Allelic subtyping of eaeA of Escherichia coli(EHEC/EPEC)isolates

Objective To understand the genotypes of the eaeA gene of Escherichia coli(EHEC/EPEC)isolates in China. Methods The eaeA genes of 60 isolates of Escherichia coli were amplified by using polymerase chain reaction(PCR). The products were sequenced and analyzed with BLASTn, and the subtype was identified according to their similarity. Phylogenetic tree was constructed based on the eaeA gene sequences. Results Genotype γ was found in the eaeA genes, with identical sequences, of all 43 EHEC isolates, however, the genotypes of eaeA genes were diverse in 17 EPEC isolates and β1 was the most common genotype(70.6%), followed by κ(11.6%), ε(5.8%), ι2(5.8%)and θ(5.8%). Conclusion Based on the sequence analysis of intimin gene family, we found genetic diversity in EPEC isolates and genetic conservativeness in EHEC isolates.