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812700.9753Microbial Multitrophic Communities Drive the Variation of Antibiotic Resistome in the Gut of Soil Woodlice (Crustacea: Isopoda). Multitrophic communities inhabit in soil faunal gut, including bacteria, fungi, and protists, which have been considered a hidden reservoir for antibiotic resistance genes (ARGs). However, there is a dearth of research focusing on the relationships between ARGs and multitrophic communities in the gut of soil faunas. Here, we studied the contribution of multitrophic communities to variations of ARGs in the soil woodlouse gut. The results revealed diverse and abundant ARGs in the woodlouse gut. Network analysis further exhibited strong connections between key ecological module members and ARGs, suggesting that multitrophic communities in the keystone ecological cluster may play a pivotal role in the variation of ARGs in the woodlouse gut. Moreover, long-term application of sewage sludge significantly altered the woodlice gut resistome and interkingdom communities. The variation portioning analysis indicated that the fungal community has a greater contribution to variations of ARGs than bacterial and protistan communities in the woodlice gut after long-term application of sewage sludge. Together, our results showed that changes in gut microbiota associated with agricultural practices (e.g., sewage sludge application) can largely alter the gut interkingdom network in ecologically relevant soil animals, with implications for antibiotic resistance, which advances our understanding of the microecological drivers of ARGs in terrestrial ecosystem.202235876241
812010.9753Insight into the fate of antibiotic resistance genes and bacterial community in co-composting green tea residues with swine manure. Green tea residues (GTRs) are byproducts of tea production and processing, and this type of agricultural waste retains nutritious components. This study investigated the co-composting of GTRs with swine manure, as well as the effects of GTRs on antibiotic resistance genes (ARGs) and the bacterial community during co-composting. The temperature and C/N ratio indicate compost was mature after processing. The addition of GTRs effectively promoted the reduction in the abundances of most targeted ARGs (tet and sul genes), mobile genetic element (MGE; intI1), and metal resistance genes (MRGs; pcoA and tcrB). Redundancy analysis (RDA) showed that GTRs can reduce the abundance of MRGs and ARGs by reducing the bioavailability of heavy metals. Network analysis shows that Firmicutes and Actinobacteria were the main hosts of ARGs and ARGs, MGEs, and MRGs shared the same potential host bacteria. Adding GTRs during composting may reduce ARGs transmission through horizontal gene transfer (HGT). GTRs affected the bacterial community, thereby influencing the variations in the ARG profiles and reducing the potential risk associated with the compost product.202032310121
691120.9753Linking bacterial life strategies with the distribution pattern of antibiotic resistance genes in soil aggregates after straw addition. Straw addition markedly affects the soil aggregates and microbial community structure. However, its influence on the profile of antibiotic resistance genes (ARGs), which are likely associated with changes in bacterial life strategies, remains unclear. To clarify this issue, a soil microcosm experiment was incubated under aerobic (WS) or anaerobic (AnWS) conditions after straw addition, and metagenomic sequencing was used to characterise ARGs and bacterial communities in soil aggregates. The results showed that straw addition shifted the bacterial life strategies from K- to r-strategists in all aggregates, and the aerobic and anaerobic conditions stimulated the growth of aerobic and anaerobic r-strategist bacteria, respectively. The WS decreased the relative abundances of dominant ARGs such as QnrS5, whereas the AnWS increased their abundance. After straw addition, the macroaggregates consistently exhibited a higher number of significantly altered bacteria and ARGs than the silt+clay fractions. Network analysis revealed that the WS increased the number of aerobic r-strategist bacterial nodes and fostered more interactions between r-and K-strategist bacteria, thus promoting ARGs prevalence, whereas AnWS exhibited an opposite trend. These findings provide a new perspective for understanding the fate of ARGs and their controlling factors in soil ecosystems after straw addition. ENVIRONMENTAL IMPLICATIONS: Straw soil amendment has been recommended to mitigate soil fertility degradation, improve soil structure, and ultimately increase crop yields. However, our findings highlight the importance of the elevated prevalence of ARGs associated with r-strategist bacteria in macroaggregates following the addition of organic matter, particularly fresh substrates. In addition, when assessing the environmental risk posed by ARGs in soil that receives crop straw, it is essential to account for the soil moisture content. This is because the species of r-strategist bacteria that thrive under aerobic and anaerobic conditions play a dominant role in the dissemination and accumulation of ARG.202438643583
