Distinctiveness of the genomic sequence of Shiga toxin 2-converting phage isolated from Escherichia coli O157:H7 Okayama strain as compared to other Shiga toxin 2-converting phages.
Shiga toxin 2-converting phage was isolated from Escherichia coli O157:H7 associated with an outbreak that occurred in Okayama, Japan in 1996 (M. Watarai, T. Sato, M. Kobayashi, T. Shimizu, S. Yamasaki, T. Tobe, C. Sasakawa and Y. Takeda, Infect. Immun. 61 (1998) 3210-3204). In this study, we analyzed the complete nucleotide sequence of Shiga toxin 2-converting phage, designated Stx2phi-I, and compared it with three recently reported Stx2-phage genomes. Stx2phi-I consisted of 61,765 bp, which included 166 open reading frames. When compared to 933W, VT2-Sakai and VT2-Sa phages, six characteristic regions (regions I-VI) were found in the Stx2 phage genomes although overall homology was more than 95% between these phages. Stx2phi-I exhibited remarkable differences in these regions as compared with VT-2 Sakai and VT2-Sa genes but not with 933W phage. Characteristic repeat sequences were found in regions I-IV where the genes responsible for the construction of head and tail are located. Regions V and VI, which are the most distinct portion in the entire phage genome were located in the upstream and downstream regions of the Stx2 operons that are responsible for the immunity and replication, and host lysis. These data indicated that Stx2phi-I is less homologous to VT2-Sakai and VT2-Sa phages, despite these three phages being found in the strains isolated at the almost same time in the same geographic region but closely related to 933W phage which was found in the E. coli O157 strain 933W isolated 14 years ago in a different geographic area.
Sato
Toshio
T
Research Institute, International Medical Center of Japan, 1-21-1, Toyama, Shinjuku-ku, Tokyo 162-8655, Japan.
Shimizu
Takeshi
T
Watarai
Masahisa
M
Kobayashi
Midori
M
Kano
Shigeyuki
S
Hamabata
Takashi
T
Takeda
Yoshifumi
Y
Yamasaki
Shinji
S
D001287:Attachment Sites, Microbiological / Q000235:genetics; D001483:Base Sequence; D002874:Chromosome Mapping; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D019453:Escherichia coli O157 / Q000821:virology*; D016679:Genome, Viral; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D017906:Siphoviridae / Q000235:genetics*
D004279:DNA, Viral