Development and application of a method for the purification of free shigatoxigenic bacteriophage from environmental samples

► Novel phage purification method that exploits the ability of a bacteriophage to infect a host cell and form a lysogen. ► The method enables Stx phage to be recovered, purified and reliably stored. ► The first description of purified free Stx phages recovered from environmental samples. ► The purified Stx phages were all genetically lambdoid but comprised members of the Podoviridae, Myoviridae and Siphoviridae. ► All 15 purified bacteriophage carried an Stx-type-2 operon, and all possessed very distinct genetic profiles.