Endolysins as a class of antimicrobial enzymes originated from bacteriophages, have been noticed in biologic controlling of multidrug resistant pathogenic strains of bacteria. In this study endolysin nucleotide sequences of different Escherichia coli (E.coli) bacteriophages were analyzed bioinformatically. The sequences were obtained from gene bank and similarity matrix and phylogenetic tree based on endolysin gene were determined using Bioedite and Mega4 softwares. The range of similarity was 0-56.6% comparing pairwise of the phage sequences. Some phages against E.coli o157H7 didn’t show any divergence while the others had 14.8-15.6% difference between the sequences. The lowest similarity was observed between phage K1G and phage RB16 that both of them were originated from USA. Based on phylogenetic tree some Canadian phages were not clustered together but they were located in distict group with the other countries phages. Also all of USA phages were not classified in one group and showed similarity between 73-76% with each other. Phages of Norway and Russia were grouped with some USA, Canada and Hong Kong phages in one cluster. Various rates of similarity between endolysin gene sequences of bacteriophages isolated against E.coli different strains even the same bacterial strain, suggests that more detailed molecular analysis needed not only for understanding the structure and function of endolysins but also using genetic engineering approaches to produce a new generation of specific and applicable antimicrobials.
