Removal of multidrug-resistant Escherichia coli by montmorillonite and its impact on plasmid conjugative transfer
Year: 2026
Type: article
Abstract: Montmorillonite (MMT) is a component used to adsorb toxins and bacteria in animal feed. However, its effect on the horizontal gene transfer of antibiotic resistance genes remains unclear. This study investigated the removal characteristics of MMT towards multidrug-resistant Escherichia coli and its subsequent impact on plasmid conjugation. The results showed that 5 mg mL –1 MMT exhibited the highest removal ratio (84.60%), reaching saturation within 15 min. MMT showed a transient inhibitory effect on planktonic bacterial growth, resulting in a significant decrease in bacterial concentration at 2 and 4 h. In conjugation assays, while MMT significantly reduced the planktonic concentrations of donor and recipient strains via sedimentation, it did not reduce the absolute number of transconjugants. Consequently, the apparent conjugation frequency within the planktonic phase significantly increased at MMT concentrations ≥5 mg mL –1 . These findings suggest that although MMT has application value as an adsorbent in feed to physically remove bacteria, its surface may act as a ‘hotbed’ that facilitates cell-to-cell contact, thereby promoting the conjugative transfer of resistance plasmids. Therefore, when assessing the safety of MMT as a feed additive, its potential role in accelerating the dissemination of antibiotic resistance genes must be considered alongside its pathogen-removal capability. Future research should focus on the functional modification of MMT to mitigate its risk of facilitating gene transfer.
Source: Clay Minerals
Institution: Nanjing Agricultural University
Language: English
Subfield: Pollution
Field: Environmental Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W7166432077
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