Effortless rule: Effects of oversized microplastic management on lettuce growth and the dynamics of antibiotic resistance genes from fertilization to harvest. - Related Documents




#
Rank
Similarity
Title + Abs.
Year
PMID
012345
696001.0000Effortless rule: Effects of oversized microplastic management on lettuce growth and the dynamics of antibiotic resistance genes from fertilization to harvest. The complexity of soil microplastic pollution has driven deeper exploration of waste management strategies to evaluate environmental impact. This study introduced oversized microplastics (OMPs, 1-5 mm) during membrane composting to produce organic fertilizers, and conducted a 2 × 2 pot experiment: exogenous OMPs were added when normal fertilizer (no OMPs intervention) was applied, while artificial removal of OMPs was implemented when contaminated fertilizer (with OMPs) was used. The study assessed the effects of these management strategies on lettuce growth, soil environments, and potential biological safety risks related to the spread and expression of high-risk antibiotic resistance genes (ARGs) in humans. Results showed that both exogenous OMPs addition and removal negatively affected plant height and harvest index, with shifts in the rhizosphere microbial community identified as a key factor rather than soil nutrients. Exogenous OMPs altered rhizosphere and endophytic microbial communities, and plant growth-promoting bacteria were transferred to the surface of OMPs from rhizosphere soil. In contrast, bacteria such as Truepera, Pseudomonas, and Streptomyces in compost-derived OMPs supported lettuce growth, and their removal negated these effects. Some endophytic bacteria may promote growth but pose public health risks when transmitted through the food chain. OMPs in composting or planting significantly enhanced the expression of target ARGs in lettuce, particularly bla(TEM). However, simulated digestion results indicated that OMPs reduced the expression of six key ARGs, including bla(TEM), among the ten critical target ARGs identified in this context. Notably, the removal management strategies raised five of them posing potential risks from lettuce consumption. This study highlights that both introducing and removing OMPs may pose ecological and food safety risks, emphasizing the need for optimized organic waste management strategies to mitigate potential health hazards.202540157188
693110.9998What role does organic fertilizer actually play in the fate of antibiotic resistome and pathogenic bacteria in planting soil? Organic fertilizer increase antibiotic resistance genes (ARGs) and bacterial pathogens have widely documented. However, how organic fertilizer is involved in changing soil ARGs and pathogenic bacteria after long-term (≥5 years) application remains unclear. Herein, the ARGs and pathogenic bacteria were compared in organic fertilized soils (AF) and non-fertilized soils (NF), and the contribution of input sources (organic fertilizer, irrigation water, air and background soil) on soil ARGs also was determined in this study. Results showed that the abundances of some ARGs, such as vanR and aac(6')-I in AF, were significantly higher than these of NF (p < 0.05). And a relatively higher abundance of potential pathogens, especially, Salmonella enterica and Stenotrophomonas maltophilia, in AF was observed. This indicated that organic fertilizer application can maintain a high level of some soil ARGs and pathogenic bacteria for at least 5 years. Traceability analysis unearthed that organic fertilizer application mainly increased its own contribution to soil ARGs from 1.16% to 9.05%, as well reduced the contribution of background soil, suggesting that the increase in soil ARGs may be partly attributable to organic fertilizer inputs. Notably, organic fertilizer application did not significantly alter the contribution ratio of input sources to microorganisms, but there was a clear change in the composition of soil microorganisms, which meant that the effect of the input source on the microorganism may emanate from other factors, rather than direct inputs. Subsequent structural equation demonstrated that organic fertilizer application significantly enhanced the effect of environmental factors on ARGs, and also indirectly increased the influence of communities on ARGs. Collectively, under the long-term fertilization, the role of organic fertilizers on soil ARGs not just stems from its own input, and also dominates the influence of environmental factors on ARGs. This study elucidates main causes for the difference in ARGs in AF vs. NF and enlightens actual role of organic fertilizer in them.202235623127
