Abstract: The instant methods and compositions represent an advance in controlling drug resistance in microbes. AcrAB-like efflux pumps have been found to control resistance to drugs, even in highly resistant microbes. Accordingly, methods of treating infection, methods of screening for inhibitors of AcrAB-like efflux pumps, and methods of enhancing antimicrobial activity of drugs are provided. Pharmaceutical composition comprising an inhibitor of an AcrAB-like efflux pump and an antimicrobial agent are also provided.