Transcript Slide 1

Assessment of Antimicrobial Properties Of Maggots
Leon Margolin M.D., Ph.D. (1) ; Philip Gialanella MSc (2)
1. UPMC 2. AECOM
Introduction
Methods
Chronic bacterial colonization or infection of ulcer is one of the major factors
interfering proper wound healing, especially in diabetic foot ulcers. The maggot
therapy has been used for debridement of necrotic tissues, however, never
been studied for potential antimicrobial properties.
Application of live maggots, larvae of Lucilia (Phaenicia) sericata to total of 48 culture plates of
Methicillin resistant Staphyloccocus Aureus (MRSA), Pseudomonas aeruginosa, Vancomycin
resistant enteroccocus (VRE), and Candida Albicans (12 plates in each group). The maggots were
covered by a small plate inside the big plate with the pathogen. All the plates were incubated in the
standard incubator and examined 24 and 48 hours after application of maggots .
Maggots clean up wounds beautifully - a fact known for centuries, especially to
military surgeons, who found that battle wounds accidentally infested with
maggots healed quickly without becoming infected. According to Dr. Ronald
Sherman (University of California, Irvine, CA, USA), maggot therapy was
introduced into civilian medicine in the USA in the 1930s but fell out of favor
with the introduction of antibiotics. But maggots are now making a comeback,
especially in the treatment of chronic wounds infected with antibiotic-resistant
bacteria.
Main outcome measures
Degree of lysis in bacterial or fungal cultures in the area of maggot application. Gram staining of
both areas was performed.
Results
Complete lysis of the bacterial or fungal cultures in the area of maggot application was observed 24
hours after application of live maggots in all culture plates and confirmed by Gram staining. This
complete lysis was persistent for more than 5 days after the maggot application.
Recently, Dr. Sherman presented the preliminary results of his prospective trial
of conventional wound care followed by maggot therapy at a Wound Healing
Society symposium in Toronto, Canada. 43 maggot-treated wounds were
debrided faster and more completely than they had been during conventional
treatment.
In a randomized trial in 12 patients with sloughy venous ulcers, Michael Walker
(West Cumberland Hospital, Whitehaven, UK) found that maggot therapy
debrided the ulcers more quickly and effectively than standard hydrogel
dressings - all six patients treated with maggots had their ulcers successfully
debrided with a single application, whereas two of the six hydrogel-treated
. patients still needed dressings a month later.
Discussion
How the maggots combat wound infection is not entirely clear and several explanations have been
suggested. Ammonia in maggot secretions may partly account for this antimicrobial effect by raising
wound pH. Dr. Sherman proposed special antimicrobial agents in maggot secretion. One report
suggested that phenylacetate and phenylacetataldehyde may exert antimicrobial effect. Direct
ingestion of bacteria along with semiliquid food by the maggots and subsequent lysis in their gut is
also possible explanation.
A
C
B
D
Live maggots were clinically suggested to kill or inhibit the growth of a range of
pathogenic bacteria, especially Methicillin resistant Staphyloccocus Aureus
(MRSA) and group A and B Streptococci. They show clinical activity against
Pseudomonas species, although no formal prospective experimental study was
arranged in the past. The clinical findings are consistent with the observations
that maggots can combat infections in a variety of wound types, including
those infected with antibiotic-resistant strains.
In fact the treatment of wounds infected with MRSA is likely to become a major
indication for the use of maggot therapy in the future. The presence of large
amounts of necrotic tissue in wounds can prevent topical antibacterials, such
as mupirocin, from reaching the site of infection.
The objective of this study is to assess the potential antimicrobial properties of
maggots in vitro.
Design: Prospective randomized experimental study.
Setting: Research microbiology laboratory.
Conclusion: Complete lysis of the bacterial or fungal cultures in the area of maggot application
provides convincing evidence for the antimicrobial properties of maggots. The exact mechanism of
antimicrobial property of maggots requires further investigation.
References:
1: Jarvis A.
Maggot therapy.
Lancet. 2000 Dec 9;356(9246):2016.
Complete lysis of the cultures 24h after maggot application:
A - Pseudomonas Aeruginosa; B - Methicillin Resistant Staphylococcus Aureus (MRSA)
C - Candida Albicans, D - Vancomycin Resistant Enterococcus (VRE)
2. Wayman J, Nirojogi V, Walker A, Sowinski A, Walker MA..
The cost effectiveness of larval therapy in venous ulcers. J Tissue Viability. 2000 Jul;10(3):91-4. Erratum in:
J Tissue Viability 2001Jan;11(1):51.
3: Bonn D.
Maggot therapy: an alternative for wound infection.
Lancet. 2000 Sep 30;356(9236):1174.
4. Dissemond J, Koppermann M, Esser S, Schultewolter T, Goos M, Wagner SN .
Treatment of methicillin-resistant Staphylococcus aureus (MRSA) as part of biosurgical
management of a chronic leg ulcer.
Hautarzt 2002 Sep;53(9):608-1