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

Abstract

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.

The maggot therapy supply chain: a review of the literature and practice

“…Instead, the literature to date has focused on isolated discussions of specific issues such as diet improvement and sterilization protocols in the production process (e.g. Zhang et al ., ; Thyssen et al ., ; Blystone & Hansen, ; Limsopatham et al ., ), or the relative effectiveness of medicinal maggot application methods in the treatment echelon (e.g. Steenvoorde et al ., ; Čičková et al ., ).…”

Effectiveness of broad‐spectrum antiseptics in production of disinfected maggots of Lucilia sericata for use in wound debridement therapy

“…Likewise, NaOCl had high efficiency on both eggs and larvae of L. cuprina, a closely related species to L. sericata, whereas larvae hatching from eggs disinfected with PI and CHX presented bacterial growth. 21 The use of 5% NaOCl to disinfect the surface of L. sericata eggs originating from colonies reared under sterile conditions has also been reported to be successful in eliminating all aerobic bacteria without affecting egg viability. 40 Conversely, the use of 1% NaOCl to rinse L. sericata and L. cuprina eggs has shown bacterial growth without affecting the eclosion rate.…”

“…14 Due to the higher rate of surface disinfection 7,20 and the better survival rate of larvae, 7 external disinfection of eggs is preferred to disinfection of larvae. Bacteria contaminate the outer surface of fly eggs, 21,22 and as a result, newly hatched larvae are also contaminated. 23 Many substances have been tested to disinfect eggs for use in MDT, for example, formalin, 14 formaldehyde (H 2 CO), [24][25][26] mercuric chloride, 14,23 chlorhexidine, 21,22 chloramine solution, 27 Lysol™ disinfectant, 24,28 sodium hypochlorite (NaOCl) 24,[29][30][31] and polyvidone iodine.…”

“…Bacteria contaminate the outer surface of fly eggs, 21,22 and as a result, newly hatched larvae are also contaminated. 23 Many substances have been tested to disinfect eggs for use in MDT, for example, formalin, 14 formaldehyde (H 2 CO), [24][25][26] mercuric chloride, 14,23 chlorhexidine, 21,22 chloramine solution, 27 Lysol™ disinfectant, 24,28 sodium hypochlorite (NaOCl) 24,[29][30][31] and polyvidone iodine. 21 The use of 5% formalin and 1% sodium hydroxide by Simmons 32 did not eliminate all sporeforming bacteria such as Clostridium perfringens or Clostridium tetani.…”

Effectiveness of Chronic Wound Debridement with the Use of Larvae of Lucilia Sericata

“…Only Lucilia sericata larvae from certified farms can be safely used in medicine. Complicated procedures of egg disinfection, using chloroamine, povidone-iodine and sodium hypochlorite, are intended to ensure safety during use of this product [25,26,27,28,29]. MDT is based on three mechanisms, observed when Lucilia sericata are introduced to the wound: the mechanical removal of necrotic tissue, bactericidal and bacteriostatic activity, and promotion of the healing process.…”