Interaction between β-lactam antibiotic and phosphorus-accumulating organisms

Area of Science:

• Environmental Microbiology
• Biotechnology
• Ecotoxicology

Background:

• β-Lactam antibiotics are widely used clinically and detected in the environment.
• Phosphorus-accumulating organisms (PAOs) are crucial for enhanced biological phosphorus removal (EBPR).

Purpose of the Study:

• To investigate the interaction mechanisms between β-lactam antibiotics (amoxicillin, aztreonam, cefoperazone) and PAOs.
• To comprehensively analyze the effects of these antibiotics on PAOs' phosphorus removal, intracellular polymer synthesis, toxicity, and the antibiotics' environmental fate.

Main Methods:

• Exposure of PAOs to amoxicillin, aztreonam, and cefoperazone at 10 mg/L.
• Analysis of phosphorus removal rates, intracellular polyphosphate (poly-P) synthesis, and antibiotic degradation.
• Bacteriostatic tests to determine antibiotic toxicity to PAOs.

Main Results:

• Amoxicillin and aztreonam increased PAO phosphorus removal rates by 19.21% and 15.75%, respectively.
• Cefoperazone exhibited an inhibitory effect on phosphorus removal efficiency.
• All three antibiotics promoted poly-P synthesis in PAOs during the aerobic stage.
• Antibiotic degradation rates followed the order: amoxicillin > aztreonam > cefoperazone.
• Antibiotic toxicity order was: cefoperazone > aztreonam > amoxicillin.

Conclusions:

• β-Lactam antibiotics exhibit varied impacts on PAOs, with some enhancing EBPR processes.
• Understanding antibiotic fate and toxicity is crucial for environmental risk assessment.
• This study provides a theoretical basis for evaluating the biological toxicity of antibiotic pollutants in aquatic environments.