Studies on the production and characterization of antimicrobial compounds in the haemolymph of the greater wax moth (Galleria mellonella)

Abstract

Escherichia coli remains one of the most frequent causes of several common bacterial infections in humans and animals. The therapeutic treatment of these bacterial diseases is threatened by the emergence of antimicrobial resistance. Therefore, new strategies are needed to prevent and treat E. coli infectious diseases. The search for new materials that are able to modulate or delay the occurrence of bacterial resistance remains under investigation by many researchers around the world. Invertebrates, which include the insects, present an extreme diversity and a potential source of a large variety of antimicrobial substances. The main source of these substances is the hemolymph. However, most of the antimicrobial molecules are not present in the hemolymph of normal insects, but are induced by an injury or infection, as they are important effectors of the innate immune response. Active immunization of insects gives protection that varies considerably with the insect species and the type of inducer. By using this immune assay, insects are able to respond against various pathogens, such as bacteria, fungi and even viral agents. Larvae of the wax moth, G. mellonella have been widely utilized as model hosts to replace conventional mammals for studying the virulence of pathogens and the assessment of the activity of antimicrobial agents and providing results that are comparable to mammalian data. Various kinds of inducers have been successfully used such as living or heat-killed microbes and even