Galleria mellonella as an Infection and Antibiotic Treatment Model for Acinetobacter baumannii
Dawn White1, Ellen M E Sykes1, Ayush Kumar2
1Department of Microbiology, University of Manitoba.
Abstract:
Galleria mellonella, commonly known as the greater wax moth or waxworm, is an insect infection model that provides researchers with an informative, simple, and economically feasible way to test the virulence of bacterial pathogens and potential treatment regimens against them. One such pathogen is Acinetobacter baumannii, a World Health Organization top-priority pathogen and a global health threat. The prevalence of deadly, multidrug-resistant A. baumannii in hospital settings, causing > 100,000 deaths in 2021, makes finding new treatment options paramount. A crucial piece of information needed to help eradicate a bacterial infection using antimicrobial compounds is the minimum inhibitory concentration-the lowest dose of a compound that can clear the infection. This value can be determined initially in vitro but then must be tested in a relevant infection model in vivo. Using the waxworm infection model and three different strains of A. baumannii-a virulent type strain, a hypervirulent clinical strain, and a virulent environmental strain-we demonstrate how to use minimum inhibitory concentration data to guide initial antibiotic treatment testing. We also compare two assay styles: infection followed by treatment (infect-wait-treat) and infection and treatment together (infect-and-treat). The results, showing similar trends in waxworm survival between both methods, demonstrate that the infect-and-treat protocol can be as informative as the more traditional infect-wait-treat method, with the benefit of saving valuable time and resources.
Insights
The waxworm model effectively tests antibiotic efficacy against Acinetobacter baumannii. The infect-and-treat method offers a time-saving alternative to traditional approaches for evaluating antimicrobial treatments.
Area of Science:
- Microbiology
- Infectious Diseases
- Insect Models
Background:
- Acinetobacter baumannii is a high-priority pathogen causing significant mortality.
- Multidrug-resistant strains necessitate novel treatment strategies.
- The Galleria mellonella model offers a cost-effective system for pathogen research.
Purpose of the Study:
- To evaluate the utility of minimum inhibitory concentration (MIC) data in guiding antibiotic treatment in vivo.
- To compare the efficacy of "infect-wait-treat" versus "infect-and-treat" assay styles.
- To assess antibiotic effectiveness against diverse Acinetobacter baumannii strains using the waxworm model.
Main Methods:
- Utilized three strains of Acinetobacter baumannii (type, hypervirulent clinical, environmental).
- Employed the Galleria mellonella insect model for in vivo infection studies.
- Compared two treatment assay methodologies: "infect-wait-treat" and "infect-and-treat".
Main Results:
- Minimum inhibitory concentration data successfully guided initial antibiotic treatment testing.
- Both "infect-wait-treat" and "infect-and-treat" methods showed similar trends in waxworm survival.
- The "infect-and-treat" protocol demonstrated comparable informativeness to the "infect-wait-treat" method.
Conclusions:
- The Galleria mellonella model is valuable for assessing antibiotic efficacy against Acinetobacter baumannii.
- The "infect-and-treat" assay provides a time- and resource-efficient alternative for evaluating antimicrobial treatments.
- MIC-guided treatment strategies are feasible in vivo using insect infection models.
