11. Selection for Antibiosis in Soil Bacteria with Sub-Minimal Inhibitory Concentrations of Protein Synthesis Inhibitors

Selection for Antibiosis in Soil Bacteria with Sub-Minimal Inhibitory Concentrations of Protein Synthesis Inhibitors

Katie Krauska, Lauren Hackbarth, Lauren Komberec, Lillian Smith
University of Wisconsin – Madison

Sub-minimal inhibitory concentrations of known antibiotics (below the clinical dose) are known to change secondary metabolite production in bacteria via transcription activation. We investigated whether sub-MIC levels of protein synthesis inhibitors streptomycin and tetracycline could manipulate bacteria metabolism to encourage antibiosis against human pathogen relatives (ESKAPES). We found that culturing soil bacteria with sub-MIC protein synthesis inhibitors is not an effective method to select for antibiosis against relatives of human pathogens. Some individual isolates showed different antibiosis against ESKAPE relatives between treatments. These isolates may undergo transcription activation in the presence of sub-MIC antibiotics. Biochemical tests and genetic analysis are needed to pinpoint the mechanisms that lead to antibiotic production in these isolates.