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Methods for External Disinfection of Blow Fly (Diptera: Calliphoridae) Eggs Prior to Use in Wound Debridement therapy

NCJ Number
Wound Repair and Regeneration Volume: 24 Issue: 2 Dated: March-April 2016 Pages: 384-393
Date Published
March 2016
10 pages
This study evaluated the efficacy of 10 disinfection techniques that involve immersion, rinse, or a combination of both in formalin, Lysol, formaldehyde, bleach, ethanol, Sporgon, or benzalkonium chloride.
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 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. In the current study, all techniques resulted in significant decreases in culturable, aerobic bacterial load on Lucilia cuprina eggs. For L. cuprina, a 10 minute 3-percent Lysol immersion was the most efficacious, disinfecting 96.67 percent of egg samples, while resulting in 31.84-percent egg mortality. The 5-percent formalin immersion was least efficacious, disinfecting only 3.33 percent of L. cuprina egg samples, while resulting in 33.51 percent egg mortality. A formaldehyde immersion, one of the most commonly used disinfection techniques, was moderately effective, disinfecting 66.7 percent of egg samples, while resulting in 40.16 percent egg mortality. For Chrysomya rufifacies and Cochliomyia macellaria egg samples, the 10 minute 3-percent Lysol immersion disinfected 100 percent of the samples, and for Lucilia sericata, 80 percent of egg samples, while resulting in 33.97 percent, 7.34 percent, and 36.96 percent egg mortality, respectively. H2CO disinfected 16.67 percent of Ch. rufifacies, 26.67 percent of C. macellaria, and 56.67 percent of L. sericata egg samples, while resulting in 21.98 percent, 10.18 percent, and 32.19 percent egg mortality, respectively. Due to its high disinfection efficacy and relatively low egg mortality, a 10 minutes 3-percent Lysol immersion is recommended for sterilizing Calliphoridae eggs prior to rearing of larvae for use in MDT. (Publisher abstract modified)

Date Published: March 1, 2016