Genotypic variations of Shiga toxin-converting phages from enterohaemorrhagic Escherichia coli O157: H7 isolates
Related Experiment Video
Updated: Oct 16, 2026

Electricity-Free, Sequential Nucleic Acid and Protein Isolation
Published on: May 15, 2012
R O Osawa, Sunao Iyoda1, Shu-Ichi Nakayama1
1Department of Bacteriology and Pathology, Kanagawa Prefectural Public Health Laboratory, Nakao-cho, Asahi-ku, Yokohama and *Department of Bacteriology, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, Japan.
Abstract:
Pulsed-field gel electrophoresis (PFGE) analysis revealed that enterohaemorrhagic Escherichia coli (EHEC) O157:H7 strains had considerable variations in their genomes. This study investigated whether or not the molecular profile of Shiga toxin (Stx) 1- and Stx2-converting phages isolated from EHEC O157:H7 strains, derived from various sources in the USA and Japan, corresponded to the variations of host strains' genotypes as determined by PFGE. A total of 51 Stx-converting phages including 12 Stx1-converting phages and 37 Stx2-converting phages was isolated from seven USA isolates and 20 Japanese isolates. The average Dice coefficient values showed 44% similarity between phage DNAs in Stx2-converting phages digested with SmaI and 55% in Stx1-converting phages digested with HindIII, indicating considerable variation among phage DNA. In particular, restriction fragment length polymorphism (RFLP) patterns of Stx2-converting phage DNA varied according to the PFGE type of their host strain, which suggests that the phage genomes have altered their genotypic characteristics with those of host genomes. However, there are several exceptions: the RFLP patterns of some Stx2-converting phages were quite similar irrespective of the different genotypes of the host strains, indicating that horizontal transfer of Stx2-converting phage may also occur under some circumstances.
More Related Videos
Related Concept Videos
Bacterial Gastroenteritis
Lysogenic Cycle of Bacteriophages
DNA Bacteriophages
Viral Replication: Lytic Cycle
Transduction
Bacteriophages of the Human Virome

