Antimicrobial activity of Luma apiculata against resistant strains of Staphylococcus aureus and Klebsiella pneumoniae

Bacterial resistance is the mechanism through which the bacteria can decrease the action of antimicrobial agents. Studies have reported an antimicrobial action of Luma apiculata, however, there are no in vitro studies demonstrating the effect of this plant against multidrug-resistant bacteria. The objective of this study was to explore the antimicrobial properties of alcoholic extract of Luma apiculata against standard multi-resistant bacterial pathogens. Multidrug-resistant strains of Staphylococcus aureus ATCC 43300 (MRSA) and Klebsiella pneumoniae ATCC BAA 1705 (CRKP) were incubated independently for 72 h at 37°C with different concentrations (1-10,000 pg/mL) of alcoholic extract of Luma apiculata. The growth curve was studied up to 72 hours. The minimum inhibitory concentration (MIC) was determined by broth macrodilution method. The agar diffusion method was used to examine bacteriostatic activity and bactericidal activity was evaluated by a commercial kit and analyzed by flow cytometry. Analyses of chromatographic data, as well as mass spectrometry, were performed to determine the main compounds present in the extracts. Luma apiculata leaves extracts showed bactericidal activity and was effective attenuating growth in both bacterial strains. Thus, Luma apiculata could represent a natural alternative against multidrug-resistant bacterial strains. However, further studies should be undertaken to test their clinical utility.