Abstract: The present invention provides compositions useful in treating drug-resistant microorganisms and cells, as well as related methods of identifying and using such compositions. In addition, the present invention includes compositions useful in enhancing the sensitivity of both drug-resistant and drug-sensitive microorganisms and cells to microbicidal and cytotoxic agents, including antibiotics and chemotherapeutic drugs. Methods of identifying these compositions, as well as methods of using these agents in treating both drug-resistant and drug-sensitive diseases and conditions are further provided.