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Updated: Jul 17, 2026
Systemic Bacterial Infection and Immune Defense Phenotypes in Drosophila Melanogaster
Published on: May 13, 2015
Native microbial colonization of Drosophila melanogaster and its use as a model of Enterococcus faecalis pathogenesis
Christopher R Cox1, Michael S Gilmore
1The Schepens Eye Research Institute, 20 Staniford Street, Boston, MA 02114, USA.
Abstract:
Enterococci are commensal organisms of the gastrointestinal (GI) tracts of a broad range of mammalian and insect hosts, but they are also leading causes of nosocomial infection. Little is known about the ecological role of enterococci in the GI tract consortia. To develop a tractable model for studying the roles of these organisms as commensals and pathogens, we characterized the Drosophila melanogaster microflora and examined the occurrence of enterococci in the gastrointestinal consortium of Drosophila. In a survey of laboratory-reared Drosophila and wild-captured flies, we found that Drosophila was naturally colonized by representatives of five bacterial phyla. Among these organisms were several species of enterococci, including Enterococcus faecalis, Enterococcus faecium, Enterococcus gallinaraum, and Enterococcus durans, as well as a previously detected but uncultured Enterococcus species. Drosophila could be cured of enterococcal carriage by antibiotic treatment and could be reassociated with laboratory strains. High-level colonization by a well-characterized strain expressing the enterococcal cytolysin was found to be detrimental to Drosophila compared to the effect of an isogenic, noncytolytic control. The anatomical distribution of enterococci in the Drosophila GI tract was determined by immunohistochemical staining of thin sections of naturally colonized and reassociated flies.
Insights
Enterococci, common gut bacteria, can cause infections. This study shows the fruit fly Drosophila melanogaster can model enterococci
Area of Science:
- Microbiology and Microbial Ecology
- Host-Microbe Interactions
- Model Organism Research
Background:
- Enterococci are commensal gut bacteria but also significant causes of hospital-acquired infections.
- The ecological role of enterococci within the gastrointestinal tract remains poorly understood.
- A suitable model system is needed to study enterococci as both commensals and pathogens.
Purpose of the Study:
- To characterize the microflora of Drosophila melanogaster.
- To investigate the presence and role of enterococci in the Drosophila gastrointestinal tract.
- To establish Drosophila as a model for studying enterococcal pathogenesis.
Main Methods:
- Survey of bacterial phyla in laboratory-reared and wild-captured Drosophila.
- Identification of enterococcal species within the Drosophila gut microbiome.
- Antibiotic treatment for enterococcal clearance and reassociation experiments with lab strains.
- Assessment of virulence using a cytolysin-expressing strain and immunohistochemical analysis of gut distribution.
Main Results:
- Drosophila harbors diverse bacteria, including multiple Enterococcus species (E. faecalis, E. faecium, E. gallinarum, E. durans).
- Enterococcal colonization can be manipulated via antibiotic treatment and reassociation.
- High-level colonization with a cytolysin-producing Enterococcus strain is detrimental to Drosophila survival.
Conclusions:
- Drosophila melanogaster serves as a tractable model for studying enterococci in the gut.
- This model allows investigation of enterococcal ecological roles and pathogenic mechanisms.
- Enterococcal cytolysin contributes to virulence in the Drosophila host.
