In vitro activity: Marbofloxacin is a fluoroquinolone antimicrobial agent developed exclusively for veterinary use. Marbofloxacin exhibits high bactericidal activity against a broad spectrum of aerobic Gram-negative and some Gram-positive bacteria, as well as Mycoplasma spp. As the third generation fluoroquinolone, Marbofloxacin also mainly targets replication and transcription enzymes such as DNA gyrase and topoisomerase IV, which are both essential for bacterial viability. Marbofloxacin has a mycoplasmacidal effect during the exponential phase but not during the lag phase, in both the M. hyopneumoniae 116 wild-type strain and a clone isolated 4 days post-marbofloxacin treatment in vivo at the therapeutic dose. Marbofloxacin significantly kills Leishmania promastigotes and intracellular amastigotes in a dose-dependent manner, more efficient than meglumine antimoniate and sodium stibogluconate. After treatment with Marbofloxacin, macrophages acquire resistance to infection and enhanced antileishmanial activity through the NO synthase pathway.