Plectasin is an antibiotic protein from the mushroom Pseudoplectania nigrella. It was initially discovered in 2005[1] and commercialised by Novozymes.[2] Plectasin belongs to the antimicrobial peptide class called fungal defensins, which is also present in invertebrates such as flies and mussels.[citation needed]
Pre-clinical tests in mice have shown promising results in that multiresistant bacteria have problems mutating resistance against plectasin,[3] which acts by directly binding the bacterial cell-wall precursor Lipid II.[4]
At the end of 2008, Novozymes signed a global licensing agreement with Sanofi-Aventis for the further development and marketing of NZ2114, a derivative of plectasin, as a treatment for gram-positive bacterial infections, e.g. Streptococcus and Staphylococcus which are resistant to all existing antibiotics.[2][5]