Rearing and Maintenance of Galleria mellonella and Its Application to Study Fungal Virulence

Abstract

Galleria mellonella larvae have been widely used as alternative non-mammalian models for the study of fungal virulence and pathogenesis. The larvae can be acquired in small volumes from worm farms, pet stores, or other independent suppliers commonly found in the United States and parts of Europe. However, in countries with no or limited commercial availability, the process of shipping these larvae can cause them stress, resulting in decreased or altered immunity. Furthermore, the conditions used to rear these larvae including diet, humidity, temperature, and maintenance procedures vary among the suppliers. Variation in these factors can affect the response of G. mellonella larvae to infection, thereby decreasing the reproducibility of fungal virulence experiments. There is a critical need for standardized procedures and incubation conditions for rearing G. mellonella to produce quality, unstressed larvae with the least genetic variability. In order to standardize these procedures, cost-effective protocols for the propagation and maintenance of G. mellonella larvae using an artificial diet, which has been successfully used in our own laboratory, requiring minimal equipment and expertise, are herein described. Examples for the application of this model in fungal pathogenicity and gene knockout studies as feasible alternatives for traditionally used animal models are also provided.

Pathogenicity Assessment of Colombian Strains of Candida auris in the Galleria mellonella Invertebrate Model

“…The advantage of using G. mellonella as a model for the study of pathogenicity in fungi is the ease of use, that is, the inoculation of the pathogen involves only a hind leg and a syringe, and they can be maintained at variable temperatures ranging from 25 to 37 °C. The innate immune response is an important component in the immune response to pathogenic infections and the reports show strong correlation between fungal pathogenicity results in larvae and mice [ 18 , 19 ].…”

Antifungal Combination of Ethyl Acetate Extract of Poincianella pluviosa (DC.) L. P. Queiros Stem Bark With Amphotericin B in Cryptococcus neoformans

“…This non-mammalian model can be maintained easily and inexpensively in laboratory conditions, at different temperatures, including the human temperature 37 • C. Similarly to mammalian models, this insect develops a specific immune response against different microbial infections (Pereira et al, 2018). Therefore, this insect has been used to study the fungal virulence and pathogenesis (Benaducci et al, 2016;Firacative et al, 2020;Grizante Barião et al, 2020) and to evaluate the efficacy of the antifungal agents against different fungal species (Singulani et al, 2019;de Castro Spadari et al, 2020). The results reported in the present study showed that early treatment with EAF from P. pluviosa combined with AmB was effective in controlling C. neoformans infection with no toxicity to larvae, supporting the in vitro results.…”

Galleria mellonella as a screening tool to study virulence factors of Aspergillus fumigatus

“…and more recently Firacative et al . proposed an optimal method to rear G. mellonella in laboratories for microbiological studies (dietary components, description of environmental conditions, and a detailed protocol for all life stages of G. mellonella ) [ 32 , 38 ].

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“…Galleria mellonella has been used for the complex study of host–microbe interactions, especially host-fungi interactions [ 4 , 6 , 24–30 ]. This model is now recognized as a pertinent model to the study of the fungal infections [ 31 , 32 ]. Aspergillus fumigatus remains one of the most common pathogenic fungi known to colonize the respiratory tract of patients with chronic lung diseases (e.g.…”