoter inversions are mediated by a single tyrosine recombinase encoded by BF2766 (orthologous to tsr19 in strain NCTC9343) in B. fragilis YCH46, which is located near IVp-I. A series of BF2766 mutants were constructed in which the two promoters were locked in different configurations (IVp-I/IVp-II = ON/ON, OFF/OFF, ON/OFF or OFF/ON). ON/ON B. fragilis mutants exhibited hypervesiculating, whereas the other mutants formed only a trace amount of OMVs. The hypervesiculating ON/ON mutants showed higher resistance to treatment with bile, LL-37, and human β-defensin 2. Incubation of wild-type cells with 5% bile increased the population of cells with the ON/ON genotype. These results indicate that B. fragilis regulates the formation of OMVs through DNA inversions at two distantly related promoter regions in response to membrane stress, although the mechanism underlying the interplay between the two regions controlled by the invertible promoters remains unknown.
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Cougnoux A, Delmas J, Gibold L, Faïs T, Romagnoli C, Robin F, Cuevas-Ramos G, Oswald E, Darfeuille-Michaud A, Prati F, Dalmasso G, Bonnet R. Small-molecule inhibitors prevent the genotoxic and protumoural effects induced by colibactin-producing bacteria. Gut 2016; 65:278-85. [PMID: 25588406 DOI: 10.1136/gutjnl-2014-307241] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 12/10/2014] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Colorectal cancers (CRCs) are frequently colonised by colibactin toxin-producing Escherichia coli bacteria that induce DNA damage in host cells and exhibit protumoural activities. Our objective was to identify small molecules inhibiting the toxic effects induced by these colibactin-producing bacteria. DESIGN A structural approach was adopted for the identification of a putative ligand for the ClbP enzyme involved in the synthesis of colibactin. Intestinal epithelial cells and a CRC mouse model were used to assess the activity of the selected compounds in vitro and in vivo. RESULTS Docking experiments identified two boron-based compounds with computed ligand efficiency values (-0.8 and -0.9 kcal/mol/atom) consistent with data expected for medicinal chemistry leads. The crystalline structure of ClbP in complex with the compounds confirmed that the compounds were binding to the active site of ClbP. The two compounds (2 mM) suppressed the genotoxic activity of colibactin-producing E coli both in vitro and in vivo. The mean degree of suppression of DNA damage for the most efficient compound was 98±2% (95% CI). This compound also prevented cell proliferation and colibactin-producing E coli-induced tumourigenesis in mice. In a CRC murine model colonised by colibactin-producing E coli, the number of tumours decreased by 3.5-fold in animals receiving the compound in drinking water (p<0.01). CONCLUSIONS These results demonstrate that targeting colibactin production controls the genotoxic and protumoural effects induced by this toxin.
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Gineste A, Martin P, Oswald E, Coppin H, Roth MP. Evidence for IL-6/STAT3-independent induction of lipocalin-2 in the liver of mice infected with Escherichia coli. Hepatology 2016; 63:673-4. [PMID: 25865824 DOI: 10.1002/hep.27845] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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Um MM, Barraud O, Kérourédan M, Gaschet M, Stalder T, Oswald E, Dagot C, Ploy MC, Brugère H, Bibbal D. Comparison of the incidence of pathogenic and antibiotic-resistant Escherichia coli strains in adult cattle and veal calf slaughterhouse effluents highlighted different risks for public health. WATER RESEARCH 2016; 88:30-38. [PMID: 26460853 DOI: 10.1016/j.watres.2015.09.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 09/09/2015] [Accepted: 09/15/2015] [Indexed: 06/05/2023]
Abstract
The goal of this study was to investigate the involvement of bovine slaughterhouse effluents and biosolids in the risk of environmental dissemination of pathogenic and antibiotic-resistant Escherichia coli. Several samples were collected from one adult cattle and one veal calf slaughterhouse wastewater treatment plant (WWTP). The treatment process had no impact on the percentage of Shiga toxin-producing E. coli (STEC) and on the percentage of atypical enteropathogenic E. coli (aEPEC). A STEC O157:H7 was isolated from the thickened sludge of the adult cattle slaughterhouse. As thickened sludge is intended to be spread on agricultural lands, the detection of this pathogenic strain is a public health issue. The percentage of antibiotic-resistant E. coli was 5.0% and 87.5% in wastewater from the adult cattle and the veal calf slaughterhouse, respectively. These percentages were not significantly different after treatment. Integron-bearing E. coli isolates were only detected in the veal calf slaughterhouse WWTP with percentages above 50.0% for all sampling points whatever the step of the treatment process. Taken together, these findings highlighted the fact that different public health risks might be associated with adult cattle or veal calf slaughterhouses regarding the dissemination of pathogenic and antibiotic-resistant E. coli isolates into the environment.
