AAADisclosed is a method for identifying an essential gene which serves as an antibiotic target in a bacterium the method comprising the steps of: (a) generating a pool of mutant bacteria by transposon mutagenesis with an activating transposon (Tn) wherein the Tn comprises a promoter such that transposon insertion into bacterial DNA increases the transcription of a gene at or near the insertion site (b) growing bacteria from the mutant pool in the presence of different amounts of said antibiotic to produce two or more test cultures and (c) comparing the distribution of Tn insertions between test cultures to identify a putative essential gene serving as a target of said antibiotic in said bacterium.
