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Publisher Summary This chapter describes the bacterial resistance to arsenicals and antimonials, other anion-translocating atpases, and arsenite resistance in eukaryotes. Arsenic is an active ingredient in a variety of commonly used insecticides, rodenticides, and herbicides and can be categorized into three groups: (1) the inorganic salts of the arsenical oxyanions arsenate (pentavalent) and arsenite (trivalent), (2) organic arsenicals, both trivalent and pentavalent, and (3) arsine gas. Bacterial resistance results from the activity of the ArsA, ArsB, and ArsC proteins. The ArsA and ArsB proteins form a membrane-bound oxyanion-translocating ATPase that confers resistance to arsenite and antimonite. Because of their toxicity, the use of arsenical and antimonial drugs is now limited to the treatment of a few topical protozoan diseases. Pentavalent antimony in the form of pentostam is still a widely used chemotherapeutic agent in the treatment of leishmaniasis. Treatment failure results from the emergence of pentostam-resistant Leishmani; Pentostam-resistant clinical isolates are cross-resistant to trivalent antimony, when cultured in macrophages. |
