RA Cooper, PhD, PC Molan, PhD, KG Harding, MRCGP, FRCS
School of Biomedical Sciences, University of Wales Institute, Llandaff Campus Western Avenue, Cardiff Cf5 2YB, UK
The antibacterial action of honey in infected wounds does not depend wholly on its high osmolality. We tested the sendivity of 58 stratins of coagulase-positive Staphylococcus aureas, isolated from infected wounds, to pasture honey and a manuka honey. There were little variations between the isolates in their sensitivity to honey: minimum inhibitory concentrations were all between 2 aand 3 % (v/v) for the manuka honey and between 3 and 4 % for the pasture honey. Thus, these honeys would prevent growth for S. aureus if diluted by body fluids a further 7 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 pyroxide, which in vivo might be reduced by catalase activity in tissue 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.