Investigating and Modeling the Regulation of Extracellular Antibiotic Resistance Gene Bioavailability by Naturally Occurring Nanoparticles

Abstract

Extracellular antibiotic resistance genes (eARGs) are widespread in the environment and can genetically transform bacteria. This work examined the role of environmentally relevant nanoparticles (NPs) in regulating eARG bioavailability. eARGs extracted from antibiotic-resistant B. subtilis were incubated with nonresistant recipient B. subtilis cells. In the mixture, particle type (either humic acid coated nanoparticles (HASNPs) or their micron-sized counterpart (HASPs)), DNase I concentration, and eARG type were systematically varied. Transformants were counted on selective media. Particles decreased bacterial growth and eARG bioavailability in systems without nuclease. When DNase I was present (≥5 μg/mL), particles increased transformation via chromosomal (but not plasmid-borne) eARGs. HASNPs increased transformation more than HASPs, indicating that the smaller nanoparticle with greater surface area per volume is more effective in increasing eARG bioavailability. These results were also modeled via particle aggregation theory, which represented eARG–bacteria interactions as transport leading to collision, followed by attachment. Using attachment efficiency as a fitting factor, the model predicted transformant concentrations within 35% of experimental data. These results confirm the ability of NPs to increase eARG bioavailability and suggest that particle aggregation theory may be a simplified and suitable framework to broadly predict eARG uptake.

CeO2 Nanoparticles-Regulated Plasmid Uptake and Bioavailability for Reducing Transformation of Extracellular Antibiotic Resistance Genes

“…Nanomaterials have been introduced as a potential alternative for controlling the conjugation transfer of iDNA [ 7 ], but their roles in the transformation of eDNA remains largely unknown. The adsorption of eDNA to the nanoparticles (NPs) was irreversible, decreasing the bioavailability of eDNA and inhibiting bacterial growth [ 21 , 22 ]. In addition, NPs might interact with the cell membrane upon direct contact and NPs with ROS scavenging capacity may contribute to the maintenance of membrane permeability [ 23 , 24 ].…”

Nematodes Degrade Extracellular Antibiotic Resistance Genes by Secreting DNase II Encoded by the nuc-1 Gene

“…The physical and chemical decay of ARGs, including processes of adsorption, fragmentation, photolysis, and oxidation, has been well studied. − However, the understanding of ARG biodegradation remains limited. Generally, it is considered that microbes dominate the degradation process, including direct degradation through nucleases and indirectly mediated ARG attenuation.…”

Charged nanoplastics differentially affect the conjugative transfer of antibiotic resistance genes

“…14 Pollutants, particularly those released through human activity, also play a significant role in the fate of ARGs. [15][16][17] Plastics, which have facilitated people's lives for decades, have increased exponentially in production and consumption. 18,19 It is estimated that global plastic production increased dramatically from 15 million tons in 1964 to 380 million tons in 2019.…”

“…14 Pollutants, particularly those released through human activity, also play a significant role in the fate of ARGs. 15–17…”