title: Modulation of antibiotic resistance in bacterial pathogens by oleanolic acid and ursolic acid.
abstract: Antibiotic resistance among bacterial pathogens is a serious problem for human and veterinary medicine, which necessitates the development of novel therapeutics and antimicrobial strategies. Some plant-derived compounds, e.g. pentacyclic triterpenoids such as oleanolic acid (OA) and ursolic acid (UA), have potential as a new class of antibacterial agents as they are active against many bacterial species, both Gram-positive and Gram-negative, and specifically target the cell envelope. The aim of the present study was to investigate the influence of OA and UA on the susceptibility of four bacterial pathogens (Pseudomonas aeruginosa, Listeria monocytogenes, Staphylococcus aureus and Staphylococcus epidermidis) to the β-lactam antibiotics ampicillin (Ap) and oxacillin (Ox). Antimicrobial assays were conducted with bacteria growing in liquid suspension cultures (planktonic cells) or as biofilms. Using FICI value estimation and the time-kill method it was demonstrated that in some combinations, the tested compounds acted in synergy to lower the susceptibility of S. aureus, S. epidermidis and L. monocytogenes to ampicillin and oxacillin, but no synergy was observed for P. aeruginosa. These results indicate that OA and UA may be useful when administered in combination with β-lactam antibiotics to combat bacterial infections caused by some Gram-positive pathogens.
authors.affiliation: Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland. annakurek@biol.uw.edu.pl
authors.forename: Anna
authors.initials: A
authors.lastname: Kurek
authors.forename: Paulina
authors.initials: P
authors.lastname: Nadkowska
authors.forename: Sylwia
authors.initials: S
authors.lastname: Pliszka
authors.forename: Krystyna I
authors.initials: KI
authors.lastname: Wolska
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D004341:Drug Evaluation; D004352:Drug Resistance, Microbial / Q000187:drug effects*; D004359:Drug Therapy, Combination; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D006801:Humans; D008089:Listeria monocytogenes / Q000187:drug effects; D009828:Oleanolic Acid / Q000494:pharmacology*; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects; D013212:Staphylococcus epidermidis / Q000187:drug effects; D014315:Triterpenes / Q000494:pharmacology*; D000097245:Ursolic Acid
chemical_list: D000900:Anti-Bacterial Agents; D009828:Oleanolic Acid; D010936:Plant Extracts; D014315:Triterpenes; D000097245:Ursolic Acid