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Updated: Oct 4, 2025
An Anaerobic Biosensor Assay for the Detection of Mercury and Cadmium
Published on: December 17, 2018
Cadmium stress efficiently enhanced meropenem degradation by the meropenem- and cadmium-resistant strain Pseudomonas
Chuanqing Zhong1, Yingping Zhou1, Jiafang Fu2
1School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, China.
Abstract:
The β-lactam antibiotic meropenem (MEM) is widely used in infectious disease treatment and consequently can be released into the environment, causing environmental pollution. In this study, Pseudomonas putida strain R51 was isolated from the wastewater of a poultry farm and found to efficiently degrade MEM. The genome of strain R51 contains a variety of heavy metal and antibiotic resistance genes, including the metallo-β-lactamase gene (JQN61_03315) and cadmium resistance gene cadA (JQN61_19995). Under cadmium stress, the degradation rate of MEM increased significantly in strain R51. Transcriptional analysis revealed that the expression of JQN61_03315 and cadA significantly increased under cadmium stress and that the expression of many genes associated with heavy metal and antibiotic resistance also changed significantly. Molecular docking analysis suggested that metallo-β-lactamase JQN61_03315 binds to MEM. In addition, no plasmid was found in strain R51, and no mobile genetic elements were found nearby JQN61_03315. In conclusion. we proposed that JQN61_03315 was responsible for the degradation of MEM, that the expression of this gene was induced under cadmium stress, and that strain R51 can be used for bioremediation of MEM without the risk for the transmission of the MEM resistance gene. These findings will have importance for studying the microbial degradation of MEM in the presence of heavy metal pollutants.
Insights
Pseudomonas putida strain R51 efficiently degrades the antibiotic meropenem (MEM). Cadmium stress enhances MEM degradation by increasing metallo-β-lactamase gene expression, offering a safe bioremediation solution.
Area of Science:
- Environmental microbiology
- Biotechnology
- Antimicrobial resistance
Background:
- Meropenem (MEM), a widely used β-lactam antibiotic, contributes to environmental pollution.
- Antibiotic resistance genes and heavy metal resistance genes are often co-located in environmental bacteria.
- Understanding microbial degradation pathways is crucial for addressing pharmaceutical pollution.
Purpose of the Study:
- To isolate and characterize microorganisms capable of degrading meropenem (MEM).
- To investigate the effect of heavy metal stress on MEM degradation efficiency.
- To elucidate the genetic basis and regulation of MEM degradation in the isolated strain.
Main Methods:
- Isolation and identification of bacteria from poultry farm wastewater.
- Meropenem (MEM) degradation assays under varying conditions.
- Genomic analysis to identify resistance genes.
- Transcriptional analysis (qRT-PCR) to assess gene expression.
- Molecular docking to predict protein-ligand interactions.
Main Results:
- Pseudomonas putida strain R51 efficiently degraded meropenem (MEM).
- Cadmium stress significantly enhanced MEM degradation rates.
- Expression of metallo-β-lactamase (JQN61_03315) and cadmium resistance (cadA) genes increased under cadmium stress.
- Molecular docking confirmed binding of metallo-β-lactamase JQN61_03315 to MEM.
- No plasmids or mobile genetic elements were found near the key degradation gene.
Conclusions:
- The metallo-β-lactamase JQN61_03315 is responsible for meropenem (MEM) degradation.
- Cadmium stress induces the expression of the MEM-degrading gene.
- Strain R51 offers a safe bioremediation strategy for MEM without horizontal gene transfer risk.
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