 For one year, plasmidic mediated quinolone resistance PMQR were detected all the Extended- Spectrum beta-lactamase producing Enterobacteriaceae isolated in the 5 teaching hospitals and 4 general hospitals of the french East inter region during the first nine months of 2009. A case-control study was performed. The cases were the 29 patients in whom a qnr gene was detected in an enterobacteriaceae. The controls were 104 patients hospitalized in the hospital with a age difference 10 years with a case and having an Enterobacteriaceae without a qnr gene. At least, 2 control patients were selected. for each case 