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Lichen metabolite has antimicrobial activity: lichens


Anaptychia ciliaris / Allélav / LicenseCC-by-nc-sa - Attribution Non-commercial Share Alike

The metabolism of lichens protect from colonization by bacteria via the secondary metabolite usnic acid.

"In modern medicine, artificial devices are used for repair or replacement of damaged parts of the body, delivery of drugs, and monitoring the status of critically ill patients. However, artificial surfaces are often susceptible to colonization by bacteria and fungi. Once microorganisms have adhered to the surface, they can form biofilms, resulting in highly resistant local or systemic infections. At this time, the evidence suggests that (+)-usnic acid, a secondary lichen metabolite, possesses antimicrobial activity against a number of planktonic gram-positive bacteria, including Staphylococcus aureus, Enterococcus faecalis, and Enterococcus faecium. Since lichens are surface-attached communities that produce antibiotics, including usnic acid, to protect themselves from colonization by other bacteria, we hypothesized that the mode of action of usnic acid may be utilized in the control of medical biofilms. We loaded (+)-usnic acid into modified polyurethane and quantitatively assessed the capacity of (+)-usnic acid to control biofilm formation by either S. aureus or Pseudomonas aeruginosa under laminar flow conditions by using image analysis. (+)-Usnic acid-loaded polymers did not inhibit the initial attachment of S. aureus cells, but killing the attached cells resulted in the inhibition of biofilm. Interestingly, although P. aeruginosa biofilms did form on the surface of (+)-usnic acid-loaded polymer, the morphology of the biofilm was altered, possibly indicating that (+)-usnic acid interfered with signaling pathways." (Francolini et al. 2004:4360)
About the inspiring organism
Med_nika2204_sized Lichen

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Organism/taxonomy data provided by:
Species 2000 & ITIS Catalogue of Life: 2008 Annual Checklist

Bioinspired products and application ideas

Application Ideas: Antimicrobial surfaces, antimicrobial textiles and tissues, antimicrobial packaging, such as edible films for food items, antimicrobial 'dips' for surgical tools and other medical items.

Industrial Sector(s) interested in this strategy: Hospitals, textiles, food, packaging, medicine

Center for Genomic Sciences
Paul Stoodley
Allegheny-Singer Research Institute, Allegheny General Hospital
Francolini; Norris, P; Piozzi, A; Donelli, G; Stoodley, P. 2004. Usnic Acid, a Natural Antimicrobial Agent Able To Inhibit Bacterial Biofilm Formation on Polymer Surfaces. Antimicrobial Agents and Chemotherapy. 48(11): 4360-4365.
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