Additive activity of royal jelly and honey against Pseudomonas aeruginosa.

As natural products garner attention in the medical field, the emergence of antibiotic-resistant strains of bacteria has confounded the current use of antibiotic therapy, leading to the re-examination of earlier remedies such as honey and royal jelly (RJ). Four varieties of honey and one variety of freshly reaped RJ were used to evaluate the additive antimicrobial action against Pseudomonas aeruginosa (ATCC 27853). Initially, honey and RJ were used separately to determine their minimum inhibitory concentration (MIC) against the tested strain. Next, sub-MIC concentrations of honey and RJ were incorporated into media to determine the minimum additive inhibitory concentration. When tested separately, the MIC of the four varieties of honey ranged from 12-18 percent (volume/volume; v/v), and that of RJ was 4 percent (v/v). When combined with RJ, each honey variety tested showed a greater than 90-percent drop in MIC using 3-percent (v/v) RJ, a 66.6-percent drop in MIC using 2-percent (v/v) RJ, and a 50-percent MIC drop with 1-percent (v/v) RJ. The MIC of RJ dropped by 75 percent when used with the half concentration of honey that alone provides the MIC and by 50 percent when used with one-third the concentration of honey that alone provides the MIC. A strong linear correlation exists between the MIC drop of each variety of honey and RJ. With increasing interest in the use of alternative therapies and as the development of antibiotic-resistant bacteria spreads, honey and RJ may receive renewed recognition as wound healers.