Analysis of yeh Fimbrial Gene Cluster in Escherichia coli O157:H7 in Order to Find a Genetic Marker for this Serotype.

yeh fimbrial gene cluster encodes a type of putative fimbrial complex belonging to chaperone-usher assembly pathway. Recent studies have shown that yeh fimbrial gene cluster is present in 94 % of Escherichia coli isolates and responsible for adhesion to some abiotic surfaces. Our preliminary comparative genomic analysis of 96 complete genomes of different E. coli strains revealed that the major region of this gene cluster is unique to E. coli O157:H7 strains. To investigate the detail of the analysis, we BLAST the sequence of this gene cluster against the existing complete and draft genome sequences of different E. coli strains and other genera belonging to Enterobacteriaceae family in NCBI database. The results showed that this gene cluster is properly unique to E. coli O157:H7 strains and could be used as a stable and specific genetic signature for the identification of this serotype. In this respect, we also experimentally validated the specificity of this gene cluster for the identification of E. coli O157:H7 strains by loop-mediated isothermal amplification method.