692130.9752Impacts of Chemical and Organic Fertilizers on the Bacterial Communities, Sulfonamides and Sulfonamide Resistance Genes in Paddy Soil Under Rice-Wheat Rotation. The responses of sulfonamides, sulfonamide-resistance genes (sul) and soil bacterial communities to different fertilization regimes were investigated by performing a field experiment using paddy soil with no fertilizer applied, chemical fertilizer applied, organic fertilizer applied, and combination of chemical and organic fertilizer applied. Applying organic fertilizer increased the bacterial community diversity and affected the bacterial community composition. Eutrophic bacteria (Bacteroidetes, Gemmatimonadetes, and Proteobacteria) were significantly enriched by applying organic fertilizer. It was also found organic fertilizer application increased sulfamethazine content and the relative abundances of sul1 and sul2 in the soil. In contrast, applying chemical fertilizer significantly increased the abundance of Nitrospirae, Parcubacteria, and Verrucomicrobia and caused no obvious changes on sul. Correlation analysis indicated that sul enrichment was associated with the increases in sulfamethazine content and potential hosts (e.g., Novosphingobium and Rhodoplanes) population. The potential ecological risks of antibiotics in paddy soil with organic fertilizer applied cannot be ignored.202236547725
871440.9751Tales from the tomb: the microbial ecology of exposed rock surfaces. Although a broad diversity of eukaryotic and bacterial taxa reside on rock surfaces where they can influence the weathering of rocks and minerals, these communities and their contributions to mineral weathering remain poorly resolved. To build a more comprehensive understanding of the diversity, ecology and potential functional attributes of microbial communities living on rock, we sampled 149 tombstones across three continents and analysed their bacterial and eukaryotic communities via marker gene and shotgun metagenomic sequencing. We found that geographic location and climate were important factors structuring the composition of these communities. Moreover, the tombstone-associated microbial communities varied as a function of rock type, with granite and limestone tombstones from the same cemeteries harbouring taxonomically distinct microbial communities. The granite and limestone-associated communities also had distinct functional attributes, with granite-associated bacteria having more genes linked to acid tolerance and chemotaxis, while bacteria on limestone were more likely to be lichen associated and have genes involved in photosynthesis and radiation resistance. Together these results indicate that rock-dwelling microbes exhibit adaptations to survive the stresses of the rock surface, differ based on location, climate and rock type, and seem pre-disposed to different ecological strategies (symbiotic versus free-living lifestyles) depending on the rock type.201829235707
713150.9751Longitudinal study of the short- and long-term effects of hospitalisation and oral trimethoprim-sulfadiazine administration on the equine faecal microbiome and resistome. BACKGROUND: Hospitalisation and antimicrobial treatment are common in horses and significantly impact the intestinal microbiota. Antimicrobial treatment might also increase levels of resistant bacteria in faeces, which could spread to other ecological compartments, such as the environment, other animals and humans. In this study, we aimed to characterise the short- and long-term effects of transportation, hospitalisation and trimethoprim-sulfadiazine (TMS) administration on the faecal microbiota and resistome of healthy equids. METHODS: In a longitudinal experimental study design, in which the ponies served as their own control, faecal samples were collected from six healthy Welsh ponies at the farm (D0-D13-1), immediately following transportation to the hospital (D13-2), during 7 days of hospitalisation without treatment (D14-D21), during 5 days of oral TMS treatment (D22-D26) and after discharge from the hospital up to 6 months later (D27-D211). After DNA extraction, 16S rRNA gene sequencing was performed on all samples. For resistome analysis, shotgun metagenomic sequencing was performed on selected