Pyridinium, 2-[[3-ethyl-5-[6-[[6-[[5-[(3aS,4S,6aR)-hexahydro-2-oxo-1H-thieno[3,4-d]imidazol-4-yl]-1-oxopentyl]amino]-1-oxohexyl]amino]-3-methyl-2(3H)-benzothiazolylidene]-4-oxo-2-thiazolidinylidene]me