Progress on research of virulence factors on plasmid pO157 of EHEC O157 ∶ H7

Enterohemorrhagic Escherichia coli (EHEC) O157 ∶ H7 is a major pathogen, which can cause severe disease in humans. Three major virulence factors of E.coli O157 ∶ H7 have been identified including Shiga toxin, products of the pathogenicity island called locus of enterocyte effacement and products of F-like plasmid pO157. Among these virulence factors, the role of pO157 is less understood. This paper summarizes the research progress on virulence factor on pO157 of E.coli O157 ∶ H7.