Abstract
Vancomycin-resistant enterococci (VRE) and methicillin-resistant staphylococci, most notably methicillin-resistant Staphylococcus aureus (MRSA), are serious clinical problems. The antibiotic arsenal available against them is limited, and new mutants worsen the situation. We studied the activity of (+)-usnic acid, an old lichen-derived drug, and its sodium salt against clinical isolates of VRE and MRSA using the agar diffusion and minimal inhibitory concentration (MIC) methods. The acid and, especially, the sodium salt had potent antimicrobial activity against all clinical isolates of VRE and MRSA studied. The MIC values of the sodium salt against VRE strains ranged between 4 and 16 μg/ml (1-day test) and between 4 and 31 μg/ml (2-day test), being below 8 μg/ml for most strains. The salt had potent activity even against those strains that were not inhibited by ampicillin (125 μg/ml), and it never lost its activity after 24 h, in contrast to ampicillin. Thus, in spite of the fact that usnic acid can in some cases cause serious toxicity, it and its salts may be worth considering in clinical practice in cases where other therapies have failed or the microbe is resistant toward other agents.
This is a preview of subscription content, log in via an institution to check access.
References
Bozdogan B, Esel D, Whitener C, Browne FA, Appelbaum PC (2003) Antibacterial susceptibility of a vancomycin-resistant Staphylococcus aureus strain isolated at the Hershey Medical Center. J Antimicrob Chemother 52:864–868
Centers for Disease Control and Prevention (2002) Staphylococcus aureus resistant to vancomycin—United States, 2002. Morb Mortal Wkly Rep 51:565–567
Cetinkaya Y, Falk P, Mayhall CG (2000) Vancomycin-resistant enterococci. Clin Microbiol Rev 13:686–707
Cocchietto M, Skert N, Nimis PL (2002) A review on usnic acid, an interesting natural compound. Naturwissenschaften 89:137–146
Cunha BA (2005) Methicillin-resistant Staphylococcus aureus: clinical manifestations and antimicrobial therapy. Clin Microbiol Infect 11:33–34
Durazo FA, Lassman C, Han SHB, Saab S, Lee NP, Kawano M, Saggi B, Gordon S, Farmer DG, Yersiz H, Goldstein RLI, Ghobrial M, Busuttil RW (2004) Fulminant liver failure due to usnic acid for weight loss. Am J Gastroenterol 99:950–952
Grasso L, Ghirardi PE, Ghione M (1989) Usnic acid, a selective antimicrobial agent against Streptococcus mutans: a pilot clinical study. Curr Ther Res Clin Exp 45:1067–1070
Hanaki H, Yamaguchi Y, Yanagisawa C, Uehara K, Matsui H, Yamaguchi Y, Hososaka Y, Barada K, Sakai F, Itabashi Y, Ikeda S, Atsuda K, Tanaka H, Inamatsu T, Nagayama A, Sunakawa K (2005) Investigation of beta-lactam antibiotic-induced vancomycin-resistant MRSA (BIVR). J Infect Chemother 11:104–106
Hausen BM, Emde L, Marks V (1993) An investigation of the allergenic constituents of Cladonia stellaris (Opiz) Pous & Vezda (‘silver moss’, ‘reindeer moss’ or ‘reindeer lichen’). Contact Dermatitis 28:70–76
Huneck S (1999) The significance of lichens and their metabolites. Naturwissenschaften 86:559–570
Hsueh P-R, Chen W-H, Teng L-J, Luh K-T (2005) Nosocomial infections due to methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci at a university hospital in Taiwan from 1991 to 2003; resistance trends, antibiotic usage and in vitro activities of newer antimicrobial agents. Int J Antimicrob Agents 26:43–49
Ingólfsdóttir K, Chung GAC, Skúlason VG, Gissurarson SR, Vilhelmsdóttir M (1998) Antimycobacterial activity of lichen metabolites in vitro. Eur J Pharm Sci 6:141–144
Kilpiö O (1956) Iakttagelser över den antibakteriella effekten hos ett usninsyraderivat (USNO) och den kliniska användningen av detta vid pyodermifall. Nordisk Hyg Tidskr 37:289–294 (in Swedish)
Krishna DR, Venkataramana D (1992) Pharmacokinetics of D(+)-usnic acid in rabbits after intravenous and oral administration. Drug Metab Dispos 20:909–911
Lauterwein M, Oethinger M, Belsner K, Peters T, Marre R (1995) In vitro activities of the lichen secondary metabolites vulpinic acid, (+)-usnic acid, and (−)-usnic acid against aerobic and anaerobic microorganisms. Antimicrob Agents Chemother 39:2541–2543
Najdenova V, Lisickov K, Zoltán D (2001) Antimicrobial activity and stability of usnic acid and its derivatives in some cosmetic products. Olaj, Szappan, Kozmetika 50:158–160 (in Hungarian)
Thune PO, Solberg YJ (1980) Photosensitivity and allergy to aromatic lichen acids, Compositae oleoresins and other plant substances. Contact Dermatitis 6:64–71
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Elo, H., Matikainen, J. & Pelttari, E. Potent activity of the lichen antibiotic (+)-usnic acid against clinical isolates of vancomycin-resistant enterococci and methicillin-resistant Staphylococcus aureus . Naturwissenschaften 94, 465–468 (2007). https://doi.org/10.1007/s00114-006-0208-9
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00114-006-0208-9