Antibacterial/Miscellaneous: High Molecular Weight Antibiotics Active Against Nesseiria

Summary

Novelty: New antibiotic substances denominated GE 2270 factors A₁, A₂, A₃, and H are disclosed. They are useful in the treatment of Gram-positive bacteria, and Gram-positive and Gram-negative anaerobes. The compounds are useful as growth-promoting agents in animals such as poultry, swine, ruminants etc.

Biology: The antimicrobial activities of the compounds have been demonstrated in vitro (MIC 0.03 to greater than 128 μg/ml for A₁; 0.06 to greater than 128 μg/ml for A₂; 0.03 to greater than 128 μg/ml for A₃ and 0.03 to greater than 128 μg/ml for factor H). The antimicrobial activities of the compounds have also been confirmed in experimental septicaemia in mice (ED₅₀ = 15.4 mg/kg for A₃; and 3.2 mg/kg for A₁).

Chemistry: The factors A₁, A₂, A₃ and H are prepared by culturing a sample of Planobispora rosem ATCC 53773 to give GE 2270 factor A and by selective transformations of factor A.