Complete genome sequence of enterohemorrhagic Eschelichia coli O157: H7 and genomic comparison with a laboratory strain K-12

Tetsuya Hayashi*, Kozo Makino, Makoto Ohnishi, Ken Kurokawa, Kazuo Ishii, Katsushi Yokoyama, Chang Gyun Han, Eiichi Ohtsubo, Keisuke Nakayama, Takahiro Murata, Masashi Tanaka, Toru Tobe, Tetsuya Iida, Hideto Takami, Takeshi Honda, Chihiro Sasakawa, Naotake Ogasawara, Teruo Yasunaga, Satoru Kuhara, Tadayoshi ShibaMasahira Hattori, Hideo Shinagawa

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1074 Citations (Scopus)


Escherichia coli O157:H7 is a major food-borne infectious pathogen that causes diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome. Here we report the complete chromosome sequence of an O157:H7 strain isolated from the Sakai outbreak, and the results of genomic comparison with a benign laboratory strain, K-12 MG1655. The chromosome is 5.5 Mb in size, 859 Kb larger than that of K-12. We identified a 4.1-Mb sequence highly conserved between the two strains, which may represent the fundamental backbone of the E. coli chromosome. The remaining 1.4-Mb sequence comprises of O157:H7-specific sequences, most of which are horizontally transferred foreign DNAs. The predominant roles of bacteriophages in the emergence of O157:H7 is evident by the presence of 24 prophages and prophage-like elements that occupy more than half of the O157:H7-specific sequences. The O157:H7 chromosome encodes 1632 proteins and 20 tRNAs that are not present in K-12. Among these, at least 131 proteins are assumed to have virulence-related functions. Genome-wide codon usage analysis suggested that the O157:H7-specific tRNAs are involved in the efficient expression of the strain-specific genes. A complete set of the genes specific to O157:H7 presented here sheds new insight into the pathogenicity and the physiology of O157:H7, and will open a way to fully understand the molecular mechanisms underlying the O157:H7 infection.

Original languageEnglish
Pages (from-to)11-22
Number of pages12
JournalDNA Research
Issue number1
Publication statusPublished - 2001
Externally publishedYes


  • Bacterial pathogenicity
  • E. coli K-12
  • E. coli O157:H7
  • Evolution
  • Genome sequence

ASJC Scopus subject areas

  • Genetics
  • Molecular Biology


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