samples. RESULTS: Hospitalisation without antimicrobial treatment did not significantly affect microbiota composition. Oral TMS treatment reduced alpha-diversity significantly. Kiritimatiellaeota, Fibrobacteres and Verrucomicrobia significantly decreased in relative abundance, whereas Firmicutes increased. The faecal microbiota composition gradually recovered after discontinuation of TMS treatment and discharge from the hospital and, after 2 weeks, was more similar to pre-treatment composition than to composition during TMS treatment. Six months later, however, microbiota composition still differed significantly from that at the start of the study and Spirochaetes and Verrucomicrobia were less abundant. TMS administration led to a significant (up to 32-fold) and rapid increase in the relative abundance of resistance genes sul2, tetQ, ant6-1a, and aph(3")-lb. lnuC significantly decreased directly after treatment. Resistance genes sul2 (15-fold) and tetQ (six-fold) remained significantly increased 6 months later. CONCLUSIONS: Oral treatment with TMS has a rapid and long-lasting effect on faecal microbiota composition and resistome, making the equine hindgut a reservoir and potential source of resistant bacteria posing a risk to animal and human health through transmission. These findings support the judicious use of antimicrobials to minimise long-term faecal presence, excretion and the spread of antimicrobial resistance in the environment. Video Abstract.202336850017
692460.9751Diversity of antibiotic resistance genes in soils with four different fertilization treatments. Although the enrichment of resistance genes in soil has been explored in recent years, there are still some key questions to be addressed regarding the variation of ARG composition in soil with different fertilization treatments, such as the core ARGs in soil after different fertilization treatments, the correlation between ARGs and bacterial taxa, etc. For soils after different fertilization treatments, the distribution and combination of ARG in three typical fertilization methods (organic fertilizer alone, chemical fertilizer alone, and conventional fertilizer) and non-fertilized soils were investigated in this study using high-throughput fluorescence quantitative PCR (HT-qPCR) technique. The application of organic fertilizers significantly increased the abundance and quantity of ARGs and their subtypes in the soil compared to the non-fertilized soil, where sul1 was the ARGs specific to organic fertilizers alone and in higher abundance. The conventional fertilizer application also showed significant enrichment of ARGs, which indicated that manure addition often had a more decisive effect on ARGs in soil than chemical fertilizers, and three bacteria, Pseudonocardia, Irregularibacter, and Castllaniella, were the key bacteria affecting ARG changes in soil after fertilization. In addition, nutrient factors and heavy metals also affect the distribution of ARGs in soil and are positively correlated. This paper reveals the possible reasons for the increase in the number of total soil ARGs and their relative abundance under different fertilization treatments, which has positive implications for controlling the transmission of ARGs through the soil-human pathway.202337928655
812370.9751The effect of bulk-biochar and nano-biochar amendment on the removal of antibiotic resistance genes in microplastic contaminated soil. Biochar amendment has significant benefits in removing antibiotic resistance genes (ARGs) in the soil. Nevertheless, there is little information on ARGs removal in microplastic contaminated soil. Herein, a 42-day soil microcosm experiment were carried out to study how two coconut shell biochars (bulk- and nano-size) eliminate soil ARGs with/without microplastic presence. The results showed that microplastic increased significantly the numbers and abundances of ARGs in soil at 14d of cultivation. And, two biochars amendment effectively inhibited soil ARGs spread whether or not microplastic was present, especially for nano-biochar which had more effective removal compared to bulk-biochar. However, microplastic weakened soil ARGs removal after applying same biochar. Two biochars removed ARGs through decreasing horizontal gene transfer (HGT) of ARGs, potential host-bacteria abundances, some bacteria crowding the eco-niche of hosts and promoting soil properties. The adverse effect of microplastic on ARGs removal was mainly caused by weakening mobile genetic elements (MGEs) removal, and by changing soil properties. Structural equation modeling (SEM) analysis indicated that biochar's effect on ARGs profile was changed by its size and microplastic presence through altering MGEs abundances. These results highlight that biochar amendment is still an effective method for ARGs removal in microplastic contaminated soil.202437907163