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Bossuet-Greif N, Dubois D, Petit C, Tronnet S, Martin P, Bonnet R, Oswald E, Nougayrède JP. Escherichia coli ClbS is a colibactin resistance protein. Mol Microbiol 2015; 99:897-908. [PMID: 26560421 DOI: 10.1111/mmi.13272] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2015] [Indexed: 12/24/2022]
Abstract
The genomic pks island codes for the biosynthetic machinery that produces colibactin, a peptide-polyketide metabolite. Colibactin is a genotoxin that contributes to the virulence of extra-intestinal pathogenic Escherichia coli and promotes colorectal cancer. In this work, we examined whether the pks-encoded clbS gene of unknown function could participate in the self-protection of E. coli-producing colibactin. A clbS mutant was not impaired in the ability to inflict DNA damage in HeLa cells, but the bacteria activated the SOS response and ceased to replicate. This autotoxicity phenotype was markedly enhanced in a clbS uvrB double mutant inactivated for DNA repair by nucleotide excision but was suppressed in a clbS clbA double mutant unable to produce colibactin. In addition, ectopic expression of clbS protected infected HeLa cells from colibactin. Thus, ClbS is a resistance protein blocking the genotoxicity of colibactin both in the procaryotic and the eucaryotic cells.
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Murase K, Martin P, Porcheron G, Houle S, Helloin E, Pénary M, Nougayrède JP, Dozois CM, Hayashi T, Oswald E. HlyF Produced by Extraintestinal PathogenicEscherichia coliIs a Virulence Factor That Regulates Outer Membrane Vesicle Biogenesis. J Infect Dis 2015; 213:856-65. [DOI: 10.1093/infdis/jiv506] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 10/14/2015] [Indexed: 11/13/2022] Open
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Oswald E, Espírito Santo V, Rudisch A, Brito C, Sommergruber W, Dolznig H, Schüler J. 273 Modelling tumor-stroma crosstalk in vivo by co-implantation of human fibroblasts and human lung cancer cells orthotopically into immuncompromized mice. Eur J Cancer 2015. [DOI: 10.1016/s0959-8049(16)30158-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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60
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Taieb F, Sváb D, Watrin C, Oswald E, Tóth I. Cytolethal distending toxin A, B and C subunit proteins are necessary for the genotoxic effect of Escherichia coli CDT-V. Acta Vet Hung 2015; 63:1-10. [PMID: 25655410 DOI: 10.1556/avet.2015.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cytolethal distending toxins (CDT) are considered the prototype of inhibitory cyclomodulins, and are produced by a wide range of Gram-negative pathogenic bacteria, including Escherichia coli strains of various sero- and pathotypes. CDT is a heterotripartite toxin consisting of three protein subunits, CdtA, CdtB and CdtC. The active subunit, CdtB has DNase activity and causes DNA damage and cell cycle arrest in the target cell. However, several studies have highlighted different roles for CdtA and CdtC subunits. In order to reveal the necessity of CdtA and CdtC subunit proteins in the CDT-specific phenotype, expression clones containing the cdt-V subunit genes were constructed. Using cell culture assays, we demonstrated that clones expressing only the CdtB subunit or in combination with only CdtA or CdtC were unable to trigger the specific cell cycle arrest and changes in cell morphology in HeLa cells. At the same time, the recombinant clone harbouring the whole cdt-V operon caused all the CDT-associated characteristic phenotypes. All these results verify that all the three CDT subunit proteins are necessary for the genotoxic effect caused by CDT-V.
