Leishmaniasis: efflux pumps and chemoresistance.

Resistance of parasitic protozoa such as Leishmania to therapeutic drugs continues to escalate in developing countries. Treatment programs for human leishmaniasis are still based on pentavalent antimonials but resistance to these compounds has been a persistent problem. In many instances, resistance of the parasite is due to over-expressed ABC efflux pumps. In Leishmania different classes of ABC transporters extrude antimonials, azoles and folates resulting in drug-resistant phenotypes. Although some studies have focused on developing inhibitors against these resistant phenotypes, new efficient modulators that are able to inhibit drug efflux are needed.