title: Genotypic variations of Shiga toxin-converting phages from enterohaemorrhagic Escherichia coli O157: H7 isolates.
abstract: Pulsed-field gel electrophoresis (PFGE) analysis revealed that enterohaemorrhagic Escherichia coli (EHEC) O157:H7 strains had considerable variations in their genomes. This study investigated whether or not the molecular profile of Shiga toxin (Stx) 1- and Stx2-converting phages isolated from EHEC O157:H7 strains, derived from various sources in the USA and Japan, corresponded to the variations of host strains' genotypes as determined by PFGE. A total of 51 Stx-converting phages including 12 Stx1-converting phages and 37 Stx2-converting phages was isolated from seven USA isolates and 20 Japanese isolates. The average Dice coefficient values showed 44% similarity between phage DNAs in Stx2-converting phages digested with SmaI and 55% in Stx1-converting phages digested with HindIII, indicating considerable variation among phage DNA. In particular, restriction fragment length polymorphism (RFLP) patterns of Stx2-converting phage DNA varied according to the PFGE type of their host strain, which suggests that the phage genomes have altered their genotypic characteristics with those of host genomes. However, there are several exceptions: the RFLP patterns of some Stx2-converting phages were quite similar irrespective of the different genotypes of the host strains, indicating that horizontal transfer of Stx2-converting phage may also occur under some circumstances.
authors.forename: R O
authors.initials: RO
authors.lastname: Osawa
authors.affiliation: Department of Bacteriology and Pathology, Kanagawa Prefectural Public Health Laboratory, Nakao-cho, Asahi-ku, Yokohama and *Department of Bacteriology, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, Japan.
authors.forename: Sunao
authors.initials: S
authors.lastname: Iyoda
authors.affiliation: Department of Bacteriology and Pathology, Kanagawa Prefectural Public Health Laboratory, Nakao-cho, Asahi-ku, Yokohama and *Department of Bacteriology, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, Japan.
authors.forename: Shu-Ichi
authors.initials: SI
authors.lastname: Nakayama
authors.affiliation: Department of Bacteriology and Pathology, Kanagawa Prefectural Public Health Laboratory, Nakao-cho, Asahi-ku, Yokohama and *Department of Bacteriology, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, Japan.
authors.forename: Akihito
authors.initials: A
authors.lastname: Wada
authors.forename: Shiro
authors.initials: S
authors.lastname: Yamai
authors.affiliation: Department of Bacteriology and Pathology, Kanagawa Prefectural Public Health Laboratory, Nakao-cho, Asahi-ku, Yokohama and *Department of Bacteriology, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, Japan.
authors.forename: Haruo
authors.initials: H
authors.lastname: Watanabe
mesh_terms: D001427:Bacterial Toxins / Q000235:genetics* / Q000378:metabolism; D015139:Blotting, Southern; D003090:Coliphages / Q000145:classification* / Q000235:genetics; D004279:DNA, Viral / Q000032:analysis*; D004196:Disease Outbreaks; D004587:Electrophoresis, Agar Gel; D016521:Electrophoresis, Gel, Pulsed-Field; D004768:Enterotoxins / Q000235:genetics / Q000378:metabolism; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology; D019453:Escherichia coli O157 / Q000145:classification* / Q000235:genetics; D005838:Genotype; D006801:Humans; D007564:Japan / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D022603:Shiga Toxins; D014481:United States / Q000453:epidemiology
chemical_list: D001427:Bacterial Toxins; D004279:DNA, Viral; D004768:Enterotoxins; D022603:Shiga Toxins