A comparison of the effect of tiamulin hydrogen fumarate and tylosin tartrate on mycoplasmas of ruminants and some animal ureaplasmas.

The in vitro efficacy of tiamulin was compared to that of tylosin against 7 bovine, 7 ovine and 3 caprine mycoplasma strains isolated from various organs and belonging to different species, as well as 7 ureaplasma strains cultured from cattle, sheep, swine, chickens and turkeys. The minimal mycoplasmacidal concentrations of tiamulin varied between 0.01 and 10.0 micrograms ml-1, while tylosin proved to be active in concentrations of 0.5 and 100.0 micrograms ml-1. Five of 17 mycoplasma strains showed identical sensitivities to both antibiotics while all other strains, including the ureaplasmas, were sensitive to tiamulin at concentrations 5-5000-times lower than tylosin.