Differential expression of virulence and stress fitness genes between Escherichia coli O157:H7 strains with clinical or bovine-biased genotypes

The expression patterns of clinical genotype I strains are compared with those of bovine-biased genotype 5 strains by using mciroarrays in order to determine whether inherent differences in gene expression have explained the variation in infectivity of these genotypes. The results have shown that the increased prevalence of Escherichia coli O157:H7 illness caused by clinical genotype I strains are because of the overexpression of key virulence genes, but the bovine-biased genotype 5 strains are more resistant to adverse environmental conditions.