Introduction

1. Assessment of Antimicrobial Properties Of Maggots Leon Margolin M.D., Ph.D. (1) ; Philip Gialanella MSc (2) 1. UPMC 2. AECOM Introduction 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. 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. 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. . 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. Methods 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. 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. 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. 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. B A C D References: 1: Jarvis A. Maggot therapy.  Lancet. 2000 Dec 9;356(9246):2016. 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 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)