title: Whole-genome sequencing and comparative genomic analysis ofEscherichia coliO91 strains isolated from symptomatic and asymptomatic human carriers.
abstract: BACKGROUND
  The Shiga toxin-producingEscherichia coli(STEC) O91:H21 strains NCCP15736 and NCCP15737 were isolated during a single outbreak in Korea, NCCP15736 from a symptomatic carrier and NCCP15737 from an asymptomatic carrier. To investigate genomic differences between the two strains, we performed whole-genome sequencing of both strains and conducted a comparative genomic analysis.
  
  
  RESULTS
  Using the Illumina HiSeq 2000 platform and Rapid Annotation using the Subsystem Technology (RAST) server, whole-genome sequences of NCCP15736 and NCCP15737 were obtained and annotated. Phylogenetic analysis of tenE. colistrains showed that NCCP15736 and NCCP15737 are evolutionarily close. The two strains were found to be most close toE. coliO91:NM str. 2009C-3745. The genomic comparison showed that thefimDgene of NCCP15737 is truncated and that the truncation could underlie the defects in infection and pathogenicity of NCCP15737. The two strains showed the same virulence factor profiles, and we identified 25 virulence factors from NCCP15736 and NCCP15737, respectively. We identified ten and nine phage-associated regions in the NCCP15736 and NCCP15737 genomes, respectively; the two strains share five of these.
  
  
  CONCLUSIONS
  NCCP15736 and NCCP15737 differ at the genomic level, even though they share features such as virulence-related genes. NCCP15737 has a deletion infimD,which may underlie its asymptomatic character. We conclude that complete genome sequencing and integration of other types of omics data are needed to fully reveal the mechanism underlying the asymptomatic character of NCCP15737.
authors.affiliation: Interdisciplinary Program in Bioinformatics, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742 Republic of Korea.
authors.forename: Taesoo
authors.initials: T
authors.lastname: Kwon
authors.affiliation: Department of Emergency Medical Service, Sun Moon University, Asan-si, Chungcheongnam-do, 31460 Republic of Korea.
authors.forename: Young-Seok
authors.initials: YS
authors.lastname: Bak
authors.affiliation: Division of Antimicrobial Resistance, Center for Infectious Diseases, Korea National Institute of Health, Cheongju, 363-951 Republic of Korea.
authors.forename: Young-Hee
authors.initials: YH
authors.lastname: Jung
authors.affiliation: Department of Biomedical Laboratory Science, College of Medical Science, Konyang University, Daejeon, 302-832 Republic of Korea.
authors.forename: Young-Bin
authors.initials: YB
authors.lastname: Yu
authors.affiliation: Department of Biomedical Laboratory Science, Kyungdong University, 815 Gyeonhwon-ro, Munmak-eup, Wonju-si, Gangwon-do 26495 Republic of Korea.
authors.forename: Jong Tae
authors.initials: JT
authors.lastname: Choi
authors.affiliation: Glycobiology Unit, Department of Biological Science, Sungkyunkwan University and Samsung Advanced Institute for Health Sciences and Technology (SAIHST), 2066 Seobu-ro, Suwon, 16419 Republic of Korea.
authors.forename: Cheorl-Ho
authors.initials: CH
authors.lastname: Kim
authors.affiliation: Department of Food Science and Technology, Sunchon National University, Sunchon, Jeonnam 540-950 Republic of Korea.
authors.forename: Jung-Beom
authors.initials: JB
authors.lastname: Kim
authors.affiliation: Interdisciplinary Program in Bioinformatics, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742 Republic of Korea.
authors.forename: Won
authors.initials: W
authors.lastname: Kim
authors.affiliation: Division of Enteric Diseases, Center for Infectious Diseases, Korea National Institute of Health, Cheongju, 363-951 Republic of Korea.
authors.forename: Seung-Hak
authors.identifier: 0000-0002-1005-4470
authors.initials: SH
authors.lastname: Cho
keywords: Draft genome; Shiga-like toxin-producing Escherichia coli O91; Truncated protein; Type I fimbriae; fimD