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Aims: To determine the sensitivity to honey of Gram‐positive cocci of clinical significance in wounds and demonstrate that inhibition is not exclusively due to osmotic effects. Methods and Results: Eighteen strains of methicillin‐resistant Staphylococcus aureus and seven strains of vancomycin‐sensitive enterococci were isolated from infected wounds and 20 strains of vancomycin‐resistant enterococci were isolated from hospital environmental surfaces. Using an agar incorporation technique to determine the minimum inhibitory concentration (MIC), their sensitivity to two natural honeys of median levels of antibacterial activity was established and compared with an artificial honey solution. For all of the strains tested, the MIC values against manuka and pasture honey were below 10% (v/v), but concentrations of artificial honey at least three times higher were required to achieve equivalent inhibition in vitro. Comparison of the MIC values of antibiotic‐sensitive strains with their respective antibiotic‐resistant strains demonstrated no marked differences in their susceptibilities to honey. Conclusions: The inhibition of bacteria by honey is not exclusively due to osmolarity. For the Gram‐positive cocci tested, antibiotic‐sensitive and ‐resistant strains showed similar sensitivity to honey. Significance and Impact of the Study: A possible role for honey in the treatment of wounds colonized by antibiotic‐resistant bacteria is indicated.

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SUMMARYThe antibacterial action of honey in infected wounds does not depend wholly on its high osmolarity. We tested the sensitivity of 58 strains of coagulase-positive Staphylococcus aureus, isolated from infected wounds, to a pasture honey and a manuka honey. There was little variation between the isolates in their sensitivity to honey: minimum inhibitory concentrations were all between 2 and 3% (v/v) for the manuka honey and between 3 and 4% for the pasture honey. Thus, these honeys would prevent growth of S. aureus if diluted by body fluids a further seven-fold to fourteen-fold beyond the point where their osmolarity ceased to be completely inhibitory. The antibacterial action of the pasture honey relied on release of hydrogen peroxide, which in vivo might be reduced by catalase activity in tissues or blood. The action of manuka honey stems partly from a phytochemical component, so this type of honey might be more effective in vivo. Comparative clinical trials with standardized honeys are needed.