Metagenomic Views of Microbial Communities in Sand Sediments Associated with Coral Reefs. - Related Documents




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766501.0000Metagenomic Views of Microbial Communities in Sand Sediments Associated with Coral Reefs. Reef sediments, the home for microbes with high abundances, provide an important source of carbonates and nutrients for the growth and maintenance of coral reefs. However, there is a lack of systematic research on the composition of microbial community in sediments of different geographic sites and their potential effect on nutrient recycling and health of the coral reef ecosystem. In combination of biogeochemical measurements with gene- and genome-centric metagenomics, we assessed microbial community compositions and functional diversity, as well as profiles of antibiotic resistance genes in surface sediments of 16 coral reef sites at different depths from the Xisha islands in the South China Sea. Reef sediment microbiomes are diverse and novel at lower taxonomic ranks, dominated by Proteobacteria and Planctomycetota. Most reef sediment bacteria potentially participate in biogeochemical cycling via oxidizing various organic and inorganic compounds as energy sources. High abundances of Proteobacteria (mostly Rhizobiales and Woeseiales) are metabolically flexible and contain rhodopsin genes. Various classes of antibiotic resistance genes, hosted by diverse bacterial lineages, were identified to confer resistance to multidrug, aminoglycoside, and other antibiotics. Overall, our findings expanded the understanding of reef sediment microbial ecology and provided insights for their link to the coral reef ecosystem health.202335113183
642910.9996Selective enrichment of bacteria and antibiotic resistance genes in microplastic biofilms and their potential hazards in coral reef ecosystems. Microplastics become hotspots for bacteria to trigger a series of ecological effects, but few studies have focused on the potential impacts of microplastic biofilms in coral reef ecosystems. Here, we measured the bacterial communities and antibiotic resistance genes (ARGs) in the seawater and microplastic biofilms. Results showed that microbial biofilms were formed on the surface of microplastics. The alpha diversity of the bacterial community in the microplastic biofilms was lower than that in the seawater, and the bacterial communities were distinct between the two. Further analysis revealed that several bacteria in the microplastic biofilms carried ARGs, and the proportion of which was correlated to the concentration of antibiotics in the seawater. Specifically, Vibrio was positively correlated to sul1 in the microplastic biofilms under higher concentrations of sulfonamides. Pathway analysis reflected significant overrepresentation of human disease related pathways in the bacterial community of microplastic biofilms. These results suggest that the microplastic biofilms could selectively enrich bacteria from the reef environments, causing the development of ARGs under antibiotic driving. This may pose a serious threat to coral reef ecosystems and human health. Our study provides new insights into the ecological impacts of microplastic biofilms in coral reef ecosystems.202438281603
737320.9995Distributional Pattern of Bacteria, Protists, and Diatoms in Ocean according to Water Depth in the Northern South China Sea. Ocean microbiomes provide insightful details about the condition of water and the global impact of marine ecosystems. A fine-scale analysis of ocean microbes may shed light on the dynamics and function of the ocean microbiome community. In this study, we evaluated the changes in the community and function of marine bacteria, protists, and diatoms corresponding to different ocean depths using next-generation sequencing methods. We found that diatoms displayed a potential water-depth pattern in species richness (alpha diversity) and community composition (beta diversity). However, for bacteria and protists, there was no significant relationship between water depth and species richness. This may be related to the biological characteristics of diatoms. The photosynthesis of diatoms and their distribution may be associated with the fluctuating light regime in the underwater climate. Moreover, salinity displayed negative effects on the abundance of some diatom and bacterial groups, which indicates that salinity may be one of the factors restricting ocean microorganism diversity. In addition, compared to the global ocean microbiome composition, function, and antibiotic resistance genes, a water depth pattern due to the fine-scale region was not observed in this study. IMPORTANCE Fine-scale analysis of ocean microbes provides insights into the dynamics and functions of the ocean microbiome community. Here, using amplicon and metagenome sequencing methods, we found that diatoms in the northern South China Sea displayed a potential water-depth pattern in species richness and community composition, which may be related to their biological characteristics. The potential effects of the differences in geographic sites mainly occurred in the diatom and bacterial communities. Moreover, given the correlation between the environmental factors and relative abundance of antibiotic resistance genes (ARGs), the study of ocean ARG distribution patterns should integrate the potential effects of environmental factors.202236222702