745620.9998Anaerobic digestion of nitrogen rich poultry manure: Impact of thermophilic biogas process on metal release and microbial resistances. Poultry manure is a nitrogen rich fertilizer, which is usually recycled and spread on agricultural fields. Due to its high nutrient content, chicken manure is considered to be one of the most valuable animal wastes as organic fertilizer. However, when chicken litter is applied in its native form, concerns are raised as such fertilizers also include high amounts of antibiotic resistant pathogenic Bacteria and heavy metals. We studied the impact of an anaerobic thermophilic digestion process on poultry manure. Particularly, microbial antibiotic resistance profiles, mobile genetic elements promoting the resistance dissemination in the environment as well as the presence of heavy metals were focused in this study. The initiated heat treatment fostered a community shift from pathogenic to less pathogenic bacterial groups. Phenotypic and molecular studies demonstrated a clear reduction of multiple resistant pathogens and self-transmissible plasmids in the heat treated manure. That treatment also induced a higher release of metals and macroelements. Especially, Zn and Cu exceeded toxic thresholds. Although the concentrations of a few metals reached toxic levels after the anaerobic thermophilic treatment, the quality of poultry manure as organic fertilizer may raise significantly due to the elimination of antibiotic resistance genes (ARG) and self-transmissible plasmids.201727932039
751130.9998Antibiotic resistome promotion in drinking water during biological activated carbon treatment: Is it influenced by quorum sensing? The contamination of antibiotic resistance genes (ARGs) in drinking water may pose a direct threat to human health. This study applied high-throughput qPCR and sequencing to investigate the dynamics of ARGs and bacterial communities during the advanced treatment of drinking water using biological activated carbon. The promotion of ARGs was observed, and the normalized copy number of ARGs increased significantly after BAC treatment, raising the number of detected ARGs from 84 to 159. Twenty-nine ARGs were identified as biofilm-influencing sources in the BAC, and they persisted after chlorination. The shift of bacterial communities primarily had effects on the changes in resistome. Firmicutes, Cyanobacteria were related to persistent ARGs mostly in the BAC biofilm. Meanwhile, the Acyl-Homoserine Lactones (AHLs), quorum sensing molecules, and bacteria that produced AHLs were identified to understand the promotion of ARGs. The isolated AHL-producing bacteria belonged to the Proteobacteria, Firmicutes and Bacteroidetes phyla. Six detectable AHLs had an influence on plasmid-based horizontal gene transfer in the intragenus mating systems, indicating that the dynamics of ARGs were strongly affected by quorum sensing between specific bacteria in the biofilm. These results provide new insight into the mechanism of antibiotic resistome promotion in BAC biofilms.201828846900
698540.9997Elevated CO(2) Increased Antibiotic Resistomes in Seed Endophytes: Evidence from a Free-Air CO(2) Enrichment (FACE) Experiment. Climate warming affects antibiotic resistance genes (ARGs) in soil and the plant microbiome, including seed endophytes. Seeds act as vectors for ARG dissemination in the soil-plant system, but the impact of elevated CO(2) on seed resistomes remains poorly understood. Here, a free-air CO(2) enrichment system was used to examine the impact of elevated CO(2) on seed-associated ARGs and seed endophytic bacteria and fungi. Results indicated that elevated CO(2) levels significantly increased the relative abundance of seed ARGs and mobile genetic elements (MGEs), especially those related to beta-lactam resistance and MGEs. Increased CO(2) levels also influenced the composition of seed bacterial and fungal communities and the complexity of bacteria-fungi interactions. Fungi were more sensitive to changes in the CO(2) level than bacteria, with deterministic processes playing a greater role in fungal community assembly. Co-occurrence network analysis revealed a stronger correlation between fungi and ARGs compared to bacteria. The structure equation model (SEM) showed that elevated CO(2) directly influenced seed resistomes by altering bacterial composition and indirectly through bacteria-fungi interactions. Together, our work offers new insights into the effects of elevated CO(2) on antibiotic resistomes in the seed endosphere, highlighting their increased dissemination potential within soil-plant systems and the associated health risks in a changing environment.202439680930
