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ARS Home » Plains Area » College Station, Texas » Southern Plains Agricultural Research Center » Food and Feed Safety Research » Research » Publications at this Location » Publication #305877
Title: Methods for external disinfection of blow fly (Diptera: Calliphoridae) eggs prior to use in wound debridement therapy

Author
item BRUNDAGE, ADRIENNE - Texas A&M University
item Crippen, Tawni - Tc
item TOMBERLIN, JEFFERY - Texas A&M University

Submitted to: Journal of Wound Repair and Regeneration
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/18/2016
Publication Date: 3/24/2016
Publication URL: https://handle.nal.usda.gov/10113/62738
Citation: Brundage, A.L., Crippen, T.L., Tomberlin, J.K. 2016. Methods for external disinfection of blow fly (Diptera: Calliphoridae) eggs prior to use in wound debridement therapy. Journal of Wound Repair and Regeneration. 24:384-393.

Interpretive Summary: Fly larvae (maggots) are used to remove dead tissue and disinfect wounds (debridement). Wound debridement requires a sterile technique to prevent the accidental introduction of pathogenic bacteria into the wound. The fly eggs, from which maggots are grown, must be cleaned of external bacteria prior to use (disinfection). The present study evaluated different disinfection techniques utilizing formalin, Lysol®, formaldehyde, bleach, EtOH, Sporgon®, or benzalkonium chloride. All techniques resulted in decreases in bacterial load on fly eggs to some extent, but in the disinfection process, many also damaged the eggs, causing death. A ten minute 3% Lysol® immersion was the most effective at disinfecting while minimizing egg death in several species of flies used for maggot debridement therapy.

Technical Abstract: Maggot debridement therapy (MDT) is the use of the larval stage of flies (i.e., Calliphoridae) to remove necrotic tissue and disinfect wounds. Effective MDT requires an aseptic technique to prevent the unintentional introduction of pathogenic bacteria into a wound to be debrided, yet the external surface of Calliphoridae eggs is often heavily contaminated with bacteria. Studies of external disinfection of dipteran eggs have been reported, but neither their efficacy nor effect on egg viability has been adequately assessed. The present study evaluated the efficacy of ten disinfection techniques involving either immersion, rinse, or a combination of both in formalin, Lysol®, formaldehyde, bleach, EtOH, Sporgon®, or benzalkonium chloride. All techniques resulted in significant decreases in culturable, aerobic bacterial load on Lucilia cuprina eggs. A ten minute 3% Lysol® immersion was the most effective, disinfecting 96.67% of egg samples, while resulting in 31.84% egg death. A 5% Formalin immersion was least effective, disinfecting 3.33% of L. cuprina egg samples, while resulting in 33.51% egg death. A formaldehyde (H2CO) immersion, one of the most commonly used disinfection techniques, was moderately effective, disinfecting 66.7% of egg samples, while resulting in 40.16% egg death. Ten minute Lysol® immersion disinfected 100% of Chrysomya rufifacies and Cochliomyia macellaria egg samples and 80% of Lucilia sericata egg samples, while resulting in 33.97%, 7.34%, and 36.96% egg death, respectively. H2CO disinfected 16.67% of Ch. rufifacies, 26.67% of C. macellaria, and 56.67% of L. sericata egg samples, while resulting in 21.98%, 10.18%, and 32.19% egg death, respectively. Due to its high disinfection efficacy and relatively low egg death, a ten minute Lysol® immersion is recommended for sterilizing Calliphoridae eggs prior to rearing of larvae for use in MDT.