Galleria mellonella larvae exhibit a weight-dependent lethal median dose when infected with methicillin-resistant
Poppy J Hesketh-Best1, Michelle V Mouritzen2, Kayleigh Shandley-Edwards1
1School of Biological and Marine Sciences, University of Plymouth, Drake Circus, Plymouth, PL4 8AA, UK.
Abstract:
Galleria mellonella is a recognised model to study antimicrobial efficacy; however, standardisation across the scientific field and investigations of methodological components are needed. Here, we investigate the impact of weight on mortality following infection with Methicillin-resistant Staphylococcus aureus (MRSA). Larvae were separated into six weight groups (180-300 mg at 20 mg intervals) and infected with a range of doses of MRSA to determine the 50% lethal dose (LD50), and the 'lipid weight' of larvae post-infection was quantified. A model of LD50 values correlated with weight was developed. The LD50 values, as estimated by our model, were further tested in vivo to prove our model. We establish a weight-dependent LD50 in larvae against MRSA and demonstrate that G. mellonella is a stable model within 180-260 mg. We present multiple linear models correlating weight with: LD50, lipid weight, and larval length. We demonstrate that the lipid weight is reduced as a result of MRSA infection, identifying a potentially new measure in which to understand the immune response. Finally, we demonstrate that larval length can be a reasonable proxy for weight. Refining the methodologies in which to handle and design experiments involving G. mellonella, we can improve the reliability of this powerful model.
Insights
Larval weight significantly impacts mortality when infected with Methicillin-resistant Staphylococcus aureus (MRSA). Galleria mellonella (G. mellonella) is a reliable model for antimicrobial studies within a specific weight range.
Area of Science:
- Microbiology and Immunology
- Invertebrate Models in Infection Research
Background:
- Galleria mellonella (G. mellonella) larvae are widely used for antimicrobial efficacy studies.
- Lack of standardization in G. mellonella models necessitates methodological refinement.
- Investigating factors influencing G. mellonella's response to infection is crucial for model reliability.
Purpose of the Study:
- To determine the impact of larval weight on mortality following Methicillin-resistant Staphylococcus aureus (MRSA) infection.
- To establish a weight-dependent lethal dose 50 (LD50) model for MRSA in G. mellonella.
- To identify reliable methodological parameters for G. mellonella infection experiments.
Main Methods:
- Larvae were grouped by weight (180-300 mg) and infected with varying doses of MRSA.
- Lethal dose 50 (LD50) values were determined and correlated with larval weight.
- Lipid weight and larval length were quantified post-infection; linear models were developed.
Main Results:
- A significant weight-dependent LD50 was established for MRSA infection in G. mellonella.
- G. mellonella demonstrated stability as a model organism within the 180-260 mg weight range.
- MRSA infection led to a reduction in larval lipid weight, suggesting a new immune response marker.
- Larval length was identified as a reliable proxy for larval weight.
Conclusions:
- Larval weight is a critical factor influencing mortality in MRSA-infected G. mellonella.
- Standardized weight ranges (180-260 mg) enhance the reliability of G. mellonella as an infection model.
- Lipid weight quantification and larval length measurement offer valuable insights into infection dynamics and experimental design.
