Tetromycin C5 is a spirotetronate polyketide incorporating a trans-decalin isolated from Streptomyces sp. MK67-CF9 by Tomio and co-workers, Microbial Chemical Research Foundation (Institute of Microbial Chemistry) Japan and patented in 1996. In 2022, researchers from University of Queensland isolated and renamed tetromycin C5 as glenthmycin B, adding confusion to the literature. Structurally, the trans-decalin is coupled to a benzoate aminoglycoside through the C6 position. Tetromycin C5 is a potent antibacterial with activity against Gram positive antibiotic-susceptible and -resistant strains of S. aureus and E. faecalis.