text: Thienamycin (also known as thienpenem) is one of the most potent naturally produced antibiotics known thus far, discovered in Streptomyces cattleya in 1976.  Thienamycin has excellent activity against both Gram-positive and Gram-negative bacteria and is resistant to bacterial β-lactamase enzymes.  Thienamycin is a zwitterion at pH 7.