Genome sequencing and comparative genomics provides insights on the evolutionary dynamics and pathogenic potential of different H-serotypes of Shiga toxin-producing Escherichia coli O104

摘要: Background: Various H-serotypes of the Shiga toxin-producing Escherichia coli (STEC) O104, including H4, H7, H21, and H¯, have been associated with sporadic cases illness caused food-borne outbreaks globally. In U.S., STEC O104:H21 an outbreak milk in 1994. However, there is little known on evolutionary origins O104 strains, how genotypic diversity contributes to pathogenic potential various H-antigen serotypes isolated from different ecological niches and/or geographical regions. Results: Two (milk strain) O104:H7 (cattle isolate) strains were shot-gun sequenced, genomes closed. The intimin (eae) gene, involved attaching-effacing phenotype diarrheagenic E. coli, was not found either strain. Examining genome sequences, we that two “complete” left right end portions locus enterocyte effacement (LEE) pathogenicity island present 13 strains; however, central portion LEE missing, where eae gene located. O104:H4 missing replaced by a carrying aidA (adhesin diffuse adherence) antibiotic resistance genes commonly carried plasmids. Enteroaggregative coli-specific virulence European O104:H4-specific stx2-encoding P13374 or TL-2011c bacteriophages some sequences available public databases. Most genomic variations examined due presence mobile genetic elements, prophages plasmids virulence-associated may play role strains. Conclusions: sequenced this study (O104:H21 O104:H7) are genetically more similar each other than Germany 2011 Central Africa. A hypothesis strain evolution proposed.