Sterilization of blow fly eggs, Chrysomya megacephala and Lucilia cuprina, (Diptera: Calliphoridae) for maggot debridement therapy application

Maggot debridement therapy (MDT) is an application of sterile laboratory-reared blow fly larvae to remove necrotic tissue and disinfect wounds for medical conditions. For effective application, the blow fly larvae used in the wound treatment are required to be in aseptic condition. Here, we report the results of a detailed assessment of bacteria and fungi isolated from the eggs of two blow fly species, Chrysomya megacephala (F.) and Lucilia cuprina (Wiedemann) before and after sterilization by disinfectants Chlorhex-C, povidone-iodine, and sodium hypochlorite. We also assess the survival ability of larvae and their sterility after the cleansing process. The results indicate that the isolated microorganisms from the control group of both the species consisted of 10 species of gram-positive bacteria, 21 species of gram-negative bacteria, and 4 species of yeast. As for sterility testing, the eggs and the larvae of C. megacephala were found to have been completely sterilized after being subjected to thioglycollate medium for 5 days, leading to aseptic larvae. By contrast, some microorganisms from the bacterial culture were still detected in the L. cuprina larvae treated with Chlorhex-C and povidone-iodine. The survival ability of the larvae in both the species was not significantly different between the treated and the control groups. Due to its high disinfection efficacy in destroying microorganisms in both the blow fly eggs, sodium hypochlorite is recommended for preparing sterile larvae before using MDT.