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Bibbal D, Loukiadis E, Kérourédan M, Ferré F, Dilasser F, Peytavin de Garam C, Cartier P, Oswald E, Gay E, Auvray F, Brugère H. Prevalence of carriage of Shiga toxin-producing Escherichia coli serotypes O157:H7, O26:H11, O103:H2, O111:H8, and O145:H28 among slaughtered adult cattle in France. Appl Environ Microbiol 2015; 81:1397-1405. [PMID: 25527532 PMCID: PMC4309698 DOI: 10.1128/aem.03315-14] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 12/10/2014] [Indexed: 11/20/2022] Open
Abstract
The main pathogenic enterohemorrhagic Escherichia coli (EHEC) strains are defined as Shiga toxin (Stx)-producing E. coli (STEC) belonging to one of the following serotypes: O157:H7, O26:H11, O103:H2, O111:H8, and O145:H28. Each of these five serotypes is known to be associated with a specific subtype of the intimin-encoding gene (eae). The objective of this study was to evaluate the prevalence of bovine carriers of these “top five” STEC in the four adult cattle categories slaughtered in France. Fecal samples were collected from 1,318 cattle, including 291 young dairy bulls, 296 young beef bulls, 337 dairy cows, and 394 beef cows. A total of 96 E. coli isolates, including 33 top five STEC and 63 atypical enteropathogenic E. coli (aEPEC) isolates, with the same genetic characteristics as the top five STEC strains except that they lacked an stx gene, were recovered from these samples.O157:H7 was the most frequently isolated STEC serotype. The prevalence of top five STEC (all serotypes included) was 4.5% in young dairy bulls, 2.4% in young beef bulls, 1.8% in dairy cows, and 1.0% in beef cows. It was significantly higher in young dairy bulls (P<0.05) than in the other 3 categories. The basis for these differences between categories remains to be elucidated. Moreover,simultaneous carriage of STEC O26:H11 and STEC O103:H2 was detected in one young dairy bull. Lastly, the prevalence of bovine carriers of the top five STEC, evaluated through a weighted arithmetic mean of the prevalence by categories, was estimated to 1.8% in slaughtered adult cattle in France.
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Oswald E, Tschuch C, Klingner K, Hammerich B, Lehnhard D, Rentsch C, Lübbert M, Fiebig H, Schüler J. 11 A panel of patient derived xenograft models of different haematological malignancies suitable for preclinical drug screening campaigns. Eur J Cancer 2014. [DOI: 10.1016/s0959-8049(14)70137-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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63
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Bihannic M, Ghanbarpour R, Auvray F, Cavalié L, Châtre P, Boury M, Brugère H, Madec JY, Oswald E. Identification and detection of three new F17 fimbrial variants in Escherichia coli strains isolated from cattle. Vet Res 2014; 45:76. [PMID: 25106491 PMCID: PMC4267768 DOI: 10.1186/s13567-014-0076-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 07/17/2014] [Indexed: 01/13/2023] Open
Abstract
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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Payros D, Secher T, Boury M, Brehin C, Ménard S, Salvador-Cartier C, Cuevas-Ramos G, Watrin C, Marcq I, Nougayrède JP, Dubois D, Bedu A, Garnier F, Clermont O, Denamur E, Plaisancié P, Theodorou V, Fioramonti J, Olier M, Oswald E. Maternally acquired genotoxic Escherichia coli alters offspring's intestinal homeostasis. Gut Microbes 2014; 5:313-25. [PMID: 24971581 PMCID: PMC4153768 DOI: 10.4161/gmic.28932] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The neonatal gut is rapidly colonized by a newly dominant group of commensal Escherichia coli strains among which a large proportion produces a genotoxin called colibactin. In order to analyze the short- and long-term effects resulting from such evolution, we developed a rat model mimicking the natural transmission of E. coli from mothers to neonates. Genotoxic and non-genotoxic E. coli strains were equally transmitted to the offspring and stably colonized the gut across generations. DNA damage was only detected in neonates colonized with genotoxic E. coli strains. Signs of genotoxic stress such as anaphase bridges, higher occurrence of crypt fission and accelerated renewal of the mature epithelium were detected at adulthood. In addition, we observed alterations of secretory cell populations and gut epithelial barrier. Our findings illustrate how critical is the genotype of E. coli strains acquired at birth for gut homeostasis at adulthood.
