Man Kit Cheung1, Lei Li, Wenyan Nong, Hoi Shan Kwan. 1. School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China. mkcheung@cuhk.edu.hk.
Abstract
BACKGROUND: A large-scale Escherichia coli O104:H4 outbreak occurred in Germany from May to July 2011, causing numerous cases of hemolytic-uremic syndrome (HUS) and deaths. Genomes of ten outbreak isolates and a historical O104:H4 strain isolated in 2001 were sequenced using different new generation sequencing platforms. Phylogenetic analyses were performed using various approaches which either are not genome-wide or may be subject to errors due to poor sequence alignment. Also, detailed pathogenicity analyses on the 2001 strain were not available. FINDINGS: We reconstructed the phylogeny of E. coli using the genome-wide and alignment-free feature frequency profile method and revealed the 2001 strain to be the closest relative to the 2011 outbreak strain among all available E. coli strains at present and confirmed findings from previous alignment-based phylogenetic studies that the HUS-causing O104:H4 strains are more closely related to typical enteroaggregative E. coli (EAEC) than to enterohemorrhagic E. coli. Detailed re-examination of pathogenicity-related virulence factors and secreted proteins showed that the 2001 strain possesses virulence factors shared between typical EAEC and the 2011 outbreak strain. CONCLUSIONS: Our study represents the first attempt to elucidate the whole-genome phylogeny of the 2011 German outbreak using an alignment-free method, and suggested a direct line of ancestry leading from a putative EAEC-like ancestor through the 2001 strain to the 2011 outbreak strain.
BACKGROUND: A large-scale Escherichia coli O104:H4 outbreak occurred in Germany from May to July 2011, causing numerous cases of hemolytic-uremic syndrome (HUS) and deaths. Genomes of ten outbreak isolates and a historical O104:H4 strain isolated in 2001 were sequenced using different new generation sequencing platforms. Phylogenetic analyses were performed using various approaches which either are not genome-wide or may be subject to errors due to poor sequence alignment. Also, detailed pathogenicity analyses on the 2001 strain were not available. FINDINGS: We reconstructed the phylogeny of E. coli using the genome-wide and alignment-free feature frequency profile method and revealed the 2001 strain to be the closest relative to the 2011 outbreak strain among all available E. coli strains at present and confirmed findings from previous alignment-based phylogenetic studies that the HUS-causing O104:H4 strains are more closely related to typical enteroaggregative E. coli (EAEC) than to enterohemorrhagic E. coli. Detailed re-examination of pathogenicity-related virulence factors and secreted proteins showed that the 2001 strain possesses virulence factors shared between typical EAEC and the 2011 outbreak strain. CONCLUSIONS: Our study represents the first attempt to elucidate the whole-genome phylogeny of the 2011 German outbreak using an alignment-free method, and suggested a direct line of ancestry leading from a putative EAEC-like ancestor through the 2001 strain to the 2011 outbreak strain.
Authors: Alexander Mellmann; Dag Harmsen; Craig A Cummings; Emily B Zentz; Shana R Leopold; Alain Rico; Karola Prior; Rafael Szczepanowski; Yongmei Ji; Wenlan Zhang; Stephen F McLaughlin; John K Henkhaus; Benjamin Leopold; Martina Bielaszewska; Rita Prager; Pius M Brzoska; Richard L Moore; Simone Guenther; Jonathan M Rothberg; Helge Karch Journal: PLoS One Date: 2011-07-20 Impact factor: 3.240
Authors: Alexander Mellmann; Martina Bielaszewska; Robin Köck; Alexander W Friedrich; Angelika Fruth; Barbara Middendorf; Dag Harmsen; M Alexander Schmidt; Helge Karch Journal: Emerg Infect Dis Date: 2008-08 Impact factor: 6.883
Authors: Tonia Zangari; Angela R Melton-Celsa; Aruna Panda; Nadia Boisen; Mark A Smith; Ivan Tatarov; Louis J De Tolla; James P Nataro; Alison D O'Brien Journal: Infect Immun Date: 2013-02-25 Impact factor: 3.441
Authors: Qianli Huang; Xuanjin Cheng; Man Kit Cheung; Sergey S Kiselev; Olga N Ozoline; Hoi Shan Kwan Journal: PLoS One Date: 2012-03-20 Impact factor: 3.240