 E. coli and related bacteria possess the ability to transfer DNA via bacterial conjugation or transduction , which allows genetic material to spread horizontally through an existing population . The process of transduction , which uses the bacterial virus called a bacteriophage , is where the spread of the gene encoding for the Shiga toxin from the Shigella bacteria to E. coli helped produce E. coli O157 : H7 , the Shiga toxin producing strain of E. coli . 
