Simultaneous antibiotic removal and mitigation of resistance induction by manganese bio-oxidation process Original paper
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Metals
Metals
Heavy metals influence microbial pathogenicity in two ways: they can be toxic to microbes by disrupting cellular functions and inducing oxidative stress, and they can be exploited by pathogens to enhance survival, resist treatment, and evade immunity. Understanding metal–microbe interactions supports better antimicrobial and public health strategies.
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Divine Aleru
What was studied?
This study investigated the simultaneous removal of antibiotics and mitigation of antibiotic resistance (AMR) induction through a manganese bio-oxidation process. The researchers used the Mn(II)-oxidizing bacterium Pseudomonas aeruginosa strain MQ2 to explore how manganese bio-oxidation could not only degrade antibiotics such as ciprofloxacin (Cip) and tetracycline (Tet) but also reduce the development and transfer of antibiotic resistance genes (ARGs). The study focused on the roles of biogenic manganese oxides (BioMnOx) and the effect of manganese oxidation on mitigating the induction of antibiotic resistance via oxidative stress.
Who was studied?
The study focused on Pseudomonas aeruginosa strain MQ2, a bacterium isolated for its ability to oxidize manganese. The research also examined Escherichia coli DH5α, used as a donor for conjugative transfer of ARGs, and P. aeruginosa strain MQ2 as the recipient. These bacterial strains were exposed to antibiotics and manganese to assess how manganese bio-oxidation influenced antibiotic degradation, resistance induction, and horizontal gene transfer (HGT).
What were the most important findings?
The study demonstrated that the manganese bio-oxidation process significantly mitigates the induction of antibiotic resistance. The P. aeruginosa strain MQ2 was able to degrade antibiotics like Cip and Tet effectively in the presence of BioMnOx, with removal efficiencies of 93% and 96%, respectively, within 24 hours. Notably, the manganese oxidation process reduced the development of resistance by decreasing oxidative stress, which is a major factor driving mutation and HGT of ARGs. The study also showed that manganese bio-oxidation decreased conjugative transfer of resistance genes between E. coli and P. aeruginosa, with a reduction of up to 26.7-fold in conjugative transfer frequency compared to control conditions. Additionally, the presence of BioMnOx shielded the bacteria by coating their surfaces, preventing oxidative damage and lowering the ROS levels inside the cells. This protective effect helped mitigate the mutation rates associated with antibiotic resistance.
What are the greatest implications of this study?
This study has important implications for wastewater treatment and environmental remediation strategies aimed at combating antibiotic resistance. By demonstrating the ability of manganese bio-oxidation to degrade antibiotics and reduce the spread of resistance genes, the research suggests that manganese-based treatments could be a promising approach to mitigate the environmental impact of antibiotic contamination. The findings also open the door for developing new bioremediation techniques that leverage manganese bio-oxidation to control both antibiotic pollution and the propagation of AMR in natural and industrial environments. This could significantly reduce the selective pressure exerted by antibiotics in polluted ecosystems, preventing the amplification of antibiotic-resistant bacteria and the transfer of resistance genes.
Manganese (Mn)
Manganese plays a pivotal role in microbial pathogenesis. As a vital cofactor for enzymes involved in antioxidant defense and metabolism, manganese is essential for pathogens, enabling them to survive within the host. However, when not properly managed, manganese can become toxic to both the host and the pathogen. The host’s immune system, through mechanisms like the secretion of calprotectin, tries to limit microbial access to manganese, creating an ongoing battle between host defenses and microbial survival .