Aogacillins A and B Produced by Simplicillium sp. FKI-5985: New Circumventors of Arbekacin Resistance in MRSA

Aogacillins A and B, capable of overcoming arbekacin resistance in methicillin-resistant Staphylococcus aureus (MRSA), were isolated from a culture broth of Simplicillium sp. FKI-5985. Their structures were elucidated by NMR spectroscopic studies and ECD analyses. The aogacillins possessed a novel carbon skeleton, including a β-keto-γ-methyliden-δ-lactone ring connected to a 2-ethyl-6-methylcyclohexane ring by spiro conjugation.