Society for General Microbiology Spring Conference 2012 (Dublin)
|In vitro activity of plant alcoholic extracts (AEs) against planktonic and biofilm (BF) of multirresistant (MDR) isolates from clinical sources Eduardo Ros, Marisa Arcos, Ignacio Carro Verdia, Melina Marques, Leticia Sibert, Alicia Farinati Universidad del Salvador, Microbiology Department, Buenos Aires, Argentina|
Aim. To study in vitro plant AEs over MDR isolates from clinical sources in planktonic and BF behaviour. Methods. Plants: Camellia sinensis (CS) Usnea hieronymi (UH); Petroselinum sativum (PS) Aloysia triphylla (AT); and Quassia amara (QA) were chosen based on ethno-pharmacological knowledge. We prepared AEs with ethanol and methanol using leaves from plants. Isolates: 16 Methicillin resistant Staphylococcus aureus (MRSA), 9 Enterococcus faecalis(Ef), 10 Acinetobacter baumannii (Ab). The MICs 90 of each AE (range 0.05-40 µl/ml) were performed. BF: qualitative and quantitative assays were investigated. Results: over MRSA, CS was active 16/16, UH 12/16, PS 0/16, AT 0/16, QA 0/16; over Ef: CS was active 8/9, UH 9/9, PS 0/9, AT 1/9, QA 0/9; over Ab: CS was active 9/10, UH 0/10, PS 0/10, AT 0/10, QA 0/10. The BF formation of MRSA with CS and UH was proportional to AE concentration, but inversely occurs with Ef and Ab. There is correlation with microscopic observations. Conclusions: Our observations suggest that AEs have different activity in planktonic bacteria than in BF. The AEs can induce or decrease BF formation. When AEs are investigated it is necessary take into account the activity in BF because it is an important virulence factor.