Dispersion of a gene that codifies fosfomycin resistance among plasmids from enterobacteriaceae isolated from sewage

The presence of plasmid encoded resistance to fostomycin among enterobacteriaceae isolated from sewage was studied. These plasmids found were classified into 7 varieties according to their original host, size, resistance determinants, restriction pattern and incompatibility group. All of them were related to the Inc M group, indicating a probable common origin from an ancestral replicon. The bacteria carrying these plasmids modified fosfomycin as did those carrying fosfomycin resistant (For) hospital plasmids. The plasmids showed positive hybridization with a 1-kb DNA fragment which carried a For-determinant from a hospital plasmid.