title: Anti-biofilm activities of quercetin and tannic acid against Staphylococcus aureus.
abstract: Staphylococcus aureus is a leading cause of nosocomial infections because of its resistance to diverse antibiotics. The formation of a biofilm is one of the mechanisms of drug resistance in S. aureus. The anti-biofilm abilities of 498 plant extracts against S. aureus were examined. Seventy-two plant extracts belonging to 59 genera and 38 families were found to significantly inhibit the formation of biofilms of S. aureus without affecting the growth of planktonic cells. The most active extract, from Alnus japonica, inhibited the formation of biofilms by three S. aureus strains by >70% at 20 μg ml(-1). Transcriptional analyses showed that extract of A. japonica repressed the intercellular adhesion genes icaA and icaD most markedly. Quercetin and tannic acid are major anti-biofilm compounds in the extract of A. japonica. Additionally, the extract of A. japonica and its component compound quercetin, reduced hemolysis by S. aureus. This phenomenon was not observed in the treatment with tannic acid. This study suggests that various plant extracts, such as quercetin and tannic acid, could be used to inhibit the formation of recalcitrant biofilms of S. aureus.
authors.affiliation: School of Chemical Engineering, Yeungnam University, Gyeongsan, Republic of Korea.
authors.forename: Jin-Hyung
authors.initials: JH
authors.lastname: Lee
authors.forename: Joo-Hyeon
authors.initials: JH
authors.lastname: Park
authors.forename: Hyun Seob
authors.initials: HS
authors.lastname: Cho
authors.forename: Sang Woo
authors.initials: SW
authors.lastname: Joo
authors.forename: Moo Hwan
authors.initials: MH
authors.lastname: Cho
authors.forename: Jintae
authors.initials: J
authors.lastname: Lee
mesh_terms: D029661:Alnus / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001422:Bacterial Adhesion / Q000187:drug effects; D001426:Bacterial Proteins / Q000235:genetics; D018441:Biofilms / Q000187:drug effects*; D002851:Chromatography, High Pressure Liquid; D024881:Drug Resistance, Bacterial; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000737:chemistry; D011794:Quercetin / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects*; D013634:Tannins / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D010936:Plant Extracts; D013634:Tannins; D011794:Quercetin