Effects of two commonly and limited used chemosterilants on Lucilia sericata egg surface sterilization

Abstract

Maggot therapy (MT) is the most common medical use of sterile fly larvae of Lucilia sericata and other species of the family Calliphoridae as an alternative to surgery and long-term antiseptic therapy in the treatment of deep and infected non-healing wounds. Effective and reliable MT requires an aseptic technique to prevent bacterial infection of the wound. However, due to the habitat of Calliphoridae flies, the outer surface of their eggs is often contaminated with bacteria. In this study, Lucilia sericata eggs were sterilized using two techniques. NaOCI (sodium hypochlorite), which is widely used as a sterilant (Sterilant 1-S1), and Lysol surface disinfectant, which is rarely used (Sterilant 2-S2), and a control (unsterilized) were chosen. Sterilization efficacy, egg survival, and mortality were evaluated comparatively at 0.05, 1, 2, and 3 (%) concentrations and 1-, 2-, 3-, and 4-min application times at each concentration, and bacterial growth in the post-sterilization environment was controlled. In the in vitro sterility efficiency and reliability test, no bacterial colonies were found in sterilized eggs transferred to tryptic soy agar (TSA) culture. In contrast, bacterial and fungal growth was detected in unsterilized eggs. Protocol S1 provided effective egg surface sterilization at a concentration of 0.05% with a 1-min exposure time. This treatment resulted in 85.12% survival rate and 14.88% egg mortality. Based on its optimal balance of low mortality, high viability, and effective sterilization, we recommend a 1-min immersion in 0.05% NaOCl solution for sterilization of Lucilia sericata eggs.