Maggots may help decrease the risk of post-operative infections

Sep 16 2004

Maggots aren’t high on most people’s favorite-animals list. But maggots - specifically, the larvae of the green blowfly, Phaenicia sericata - can be helpful for the very reason they horrify.

By eating dead tissue at a patient’s wound site, maggots may help decrease the risk of post-operative infections, according to an article in the October 1 issue of Clinical Infectious Diseases, now available online.

Although military surgeons noticed maggots’ beneficial effect on soldiers’ wounds centuries ago, maggot debridement therapy (MDT) as it is practiced today began in the 1920s and is undergoing a revival in popularity. Debridement, or the removal of contaminated tissue to expose healthy tissue, can be done surgically. However, maggots that have been disinfected during the egg stage so that they don’t carry bacteria into the wound have their advantages. The larvae preferentially consume dead tissue (steering clear of live), they excrete an antibacterial agent, and they stimulate wound healing--all factors that could be linked to the lower occurrence of infection in maggot-treated wounds.

MDT typically involves applying maggot dressings to patients’ wounds twice a week for 48-72 hours at a time. California researchers conducted a small, retrospective study of MDT procedures performed at one hospital between 1990 and 1995. The researchers found that none of 10 wounds treated with MDT within three weeks prior to surgery developed infections, but 32 percent of 19 wounds not treated with MDT in the same time period before surgery became infected.

Many patients accept the idea of maggot therapy more readily than one might think. “Patients reacted much better than the administration. They reacted a lot better than the surgeons,” said Dr. Ronald Sherman, MD, director of BioTherapeutics, Education & Research Foundation and lead author of the article. “After the first year or two, most of the patients that I treated came to me looking for maggot therapy, having heard about it from other patients in the clinics or in the hospital.”

Patients’ attitudes may be less of a deterrent to MDT’s resurgence than simple economics. “Technically, producing maggots is not expensive. However, it is very labor-intensive, and maggots are highly perishable so they cannot be stored and stocked,” said Dr. Sherman. “They have to be made fresh every day, and so they are not as inexpensive as we would like.” Disinfected maggots are FDA-approved for medical therapy, Dr. Sherman notes, and if interest in biological methods of preventing infections continues to increase, patients may be willing to overlook revulsion for the sake of recuperation.