title: Activity of azithromycin against Leishmania major in vitro and in vivo.
abstract: Azithromycin, an azalide antibiotic of the macrolide family, concentrates in the tissues and especially in macrophages. Because Leishmania parasites reside in these cells, we tested this antibiotic for a possible antileishmanial activity in vitro and in vivo. Azithromycin decreased the Leishmania major promastigote count in cell-free cultures at log phase approximately 50-fold. In macrophage cultures infected with L. major amastigotes, azithromycin caused a significant decrease in parasite levels with an ED50 of 12 microg/ml. The activity in vivo was evaluated after infection of the footpads of susceptible BALB/cByJ mice and resistant C57BL/6J mice with L. major. Treatment of BALB/cByJ mice with azithromycin, 100 to 200 mg/kg/d, resulted in a significant decrease in lesion size and in the number of parasites per lesion, whereas no effect was seen in the treated C57BL/6J mice. Azithromycin has activity against L. major in vitro and in vivo. Given the severity of the disease and the limitations of the available therapeutic agents, azithromycin may have a significant role in the treatment of this group of diseases.
authors.affiliation: Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Krolewiecki
authors.forename: Shalom
authors.initials: S
authors.lastname: Leon
authors.forename: Phillip
authors.initials: P
authors.lastname: Scott
authors.forename: David
authors.initials: D
authors.lastname: Abraham
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017963:Azithromycin / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D018320:Leishmania major / Q000187:drug effects* / Q000254:growth & development; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL
chemical_list: D000900:Anti-Bacterial Agents; D017963:Azithromycin