Anti-staphylococcus activity of Uruguayan riverside forest plants

Abstract

Methicillin resistant Staphylococcus aureus is a major nosocomial pathogen which causes increased morbidity and mortality worldwide. Interest in plants with antimicrobial properties has thus revived as a consequence of current problems associated with the use of antibiotics. In previous work we undertook the biological and chemical prospection of the gallery forest of the northern Uruguay River basin. Plants were selected after an exhaustive review of the available literature according at its ethnopharmacological use and submitted to antimicrobial assays and phytochemical characterization. Extracts that were positive in the qualitative diffusion tests against S. aureus were selected for a more detailed study. The objective of the present work is to study the anti MRSA activity of 37 plant extracts that have previously shown activity against S. aureus in a qualitative diffusion assay. The plant material were separately twice extracted by maceration with EtOH/H2O 70:30, acetone and CHCl3. Minimum inhibitory concentration (MIC) was determined by the microdilution technique according to Clinical and Laboratory Standards Institute using sensitive (ATC 6538p) and resistant (ATC 43300, ATC 700699 and USA 100) strains. Some of the extracts showed good activity specially species of the Myrtaceae family with MICs as low s 7.8 μg/mL. These promissory results were obtained encourage further work to be done regarding the isolation and structural elucidation of the active compound(s).