| abstract |
A new acidic polycyclic ether antibiotic UK-58,852 has the formula:wherein R and R<sup>1</sup> are both hydrogen, and can be prepared by the submerged aerobic propagation in aqueous nutrient media of Actinomadura sp. ATCC 39697. The antibiotic and its cationic salts are active against a variety of microorganisms and are effective in controlling coccidiosis, enteritis, swine dysentery and theileriosis as well as being effective in promotion of growth and/or improving efficiency of feed utilisation in swine and ruminants. Two minor components, wherein R is H and R<sup>1</sup> is CH<sub>3</sub> and wherein R and R are both CH<sub>3</sub>, have also been isolated from the fermentation. |