Antibiotic exposure at environmental concentrations under high-fat diet: Impacts on gut microbiota and metabolism

Area of Science:

• Environmental Science
• Microbiology
• Metabolomics
• Toxicology

Background:

• Antibiotics are widespread environmental contaminants, leading to inevitable human exposure.
• High-fat diets (HFD) significantly impact gut microbiota and host metabolism.
• The combined effects of low-dose antibiotics and HFD on gut health are not fully understood.

Purpose of the Study:

• To investigate the impact of environmentally relevant concentrations of Azithromycin (AZI) and Ciprofloxacin (CIP) on gut microbiota and host metabolism.
• To assess these effects in mice maintained on a high-fat diet (HFD).
• To explore the alterations in microbial community structure, short-chain fatty acid (SCFA) profiles, and host metabolic parameters.

Main Methods:

• Mice were administered trace amounts of AZI and CIP via drinking water.
• Mice were maintained on a high-fat diet (HFD) for the duration of the study.
• Analysis included gut microbial community structure, SCFA profiling, serum hormone levels, and serum metabolic profiling.

Main Results:

• Long-term exposure to trace antibiotics significantly altered gut microbial community structure.
• AZI markedly increased acetate, butyrate, and propionate production in both sexes.
• AZI and CIP elevated body weight in male mice, altered serum hormone levels, and changed the serum metabolic profile. Lactobacillus played a key role in SCFA profiles in female mice exposed to AZI.

Conclusions:

• Exposure to trace antibiotics, particularly in conjunction with an HFD, induces significant gut microbiota and host metabolism alterations.
• These changes highlight potential health risks associated with environmental antibiotic exposure, especially for susceptible populations.
• Further research is warranted to fully elucidate the long-term consequences and mechanisms of these interactions.