The impact of silver nanoparticles on microbial communities and antibiotic resistance determinants in the environment

Characterizing the response of microbial communities to a range of antibiotic concentrations is one of the strategies used to understand the impact of antibiotic resistance. Many studies have described the occurrence and prevalence of antibiotic resistance in microbial communities from reservoirs such as hospitals, sewage, and farm feedlots, where bacteria are often exposed to high and/or constant concentrations of antibiotics. Outside of these sources, antibiotics generally occur at lower, sub-minimum inhibitory concentrations (sub-MICs). The constant exposure to low concentrations of antibiotics may serve as a chemical “cue” that drives development of antibiotic resistance. Low concentrations of antibiotics have not yet been broadly described in reservoirs outside of the aforementioned environments, nor is the transfer and dissemination of antibiotic resistant bacteria and genes within natural microbial communities fully understood. This review will thus focus on low antibiotic-concentration environmental reservoirs and mechanisms that are important in the dissemination of antibiotic resistance to help identify key knowledge gaps concerning the environmental resistome.

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Mobile resistome of human gut and pathogen drives anthropogenic bloom of antibiotic resistance

Microbiome ◽

10.1186/s40168-019-0774-7 ◽

2020 ◽

Vol 8 (1) ◽

Cited By ~ 7

Author(s):

Kihyun Lee ◽

Dae-Wi Kim ◽

Do-Hoon Lee ◽

Yong-Seok Kim ◽

Ji-Hye Bu ◽

...

Keyword(s):

Antibiotic Resistance ◽

Microbial Communities ◽

Human Activities ◽

Pathogenic Bacteria ◽

Anthropogenic Activities ◽

Antibiotic Resistance Genes ◽

Anthropogenic Influences ◽

Human Gut ◽

The Impact ◽

Spatial Continuum

Abstract Background The impact of human activities on the environmental resistome has been documented in many studies, but there remains the controversial question of whether the increased antibiotic resistance observed in anthropogenically impacted environments is just a result of contamination by resistant fecal microbes or is mediated by indigenous environmental organisms. Here, to determine exactly how anthropogenic influences shape the environmental resistome, we resolved the microbiome, resistome, and mobilome of the planktonic microbial communities along a single river, the Han, which spans a gradient of human activities. Results The bloom of antibiotic resistance genes (ARGs) was evident in the downstream regions and distinct successional dynamics of the river resistome occurred across the spatial continuum. We identified a number of widespread ARG sequences shared between the river, human gut, and pathogenic bacteria. These human-related ARGs were largely associated with mobile genetic elements rather than particular gut taxa and mainly responsible for anthropogenically driven bloom of the downstream river resistome. Furthermore, both sequence- and phenotype-based analyses revealed environmental relatives of clinically important proteobacteria as major carriers of these ARGs. Conclusions Our results demonstrate a more nuanced view of the impact of anthropogenic activities on the river resistome: fecal contamination is present and allows the transmission of ARGs to the environmental resistome, but these mobile genes rather than resistant fecal bacteria proliferate in environmental relatives of their original hosts.

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Faculty Opinions recommendation of The impact and mechanism of quaternary ammonium compounds on the transmission of antibiotic resistance genes.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.736365401.793563724 ◽

2019 ◽

Author(s):

Günter Kampf

Keyword(s):

Antibiotic Resistance ◽

Resistance Genes ◽

Quaternary Ammonium ◽

Antibiotic Resistance Genes ◽

Quaternary Ammonium Compounds ◽

The Impact ◽

Ammonium Compounds

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Curcumin-containing Silver Nanoparticles prevent carbon tetrachlorideinduced hepatotoxicity in mice

Combinatorial Chemistry & High Throughput Screening ◽

10.2174/1386207323666201211100830 ◽

2020 ◽

Vol 23 ◽

Author(s):

Hossam Ebaid ◽

Mohamed Habila ◽

Iftekhar Hassan ◽

Jameel Al-Tamimi ◽

Mohamed S. Omar ◽

...

