First microbiological approach to dactimicin, a novel aminoglycoside antibiotic.

Dactimicin (ST 900) is the first aminoglycoside antibiotic of Dactylosporangium origin. This drug shows resistance to many enzymes that destroy aminoglycosides. In this first approach, the authors have pointed out the activity of dactimicin against Gram-negative rods, particularly Klebsiella, Enterobacter, Serratia and Gram-positive bacteria, especially methicillin susceptible and resistant staphylococci. Dactimicin showed remarkable antibacterial activity against all strains tested; however this activity was strongly influenced by the inoculum size. The bactericidal activity of dactimicin towards some Gram-positive and Gram-negative bacteria was also evaluated.