Dactylocyclines, novel tetracycline derivatives produced by a Dactylosporangium sp. A screen for antibiotics with activity against tetracycline-resistant microorganisms has led to the isolation of Dactylosporangium sp. (ATCC 53693), a producer of several novel tetracycline derivatives. The major fermentation products, dactylocyclines A and B, were purified and MIC values determined against tetracycline-resistant and tetracycline-sensitive Gram-positive bacteria. The dactylocyclines represent the first naturally occurring tetracycline C2 amides which lack cross resistance with tetracycline.
