Incidences of simple and transferable drug resistance in Escherichia coli and Salmonella isolated from various foods: identification of a R plasmid in S. saint-paul.

A study of 1,043 strains of E. coli and 22 strains of Salmonella isolated from various foods in eastern France between the dates of June 1974 and December 1976 showed that 164 (15.6%) of E. coli and nine Salmonella were resistant to one or several drugs. Only 18 of the 83 resistant E. coli strains were able to transfer their resistance to tetracycline and some other drug resistance to E. coli K12 in vitro. A conjugative R plasmid has been identified by transfer experiments, incompatibility testing and agarose gel electrophoresis in a strain of multiresistant S. saint-paul.