Silent biosynthetic gene clusters represent a potentially rich source for new bioactive compounds. We report the discovery, characterization and biosynthesis of a novel doubly glycosylated 24-membered polyene macrolactam from a silent biosynthetic gene cluster in Streptomyces roseosporus using the CRISPR-Cas9 gene cluster activation strategy. Structural characterization of this polyketide, named auroramycin, revealed a rare isobutyrylmalonyl extender unit and a unique pair of aminosugars. Relative and absolute stereochemistry were determined using a combination of spectroscopic analyses, chemical derivatization, and computational analysis. The activated gene cluster for auroramycin production was also verified by transcriptional analyses and gene deletions. Finally, auroramycin exhibited potent anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) activity towards clinical drug-resistant isolates.© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.