Natural products are considered to have pharmaceutical potential because of their pharmacophore-like structures and unique chemical spaces. In the field of infectious diseases, in particular, natural products account for a large proportion of pharmaceuticals. Thus, natural products play an active role in the development of treatments to overcome antimicrobial resistance (AMR).

Staphylococcus aureus (S. aureus) is one of the most widespread bacterial pathogenic causes of infections. It causes both serious invasive infections and simple skin infections. Among them, Methicillin-resistant Staphylococcus aureus (MRSA) is a group of Gram-positive bacteria that are genetically distinct from other strains of Staphylococcus aureus. Specifically, MRSA is any strain of S. aureus that has developed or acquired multiple drug resistance to beta-lactam antibiotics. However, MRSA is responsible for several difficult-to-treat infections in humans. Furthermore, MRSA has the highest mortality rate among all antibiotic-resistant isolates. Therefore, there is a need to develop novel antibacterial agents that are effective against drug-resistant MRSA strains.

Wychimicin A is a spirotetronate polyketide with antibacterial activity.

Wychimicin A can be isolated from the rare actinomycete Actinocrispum wychmicini strain MI503-AF4. In addition, Wychimicin A possesses a macrocyclic 13-membered ring containing trans-decalin and β-d-xylo-hexopyranose moieties connected to C-17 by an O-glycosidic linkage. More importantly, Wychimicin A shows strong antibacterial activity against MRSA. For example, Wychimicin A shows low MIC values against Gram-positive bacteria such as S. aureus (including MRSA) and Enterococcus faecalis/faecium (including VRE).

To sum up, Wychimicin A is a natural spirotetronate polyketide, and exhibits strong antibacterial activity against MRSA.


[1] Kimura T, et al. J Antibiot (Tokyo). 2022 Oct;75(10):535-541.