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Marcq I, Martin P, Payros D, Cuevas-Ramos G, Boury M, Watrin C, Nougayrede JP, Olier M, Oswald E. The Genotoxin Colibactin Exacerbates Lymphopenia and Decreases Survival Rate in Mice Infected With Septicemic Escherichia coli. J Infect Dis 2014; 210:285-94. [DOI: 10.1093/infdis/jiu071] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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66
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Bihannic M, Ghanbarpour R, Auvray F, Cavalié L, Châtre P, Boury M, Brugère H, Madec JY, Oswald E. Identification and detection of three new F17 fimbrial variants in. Vet Res 2014. [DOI: 10.1186/preaccept-1790328501124638] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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67
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Bibbal D, Kérourédan M, Loukiadis E, Scheutz F, Oswald E, Brugère H. Slaughterhouse effluent discharges into rivers not responsible for environmental occurrence of enteroaggregative Escherichia coli. Vet Microbiol 2013; 168:451-4. [PMID: 24388632 DOI: 10.1016/j.vetmic.2013.11.042] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 11/18/2013] [Accepted: 11/30/2013] [Indexed: 10/25/2022]
Abstract
Enteroaggregative Shiga-toxin-producing Escherichia coli strains were responsible for a massive outbreak in Europe in 2011, and had been previously isolated from French patients. The objective of this study was to investigate the presence of enteroaggregative E. coli (EAEC) in slaughterhouse effluents (wastewater, slurry, sludge and effluents), and in river waters near these slaughterhouses. A total of 10,618 E. coli isolates were screened by PCR for the presence of EAEC-associated genetic markers (aggR, aap and aatA). None of these markers was detected in E. coli isolated from slaughterhouse samples. A unique enteroaggregative E. coli (EAEC) O126:H8 was detected in river water sampled upstream from slaughterhouse effluent discharge. These results confirmed that animals might not be reservoirs of EAEC, and that further studies are required to evaluate the role of the environment in the transmission of EAEC to humans.
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Secher T, Samba-Louaka A, Oswald E, Nougayrède JP. Escherichia coli producing colibactin triggers premature and transmissible senescence in mammalian cells. PLoS One 2013; 8:e77157. [PMID: 24116215 PMCID: PMC3792898 DOI: 10.1371/journal.pone.0077157] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 08/30/2013] [Indexed: 01/19/2023] Open
Abstract
Cellular senescence is an irreversible state of proliferation arrest evoked by a myriad of stresses including oncogene activation, telomere shortening/dysfunction and genotoxic insults. It has been associated with tumor activation, immune suppression and aging, owing to the secretion of proinflammatory mediators. The bacterial genotoxin colibactin, encoded by the pks genomic island is frequently harboured by Escherichia coli strains of the B2 phylogenetic group. Mammalian cells exposed to live pks+ bacteria exhibit DNA-double strand breaks (DSB) and undergo cell-cycle arrest and death. Here we show that cells that survive the acute bacterial infection with pks+ E. coli display hallmarks of cellular senescence: chronic DSB, prolonged cell-cycle arrest, enhanced senescence-associated β-galactosidase (SA-β-Gal) activity, expansion of promyelocytic leukemia nuclear foci and senescence-associated heterochromatin foci. This was accompanied by reactive oxygen species production and pro-inflammatory cytokines, chemokines and proteases secretion. These mediators were able to trigger DSB and enhanced SA-β-Gal activity in bystander recipient cells treated with conditioned medium from senescent cells. Furthermore, these senescent cells promoted the growth of human tumor cells. In conclusion, the present data demonstrated that the E. coli genotoxin colibactin induces cellular senescence and subsequently propel bystander genotoxic and oncogenic effects.
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Diallo AA, Brugère H, Kérourédan M, Dupouy V, Toutain PL, Bousquet-Mélou A, Oswald E, Bibbal D. Persistence and prevalence of pathogenic and extended-spectrum beta-lactamase-producing Escherichia coli in municipal wastewater treatment plant receiving slaughterhouse wastewater. WATER RESEARCH 2013; 47:4719-4729. [PMID: 23774186 DOI: 10.1016/j.watres.2013.04.047] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 04/09/2013] [Accepted: 04/24/2013] [Indexed: 06/02/2023]
Abstract
We compared the prevalence of pathogenic and extended-spectrum beta-lactamase (ESBL) - producing Escherichia coli in effluents of a municipal wastewater treatment plant (WWTP) receiving wastewater from a slaughterhouse. A total of 1248 isolates were screened for the presence of virulence genes associated with enterohemorrhagic E. coli (EHEC) (stx1, stx2, and eae) and extraintestinal pathogenic E. coli (ExPEC) (sfa/focDE, kpsMT K1, hlyA, papEF, afa/draBC, clbN, f17A and cnf). The prevalence of atypical enteropathogenic E. coli (EPEC) was 0.7%, 0.2% and 0.5% in city wastewater, slaughterhouse wastewater and in the treated effluent, respectively. One stx1a and stx2b-positive E. coli isolate was detected in city wastewater. The prevalence of ExPEC was significantly higher in city wastewater (8.4%), compared to slaughterhouse wastewater (1.2%). Treatment in the WWTP did not significantly impact the prevalence of ExPEC in the outlet effluent (5.0%) compared to city wastewater. Moreover, the most potentially pathogenic ExPEC were isolated from city wastewater and from the treated effluent. ESBL-producing E. coli was also mainly detected in city wastewater (1.7%), compared to slaughterhouse wastewater (0.2%), and treated effluent (0.2%). One ESBL-producing E. coli, isolated from city wastewater, was eae-β1 positive. These results showed that pathogenic and/or ESBL-producing E. coli were mainly detected in human wastewater, and at a lesser extend in animal wastewater. Treatment failed to eliminate these strains which were discharged into the river, and then these strains could be transmitted to animals and humans via the environment.
