Researchers at Kaiser Hospital, Honolulu, Hawaii, have shown that maggot debridement therapy (MDT) is an effective, low-cost, limb-salvage option for the treatment of complex wounds in people with diabetes. The maggot secretions release bacteriostatic substances into wounds to fight infection and also stimulate growth factors that result in accelerated healing, according to study leader Lawrence Eron, MD, from Kaiser Hospital and an associate professor at the John A. Burns School of Medicine (JABSOM), University of Hawaii at Manoa, Honolulu.
Patients with diabetes have difficulty healing wounds due to underlying comorbidities, such as peripheral vascular disease, peripheral neuropathy, and chronic kidney disease. These wounds may become infected with resistant organisms that defy treatment with conventional antibiotics. According to Eron, the annual cost for managing these wounds exceeds $20 billion. An uninfected diabetic foot ulcer may cost $7,000 to $10,000 to treat. Many of these ulcers may ultimately require amputation of a limb, where the cost may be as high as $65,000. Comparatively, medical-grade maggots sufficient for two treatments were purchased for $100.
“These problem patients with diabetes really need better treatments in order to salvage their limbs,” he told Reuters Health. “Maggot debridement treatment is overwhelmingly effective. After just one treatment these wounds start looking better.”
Eron’s team treated 27 people with diabetes using medical-grade maggots. The cohort suffered from a type of artery disease that causes poor circulation in the limbs, and they all had stubborn wounds-some up to five years old. The doctors encased 50 to 100 maggots of the species Lucilia sericata in mesh-like material, placed them on the wounds, and left them there for two days, at which time they applied new ones. They repeated this five times on average.
Twenty-one patients had successful outcomes, defined as eradication of infection, complete removal of dead tissue, formation of robust connective tissue in the wound, and more than three-quarters closure of the wound. The treatment failed in six patients. One had excessive inflammation surrounding the wound, two bled too much, and three had problems with infected bones. Five wounds were infected with Methicillin-resistant Staphylococcus aureus (MRSA), but they healed successfully with the MDT. Nine wounds were infected with another bacterium called Methicillin-sensitive Staphylococcus aureus (MSSA), and six of those healed up. All ten cases with infection due to group B streptococci were successfully treated, Eron said.
Maggots secrete substances into the wounds that liquefy dead tissue and then they ingest the material to further degrade it in their gut, Eron explained. The wounds are cleaned, and other substances contained in the maggot secretions allow the development of granulation tissue, a type of connective tissue that forms during wound healing.
“After this, we go on to do further treatment with hydrogels, grafts of cell culture tissue, or negative pressure dressings,” said Eron. “But to get to this point where these techniques will work, you really need to clean up the wound, get rid of dead tissue, and get robust granulation tissue into the wound. And this is where the maggots help.”
Eron and his colleagues presented their findings September 18 at the 51st Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Chicago, Illinois.
