Is there a Trade-off? Impacts of Antibiotic Treatments on Gut Microbiota and Immune Gene Expression in Honey Bees (Apis Mellifera)
Open Access
- Author:
- Tomasko, Nicholas
- Area of Honors:
- Biochemistry and Molecular Biology
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Margarita Maria Lopez-Uribe, Thesis Supervisor
Joseph C. Reese, Thesis Honors Advisor - Keywords:
- Apis mellifera
Oxytetracycline
E. coli
Microbiome
Antimicrobial peptides
Immune genes
Immune response - Abstract:
- Antibiotics serve as fundamental treatments for bacterial infections in all organisms. However, these treatments can also deplete beneficial microbes that maintain immune homeostasis. Considering the links between beneficial microbes and immunity, it is critical to understand whether changes in the microbiome can reduce the individual’s ability to fight infection and decrease the long-term effectiveness of antibiotic treatments. Here, we used honey bees (Apis mellifera) to study the immunological effects of antibiotics. Honey bees are often treated with antibiotics when infected with devastating bacterial pathogens, such as Paenibacillus larvae: the causative agent of American foulbrood. To quantify the consequences of antibiotic treatment for immune function, we fed honey bees oxytetracycline followed by an immune challenge of heat-killed Escherichia coli (E. coli) to characterize changes in key gut bacteria and test for immunosuppression effects. We collected honey bees from five colonies and treated them in a laboratory incubator over 10 days. We then quantified the relative expression of three immune genes and quantified key groups of gut bacteria through qRT-PCR to assess changes in immune gene expression and gut microbiota abundance after each treatment. Antibiotic treatments caused general depletion in the honey bee microbial communities and a corresponding weak downregulation in AMPs, with the combined oxytetracycline and heat-killed E. coli treatment inducing a microbial rebound reflective of a typical immune response. Heat-killed E. coli treatments did not induce a significant response in immune gene expression. We also did not find significant survival differences between treatments.