Metallic nanoparticles and ions accelerate the uptake of extracellular antibiotic resistance genes through transformation
Background: Antibiotic resistance genes (ARGs), heavy metal ions and nanoparticles (NPs) are emerging and ubiquitous contaminants in the environment. However, little is known about whether heavy metal-based NPs or ions could facilitate the dissemination of ARGs through natural transformation. This study evaluated the contributions of heavy metal-based NPs (Ag NPs, CuO NPs and ZnO NPs) and their ion forms (Ag + , Cu 2+ and Zn 2+ ) to the transformation of extracellular ARGs in Acinetobacter baylyi ADP1.
Results: We found that these commonly-used NPs and ions from environmentally relevant concentrations can significantly promote the natural transformation frequency of ARGs by a factor of 11.0-folds, which is comparable to the effects of antibiotics. The enhanced transformation by Ag NPs, CuO NPs, Ag + and Cu 2+ was primarily associated with reactive oxygen species (ROS) over-production and cell membrane damage, which was also evident from up-regulations of both transcription and translation of ROS and outer membrane-related genes. Additionally, transmission electron microscope imaging revealed the roughened cell membrane after Ag NPs, CuO NPs, Ag + and Cu 2+ exposure. ZnO NPs and Zn 2+ might increase the natural transformation rate by stimulating the stress response and ATP synthesis. All tested NPs and ions resulted in up-regulating the competence and SOS response-associated genes.
Conclusions: Our results demonstrate that Ag, CuO and ZnO-based NPs/ions from environmental concentrations could promote the natural transformation of plasmid-encoded ARGs into naturally competent A. baylyi . Our findings provide insights into the contributions of heavy metals and NPs to the spread of antibiotic resistance.
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Posted 09 Jan, 2020
Metallic nanoparticles and ions accelerate the uptake of extracellular antibiotic resistance genes through transformation
Posted 09 Jan, 2020
Background: Antibiotic resistance genes (ARGs), heavy metal ions and nanoparticles (NPs) are emerging and ubiquitous contaminants in the environment. However, little is known about whether heavy metal-based NPs or ions could facilitate the dissemination of ARGs through natural transformation. This study evaluated the contributions of heavy metal-based NPs (Ag NPs, CuO NPs and ZnO NPs) and their ion forms (Ag + , Cu 2+ and Zn 2+ ) to the transformation of extracellular ARGs in Acinetobacter baylyi ADP1.
Results: We found that these commonly-used NPs and ions from environmentally relevant concentrations can significantly promote the natural transformation frequency of ARGs by a factor of 11.0-folds, which is comparable to the effects of antibiotics. The enhanced transformation by Ag NPs, CuO NPs, Ag + and Cu 2+ was primarily associated with reactive oxygen species (ROS) over-production and cell membrane damage, which was also evident from up-regulations of both transcription and translation of ROS and outer membrane-related genes. Additionally, transmission electron microscope imaging revealed the roughened cell membrane after Ag NPs, CuO NPs, Ag + and Cu 2+ exposure. ZnO NPs and Zn 2+ might increase the natural transformation rate by stimulating the stress response and ATP synthesis. All tested NPs and ions resulted in up-regulating the competence and SOS response-associated genes.
Conclusions: Our results demonstrate that Ag, CuO and ZnO-based NPs/ions from environmental concentrations could promote the natural transformation of plasmid-encoded ARGs into naturally competent A. baylyi . Our findings provide insights into the contributions of heavy metals and NPs to the spread of antibiotic resistance.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5