Interaction ofEscherichia coli O55 hybrids with bacteriophage lambda. A new type of host specificity betweenEscherichia coli O55 and urinaryEscherichia coli

Escherichia coli O55 hybrids able to adsorb the lambda phage were obtained by mating anEscherichia coli O55 recipient with anEscherichia coli K12HfrC donor. λ mutants, capable of forming plaques on these hybrids, were not isolated. A new type of host specificity betweenEscherichia coli O55 and urinaryEscherichia coli J was established. For efficient reduction of the phage plating ability more growth steps on the new strain are required in this type. Host specificities O55 and J proved to be different from K specificity.