Closthioamide is a potent inhibitor of bacterial DNA gyrase and highly active against Ec, MRSA, VRE and Mv), with MICs of 9.00 μM, 0.58 μM, 0.58 μM and 72.03 μM respectively.

Bacterial DNA gyrase^[1].
MIC: 9.00 μM (Ec), 0.58 μM (MRSA), 0.58 μM (VRE), 72.03 μM (Mv)^[2].

Closthioamide is a potent inhibitor of bacterial DNA gyrase, isolated from the strictly anaerobic banterium Clostridium cellulolyticum and belongs to a new class of natural products^[1]. In a standardized antimicrobial assay, it is found that closthioamide is highly active against a pathogenic, methicillin-resistant Staphylococcus aureus (MRSA) strain with a minimum inhibitory concentration (MIC) of 0.4 μg/mL^-1 (0.58 μM). Closthioamide is even active against vancomycin-resistant Enterococcus faecalis (VRE) with the same low MIC value, and is thus significantly more potent against these bacteria than ciprofloxacin, the standard drugused against VRE, with remarkable strain selectivity. Furthermore, in a standardized cytotoxicity assay, closthioamide shows moderate antiproliferative and cytotoxic effects^[2].

• [1]. Chiriac AI, et al. Mode of action of closthioamide: the first member of the polythioamide class of bacterial DNA gyrase inhibitors. J AntimicrobChemother. 2015Sep;70(9):2576-88.

  [2]. Lincke T, et al. Closthioamide: an unprecedented polythioamide antibiotic from the strictly anaerobic bacterium Clostridium cellulolyticum.Angew Chem Int Ed Engl. 2010 Mar 8;49(11):2011-3.