866330.9995CPR bacteria and DPANN archaea play pivotal roles in response of microbial community to antibiotic stress in groundwater. The accumulation of antibiotics in the natural environment can disrupt microbial population dynamics. However, our understanding of how microbial communities adapt to the antibiotic stress in groundwater ecosystems remains limited. By recovering 2675 metagenome-assembled genomes (MAGs) from 66 groundwater samples, we explored the effect of antibiotics on bacterial, archaeal, and fungal communities, and revealed the pivotal microbes and their mechanisms in coping with antibiotic stress. The results indicated that antibiotics had the most significant influence on bacterial and archaeal communities, while the impact on the fungal community was minimal. Analysis of co-occurrence networks between antibiotics and microbes revealed the critical roles of Candidate Phyla Radiation (CPR) bacteria and DPANN archaea, two representative microbial groups in groundwater ecosystem, in coping with antibiotic resistance and enhancing network connectivity and complexity. Further genomic analysis demonstrated that CPR bacteria carried approximately 6 % of the identified antibiotic resistance genes (ARGs), indicating their potential to withstand antibiotics on their own. Meanwhile, the genomes of CPR bacteria and DPANN archaea were found to encode diverse biosynthetic gene clusters (BGCs) responsible for producing antimicrobial metabolites, which could not only assist CPR and DPANN organisms but also benefit the surrounding microbes in combating antibiotic stress. These findings underscore the significant impact of antibiotics on prokaryotic microbial communities in groundwater, and highlight the importance of CPR bacteria and DPANN archaea in enhancing the overall resilience and functionality of the microbial community in the face of antibiotic stress.202438246077
747640.9995Bacterial phylogeny structures soil resistomes across habitats. Ancient and diverse antibiotic resistance genes (ARGs) have previously been identified from soil, including genes identical to those in human pathogens. Despite the apparent overlap between soil and clinical resistomes, factors influencing ARG composition in soil and their movement between genomes and habitats remain largely unknown. General metagenome functions often correlate with the underlying structure of bacterial communities. However, ARGs are proposed to be highly mobile, prompting speculation that resistomes may not correlate with phylogenetic signatures or ecological divisions. To investigate these relationships, we performed functional metagenomic selections for resistance to 18 antibiotics from 18 agricultural and grassland soils. The 2,895 ARGs we discovered were mostly new, and represent all major resistance mechanisms. We demonstrate that distinct soil types harbour distinct resistomes, and that the addition of nitrogen fertilizer strongly influenced soil ARG content. Resistome composition also correlated with microbial phylogenetic and taxonomic structure, both across and within soil types. Consistent with this strong correlation, mobility elements (genes responsible for horizontal gene transfer between bacteria such as transposases and integrases) syntenic with ARGs were rare in soil by comparison with sequenced pathogens, suggesting that ARGs may not transfer between soil bacteria as readily as is observed between human pathogens. Together, our results indicate that bacterial community composition is the primary determinant of soil ARG content, challenging previous hypotheses that horizontal gene transfer effectively decouples resistomes from phylogeny.201424847883
