[Prevalence and dispersion of plasmids conferring fosfomycin resistance in enterobacteria].

The mechanisms of resistance to fosfomycin which, at the present, predominate among clinical isolates of Serratia marcescens as well as the incidence and dispersion of For plasmids among other species of Enterobacteriaceae were studied. It was found that that 23 of the 29 strains under study phenotypically behaved as glp T- mutants, another as glp T- and uhp- and five of them showed no alterations in their transport system. Self-transferable plasmids involved in For were isolated from the latter. For plasmids were also found in strains of Klebsiella pneumoniae but not in other enterobacteria. Plasmids were studied in order to establish their resistance phenotype, molecular weight and incompatibility group. The data obtained along with the restriction pattern allow us to conclude that the trait For is linked to, at least, two different replicons.