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Investigation of horizontal gene transfer and characterisation of stx bacteriophages in southern hemisphere Enterohaemorrhagic Escherichia coli O157 strains

Project Member(s): Petty, N.

Funding or Partner Organisation: Commonwealth Scientific and Industrial Research Organisation (Commonwealth Scientific & Industrial Research Organisation)
Commonwealth Scientific and Industrial Research Organisation (Commonwealth Scientific & Industrial Research Organisation)

Start year: 2013

Summary: Shiga toxigenic Escherichia coli (STEC) and Enterohaemorrhagic Escherichia coli (EHEC) are bacterial foodborne pathogens commonly associated with, but not limited to consumption of contaminated beef. The incidence of STEC/EHEC clinical disease is substantial in many countries, but relatively low in Australia, despite the equivalent prevalence of STEC in cattle populations. Shiga toxin is the key virulence factor of STEC/EHEC and the stx toxin genes are carried by bacterial viruses known as stx bacteriophages. The stx bacteriophages convert E. coli to produce Shiga toxins through the process of lysogeny, when viral DNA copies are integrated into the bacterial chromosome (also referred to as prophage integration). We have recently identified that diverse stx prophages can influence both the virulence and genome diversity of STEC. In this study we will further investigate the role of stx prophage in transferring bacterial virulence genes among different E. coli strains, and the influence of stx prophage genome diversity on bacterial pathogenicity, bacterial genome evolution and geographical specialisation.

Keywords: EHEC, STEC, Bacteriophage, Horizontal gene transfer

FOR Codes: Microbiology, Infectious Diseases