693050.9997Effect of fertilizer type on antibiotic resistance genes by reshaping the bacterial community and soil properties. Conventional and bio-organic fertilizers play an important role in maintaining soil health and promoting crop growth. However, the effect of organic fertilizers on the prevalence of antibiotic resistance genes (ARGs) in the vegetable cropping system has been largely overlooked. In this study, we investigated the impacts of soil properties and biotic factors on ARG profiles by analyzing ARG and bacterial communities in vegetable copping soils with a long-term history of manure and bio-organic fertilizer application. The ARG abundance in the soil was significantly increased by 116% with manure application compared to synthetic NPK fertilizer application. This finding was corroborated by our meta-analysis that the longer the duration of manure application, the greater the response of increased soil ARG abundance. However, bio-organic fertilizers containing Trichoderma spp. Significantly reduced ARG contamination by 31% compared to manure application. About half of the ARG variation was explained by changes in bacterial abundance and structure, followed by soil properties. The mitigation of ARG by Trichoderma spp. Is achieved by altering the structure of the bacterial community and weakening the close association between bacteria and ARG prevalence. Taken together, these findings shed light on the contribution of bio-organic fertilizers in mitigating ARG contamination in agricultural soils, which can help manage the ecological risk posed by ARG inputs associated with manure application.202337343633
752360.9997Transfer of antibiotic resistance genes from soil to wheat: Role of host bacteria, impact on seed-derived bacteria, and affecting factors. The transfer of antibiotic resistance genes (ARGs) from soils to plants is poorly understood, especially the role of host bacteria in soils and its impact on seed-derived bacteria. Wheat (Triticum aestivum L.) was thus used to fill the gap by conducting pot experiments, with target ARGs and bacterial community analyzed. Results showed that the relative abundances of target ARGs gradually decreased during transfer of ARGs from the rhizosphere soil to root and shoot. Host bacteria in the rhizosphere soil were the primary source of ARGs in wheat. The 38, 21, and 19 potential host bacterial genera of target ARGs and intI1 in the rhizosphere soil, root, and shoot were identified, respectively, and they mainly belonged to phylum Proteobacteria. The abundance of ARGs carried by pathogenic Corynebacterium was reduced in sequence. During transfer of ARGs from the rhizosphere soil to root and shoot, some seed-derived bacteria and pathogenic Acinetobacter obtained ARGs through horizontal gene transfer and became potential host bacteria. Furthermore, total organic carbon, available nitrogen of the rhizosphere soil, water use efficiency, vapor pressure deficit, and superoxide dismutase of plants were identified as the key factors affecting potential host bacteria transfer in soils to wheat. This work provides important insights into transfer of ARGs and deepens our understanding of potential health risks of ARGs from soils to plants.202337741386
857970.9997Microplastics and chemical leachates from plastic pipes are associated with increased virulence and antimicrobial resistance potential of drinking water microbial communities. There is increasing recognition of the potential impacts of microplastics (MPs) on human health. As drinking water is the most direct route of human exposure to MPs, there is an urgent need to elucidate MPs source and fate in drinking water distribution system (DWDS). Here, we showed polypropylene random plastic pipes exposed to different water quality (chlorination and heating) and environmental (freeze-thaw) conditions accelerated MPs generation and chemical leaching. MPs showed various morphology and aggregation states, and chemical leaches exhibited distinct profiles due to different physicochemical treatments. Based on the physiological toxicity of leachates, oxidative stress level was negatively correlated with disinfection by-products in the leachates. Microbial network analysis demonstrated exposure to leachates (under three treatments) undermined microbial community stability and increased the relative abundance and dominance of pathogenic bacteria. Leachate physical and chemical properties (i.e., MPs abundance, hydrodynamic diameter, zeta potential, total organic carbon, dissolved ECs) exerted significant (p < 0.05) effects on the functional genes related to virulence, antibiotic resistance and metabolic pathways. Notably, chlorination significantly increased correlations among pathogenic bacteria, virulence genes, and antibiotic resistance genes. Overall, this study advances the understanding of direct and indirect risks of these MPs released from plastic pipes in the DWDS.202437935064
