title: A novel transducible chimeric phage from Escherichia coli O157:H7 Sakai strain encoding Stx1 production.
abstract: Shiga toxin-producing Escherichia coli (STEC), and especially enterohaemorrhagic E. coli (EHEC) are important, highly virulent zoonotic and food-borne pathogens. The genes encoding their key virulence factors, the Shiga toxins, are distributed by converting bacteriophages, the Stx phages. In this study we isolated a new type of inducible Stx phage carrying the stx1 gene cluster from the prototypic EHEC O157:H7 Sakai strain. The phage showed Podoviridae morphology, and was capable of converting the E. coli K-12 MG1655 strain to Shiga toxin-producing phenotype. The majority of the phage genes originate from the stx2-encoding Sakai prophage Sp5, with major rearrangements in its genome. Beside certain minor recombinations, the genomic region originally containing the stx2 genes in Sp5 was replaced by a region containing six open reading frames from prophage Sp15 including stx1 genes. The rearranged genome, together with the carriage of stx1 genes, the morphology and the capability of lysogenic conversion represent a new type of recombinant Stx1 converting phage from the Sakai strain.
authors.affiliation: Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, H-1143, Hungária krt. 21, Budapest, Hungary.
authors.forename: Domonkos
authors.initials: D
authors.lastname: Sváb
authors.affiliation: Seqomics Biotechnology Ltd., H-6782, Vállalkozók útja 7, Mórahalom, Hungary.
authors.forename: Balázs
authors.initials: B
authors.lastname: Bálint
authors.affiliation: Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, H-6726, Temesvári krt. 62, Szeged, Hungary.
authors.forename: Gergely
authors.initials: G
authors.lastname: Maróti
authors.affiliation: Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, H-1143, Hungária krt. 21, Budapest, Hungary. Electronic address: tothi@vmri.hu.
authors.forename: István
authors.initials: I
authors.lastname: Tóth
mesh_terms: D019453:Escherichia coli O157 / Q000235:genetics / Q000502:physiology / Q000821:virology*; D016679:Genome, Viral; D008242:Lysogeny; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D017902:Podoviridae / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D022621:Shiga Toxin / Q000235:genetics / Q000378:metabolism*
chemical_list: D022621:Shiga Toxin
keywords: Lysogenic conversion; O157:H7; Phage recombination; Sakai strain; Stx phages