Keyword(s):

Dna Damage ◽

Silver Nanoparticles ◽

Nuclear Dna ◽

Liquid Paraffin ◽

Tail Length ◽

Hepatic Tissue ◽

Tissue Destruction ◽

Group 2 ◽

The Impact

Background: Hepatotoxicity remains an important clinical challenge. Hepatotoxicity observed in response to toxins and hazardous chemicals may be alleviated by delivery of the curcumin in silver nanoparticles (AgNPs-curcumin). In this study, we examined the impact of AgNPs-curcumin in a mouse model of carbon tetrachloride (CCl4)-induced hepatic injury. Methods: Male C57BL/6 mice were divided into three groups (n=8 per group). Mice in group 1 were treated with vehicle control alone, while mice in Group 2 received a single intraperitoneal injection of 1 ml/kg CCl4 in liquid paraffin (1:1 v/v). Mice in group 3 were treated with 2.5 mg/kg AgNPs-curcumin twice per week for three weeks after the CCl4 challenge. Results: Administration of CCL4 resulted in oxidative dysregulation, including significant reductions in reduced glutathione and concomitant elevations in the level of malondialdehyde (MDA). CCL4 challenge also resulted in elevated levels of serum aspartate transaminase (AST) and alanine transaminase (ALT); these findings were associated with the destruction of hepatic tissues. Treatment with AgNPs-curcumin prevented oxidative imbalance, hepatic dysfunction, and tissue destruction. A comet assay revealed that CCl4 challenge resulted in significant DNA damage as documented by a 70% increase in nuclear DNA tail-length; treatment with AgNPs-curcumin inhibited the CCL4-mediated increase in nuclear DNA tail-length by 34%. Conclusion: Administration of AgNPs-curcumin resulted in significant antioxidant activity in vivo. This agent has the potential to prevent the hepatic tissue destruction and DNA damage that results from direct exposure to CCL4.

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Effects of polyethylene microplastics on the fate of antibiotic resistance genes and microbial communities in anaerobic digestion of dairy wastes

Journal of Cleaner Production ◽

10.1016/j.jclepro.2021.125909 ◽

2021 ◽

Vol 292 ◽

pp. 125909

Author(s):

Qiuping Zhang ◽

Deliang Fan ◽

Xiaoke Pang ◽

Wenbo Zhu ◽

Ji Zhao ◽

...

Keyword(s):

Antibiotic Resistance ◽

Anaerobic Digestion ◽

Microbial Communities ◽

Resistance Genes ◽

Antibiotic Resistance Genes ◽

Dairy Wastes

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Metagenomics Analysis Reveals the Microbial Communities, Antimicrobial Resistance Gene Diversity and Potential Pathogen Transmission Risk of Two Different Landfills in China

Diversity ◽

10.3390/d13060230 ◽

2021 ◽

Vol 13 (6) ◽

pp. 230

Author(s):

Shan Wan ◽

Min Xia ◽

Jie Tao ◽

Yanjun Pang ◽

Fugen Yu ◽

...

Keyword(s):

Antibiotic Resistance ◽

Microbial Communities ◽

Resistance Gene ◽

Resistance Genes ◽

Gene Diversity ◽

Antibiotic Resistance Gene ◽

Antibiotic Resistance Genes ◽

Pathogen Transmission ◽

Transmission Risk ◽

Antimicrobial Resistance Gene

In this study, we used a metagenomic approach to analyze microbial communities, antibiotic resistance gene diversity, and human pathogenic bacterium composition in two typical landfills in China. Results showed that the phyla Proteobacteria, Bacteroidetes, and Actinobacteria were predominant in the two landfills, and archaea and fungi were also detected. The genera Methanoculleus, Lysobacter, and Pseudomonas were predominantly present in all samples. sul2, sul1, tetX, and adeF were the four most abundant antibiotic resistance genes. Sixty-nine bacterial pathogens were identified from the two landfills, with Klebsiella pneumoniae, Bordetella pertussis, Pseudomonas aeruginosa, and Bacillus cereus as the major pathogenic microorganisms, indicating the existence of potential environmental risk in landfills. In addition, KEGG pathway analysis indicated the presence of antibiotic resistance genes typically associated with human antibiotic resistance bacterial strains. These results provide insights into the risk of pathogens in landfills, which is important for controlling the potential secondary transmission of pathogens and reducing workers’ health risk during landfill excavation.

