Monday, August 11, 2008

Maggot Therapy Revisited

Last week the WSJ posted an article on using maggots to "gag" superbugs which includes a video (don't watch if you are squeamish).

For more technical details on Ratcliffe’s work, there’s a recent paper in the journal Microbes and Infection.

Maggots’ flesh-eating ways have long been used to cleaning nasty wounds. Just a few years back the FDA even decided maggots could be regulated as medical devices for prescription wound care. .......take a look at the package insert for Medical Maggots.

Last October I wrote a post on maggot therapy. Here it is:

When I was a general surgery resident, we had a couple of patients come in with maggots in their wounds--both with venous stasis ulcers on their legs. As "icky" as it was to clean the maggots out of the wounds, it was down right impressive how clean the wounds were (and yes it was my job to do the cleaning). Those maggots sure had done a wonderful job of removing the necrotic tissue and leaving behind healthy granulation tissue. (photo credit) So for Halloween, how about some bug therapy.

Maggot therapy waxes and wanes in popularity throughout time. Ambroise Pare (1509-1590) is generally given credit for first noting the beneficial effects of maggots in suppurative wounds. Napoleon's famous military surgeon, Baron D. J. Larrey (1766-1842) noted larvae of the blue fly in the wounds of soldiers in Syria during the Egyptian expedition. He noted that the maggots only attacked putrefying substances rather than living tissues and that they promoted their cicatrization. W. W. Keen commented on the presence of maggots in wounds during the Civil War, saying that the maggots were disgusting but did no apparent harm. The first scientific study of the use of maggots was done by Dr. William S. Baer of Baltimore, Maryland. He first mentioned this "viable antiseptic" for the treatment of chronic osteomyelitis in a discussion following an article by Bitting that appeared in 1921. Baer commented on the clean wound of two soldiers with neglected compound femur fractures and abdominal wounds who had lain neglected for 7 days on the battlefields of World War I in 1917. Inspection of the wounds showed that they were infected with thousands of maggots, but had healthy granulation tissue beneath. At that time, the mortality from such wounds with the best medical care was close to 75%, and therefore the maggots made a profound impression. He went on to study maggots in detail.

Maggots, by definition, are fly larvae, just as caterpillars are butterfly or moth larvae. Phaenicia sericata (green blow fly) larvae is the one used in maggot therapy.

A drawing of the life cycle of this fly appears below. (photo credit)

One-day-old larvae are only about 2 mm in length, and almost transparent. By the time the maggots are 3 or 4 days old, they have grown to about 1 cm (1/2 inch) long. (photo credit)

Maggot Therapy

Maggots may be used intentionally as biological debriding agents. They are an effective alternative to surgical debridement in patients who cannot go to the operating room for medical reasons. It is the larvae of the green blowfly (Phaenicia sericata) that is used. This larvae is sterilized with radiation before being used so that they will not be able to convert from the larvae to the pupae stage. They secrete enzymes that dissolve the necrotic tissue and the biofilm that surrounds bacteria. This forms a nutrient-rich liquid that larvae can feed on. Thirty larvae can consume 1 gram of tissue per day. They are placed on wounds and covered with a semipermeable dressing. The debridement is painless, but the sensate patient can feel the larvae moving. More importantly, maggots help to sterilize wounds, because they consume all bacteria regardless of their resistance to antibiotics (including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus). Maggots have to be replaced every 2 to 3 days. Maggot therapy can be administered on an outpatient basis, provided that visiting nurses are familiar with their use. This is a good technique for painlessly removing necrotic tissue and destroying antibiotic-resistant bacteria in patients who cannot undergo surgical debridement for medical reasons. They work well in infected and gangrenous wounds, with the best results reported in diabetic wounds.

Medical grade larvae are available from Zoobiotic Ltd and Monarch Labs.

REFERENCES

Maggot Therapy: The Surgical Metamorphosis; Plastic & Reconstructive Surgery. 72(4):567-570, October 1983; Pechter, Edward A. M.D.; Sherman, Ronald A. B.S.

From the Bible to Biosurgery: Lucilia sericata--Plastic Surgeon's Assistant in the 21st Century; Plastic & Reconstructive Surgery. 117(5):1670-1671, April 15, 2006; Whitaker, Iain S. M.A.Cantab., M.R.C.S.; Welck, Matthew M.B.Ch.B.; Whitaker, Michael J. M.A.Cantab.; Conroy, Frank J. M.R.C.S.

Maggot Debridement Therapy; Plastic & Reconstructive Surgery. 120(6):1738-1739, November 2007; Mumcuoglu, Kosta Y. Ph.D.

Clinical Approach to Wounds: Debridement and Wound Bed Preparation Including the Use of Dressings and Wound-Healing Adjuvants; Plastic & Reconstructive Surgery. Current Concepts in Wound Healing. 117(7S) SUPPLEMENT:72S-109S, June 2006 ; Attinger, Christopher E. M.D.; Janis, Jeffrey E. M.D.; Steinberg, John D.P.M.; Schwartz, Jaime M.D.; Al-Attar, Ali M.D.; Couch, Kara M.S., C.R.N.P., C.W.S.

Maggot Therapy Project

4 comments:

Bongi said...

we get the occasional patient who has had a 'natural debridement' but i hate the smell. i clean them up and get rid of the putrid little creatures. what they can do i can do also. i just release less amonia smelling odours.

Buckeye Surgeon said...

Im with bongi. My scalpel works better than the itty bitty jaws of maggots crunching through gangrene. Good review, though.

purplesque said...

Great post..maggots and leeches, back to mother nature for treatment.

I was asked to clean a diabetic foot full of maggots on my first clinical rotation as a med student. I wonder how much that had to do with my picking up psychiatry.

storkdok said...

Great post! I love the Medical Maggot insert!

I had a very obese patient who showed up in the ER a year after her abdominal hysterectomy for a gyn cancer. I had to have a couple of medical students help me with her pannus. When we lifted it up, I saw that her wound had never fully closed. It smelled pretty bad, and I could see I was deeper than my hand, so we opted to go to a surgical debridement. When we got her a spinal anesthesia in the OR, and got a good look, deeper in the wound there were maggots. They had done a pretty good job of cleaning up some of the dead tissue. She was mortified. I tried to act like it wasn't such a big deal, but how do you play that down?

We did have a hard time eating that day.