703480.9997Meta-analysis reveals the processes and conditions of using biochar to control antibiotic resistance genes in soil. Soil is a significant reservoir of antibiotic resistance genes (ARGs) and an important habitat for pathogens associated with many clinical infections and plant disease outbreaks. Although scientists have found that biochar can reduce ARGs in soil, the understanding of how biochar removes soil ARGs and the influencing factors remains limited. Here, a meta-analysis of 65 published studies was conducted to illuminate the mechanisms through which biochar remediates ARG-contaminated soils. In biochar-amended soil, the antibiotic content significantly decreased by 24.1 %, while the abundances of mobile genetic elements and ARG host bacteria declined by 23.5 % and 12.1 %, respectively. The reduced antibiotic content, suppressed mobile genetic elements, and altered bacterial community structure collectively led to a 41.8 % reduction in soil ARG abundance. In addition, wood-derived biochar pyrolyzed at 300-500 °C exhibited a substantial advantage in the remediation of ARGs. Furthermore, biochar application decreased the abundance of ARGs in alkaline and neutral soil more markedly than that in acidic soil. The results of this research confirmed the positive mitigating effect of biochar on ARGs in soil, providing valuable insights for the prevention and control of ARG pollution.202540359860
750990.9997Assessing biofilm formation and resistance of vibrio parahaemolyticus on UV-aged microplastics in aquatic environments. UV degradation of marine microplastics (MPs) could increase their vector potential for pathogenic bacteria and threaten human health. However, little is known about how the degree of UV aging affects interactions between MPs and pathogens and how various types of MPs differ in their impact on seafood safety. This study investigated five types of UV-aged MPs and their impact on Vibrio parahaemolyticus, a seafood pathogen. MPs exposed to UV for 60 days showed similar physicochemical changes such as surface cracking and hydrophobicity reduction. Regardless of the type, longer UV exposure of MPs resulted in more biofilm formation on the surface under the same conditions. V. parahaemolyticus types that formed biofilms on the MP surface showed 1.4- to 5.0-fold upregulation of virulence-related genes compared to those that did not form biofilms, independently of UV exposure. However, longer UV exposure increased resistance of V. parahaemolyticus on MPs to chlorine, heat, and human gastrointestinal environment. This study implies that the more UV degradation occurs on MPs, the more microbial biofilm formation is induced, which can significantly increase virulence and environmental resistance of bacteria regardless of the type of MP.202438422694
7496100.9997Effects of microplastics and tetracycline induced intestinal damage, intestinal microbiota dysbiosis, and antibiotic resistome: metagenomic analysis in young mice. Microplastics (MPs) and antibiotic tetracycline (TC) are widespread in the environment and constitute emerging combined contaminants. Young individuals are particularly vulnerable to agents that disrupt intestinal health and development. However, the combined effects of MPs and TC remain poorly understood. In this study, we developed a young mouse model exposed to polystyrene MPs, either alone or in combination with TC for 8 weeks to simulate real-life dietary exposure during early life. Our findings revealed that concurrent exposure to MPs and TC caused the most severe intestinal barrier dysfunction driven by inflammatory activation and oxidative imbalance. Moreover, exposure to MPs and TC reduced the abundance of potential probiotics while promoting the growth of opportunistic pathogens. Metagenomic analysis further indicated that co-exposure to MPs and TC enhanced the abundance of bacteria carrying either antibiotic resistance genes (ARGs) or virulence factor genes (VFGs), contributing to the widespread dissemination of potentially harmful genes. Finally, a strong positive correlation was observed between microbiota dysbiosis, ARGs, and VFGs. In general, this study highlighted the hazards of MPs and antibiotics to intestinal health in young mice, which provided a new perspective into the dynamics of pathogens, ARGs, and VFGs in early-life intestinal environments.202540328090
