The Use of Galleria mellonella Larvae to Identify Novel Antimicrobial Agents against Fungal Species of Medical Interest

Abstract

The immune system of insects and the innate immune response of mammals share many similarities and, as a result, insects may be used to assess the virulence of fungal pathogens and give results similar to those from mammals. Larvae of the greater wax moth Galleria mellonella are widely used in this capacity and also for assessing the toxicity and in vivo efficacy of antifungal drugs. G. mellonella larvae are easy to use, inexpensive to purchase and house, and have none of the legal/ethical restrictions that are associated with use of mammals. Larvae may be inoculated by intra-hemocoel injection or by force-feeding. Larvae can be used to assess the in vivo toxicity of antifungal drugs using a variety of cellular, proteomic, and molecular techniques. Larvae have also been used to identify the optimum combinations of antifungal drugs for use in the treatment of recalcitrant fungal infections in mammals. The introduction of foreign material into the hemocoel of larvae can induce an immune priming effect which may operate independently with the activity of the antifungal drug. Procedures to identify this effect and limit its action are required.

In vivo Activity of Copper(II), Manganese(II), and Silver(I) 1,10-Phenanthroline Chelates Against Candida haemulonii Using the Galleria mellonella Model

“…The infection profile was assessed using a previously described methodology (Desbois and Coote, 2012;Kavanagh and Sheehan, 2018). C. haemulonii cells were suspended in PBS in the following concentrations: 5 × 10 4 , 5 × 10 5 , 5 × 10 6 , 5 × 10 7 , and 5 × 10 8 cells/mL.…”

“…Most importantly, the innate immune system of G. mellonella possess several similarities with humans such as the similar lectin-mediated phagocytic mechanisms between hemocytes and neutrophils, respectively, identical cell surface receptors such as 3-glucan, identical signaling cascades of immune deficiency (IMD), c-Jun N-terminal kinases (JNK) and the Janus kinase/signal transducers and activators of transcription (JAK-STAT) pathways as well as nuclear factor-kappa B (NFkB) and IkB kinase transcription factors modulation by the toll and IMD pathways in the larvae and by the toll-like receptors and tumor necrosis factor alpha (TNF-α) in mammals (Browne et al, 2013;Wu et al, 2016). Moreover, a strong correlation involving microbial virulence and toxicity of novel antimicrobials between the G. mellonella and mammalian models has been established (Chamilos et al, 2007;Wang et al, 2013;Kavanagh and Sheehan, 2018). Therefore, the G. mellonella model has been widely used to assess the virulence of microbial pathogens and it was optimized to increase susceptibility to bacterial and fungal infections for testing the in vivo activity of antimicrobial agents (Kavanagh and Sheehan, 2018), which directly influenced our choice for this model in the current study.…”

“…Moreover, a strong correlation involving microbial virulence and toxicity of novel antimicrobials between the G. mellonella and mammalian models has been established (Chamilos et al, 2007;Wang et al, 2013;Kavanagh and Sheehan, 2018). Therefore, the G. mellonella model has been widely used to assess the virulence of microbial pathogens and it was optimized to increase susceptibility to bacterial and fungal infections for testing the in vivo activity of antimicrobial agents (Kavanagh and Sheehan, 2018), which directly influenced our choice for this model in the current study. Corroborating these findings, recently, we showed that G. mellonella offered a simple and feasible model to study C. haemulonii complex virulence and drug efficacy, in which the first-line antifungals (fluconazole, amphotericin B, and caspofunfin) were tested with equivalent therapeutic doses and minimal inhibitory concentrations (MIC) profile in vitro was correlated with in vivo antifungal efficacy (Silva et al, 2018).…”

Galleria mellonella as a consolidated in vivo model hosts: New developments in antibacterial strategies and novel drug testing

“…Although insects do not possess an adaptive immune response, they own innate immune response mechanisms (at epithelial, cellular and humoral levels) that are surprisingly well preserved and which share part of the evolutionary scale to mammals [11][12][13]. The lack of adaptive immunity is not a disadvantage, rather the insect models permit the study of host-parasite interactions and related innate-immunity mechanisms without the interference of adaptive responses [14].…”

Candida albicans increases the pathogenicity of Staphylococcus aureus during polymicrobial infection of Galleria mellonella larvae

“…Larvae of the greater wax moth Galleria mellonella are a widely used model to study the virulence of microbial pathogens and to assess the efficacy of antimicrobial agents due to the many advantages associated with their use (e.g. ease of use, cost-effectiveness, lack of legal and ethical restrictions) [29–33]. More recently, larvae have been utilized to study the virulence of bacterial (e.g.…”