643050.9995Plastic leachate exposure drives antibiotic resistance and virulence in marine bacterial communities. Plastic pollution is a serious global problem, with more than 12 million tonnes of plastic waste entering the oceans every year. Plastic debris can have considerable impacts on microbial community structure and functions in marine environments, and has been associated with an enrichment in pathogenic bacteria and antimicrobial resistance (AMR) genes. However, our understanding of these impacts is largely restricted to microbial assemblages on plastic surfaces. It is therefore unclear whether these effects are driven by the surface properties of plastics, providing an additional niche for certain microbes residing in biofilms, and/or chemicals leached from plastics, the effects of which could extend to surrounding planktonic bacteria. Here, we examine the effects of polyvinyl chloride (PVC) plastic leachate exposure on the relative abundance of genes associated with bacterial pathogenicity and AMR within a seawater microcosm community. We show that PVC leachate, in the absence of plastic surfaces, drives an enrichment in AMR and virulence genes. In particular, leachate exposure significantly enriches AMR genes that confer multidrug, aminoglycoside and peptide antibiotic resistance. Additionally, enrichment of genes involved in the extracellular secretion of virulence proteins was observed among pathogens of marine organisms. This study provides the first evidence that chemicals leached from plastic particles alone can enrich genes related to microbial pathogenesis within a bacterial community, expanding our knowledge of the environmental impacts of plastic pollution with potential consequences for human and ecosystem health.202337019264
751860.9995Deciphering the toxic effects of metals in gold mining area: Microbial community tolerance mechanism and change of antibiotic resistance genes. Mine tailing dumps represent significant threats to ecological environments due to the presence of toxic substances. The present work investigated the relationship among microbial activity, the community, antibiotic resistance genes (ARGs) and trace metals in soil surrounding gold mine tailings. Using microbial metabolic activity and high-throughput sequencing analysis, we found the trace metals Cd and Hg could be main factors influencing the microbial community. According to bacterial co-occurrence pattern analysis, the effects of total cadmium and total mercury on bacterial diversity are potentially mediated by influencing bacteria community in the keystone module II. Additionally, most of metal-resistant bacteria belong to Actinobacteria and Proteobacteria, and the metal tolerance suggested to be linked with various functions including replication, recombination and repair, as well as inorganic ion transport and metabolism based on PICRUSt2 analysis. We also found that metals generated by mining activity may trigger the co-selection of antibiotic resistance in the phyla Actinobacteria and Proteobacteria due to co-resistance or cross resistance. Additionally, PLS-PM analysis revealed that metals could indirectly affect ARGs by influencing bacterial diversity in gold mining areas.202032678731
766470.9995A catalog of metagenome-assembled genomes from Amazonian forest and pasture soils. The Amazon rainforest is facing multifaceted anthropogenic pressures, and we previously showed that forest-to-pasture conversion has led to soil microbial communities with distinct genomic traits. Here, we present 69 archaeal and bacterial metagenome-assembled genomes and detail their virulence- and antimicrobial resistance-associated genes.202541036867
748680.9995Body size: A hidden trait of the organisms that influences the distribution of antibiotic resistance genes in soil. Body size is a key life-history trait of organisms, which has important ecological functions. However, the relationship between soil antibiotic resistance gene (ARG) distribution and organisms' body size has not been systematically reported so far. Herein, the impact of organic fertilizer on the soil ARGs and organisms (bacteria, fungi, and nematode) at the aggregate level was analyzed. The results showed that the smaller the soil aggregate size, the greater the abundance of ARGs, and the larger the body size of bacteria and nematodes. Further analysis revealed significant positive correlations of ARG abundance with the body sizes of bacteria, fungi, and nematodes, respectively. Additionally, the structural equation model demonstrated that changes in soil fertility mainly regulate the ARG abundance by affecting bacterial body size. The random forest model revealed that total phosphorus was the primary soil fertility factor influencing the body size of organisms. Therefore, these findings proposed that excessive application of phosphate fertilizers could increase the risk of soil ARG transmission by increasing the body size of soil organisms. This study highlights the significance of organisms' body size in determining the distribution of soil ARGs and proposes a new disadvantage of excessive fertilization from the perspective of ARGs.202438696961
