PHENOTYPIC CONVERSION OF DRUG-RESISTANT BACTERIA TO DRUG-SENSITIVITY

Plasmids that contain synthetic genes coding for small oligoribonucleo tides called external guide sequences (EGSs) have been introduced into strains of Escherichia coli harboring antibiotic resistance genes. Th e EGSs direct RNase P to cleave the mRNAs transcribed from these genes thereby converting the phenotype of drug-resistant cells to drug sens itivity, Increasing the EGS-to-target mRNA ratio by changing gene copy number or the number of EGSs complementary to different target sites enhances the efficiency of the conversion process, We demonstrate a ge neral method for the efficient phenotypic conversion of drug-resistant bacterial cultures.