Methods of selecting wide host range bacteriophage capable of growing in a plurality of bacteria including pathogenic and non-pathogenic bacteria and bacteriophage selected are described. In addition to methods of treating a subject infected with a pathogenic bacterium using bacteriophage, of decontaminating objects using bacteriophage, of producing vaccines. In another aspect, methods of determining bacterial viability and methods of improving the sensitivity of a biosensor using wide host range bacteriophages are also disclosed
