Wound Management Using Honey *

Large, contaminated wounds are difficult and expensive to treat. Honey contain; many nutrients and minerals and has a bactericidal effect due to hydrogen peroxide liberation and a phytochemical constituent. The use of honey in the management of wounds enhances healing and eliminates invading bacteria without the use of systemic antibiotics. Honey also decreases inflammatory edema. Thus the use of honey can be an effective and economica 7 nnnroach to managing large woundc C ontaminated wounds, especially large wounds (e.g., major degloving injuries, burns), and conditions such as necrotizing fasciitis acquired through infections with P s e ~ m o n m species, Eschen'chia coli, or streptococci, can be difficult and expensive to treat using conventional methods. As a result, owners whose pets have extensive wounds often opt to have the affected limb amputated or the animal euthanized. Honey has been shown to be effective against the growth of bacteria, and its use enhances wound healing. Thus it is an inexpensive topical treatment that is extremely effective in wound management and its use makes management of large, open wounds financially feasible. HISTORY OF THE USE OF HONEY IN WOUND CARE The use of honey to treat wounds dates back to 2000 BC. ' Numerous reports document the efficacy of honey in wound healing, and several studies even indicate that honey appears to be superior to many modern methods of treatment. "26 Honey has been used for cleansing and accelerating the healing of wounds for centuries; however, the scientific basis for its success was not elucidated until the twentieth century. Honey is currently used worldwide to treat human patients with contaminated wounds or infected body cavities. The use of honey to treat wounds on animals has been slow to come into acceptance. HEALING PROPERTIES OF HONEY Mechanisms associated with wound cleansing and healing properties of honey include decreased inflammatory edema, attraction of macrophages to further cleanse the wound, accelerated sloughing of devitalized tissue, provision of a local cellular energy source, and formation of a protective layer of protein over the wound and a healthy granulation bed.27 Honey also has a deodorizing *A companion article entitled "Wound Management Using Sugar" appears on page 41. I Small AnimalIExotics Compendium January 2002 ( action; this may be due to its rich supply of glucose, which would be used by the infecting bacteria in preference to amino acids, resulting in the production of lactic acid instead of malodorous compound^.^ The cleansing and healing properties of honey are not widely known in veterinary medicine. Honey also has antibacterial properties that have been attributed to its high osmolarity, acidity, and hydrogen peroxide (H,02) content. ' The effects of osmolarity in contaminated wounds is based on the low water content (or high osmolality) created in the wound.28 As the high osmolarity of honey draws lymph from a wound, dissolved nutrients within the lymph provide nutrition for regenerating tissue. '" The antibacterial factor inhibine has been isolated from honey produced from several different plant source^. ^ Inhibine, which was determined to be H,O,, is produced by the natural glucose oxidase in honey. Glucose oxidase produces gluconic acid (which is the principal acid in honey) and H,O, from glucose. Although H20, is primarily responsible for the antibacterial properties of honey, it is present at harmlessly low levels. H,02 is continuously produced by the activity of the glucose oxidase enzyme, which is only activated when diluted. >' The concentration of H,O, that accumulates in 1 hour is approximately 1000 times less than that found in the H,02 solution (3%) that is commonly used as an antiseptic. ',' In addition to its i n h i b i ~ component, pure, unpasteurized, commercial honey is composed of approximately 40% glucose; 40% fructose; 20% water; and trace amounts of amino acids, vitamins (i.e., biotin, nicotinic acid, folic acid, pentotenic acid, pyridoxine, and thiamine), enzymes (i.e., diastase, invertase, glucose oxidase, and catalase), and minerals (i.e., potassium, iron, magnesium, phosphorus, copper, and calcium). '' The rate of granulation tissue formation and epithelialization of wounds may be enhanced by the various constituents of honey. '' Honey is an excellent cellular energy source, provides a viscous barrier to wound invasion, and has a hygroscopic effect, which reduces edema. Honey also has high levels of antioxidants: which protect wound tissues from oxygen radicals that may be produced by the H202. ' H20, has been shown to be more effective against bacteria when it is continuously generated. " The generation of low levels of H,02 stimulates angiogenesis and the growth of fibroblasts. ' This increased angiogenesis increases oxygen delivery to tissues, which is a limiting factor for tissue generati~n. ~ Topical acidification of wounds has been shown to promote healing"; therefore, honey's low pH (3.6 to 3.7) will accelerate healing as well as increase antibacterial effects. aFor more information, see the companion article entitled "Wound Management Using Sugar" on page 41. VARIATIONS IN f HE ANTIBACTERIAL ACTIVITY OF DIFFERENT HONEYS Two millennia ago, it was recommended that ho be collected in specific regions and during certain s used for the treatment of different ailments.I3 Today, honey is produced from many sources of plants and its antimicrobial activity varies greatly with origin and processing.I2 Honey used to treat wounds must be unpasteurized and ideally should not be heated above 37°C. However, the honeycombs have to be heated t get the honey out, and sometimes heating the ho combs to 39°C is necessary to do this (although ideal, this temperature has not caused any problem To assess the variation in antibacterial activity of hone numerous varieties of New Zealand honeys were tes in vitro against Stapbyhcoccus aurw in an agar well fusion assay.14 This study demonstrated a highly sig cant difference in the antibacterial activity of ho from different floral sources. Kanuka, manuka, hea and ling kamahi were shown to be sources likely to duce honey with high antibacterial activity. When anti bacterial activity was assayed with catalase added to remove H,O, liberated into the agar, most of the hon eys showed no detectable antibacterial activity. How ever, manuka and vipers bugloss honeys retained thei antibacterial activity in the catalase environment, indi cating that these honeys also contained a nonperoxid component of activity. This activity stems partly from phytochemical ~omponent. '~ When manuka honey an pasture honey were tested against 58 strains of coagulase-positive S. aureus isolated from infected wounds, the minimum inhibitory concentrations were between 2% to 3% for manuka honey and 3% to 4% for pasture haney.12This activity is beyond the point at which the osmolarity would have had an antibacterial effect; therefore, it was concluded that the previously identified phytochemical components of honey and the lo pH are also active components. Another study1> showed that E. coli, Proteus mirabilis, ~seudomonas aeruginosa, Salmonella typhimurium, Serratia marcescens, S. aumw (including methicillin-resistant strains), and Streptococcus were all susceptible in vitro to a manuka honey and Knightia exceha honey. In quite dilute solutions, bot types of honey completely inhibited growth of all bacterial strains over an incubation period of 8 hours. " The antimicrobial effects of honey are also effective against Candida albicans. The susceptibility of 72 isolates of C. albicans to a honey distillate fraction and several antimycotic agents showed all the isolates to b sensitive to the honey distillate, although 10% wer variably resistant to nystatin, miconazole nitrate, ointment was used to keep the wound clean