It is an aminoglycoside antibiotic produced by the strain of Str. hofunensis nor. sp. (ATCC 21970). It has a broad spectrum of antimicrobial activity, and Seldomycin F5 has the strongest antimicrobial activity. It is cross-resistant to E. coli with aminoglycoside antibiotic passivation enzyme (such as APH (3')-Ⅰ, APH(3')-II, AAC(6'), AAC(2)).