title: Rosmarinic acid interaction with planktonic and biofilm Staphylococcus aureus.
abstract: The subject of study was the evaluation of antibacterial activities of rosmarinic acid (RA) on clinical Staphylococcus aureus strains obtained from catheter-related infections. Minimal inhibitory (MIC) and minimal bactericidal concentrations (MBC) of RA were tested by broth microdilution assay. Biofilm-eradication activity was detected on 24-hour biofilm in microtiter plates using a regrowth technique; activity on biofilm formation was measured by a microtiter plate method after RA application to bacterial samples after 0, 1, 3 and 6 hours of biofilm development. RA had antimicrobial activity on all tested strains in concentrations from 625 to 1250 microg.mL-1 (MICs equal to MBCs). No biofilm-eradication activity on 24-hour biofilm was observed in the tested range of concentrations (from 156 to 5000 microg.mL-1). Subinhibitory RA concentrations suppressed the biofilm production, when applied at early stages of its development. Concentrations lower than subinhibitory stimulated the biofilm mass production in a concentration- and time-dependent manner. Considering our results, RA could be a candidate for a topical antimicrobial agent with killing activity on planktonic forms of bacteria and suppressing activity in the early stages of biofilm development, but probably not for the therapy of catheter-related infections as a sole agent.
authors.affiliation: Comenius University in Bratislava, Faculty of Medicine, Institute ofMicrobiology, Sasinkova 4, 811 08 Bratislava, Slovakia
authors.forename: Lívia
authors.initials: L
authors.lastname: Slobodníková
authors.affiliation: Comenius University in Bratislava, Faculty of Pharmacy, Department ofPharmacognosy and Botany, Odbojárov 10, 832 32 Bratislava, Slovakia.
authors.forename: Silvia
authors.initials: S
authors.lastname: Fialová
authors.affiliation: Comenius University in Bratislava, Faculty of Medicine, Institute ofMicrobiology, Sasinkova 4, 811 08 Bratislava, Slovakia
authors.forename: Helena
authors.initials: H
authors.lastname: Hupková
authors.affiliation: Comenius University in Bratislava, Faculty of Pharmacy, Department ofPharmacognosy and Botany, Odbojárov 10, 832 32 Bratislava, Slovakia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Grancai
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology* / Q000627:therapeutic use; D018441:Biofilms / Q000187:drug effects*; D055499:Catheter-Related Infections / Q000188:drug therapy*; D002934:Cinnamates / Q000494:pharmacology* / Q000627:therapeutic use; D053630:Depsides / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D008826:Microbial Sensitivity Tests; D013211:Staphylococcus aureus / Q000187:drug effects*; D000097123:Rosmarinic Acid
chemical_list: D000890:Anti-Infective Agents; D002934:Cinnamates; D053630:Depsides; D000097123:Rosmarinic Acid