Antibacterial activity of honey from stingless bees Scaptotrigona bipunctata Lepeletier, 1836 and S. postica Latreille, 1807 (Hymenoptera: Apidae: Meliponinae) against methicillin-resistant Staphylococcus aureus (MRSA)

Abstract

The antibacterial activity of honey produced by the stingless bees Scaptotrigona postica (H6) and Scaptotrigona bipunctata (H7) was evaluated against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) strains. Fifty-three MRSA strains in the bacterial collection of the hospital of Londrina State University, three standard MRSA strains and two standard MSSA strains were used. Evaluation of the antibacterial activity of honey samples was determined by agar well diffusion assay, calculation of minimum inhibitory concentrations (MICs), and construction of growth and viability curves. The inhibition zones generated by the honey samples ranged from 20 to 27 mm for H6 and 20 to 24 mm for H7, while MIC values ranged from 0.62 to 1.25% for H6 and 1.25 to 2.5% for H7. According to the growth curves, the growth of all MRSA and MSSA strains was completely inhibited. Honey cytotoxicity was evaluated by dimethylthiazol diphenyl tetrazolium bromide (MTT) assay, and the CC50 values were found to be 13% for H6 and 7.3% for H7, which were significantly higher when compared to the MIC values. The honey of both the stingless bees S. bipunctata and S. postica can thus be utilized as antibacterial substances against MSSA and MRSA strains, and this action is probably due to a synergistic action of different components such as hydrogen peroxide, sugars, and other compounds not identified in this study. The application of natural products is important for the control of MRSA infections. Further studies are warranted to demonstrate that the antimicrobial activity of the honey examined here could be used in clinical applications for the prevention of MRSA infections.