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Martin P, Marcq I, Magistro G, Penary M, Garcie C, Payros D, Boury M, Olier M, Nougayrède JP, Audebert M, Chalut C, Schubert S, Oswald E. Interplay between siderophores and colibactin genotoxin biosynthetic pathways in Escherichia coli. PLoS Pathog 2013; 9:e1003437. [PMID: 23853582 PMCID: PMC3708854 DOI: 10.1371/journal.ppat.1003437] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 05/02/2013] [Indexed: 01/19/2023] Open
Abstract
In Escherichia coli, the biosynthetic pathways of several small iron-scavenging molecules known as siderophores (enterobactin, salmochelins and yersiniabactin) and of a genotoxin (colibactin) are known to require a 4'-phosphopantetheinyl transferase (PPTase). Only two PPTases have been clearly identified: EntD and ClbA. The gene coding for EntD is part of the core genome of E. coli, whereas ClbA is encoded on the pks pathogenicity island which codes for colibactin. Interestingly, the pks island is physically associated with the high pathogenicity island (HPI) in a subset of highly virulent E. coli strains. The HPI carries the gene cluster required for yersiniabactin synthesis except for a gene coding its cognate PPTase. Here we investigated a potential interplay between the synthesis pathways leading to the production of siderophores and colibactin, through a functional interchangeability between EntD and ClbA. We demonstrated that ClbA could contribute to siderophores synthesis. Inactivation of both entD and clbA abolished the virulence of extra-intestinal pathogenic E. coli (ExPEC) in a mouse sepsis model, and the presence of either functional EntD or ClbA was required for the survival of ExPEC in vivo. This is the first report demonstrating a connection between multiple phosphopantetheinyl-requiring pathways leading to the biosynthesis of functionally distinct secondary metabolites in a given microorganism. Therefore, we hypothesize that the strict association of the pks island with HPI has been selected in highly virulent E. coli because ClbA is a promiscuous PPTase that can contribute to the synthesis of both the genotoxin and siderophores. The data highlight the complex regulatory interaction of various virulence features with different functions. The identification of key points of these networks is not only essential to the understanding of ExPEC virulence but also an attractive and promising target for the development of anti-virulence therapy strategies.
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Revelles O, Millard P, Nougayrède JP, Dobrindt U, Oswald E, Létisse F, Portais JC. The carbon storage regulator (Csr) system exerts a nutrient-specific control over central metabolism in Escherichia coli strain Nissle 1917. PLoS One 2013; 8:e66386. [PMID: 23840455 PMCID: PMC3688793 DOI: 10.1371/journal.pone.0066386] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 05/05/2013] [Indexed: 01/25/2023] Open
Abstract
The role of the post-transcriptional carbon storage regulator (Csr) system in nutrient utilization and in the control of the central metabolism in E. coli reference commensal strain Nissle 1917 was investigated. Analysis of the growth capabilities of mutants altered for various components of the Csr system (csrA51, csrB, csrC and csrD mutations) showed that only the protein CsrA - the key component of the system - exerts a marked role in carbon nutrition. Attenuation of CsrA activity in the csrA51 mutant affects the growth efficiency on a broad range of physiologically relevant carbon sources, including compounds utilized by the Entner-Doudoroff (ED) pathway. Detailed investigations of the metabolomes and fluxomes of mutants and wild-type cells grown on carbon sources representative of glycolysis and of the ED pathway (glucose and gluconate, respectively), revealed significant re-adjusting of central carbon metabolism for both compounds in the csrA51 mutant. However, the metabolic re-adjusting observed on gluconate was strikingly different from that observed on glucose, indicating a nutrient-specific control of metabolism by the Csr system.