7505110.9997A Review on the Degradation of Antibiotic Resistance Genes During Composting of Livestock Manure. As emerging pollutants, antibiotic resistance genes (ARGs) have been recognized as originating from diverse sources. Among these, the use of livestock feed and veterinary drugs was identified as the primary source of ARGs in livestock manure. ARGs were found to be widely distributed in global environments, particularly in agriculture-related soils, water bodies, and the atmosphere, posing potential threats to ecological environments and human health. This paper reviewed the degradation mechanisms of ARGs during aerobic composting of livestock manure and the safety evaluation of compost products. Aerobic composting was demonstrated to be an effective method for degrading ARGs, primarily through mechanisms such as high-temperature elimination of ARG-carrying microorganisms, reduction in host bacterial abundance, and inhibition of horizontal gene transfer. Factors including the physicochemical properties of the composting substrate, the use of additives, and the presence of antibiotic and heavy metal residues were shown to influence the degradation efficiency of ARGs, with compost temperature being the core factor. The safety of organic fertilizers encompassed multiple aspects, including heavy metal content, seed germination index, and risk assessments based on ARG residues. The analysis indicated that deficiencies existed in areas such as the persistence of thermotolerant bacteria carrying ARGs, the dissemination of extracellular antibiotic resistance genes (eARGs), and virus-mediated gene transfer. Future research should focus on (1) the removal of thermotolerant bacteria harboring ARGs; (2) the decomposition of eARGs or the blocking of their transmission pathways; (3) the optimization of ultra-high temperature composting parameters; and (4) the analysis of interactions between viruses and resistant hosts. This study reviews the mechanisms, influencing factors, and safety assessment of aerobic composting for degrading ARGs in livestock manure. It not only deepens the understanding of this important environmental biotechnology process but also provides a crucial knowledge base and practical guidance for effectively controlling ARG pollution, ensuring agricultural environmental safety, and protecting public health. Additionally, it clearly outlines the key paths for future technological optimization, thus holding significant implications for the environment, agriculture, and public health.202540863943
7040120.9997The maturity period is the main stage of antibiotic resistance genes reduction in aerobic composting process of swine manure in sub-scale farms. This study was focused on the changes of antibiotic resistance genes (ARGs) and their potential host bacteria during the swine manure composting on sub-scale farms. Eight target ARGs increased 427% on average, with a trend of increase at early stage and decrease at later stage, and the main reduction stage appeared in maturity stage. The abundance of ARGs was mainly affected by the community succession of potential host bacteria. Composting could reduce the abundance of potential host bacteria of ARGs as well as pathogens such as Pseudomonas, and reduce the environmental risks of swine manure. N/C and S levels had a positive effect on the potential host of most ARGs. Prolonging the maturity period would inhibit the growth of potential host bacteria of ARGs during composting, therefore inhibiting the transmission of ARGs.202132971337
7559130.9997Fate of antibiotic resistance genes and resistant bacteria under various operating temperatures of sludge anaerobic digestion. This study investigates the impact of varying temperatures on reducing antibiotic resistance genes (ARGs) during anaerobic digestion (AD) of mixed raw sludge in wastewater treatment plants. Employing three different operating temperatures, i.e., 37, 55, and 65 °C, the research aims to identify how these conditions affect the diminution of resistant genes. The results, based on quantitative PCR analysis and metagenomic sequencing, show that higher temperatures significantly enhance the reduction of ARGs, with the most substantial decreases observed at 65 °C. This temperature-dependent reduction correlates with changes in the microbial community structure, where specific bacterial genera like Alicycliphilus, Macellibacteroides, Dokdonella, Ahniella, Thauera, and Zoogloea associated with ARGs exhibit decreased abundance at elevated temperatures. The study infers that AD at higher temperatures could be a more effective strategy in mitigating the spread of antibiotic resistance in the environment, suggesting a pivotal role of operational temperature in optimizing wastewater treatment processes for ARGs attenuation. The findings highlight the need for further research to refine AD protocols, aiming to minimize the environmental impact of antibiotic resistance dissemination.202540662898