737590.9995Assessing microbial ecology and antibiotic resistance genes in river sediments. Anthropogenic activities greatly affect the Karon River leading to deterioration of water quality. This investigation utilizes environmental genomic techniques to delineate microbial populations, examine functional genomics, and evaluate the occurrence of virulence determinants and antibiotic resistance genes (ARGs) in fluvial sediment. Taxonomic assessment identified that Firmicutes were the predominant phyla, with Bacillus being the most abundant genus across samples. Functional analysis revealed the metabolic capabilities of sediment-associated bacteria, linking them to biogeochemical processes and potential health impacts. The S2 samples exhibited the highest virulence factor genes, while the S3 samples had the most ARGs (30), highlighting concerns about pathogenicity. Analyzing ARGs provides critical insights into environmental data collected, such as water quality parameters (e.g., nutrient concentrations, pH) or pollution levels, prevalence, and distribution of these resistance factors within the sediment samples, helping to identify potential hotspots of antibiotic resistance in the Karon River ecosystem. The study identified similar operational taxonomic units (OTUs) across sampling sites at the phylogenetic level, indicating a consistent presence of certain microbial taxa. However, the lack of variation in functional classification suggests that while these taxa may be present, they are not exhibiting significant differences in metabolic capabilities or functional roles. These findings emphasize the significance of metagenomic methods in understanding microbial ecology and antibiotic resistance in aquatic environments, suggesting a need for further research into the restoration of microbial functions related to ARGs and virulence factors.202540127879
6975100.9995The composition of antibiotic resistance genes is not affected by grazing but is determined by microorganisms in grassland soils. Grazing is expected to exert a substantial influence on antibiotic resistance genes (ARGs) in grassland ecosystems. However, the precise effects of grazing on the composition of ARGs in grassland soils remain unclear. This is especially the case for grassland soils subject to long-term grazing. Here, we investigated ARGs and bacterial community composition in soils subject to long-term historic grazing (13-39 years) and corresponding ungrazed samples. Using a combination of shotgun metagenomics, amplicon analyses and associated soil physicochemical data, we provide novel insights regarding the structure of ARGs in grassland soils. Interestingly, our analysis revealed that long-term historic grazing had no impacts on the composition of ARGs in grassland soils. An average of 378 ARGs, conferring resistance to 14 major categories of antibiotics (80%), were identified in both grazing and ungrazed sites. Actinobacteria, Proteobacteria and Acidobacteria were the most prevalent predicted hosts in these soils and were also shown to harbour genetic capacity for multiple-resistant ARGs. Our results suggested that positive effects of bacterial community composition on ARGs could potentially be controlled by affecting MGEs. Soil properties had direct effects on the composition of ARGs through affecting the frequency of horizontal gene transfer among bacteria. Twelve novel ARGs were found in S. grandis steppe grasslands, indicating that different vegetation types might induce shifts in soil ARGs. Collectively, these findings suggest that soil properties, plants and microorganisms play critical roles in shaping ARG patterns in grasslands. Together, these data establish a solid baseline for understanding environmental antibiotic resistance in grasslands.202133187698
7470110.9995Oil-contaminated sites act as high-risk pathogen reservoirs previously overlooked in coastal zones. In addition to the organic pollutants and disturbance to the microbial, plant and animal systems, oil contamination can also enrich opportunistic pathogens. But little is known about whether and how the most common coastal oil-contaminated water bodies act as reservoirs for pathogens. Here, we delved into the characteristics of pathogenic bacteria in coastal zones by constructing seawater-based microcosms with diesel oil as a pollutant. 16S rRNA gene full-length sequencing and genomic exploration revealed that pathogenic bacteria with genes involved in alkane or aromatic degradation were significantly enriched under oil contamination, providing a genetic basis for them to thrive in oil-contaminated seawater. Moreover, high-throughput qPCR assays showed an increased abundance of the virulence gene and enrichment in antibiotics resistance genes (ARGs), especially those related to multidrug resistance efflux pumps, and their high relevance to Pseudomonas, enabling this genus to achieve high levels of pathogenicity and environmental adaptation. More importantly, infection experiments with a culturable P. aeruginosa strain isolated from an oil-contaminated microcosm provided clear evidence that the environmental strain was pathogenic to grass carp (Ctenopharyngodon idellus), and the highest lethality rate was found in the oil pollutant treatment, demonstrating the synergistic effect of toxic oil pollutants and pathogens on infected fish. A global genomic investigation then revealed that diverse environmental pathogenic bacteria with oil degradation potential are widely distributed in marine environments, especially in coastal zones, suggesting extensive pathogenic reservoir risks in oil-contaminated sites. Overall, the study uncovered a hidden microbial risk, showing that oil-contaminated seawater could be a high-risk pathogen reservoir, and provides new insights and potential targets for environmental risk assessment and control.202337329716
