Wychimicin C is a spirotetronate polyketide, can be isolated from the rare actinomycete Actinocrispum wychmicini strain MI503-AF4. Wychimicin C shows strong antibacterial activity against methicillin-resistant Staphylococcus. aureus ( IC 50 =0.125-0.5 μg/mL) and Enterococcus. faecalis/faecium ( IC 50 =0.125-0.25 μg/mL).