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Phytotoxicity of Silver Nanoparticles on Tobacco Plants: Evaluation of Coating Effects on Photosynthetic Performance and Chloroplast Ultrastructure

Nanomaterials ◽

10.3390/nano11030744 ◽

2021 ◽

Vol 11 (3) ◽

pp. 744

Author(s):

Petra Peharec Štefanić ◽

Karla Košpić ◽

Daniel Mark Lyons ◽

Lara Jurković ◽

Biljana Balen ◽

...

Keyword(s):

Silver Nanoparticles ◽

Cetyltrimethylammonium Bromide ◽

Photosynthetic Apparatus ◽

Chloroplast Ultrastructure ◽

Photosynthetic Performance ◽

Pigment Content ◽

Inhibitory Effects ◽

Tobacco Plants ◽

Agriculture And Food ◽

The Impact

Silver nanoparticles (AgNPs) are the most exploited nanomaterial in agriculture and food production, and their release into the environment raises concern about their impact on plants. Since AgNPs are prone to biotransformation, various surface coatings are used to enhance their stability, which may modulate AgNP-imposed toxic effects. In this study, the impact of AgNPs stabilized with different coatings (citrate, polyvinylpyrrolidone (PVP), and cetyltrimethylammonium bromide (CTAB)) and AgNO3 on photosynthesis of tobacco plants as well as AgNP stability in exposure medium have been investigated. Obtained results revealed that AgNP-citrate induced the least effects on chlorophyll a fluorescence parameters and pigment content, which could be ascribed to their fast agglomeration in the exposure medium and consequently weak uptake. The impact of AgNP-PVP and AgNP-CTAB was more severe, inducing a deterioration of photosynthetic activity along with reduced pigment content and alterations in chloroplast ultrastructure, which could be correlated to their higher stability, elevated Ag accumulation, and surface charge. In conclusion, intrinsic properties of AgNP coatings affect their stability and bioavailability in the biological medium, thereby indirectly contributing changes in the photosynthetic apparatus. Moreover, AgNP treatments exhibited more severe inhibitory effects compared to AgNO3, which indicates that the impact on photosynthesis is dependent on the form of Ag.

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Benchmarking microbiome transformations favors experimental quantitative approaches to address compositionality and sampling depth biases

Nature Communications ◽

10.1038/s41467-021-23821-6 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Verónica Lloréns-Rico ◽

Sara Vieira-Silva ◽

Pedro J. Gonçalves ◽

Gwen Falony ◽

Jeroen Raes

Keyword(s):

Microbial Communities ◽

Quantitative Methods ◽

Microbial Load ◽

Metagenomic Sequencing ◽

Sampling Depth ◽

Microbiome Research ◽

Microbiome Data ◽

The Impact ◽

Analytical Approaches ◽

Quantitative Approaches

AbstractWhile metagenomic sequencing has become the tool of preference to study host-associated microbial communities, downstream analyses and clinical interpretation of microbiome data remains challenging due to the sparsity and compositionality of sequence matrices. Here, we evaluate both computational and experimental approaches proposed to mitigate the impact of these outstanding issues. Generating fecal metagenomes drawn from simulated microbial communities, we benchmark the performance of thirteen commonly used analytical approaches in terms of diversity estimation, identification of taxon-taxon associations, and assessment of taxon-metadata correlations under the challenge of varying microbial ecosystem loads. We find quantitative approaches including experimental procedures to incorporate microbial load variation in downstream analyses to perform significantly better than computational strategies designed to mitigate data compositionality and sparsity, not only improving the identification of true positive associations, but also reducing false positive detection. When analyzing simulated scenarios of low microbial load dysbiosis as observed in inflammatory pathologies, quantitative methods correcting for sampling depth show higher precision compared to uncorrected scaling. Overall, our findings advocate for a wider adoption of experimental quantitative approaches in microbiome research, yet also suggest preferred transformations for specific cases where determination of microbial load of samples is not feasible.

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