Antibacterial activity of Euterpe oieracea Mart. seeds against clinical isolates

Introduction: The use of antibiotics – including the over- and misuse – in human and veterinary practices selected for resistant pathogens led to their emergence and dissemination along with the transmission of resistant bacteria [1]. Due to this problem, there is a need to investigate new strategies to reverse this tendency in order to achieve the appropriate and effective treatment against infections. Aims: The present work aimed to evaluate the antibacterial activity of an aqueous extract prepared from Euterpe Oleracea Mart. (açai) seeds (originated from Brazil [2]), against clinical isolates from “Centro Hospitalar de Trás-os-Montes e Alto Douro- Unidade de Vila Real”, with high resistance profiles to different antibiotics. Material and Methods: The minimal inhibitory concentrations (MIC) of the growth of Gram-positive and Gram-negative bacteria were determined by the colorimetric assay based on the use of p-iodonitrotetrazolium chloride (INT) dye, after application of the microdilution method. Results and discussion: The açaí aqueous extract showed antimicrobial activity against all the tested Gram-positive bacteria. The lowest MICs (0.25 mg/ml) were obtained against Methicillin Susceptible Staphylococcus aureus (MSSA) and Methicillin Resistant S. aureus (MRSA), followed by the MIC 0.5 mg/ml correspondent to Streptococcus agalactiae and Enterococcus faecalis. Regarding the inhibition of the growth of Gram-negative bacteria, the extract was active against Morganella morganii, Pseudomonas aeruginosa and Acinetobacter baumannii with MICs 1 mg/ml e 2 mg/ml, respectively. The results were better for Gram-positive bacteria in comparison with Gram-negative bacteria. Conclusion: However, even at low concentration (2 mg/ml) the results are very promising for Gram-negative bacteria with high resistance profiles and commonly related with health care-associated infections, namely Pseudomonas aeruginosa and Acinetobacter baumannii.