A simple method for the detection of resistance plasmids in Serratia species by transfer to members of the genus Enterobacter

Abstract

A simple conjugation system is described for the transfer of resistance plasmids from Serratia species to members of the genus Enterobacter. A surface-mating technique was employed using a supplemented minimal agar medium. Inhibition of the recipient was mediated by the antimicrobial agent under investigation and counter-selection against the donor was achieved by the incorporation of rhamnose as the carbon source. Plasmid transfer and expression occurred readily in the presence of the antimicrobial agent. The plasmids transferred were RP4, R446b and four naturally occurring serratia plasmids designated pDJP1, 2, 3, and 4. The incidence and frequency of plasmid transfer to Enterobacter species were markedly higher than to Escherichia coli K12.