7483120.9995Enrichment of antibiotic resistance genes (ARGs) in polyaromatic hydrocarbon-contaminated soils: a major challenge for environmental health. Polyaromatic hydrocarbons (PAHs) are widely spread ecological contaminants. Antibiotic resistance genes (ARGs) are present with mobile genetic elements (MGE) in the bacteria. There are molecular evidences that PAHs may induce the development of ARGs in contaminated soils. Also, the abundance of ARGs related to tetracycline, sulfonamides, aminoglycosides, ampicillin, and fluoroquinolones is high in PAH-contaminated environments. Genes encoding the efflux pump are located in the MGE and, along with class 1 integrons, have a significant role as a connecting link between PAH contamination and enrichment of ARGs. The horizontal gene transfer mechanisms further make this interaction more dynamic. Therefore, necessary steps to control ARGs into the environment and risk management plan of PAHs should be enforced. In this review, influence of PAH on evolution of ARGs in the contaminated soil, and its spread in the environment, has been described. The co-occurrence of antibiotic resistance and PAH degradation abilities in bacterial isolates has raised the concerns. Also, presence of ARGs in the microbiome of PAH-contaminated soil has been discussed as environmental hotspots for ARG spread. In addition to this, the possible links of molecular interactions between ARGs and PAHs, and their effect on environmental health has been explored.202133394421
6431130.9995The dynamics and transmission of antibiotic resistance associated with plant microbiomes. Antibiotic resistance genes (ARGs) have been widely found and studied in soil and water environments. However, the propagation of ARGs in plant microbiomes has attracted insufficient attention. Plant microbiomes, especially the rhizosphere microorganisms, are closely connected with water, soil, and air, which allows ARGs to spread widely in ecosystems and pose a threat to human health after entering the human body with bacteria. Therefore, it is necessary to deeply understand and explore the dynamics and the transmission of ARGs in rhizosphere microorganisms and endophytes of plants. In this review, the transmission and influencing factors of ARGs in the microorganisms associated with plants, especially the influence of root exudates on plant microbiomes, are analyzed. Notably, the role of intrinsic genes of plants in determining root exudates and their potential effects on ARGs are proposed and analyzed. The important role of phyllosphere microorganisms and endophytes in the transmission of ARGs and co-resistance of antibiotics and other substances are also emphasized. The proliferation and transmission of ARGs associated with plant microbiomes addressed in this review is conducive to revealing the fate of ARGs in plant microorganisms and alleviating ARG pollution.202337257204
7485140.9994Fungal networks serve as novel ecological routes for enrichment and dissemination of antibiotic resistance genes as exhibited by microcosm experiments. Antibiotic resistance genes (ARGs) in the environment and their subsequent acquisition by clinically important microorganisms are a serious concern. However, the spread of environmental ARGs remain largely unknown. We report, for the first time, the involvement of soil fungi in the distribution of bacteria with ARGs via soil microcosms. qPCR assay detected unique ARGs specifically found in the mycosphere of different fungi. Interestingly, the taxonomically and ecologically different fungi exerted different selection pressures on ARGs originating from the same source. Test fungi supported different antibiotic resistance bacteria enriched in the mycosphere and even transported to distant places. The relative abundance of the tnpA gene decreased, for manure, along mycelial networks of all fungi. While the fungal strain NFC-5 enriched the intI1 gene more, opposite to two other fungi at the migration front compared with the inoculation point for both sources. Such data indicate the differential effect of different fungi to facilitate horizontal gene transfer potential under fungal selection pressure. Our study provides the evidence that fungi can contribute ARGs, host bacterial diversity and abundance, and such interactive microbial consortia have the potential to disseminate the resistance determinants from one place to another, thus increasing the ARGs exposure risk to humans.201729133838
