[Inhibition of the diffusion of plasmids by a nitrofuran derivative]

Antibiotic resistance plasmids PR4, R6K, and RGN238 can transfer between Escherichia coli cells by conjugation (transfer frequency: 3 to 3.5 x 10(-4)). Nifurzide, a nitrofuran derivative, greatly depresses plasmid transfer at concentrations (59 microM) which do not affect cell viability.