VIRULENCE PLASMID-ASSOCIATED SENSITIVITY TO RIFAMPICIN AND NOVOBIOCIN IN ESCHERICHIA-COLI

Introduction of the ColV, I-K94 or ColV-K30 plasmid into Escherichia coli K12 resulted in increased sensitivity to growth inhibition and killing by rifampicin and novobiocin. For increased rifampicin sensitivity, both transfer and colicin components had to be present whereas transfer components plus another unidentified ColV component were needed for novobiocin sensitivity.The Col factor Col B-K98 conferred increased rifampicin sensitivity, an effect not dependent on transfer components, but this plasmid had no effect on the novobiocin sensitivity of E. coli. The effects of ColV, I-K94 on rifampicin sensitivity were fully reversed by magnesium ions but Mg2+ had only a slight effect on the novobiocin inhibition of the ColV, I-K94+ strain and the rifampicin inhibition of the ColB-K98+ strain. Prior growth at 25°C greatly reduced the effects of ColV, I-K94 on rifampicin and novobiocin sensitivity but had essentially no effect on rifampicin sensitivity of the ColB-K98+ strain. © 1986 The Society for Applied Microbiology.