| abstract |
A biologically pure culture of Streptomyces resistomycificus No. 7622 (FERM BP-2306), new compounds WS7622A, B, C and D obtainable by culturing Streptomyces resistomycificus No. 7622 in a nutrient medium and isolating them or their pharmaceutically acceptable salts, and derivatives of such new compounds, and pharmaceutical compositions comprising such new compounds or their pharmaceutically acceptable salts as an active ingredient. |