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Updated: Jun 10, 2026
Use of Galleria mellonella as a Model Organism to Study Legionella pneumophila Infection
Published on: November 22, 2013
Molecular pathogenesis of Listeria monocytogenes in the alternative model host Galleria mellonella
Susan A Joyce1,2, Cormac G M Gahan3,1,2
1Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland.
Abstract:
Larvae of Galleria mellonella, the greater wax moth, provide an alternative infection model for many human pathogens as they are amenable to use at elevated incubation temperatures (37 °C). This study and a parallel study by Mukherjee et al. [Mukherjee, K., Altincicek, B., Hain, T., Domann, E., Vilcinskas, A. & Chakraborty, T. (2010). Appl Environ Microbiol 76, 310-317] establish this insect host as an appropriate model to investigate the pathogenesis of Listeria species. In this study we show that inoculation with Listeria monocytogenes initiates a dynamic infection in G. mellonella and that production of the cytolysin listeriolysin O (LLO) is necessary for toxicity and bacterial growth. Production of LLO by the non-pathogenic species Lactococcus lactis is sufficient to induce mortality in the insect model. We employed real-time bioluminescence imaging to examine the dynamics of listerial growth and virulence gene expression in the G. mellonella model. Analysis of lux promoter fusions demonstrated significant induction of virulence gene expression upon introduction of the pathogen into insects at both 30 and 37 °C. The host response to listerial infection was examined which demonstrated that haemocyte destruction accompanies L. monocytogenes pathogenesis and is preceded by activation of the phenoloxidase system. Furthermore, we demonstrate that Listeria innocua is pathogenic to G. mellonella through a persistence mechanism that implicates an alternative mechanism for pathogenicity in this model.
Insights
The greater wax moth, Galleria mellonella, serves as a model for Listeria pathogenesis. Listeriolysin O (LLO) is crucial for Listeria monocytogenes virulence, and its production by other bacteria can cause insect mortality.
Area of Science:
- Microbiology
- Infectious Diseases
- Insect Models
Background:
- The greater wax moth (Galleria mellonella) is a viable infection model for human pathogens at 37°C.
- This study, alongside Mukherjee et al. (2010), validates Galleria mellonella for Listeria pathogenesis research.
Purpose of the Study:
- To investigate Listeria monocytogenes pathogenesis in Galleria mellonella.
- To determine the role of listeriolysin O (LLO) in L. monocytogenes virulence.
- To explore host responses and alternative pathogenicity mechanisms in this insect model.
Main Methods:
- Inoculation of Galleria mellonella with Listeria monocytogenes.
- Real-time bioluminescence imaging to track bacterial growth and gene expression.
- Analysis of lux promoter fusions to assess virulence gene induction.
- Examination of host immune responses, including haemocyte destruction and phenoloxidase activation.
Main Results:
- Listeria monocytogenes infection is dynamic in G. mellonella, with LLO production essential for toxicity and growth.
- Lactococcus lactis expressing LLO induced mortality in the insect model.
- Virulence gene expression was significantly upregulated in G. mellonella at both 30°C and 37°C.
- L. monocytogenes infection led to haemocyte destruction, preceded by phenoloxidase system activation.
- Listeria innocua demonstrated pathogenicity via a persistence mechanism.
Conclusions:
- Galleria mellonella is a suitable model for studying Listeria pathogenesis and virulence factors like LLO.
- LLO is a key virulence factor for L. monocytogenes in this insect model.
- Listeria species can employ diverse mechanisms, including persistence, to cause disease in G. mellonella.