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Olier M, Marcq I, Salvador-Cartier C, Secher T, Dobrindt U, Boury M, Bacquié V, Penary M, Gaultier E, Nougayrède JP, Fioramonti J, Oswald E. Genotoxicity of Escherichia coli Nissle 1917 strain cannot be dissociated from its probiotic activity. Gut Microbes 2012; 3:501-9. [PMID: 22895085 PMCID: PMC3495787 DOI: 10.4161/gmic.21737] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Oral administration of the probiotic bacterium Escherichia coli Nissle 1917 improves chronic inflammatory bowel diseases, but the molecular basis for this therapeutic efficacy is unknown. E. coli Nissle 1917 harbors a cluster of genes coding for the biosynthesis of hybrid nonribosomal peptide-polyketide(s). This biosynthetic pathway confers the ability for bacteria to induce DNA double strand breaks in eukaryotic cells. Here we reveal that inactivation of the clbA gene within this genomic island abrogated the ability for the strain to induce DNA damage and chromosomal abnormalities in non-transformed cultured rat intestinal epithelial cells but is required for the probiotic activity of E. coli Nissle 1917. Thus, evaluation of colitis severity induced in rodent fed with E. coli Nissle 1917 or an isogenic non-genotoxic mutant demonstrated the need for a functional biosynthetic pathway both in the amelioration of the disease and in the modulation of cytokine expression. Feeding rodents with a complemented strain for which genotoxicity was restored confirmed that this biosynthetic pathway contributes to the health benefits of the probiotic by modulating its immunomodulatory properties. Our data provide additional evidence for the benefit of this currently used probiotic in colitis but remind us that an efficient probiotic may also have side effects as any other medication.
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Auvray F, Dilasser F, Bibbal D, Kérourédan M, Oswald E, Brugère H. French cattle is not a reservoir of the highly virulent enteroaggregative Shiga toxin-producing Escherichia coli of serotype O104:H4. Vet Microbiol 2012; 158:443-5. [DOI: 10.1016/j.vetmic.2012.02.029] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 02/17/2012] [Accepted: 02/20/2012] [Indexed: 11/26/2022]
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Nowrouzian FL, Oswald E. Escherichia coli strains with the capacity for long-term persistence in the bowel microbiota carry the potentially genotoxic pks island. Microb Pathog 2012; 53:180-2. [PMID: 22709536 DOI: 10.1016/j.micpath.2012.05.011] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 05/22/2012] [Accepted: 05/29/2012] [Indexed: 10/28/2022]
Abstract
The pks genomic island found in Escherichia coli strains of phylogenetic group B2 encodes colibactin, a polyketide-peptide genotoxin that causes DNA double-strand breaks. We investigated the relationship between carriage of the pks island and the capacity of E. coli strains to persist in the gut microbiota of 130 Swedish infants, who were followed from birth to 18 months of age. Long-term colonizers were significantly more likely to have the pks island than either intermediate-term colonizers or transient strains, which suggests that the pks island contributes to the pronounced gut-colonizing capacity of group B2 strains. Long-term persistence in the colon of pks island-containing E. coli strains may be associated with the induction of genomic mutations in the host intestine.
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Dubois D, Baron O, Cougnoux A, Delmas J, Pradel N, Boury M, Bouchon B, Bringer MA, Nougayrède JP, Oswald E, Bonnet R. ClbP is a prototype of a peptidase subgroup involved in biosynthesis of nonribosomal peptides. J Biol Chem 2011; 286:35562-35570. [PMID: 21795676 DOI: 10.1074/jbc.m111.221960] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The pks genomic island of Escherichia coli encodes polyketide (PK) and nonribosomal peptide (NRP) synthases that allow assembly of a putative hybrid PK-NRP compound named colibactin that induces DNA double-strand breaks in eukaryotic cells. The pks-encoded machinery harbors an atypical essential protein, ClbP. ClbP crystal structure and mutagenesis experiments revealed a serine-active site and original structural features compatible with peptidase activity, which was detected by biochemical assays. Ten ClbP homologs were identified in silico in NRP genomic islands of closely and distantly related bacterial species. All tested ClbP homologs were able to complement a clbP-deficient E. coli mutant. ClbP is therefore a prototype of a new subfamily of extracytoplasmic peptidases probably involved in the maturation of NRP compounds. Such peptidases will be powerful tools for the manipulation of NRP biosynthetic pathways.
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