6831150.9994Diversity of herbaceous plants and bacterial communities regulates soil resistome across forest biomes. Antibiotic resistance is ancient and prevalent in natural ecosystems and evolved long before the utilization of synthetic antibiotics started, but factors influencing the large-scale distribution patterns of natural antibiotic resistance genes (ARGs) remain largely unknown. Here, a large-scale investigation over 4000 km was performed to profile soil ARGs, plant communities and bacterial communities from 300 quadrats across five forest biomes with minimal human impact. We detected diverse and abundant ARGs in forests, including over 160 genes conferring resistance to eight major categories of antibiotics. The diversity of ARGs was strongly and positively correlated with the diversity of bacteria, herbaceous plants and mobile genetic elements (MGEs). The ARG composition was strongly correlated with the taxonomic structure of bacteria and herbs. Consistent with this strong correlation, structural equation modelling demonstrated that the positive effects of bacterial and herb communities on ARG patterns were maintained even when simultaneously accounting for multiple drivers (climate, spatial predictors and edaphic factors). These findings suggest a paradigm that the interactions between aboveground and belowground communities shape the large-scale distribution of soil resistomes, providing new knowledge for tackling the emerging environmental antibiotic resistance.201829687575
7462160.9994A global atlas of marine antibiotic resistance genes and their expression. Oceans serve as global reservoirs of antibiotic-resistant bacteria and antibiotic resistance genes (ARGs). However, little is known about the traits and expression of ARGs in response to environmental factors. We analyzed 347 metagenomes and 182 metatranscriptomes to determine the distribution, hosts, and expression of ARGs in oceans. Our study found that the diversity and abundance of ARGs varied with latitude and depth. The core marine resistome mainly conferred glycopeptide and multidrug resistance. The hosts of this resistome were mainly limited to the core marine microbiome, with phylogenetic barriers to the horizontal transfer of ARGs, transfers being more frequent within species than between species. Sixty-five percent of the marine ARGs identified were expressed. More than 90% of high-risk ARGs were more likely to be expressed. Anthropogenic activity might affect the expression of ARGs by altering nitrate and phosphate concentrations and ocean temperature. Machine-learning models predict >97% of marine ARGs will change expression by 2100. High-risk ARGs will shift to low latitudes and regions with high anthropogenic activity, such as the Pacific and Atlantic Oceans. Certain ARGs serve a dual role in antibiotic resistance and potentially participate in element cycling, along with other unknown functions. Determining whether changes in ARG expression are beneficial to ecosystems and human health is challenging without comprehensive understanding of their functions. Our study identified a core resistome in the oceans and quantified the expression of ARGs for the development of future control strategies under global change.202337604017
6480170.9994Antibiotics in the Soil Environment-Degradation and Their Impact on Microbial Activity and Diversity. Antibiotics play a key role in the management of infectious diseases in humans, animals, livestock, and aquacultures all over the world. The release of increasing amount of antibiotics into waters and soils creates a potential threat to all microorganisms in these environments. This review addresses issues related to the fate and degradation of antibiotics in soils and the impact of antibiotics on the structural, genetic and functional diversity of microbial communities. Due to the emergence of bacterial resistance to antibiotics, which is considered a worldwide public health problem, the abundance and diversity of antibiotic resistance genes (ARGs) in soils are also discussed. When antibiotic residues enter the soil, the main processes determining their persistence are sorption to organic particles and degradation/transformation. The wide range of DT50 values for antibiotic residues in soils shows that the processes governing persistence depend on a number of different factors, e.g., physico-chemical properties of the residue, characteristics of the soil, and climatic factors (temperature, rainfall, and humidity). The results presented in this review show that antibiotics affect soil microorganisms by changing their enzyme activity and ability to