8574140.9997Impact of different manure-derived dissolved organic matters on the fate of arsenic-antibiotic in co-contaminated paddy soils. Manure application increases the transfer risk of antibiotic resistance to farmland. Especially, its impact remains unclear when it occurs in arsenic (As)-contaminated paddy soils, which is considered as a global environmental problem. In this work, we investigated the fate of antibiotic resistance genes (ARGs) in As-antibiotic co-contaminated paddy soils under the application of manure from different sources (pig manure, cow dung, and chicken manure). Differences in the aliphatic carbon and electron-donating capacities of these dissolved organic matters (DOM) regulated the transformation of iron and As by both biotic and abiotic processes. The regulation by pig manure was stronger than that by cow dung and chicken manure. DOM regulation increased the abundance of As-related functional genes (arsC, arrA, aioA, and arsM) in the soil and accelerated the transformation of As speciation, the highest proportion of As(III) being 45%-61%. Meanwhile, the continuous selection pressure provided by the highly toxic As(III) increased the risk of ARGs and mobile genetic elements (MGEs) via horizontal gene transfer. As-resistant bacteria, including Bacillus, Geobacter, and Desulfitobacterium, were finally considered as potential host bacteria for ARGs and MGEs. In summary, this study clarified the synergistic mechanism of As-antibiotic on the fate of ARGs in co-contaminated paddy soils, and provided practical guidance for the proper application of organic fertilizers.202235491001
7506150.9997Risk assessment and dissemination mechanism of antibiotic resistance genes in compost. In recent years, the excessive of antibiotics in livestock and poultry husbandry, stemming from extensive industry experience, has resulted in the accumulation of residual antibiotics and antibiotic resistance genes (ARGs) in livestock manure. Composting, as a crucial approach for the utilization of manure resources, has the potential to reduce the levels of antibiotics and ARGs in manure, although complete elimination is challenging. Previous studies have primarily focused on the diversity and abundance of ARGs in compost or have solely examined the correlation between ARGs and their carriers, potentially leading to a misjudgment of the actual risk associated with ARGs in compost. To address this gap, this study investigated the transfer potential of ARGs in compost and their co-occurrence with opportunistic pathogenic bacteria by extensively analyzing metagenomic sequencing data of compost worldwide. The results demonstrated that the potential risk of ARGs in compost was significantly lower than in manure, suggesting that composting effectively reduces the risk of ARGs. Further analysis showed that the microbes shifted their life history strategy in manure and compost due to antibiotic pressure and formed metabolic interactions dominated by antibiotic-resistant microbes, increasing ARG dissemination frequency. Therefore, husbandry practice without antibiotic addition was recommended to control ARG evolution, dissemination, and abatement both at the source and throughout processing.202337562342
7452160.9997Elevation of antibiotic resistance genes at cold temperatures: implications for winter storage of sludge and biosolids. Prior research suggests that cold temperatures may stimulate the proliferation of certain antibiotic resistance genes (ARGs) and gene transfer elements during storage of biosolids. This could have important implications on cold weather storage of biosolids, as often required in northern climates until a time suitable for land application. In this study, levels of an integron-associated gene (intI1) and an ARG (sul1) were monitored in biosolids subject to storage at 4, 10 and 20°C. Both intI1 and sul1 were observed to increase during short-term storage (<2 months), but the concentrations returned to background within 4 months. The increases in concentration were more pronounced at lower temperatures than ambient temperatures. Overall, the results suggest that cold stress may induce horizontal gene transfer of integron-associated ARGs and that biosolids storage conditions should be considered prior to land application. SIGNIFICANCE AND IMPACT OF THE STUDY: Wastewater treatment plants have been identified as the hot spots for the proliferation and dissemination of antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB) to the environment through discharge of treated effluent to water bodies as well as application of biosolids to land. Identifying critical control points within the treatment process may aid in the development of solutions for the reduction of ARGs and ARB and curbing the spread of antibiotic resistance. This study found increases in ARGs during biosolids storage and identifies changes in operational protocols that could help reduce ARG loading to the environment when biosolids are land-applied.201425196177
