Genetic Analysis of Enterohaemorrhagic Escherichia Coli Colonisation and Pathogenesis in Cattle

Analysis of the E. coli O157:H7 complete genome sequence has indicated that E. coli O157:H7 contains 1386 genes that are not present in the E. coli K-12 laboratory strain. Approximately 60 percent of these E. coli O157:H7-specific genes have no known function and their distribution in other EHEC serotypes in unknown. <P>
As part of an ongoing collaboration with Imperial College London Dr Stevens will use an oligonucleotide microarray based on the complete E. coli O157:H7 genome to study the prevalence of O157-specific genes in other EHEC serotypes (genome indexing) and to analyse the transcription of EHEC genes in vitro and in vivo. <P>
Studies have already been initiated to recover EHEC RNA from the intestines of gnotobiotic calves. If successful these studies will be extended to other EHEC serotypes that interact with the bovine intestine in a distinct way from E. coli O157:H7. <P>
Such studies will shed light on the timing and level of expression of EHEC genes during the interaction with the bovine host and will facilitate the development of intervention strategies.