metabolize different carbon sources, as well as by altering the overall microbial biomass and the relative abundance of different groups (i.e., Gram-negative bacteria, Gram-positive bacteria, and fungi) in microbial communities. Studies using methods based on analyses of nucleic acids prove that antibiotics alter the biodiversity of microbial communities and the presence of many types of ARGs in soil are affected by agricultural and human activities. It is worth emphasizing that studies on ARGs in soil have resulted in the discovery of new genes and enzymes responsible for bacterial resistance to antibiotics. However, many ambiguous results indicate that precise estimation of the impact of antibiotics on the activity and diversity of soil microbial communities is a great challenge.201930906284
8648180.9994Host-specific assembly of phycosphere microbiome and enrichment of the associated antibiotic resistance genes: Integrating species of microalgae hosts, developmental stages and water contamination. Phytoplankton-bacteria interactions profoundly impact ecosystem function and biogeochemical cycling, while their substantial potential to carry and disseminate antibiotic resistance genes (ARGs) poses a significant threat to global One Health. However, the ecological paradigm behind the phycosphere assembly of microbiomes and the carrying antibiotic resistomes remains unclear. Our field investigation across various freshwater ecosystems revealed a substantial enrichment of bacteria and ARGs within microalgal niches. Taking account of the influence for species of microalgae hosts, their developmental stages and the stress of water pollution, we characterized the ecological processes governing phycosphere assembly of bacterial consortia and enrichment of the associated ARGs. By inoculating 6 axenic algal hosts with two distinct bacterial consortia from a natural river and the phycosphere of Scenedesmus acuminatus, we observed distinct phycosphere bacteria recruitment among different algal species, yet consistency within the same species. Notably, a convergent bacterial composition was established for the same algae species for two independent inoculations, demonstrating host specificity in phycosphere microbiome assembly. Host-specific signature was discernible as early as the algal lag phase and more pronounced as the algae developed, indicating species types of algae determined mutualism between the bacterial taxa and hosts. The bacteria community dominated the shaping of ARG profiles within the phycosphere and the host-specific phycosphere ARG enrichment was intensified with the algae development. The polluted water significantly stimulated host's directional selection on phycosphere bacterial consortia and increased the proliferation antibiotic resistome. These consortia manifested heightened beneficial functionality, enhancing microalgal adaptability to contamination stress.202540349825
6428190.9994Effluents of wastewater treatment plants promote the rapid stabilization of the antibiotic resistome in receiving freshwater bodies. Treated wastewater discharged into the environment acts as a disturbance of the natural microbial communities in terms of taxonomic composition and of functional gene pool, including antibiotic resistance genes. We tested whether stochastic and heterogeneous site-specific trajectories or generalities, potentially driven by deterministic processes, control the fate of allochthonous bacteria from anthropogenic sources and the persistence of their functional traits in freshwater. Finding generalities would allow the identification of wastewater treatments that could be effective in abating determinants of antibiotic resistance. We analysed the short-term response of native bacterial communities in waters exposed to the disturbance of wastewater at different dilutions, using a metagenomic approach that revealed both microbial community composition and the scope and abundance of the resistome that can pose indirect risks to human health. We found that the taxonomic composition of the communities after the disturbance was driven by case-specific stochastic processes, whereas the resistome had a deterministic trajectory, rapidly stabilising its functional traits with higher proportions of wastewater effluents, regardless of differences in taxonomic composition, richness of antibiotic resistance genes and of bacterial taxa, phenotypic features of the bacterial communities, and type of wastewater treatment. The observed deterministic proliferation of resistomes in freshwater bodies receiving wastewater effluents, suggests that this process may contribute to the global propagation of antibiotic resistance, and thus calls for new legislations promoting alternative tertiary treatments for the wastewater reuse, and targeting bacterial functional traits and not only bacterial abundances.201931015144