6954170.9997Temporal effects of repeated application of biogas slurry on soil antibiotic resistance genes and their potential bacterial hosts. Biogas slurry, a liquid end product of animal manure fermentation, is widely used as fertilizer in crop fields. Land application may introduce antibiotics and related resistance genes from livestock production into agricultural soil. Nevertheless, changes in antimicrobial resistance in soil where biogas slurry has been repeatedly applied are not fully understood. In the present study, 13 veterinary antibiotics were analyzed in soils that were repeatedly sprayed with biogas slurry, and simultaneously, temporal changes in antibiotic resistance genes (ARGs) and bacterial community composition were investigated using a real-time quantitative PCR assay and MiSeq sequencing. Long-term repeated application of biogas slurry did not result in excessive accumulation of antibiotic residuals in the soil but increased the abundance of ARGs and facilitated ARG transfer among potential hosts. Although the quantitative PCR assay showed a decreasing trend for the relative abundance of ARGs over time, a relevance network analysis revealed highly complex bacteria-ARG co-occurrence after long-term application, which implied that repeated application might intensify horizontal gene transfer (HGT) of ARGs among different bacterial hosts in soil. The increased relative abundance of the intl1 gene supported the shift in ARG-bacteria co-occurrence. Furthermore, ordination analysis showed that the distributions of antibiotic resistance bacteria (ARB) and ARGs were closely related to application duration than to the influence of antibiotic residuals in the biogas slurry-treated soil environment. Additionally, natural level of ARG abundance in untreated soils indirectly suggested the presence/absence of antibiotics was not a key determinant causing the spread of antimicrobial resistance. This study provides improved insight into the effects of long-term repeated application of biogas slurry on the shift in ARG abundances and bacteria-ARG co-occurrence in soils, highlighting the need to focus on the influence of changed soil environment on the ARG transfer.202031818620
6961180.9997Impacts of supplementing chemical fertilizers with organic fertilizers manufactured using pig manure as a substrate on the spread of tetracycline resistance genes in soil. Using pig manure (PM) compost as a partial substitute for the conventional chemical fertilizers (CFs) is considered an effective approach in sustainable agricultural systems. This study aimed to analyze the impacts of supplementing CF with organic fertilizers (OFs) manufactured using pig manure as a substrate on the spread of tetracycline resistance genes (TRGs) as well as the community structures and diversities of tetracycline-resistant bacteria (TRB) in bulk and cucumber rhizosphere soils. In this study, three organic fertilizers manufactured using the PM as a substrate, namely fresh PM, common OF, and bio-organic fertilizer (BF), were supplemented with a CF. Composted manures combined with a CF did not significantly increase TRB compared with the CF alone, but PM treatment resulted in the long-term survival of TRB in soil. The use of CF+PM also increased the risk of spreading TRGs in soil. As beneficial microorganisms in BF may function as reservoirs for the spread of antibiotic resistance genes, care should be taken when adding them to the OF matrix. The PM treatment significantly altered the community structures and increased the species diversity of TRB, especially in the rhizosphere soil. BF treatment caused insignificant changes in the community structure of TRB compared with CF treatment, yet it reduced the species diversities of TRB in soil. Thus, the partial use of fresh PM as a substitute for CF could increase the risk of spread of TRGs. Apart from plant growth promotion, BF was a promising fertilizer owing to its potential ability to control TRGs.201627152658
6815190.9997Bacterial community succession and the enrichment of antibiotic resistance genes on microplastics in an oyster farm. Microplastics can be colonized by microorganisms and form plastisphere. However, knowledge of bacterial community succession and the enrichment of antibiotic resistance genes (ARGs) and pathogens on microplastics in aquaculture environments is limited. Here, we conducted a 30-day continuous exposure experiment at an oyster farm. Results showed that the alpha-diversity of communities on most microplastics continuously increased and was higher than in planktonic communities after 14 days. Microplastics could selectively enrich certain bacteria from water which can live a sessile lifestyle and promote colonization by other bacteria. The composition and function of plastisphere communities were distinct from those in the surrounding water and influenced by polymer type and exposure time. Microplastics can enrich ARGs (sul1, qnrS and bla(TEM)) and harbor potential pathogens (e.g., Pseudomonas aeruginosa). Therefore, microplastic pollution may pose a critical threat to aquaculture ecosystems and human health. Our study provides further insight into the ecological risks of microplastics.202337611336