Genetic platform to investigate the functions of bacterial drug efflux pumps

A method for identifying a compound that is an antibacterial agent, comprising

• (a) i) contacting the compound with an Escherichia coli strain of comprising at least 20 of inactivated genes acrB, acrD, acrF, mdtF, macB, emrB, mdtL, mdtK, bcr, ydeA, mdtM, yddA, yebQ, emrE, mdtD, sugE, ynfM, emrD, ydeF, mdtJ, ydiM, mdtB, mdlA, emrY, mdfA, fsr, mdtG, mdtH, yieO, mdlB, mdtO, yojI, yajR, ydhC, and cusA (Strain A) and with wild-type Escherichia coli;
• and/or
• ii) contacting the compound with Strain A and an Escherichia coli strain comprising inactivated genes acrB, acrD, acrF, mdtF, macB, emrB, mdtL, mdtK, bcr, ydeA, mdtM, yddA, yebQ, emrE, mdtD, sugE, ynfM, emrD, ydeF, mdtJ, ydiM, mdtB, mdlA, emrY, mdfA, fsr, mdtG, mdtH, yieO, mdlB, mdtO, yojI, yajR, ydhC, and cusA, wherein at least one of acrB, acrD, acrF, mdtF, macB, emrB, mdtL, mdtK, bcr, ydeA, mdtM, yddA, yebQ, emrE, mdtD, sugE, ynfM, emrD, ydeF, mdtJ, ydiM, mdtB, mdlA, emrY, mdfA, fsr, mdtG, mdtH, yieO, mdlB, mdtO, yojI, yajR, ydhC, and cusA, is reactivated (Strain B);
• and/or
• iii) contacting the compound with Strain A and an Escherichia coli strain comprising inactivated genes acrB, acrD, acrF, mdtF, macB, emrB, mdtL, mdtK, bcr, ydeA, mdtM, yddA, yebQ, emrE, mdtD, sugE, ynfM, emrD, ydeF, mdtJ, ydiM, mdtB, mdlA, emrY, mdfA, fsr, mdtG, mdtH, yieO, mdlB, mdtO, yojI, yajR, ydhC, and cusA, wherein one of acrB, acrD, acrF, mdtF, macB, emrB, mdtL, mdtK, bcr, ydeA, mdtM, yddA, yebQ, emrE, mdtD, sugE, ynfM, emrD, ydeF, mdtJ, ydiM, mdtB, mdlA, emrY, mdfA, fsr, mdtG, mdtH, yieO, mdlB, mdtO, yojI, yajR, ydhC, and cusA, is reactivated (Strain C);
• and
• (b) detecting viability of each of the Escherichia coli;
• wherein the compound is identified as an antibacterial agent if the compound decreases viability of wild-type less than Strain A;
• optionally wherein the compound is identified as an antibacterial agent if the compound decreases viability of Strain B less than Strain A;
• optionally wherein the compound is identified as an antibacterial agent if the wild-type Escherichia coli or Strain B is resistant to the compound, and the compound decreases the viability of Strain A.