Inosamycin, a complex of new aminoglycoside antibiotics. I. Production, isolation and properties

A strain of Streptomyces hygroscopicus No. J296-21 (ATCC 39150) was found to produce a complex of new antibiotics, called inosamycins, which consisted of components A, B, C, D and E. They are novel aminocyclitol antibiotics structurally related to neomycin, paromomycin and ribostamycin. The antibiotic complex and each component of inosamycin exhibit a broad antibacterial spectrum but they are inactive against most of the aminoglycoside-resistant organisms. The antibacterial activity of inosamycin A, the major component of the complex, is comparable to that of neomycin but its acute toxicity is significantly lower (ca. 1/3) than that of neomycin.