Antimicrobial activity of Eugenia dysenterica against Staphylococcus intermedius

In veterinary dermatology, S. intermedius is one of the principal agents of canine bacterial skin infections, such as otitis, abscesses and pyodermas. However, this organism is increasingly reported to be resistant to many antibiotics, and failures in treatment are a cause of problems in small animal veterinary practices. S. intermedius can be transferred from dogs to humans, leading to a risk of human infections with the resistant bacteria. In the aim to test plant extracts against this important zoonotic bacteria, Eugenia dysenterica growing in the Brazilian Cerrado was selected because of multiple popular uses and some published scientific data. Leaves of E. dysenterica were collected in Lagoa Bonita Farm, Federal District. Air-dried leaves were powdered and exhaustively extracted with ethanol at room temperature for 5 days. Extracts were filtered and the solvent removed by evaporating at 50 ° C. The in vitro antimicrobial activity of the extract was determined in 96-well plates, and the bacterial growth was measured in an MTT assay, with MIC 0,009 µg/µL. The S. intermedius bacterial strain used was an isolate from canine skin infection. The potent antimicrobial effect of this plant against these zoonotic important bacteria increased the interest to investigate the content of the extract. The phenolic content of the plant extract was determined by Folin-Ciocalteau method, showing 201 mg/100 g. The antioxidant activity of this plant, also determined by Folin-Ciocalteau, corresponding to 729 mM/g. Further studies are needed to identify the constituents responsible for the antimicrobial activity.