Imipenem-metal complexes: Computational analysis and toxicity studies with wastewater model microorganisms

Area of Science:

• Environmental Chemistry
• Microbiology
• Computational Chemistry

Background:

• Antibiotic residues in water pose risks of antibiotic resistance.
• Limited research exists on antibiotic-metal complexes (AMCs) in wastewater.
• The impact of AMCs on microbial communities is not well understood.

Purpose of the Study:

• Investigate the stability and antibacterial activity of Imipenem-metal complexes (AMCs).
• Assess the impact of AMCs on model wastewater microorganisms, Bacillus subtilis and Escherichia coli.
• Understand the mechanisms behind the enhanced antimicrobial properties of AMCs.

Main Methods:

• Computational studies (Density Functional Theory - DFT) for energy optimization.
• Potentiometric measurements for determining stoichiometry.
• Colony Forming Unit (CFU) method to evaluate antibacterial activity.

Main Results:

• Imipenem-metal complexes exhibited lower energy, indicating enhanced stability compared to Imipenem alone.
• AMCs demonstrated significantly higher antimicrobial activity against both E. coli and B. subtilis than Imipenem.
• Growth inhibition exceeded 97% for B. subtilis at a Minimum Inhibitory Concentration (MIC90) of 20 nM (6 ppb).
• Increased lipophilicity of AMCs facilitated stronger interaction with bacterial cell membranes.

Conclusions:

• Imipenem-metal complexes are more stable and possess enhanced antibacterial efficacy.
• AMCs represent emerging environmental contaminants of concern in wastewater.
• Further research is needed to develop effective removal strategies for AMCs from water sources.