A method for the direct isolation of IncH plasmid-dependent bacteriophages

A method is described for the isolation of IncH plasmid‐dependent bacteriophages present in very low numbers in sewage. An isogenic plasmid‐lacking host was used to absorb the majority of non‐specific phages. This resulted in an enrichment of 100‐to 400‐fold of the IncH‐dependent phages. A total of 27 IncH‐dependent phages were isolated and all were shown to be temperature‐sensitive RNA phages which produced turbid plaques.