A transferable kanamycin resistance plasmid isolated from Haemophilus influenzae

Kanamycin resistance was transferred by conjugation from a Haemophilus influenzae strain into Escherichia coli K12, and between E. coli K12 strains in subsequent transfers. Covalently closed molecules of DNA were isolated by sedimentation analysis of the DNA of the resistant E. coli K12 strains. These facts support the hypothesis that kanamycin resistance is mediated by a transferable plasmid in this strain of H. influenzae.