Bacterial interspecies interactions modulate pH-mediated antibiotic tolerance.

Area of Science:

• Microbiology
• Microbial Ecology
• Pharmacology

Background:

• Predicting antibiotic efficacy in microbial communities is difficult.
• Interspecies interactions can alter bacterial physiology and antibiotic activity.
• The fruit fly gut microbiota provides a model system for studying these interactions.

Purpose of the Study:

• To investigate how interspecies interactions influence antibiotic tolerance in a synthetic microbial community.
• To elucidate the mechanisms by which microbial interactions modulate antibiotic efficacy.
• To enable better prediction of antibiotic effects in complex microbial ecosystems.

Main Methods:

• Constructed synthetic microbial communities from core fruit fly gut bacteria.
• Co-cultured Lactobacillus plantarum with Acetobacter species.
• Measured key metabolites and environmental pH.
• Assessed bacterial tolerance to antibiotics like rifampin and erythromycin.

Main Results:

• Co-culturing Lactobacillus plantarum with Acetobacter species altered its tolerance to rifampin.
• Acetobacter species counteracted acidification caused by L. plantarum's lactate production, altering environmental pH.
• Shifts in pH were sufficient to modulate L. plantarum tolerance to rifampin and erythromycin.
• Reduced lag time exiting stationary phase correlated with L. plantarum rifampicin tolerance.

Conclusions:

• Interspecies interactions, specifically pH modulation by Acetobacter species, significantly impact antibiotic tolerance in microbial communities.
• Understanding these interactions is crucial for predicting antibiotic efficacy.
• This mechanistic insight facilitates future predictions of microbial growth and antibiotic effects in complex communities.