Limitations in the use of Drosophila melanogaster as a model host for gram-positive bacterial infection
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Updated: Jul 17, 2026
Systemic Bacterial Infection and Immune Defense Phenotypes in Drosophila Melanogaster
Published on: May 13, 2015
R L Jensen1, K S Pedersen, V Loeschcke
1Department of Veterinary Pathobiology, Royal Veterinary and Agricultural University, Copenhagen, Denmark.
Aims:
To examine sensitivities of various Drosophila melanogaster strains towards human pathogenic and nonpathogenic gram-positive bacteria.
Methods And Results:
The D. melanogaster Oregon R strain was infected by injecting the thorax with a needle containing Escherichia coli (negative control), Listeria monocytogenes, Staphylococcus aureus (both food-borne pathogens), Listeria innocua, Bacillus subtilis, Carnobacterium maltaromaticum, Lactobacillus plantarum or Pediococcus acidilactici (all nonpathogenic bacteria). Listeria monocytogenes and S. aureus killed the host rapidly compared with the negative control. Infection with L. innocua, B. subtilis or C. maltaromaticum also resulted in a high fly mortality, whereas Lact. plantarum and P. acidilactici resulted in a slightly increased mortality. Four additional D. melanogaster lines, three of which had been selected for heat, cold and desiccation resistance respectively, were subjected to infection by L. monocytogenes, S. aureus and E. coli. Mortality rates were comparable with that of the Oregon R strain.
Conclusions:
Use of the injection method shows the limitation of D. melanogaster as a model host for gram-positive bacteria as opportunistic infection by nonpathogenic gram-positive bacteria results in partial or high mortality. In addition, lines of fruit flies resistant to various stress exposures did not show an increased resistance to infection by gram-positive pathogens under the conditions tested.
Significance And Impact Of The Study:
This study demonstrates the inadequacy of D. melanogaster infected by the injection method in order to distinguish between virulent and nonvirulent gram-positive bacteria.
Insights
Fruit flies (Drosophila melanogaster) show high mortality from both pathogenic and nonpathogenic gram-positive bacteria when injected. This limits their use as a model for distinguishing bacterial virulence.
Area of Science:
- Microbiology
- Genetics
- Immunology
Background:
- Drosophila melanogaster is a common model organism for studying host-pathogen interactions.
- Gram-positive bacteria, including human pathogens and nonpathogenic strains, pose significant health concerns.
Purpose of the Study:
- To investigate the sensitivity of different Drosophila melanogaster strains to human pathogenic and nonpathogenic gram-positive bacteria.
- To assess the utility of D. melanogaster as a model for distinguishing bacterial virulence.
Main Methods:
- Drosophila melanogaster Oregon R strain and four other lines were infected via thoracic injection.
- Bacteria used included Escherichia coli (control), Listeria monocytogenes, Staphylococcus aureus, Listeria innocua, Bacillus subtilis, Carnobacterium maltaromaticum, Lactobacillus plantarum, and Pediococcus acidilactici.
- Mortality rates were compared between strains and bacterial types.
Main Results:
- Listeria monocytogenes and Staphylococcus aureus caused rapid mortality.
- Nonpathogenic bacteria like Listeria innocua, Bacillus subtilis, and Carnobacterium maltaromaticum also induced high fly mortality.
- Strains selected for stress resistance did not exhibit enhanced resistance to bacterial infection.
Conclusions:
- The injection method in D. melanogaster is limited for studying gram-positive bacteria due to high mortality from opportunistic infections by nonpathogenic strains.
- Drosophila melanogaster is inadequate for differentiating between virulent and nonvirulent gram-positive bacteria using the injection method.