693580.9750Effects of soil protists on the antibiotic resistome under long term fertilization. Soil protists are key in regulating soil microbial communities. However, our understanding on the role of soil protists in shaping antibiotic resistome is limited. Here, we considered the diversity and composition of bacteria, fungi and protists in arable soils collected from a long-term field experiment with multiple fertilization treatments. We explored the effects of soil protists on antibiotic resistome using high-throughput qPCR. Our results showed that long term fertilization had stronger effect on the composition of protists than those of bacteria and fungi. The detected number and relative abundance of antibiotic resistance genes (ARGs) were elevated in soils amended with organic fertilizer. Co-occurrence network analysis revealed that changes in protists may contribute to the changes in ARGs composition, and the application of different fertilizers altered the communities of protistan consumers, suggesting that effects of protistan communities on ARGs might be altered by the top-down impact on bacterial composition. This study demonstrates soil protists as promising agents in monitoring and regulating ecological risk of antibiotic resistome associated with organic fertilizers.202235609845
693690.9749Pivotal role of earthworm gut protists in mediating antibiotic resistance genes under microplastic and sulfamethoxazole stress in soil-earthworm systems. Microplastics (MPs) are currently receiving widespread attention worldwide, and their co-occurrence with antibiotics is unavoidable. However, our understanding of how protists respond to co-pollution and mediate antibiotic resistance genes (ARGs) profiles remains exceedingly limited, particularly within non-target animals' guts. To bridge these gaps, we investigated the individual and combined effects of polyethylene and sulfamethoxazole (SMZ) on microbial communities and ARGs in soil and earthworm guts. We found that the MP-SMZ combination significantly elevated the abundance and richness of ARGs in the soil and earthworm. Protistan compositions (particularly consumers) responded more strongly to pollutants than did bacterial and fungal communities, especially under combined pollution. Interkingdom cooccurrence network analysis revealed that protists had stronger and more effective interactions with the resistome in the earthworm guts, suggesting that the impact of these protists on ARGs compositional changes was potentially modulated through the "top-down" regulation of bacteria and fungi. Meta-cooccurrence networks further confirmed that protist-related networks had more keystone pollution-sensitive ASVs (psASVs) and these psASVs were mostly associated with protistan consumers. Our study highlights protists as promising agents for regulating and monitoring microbial functions, as well as the ecological risks of the antibiotic resistome associated with MPs and SMZ pollution in agricultural ecosystems.202540412325
7004100.9748Sheep and rapeseed cake manure promote antibiotic resistome in agricultural soil. The application of manure in agriculture caused the emergence and spread of antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) in soil environments. However, the co-occurrence pattern and host diversity of ARGs and MGEs in soils amended with animal and green manures remains unclear. In this study, metagenomic assembly and binning techniques were employed to comprehensively explore the effects of sheep manure and green manure on soil microbiome, antibiotic resistomes, and ARG hosts. Both rapeseed cake manure and sheep manure increased the abundance and diversity of ARGs, with sheep manure particularly enhancing the abundance of ARGs conferring resistant to multidrug, quinolone, rifampicin, and macrolide-lincosamide-streptogramin (MLSB). Mobile genetic elements (MGEs), such as plasmids, transposases, and integrases, preferentially enhanced the potential mobility of some ARGs subtypes (i.e. sul2, aadA, qacH, and folp), facilitating the spread of ARGs. Additionally, sheep manure reshaped the bacterial community structure and composition as well as ARG hosts, some opportunistic pathogens (i.e. Staphylococcus, Streptococcus, and Pantoea) acquired antibiotic resistance and remained recalcitrant. It is concluded that rapeseed cake manure and sheep manure increased the co-occurrence of ARGs and MGEs, enriched the potential ARG hosts, and promoted the dissemination of ARGs in agricultural soils.202540633350
6793110.9748Interplays between cyanobacterial blooms and antibiotic resistance genes. Cyanobacterial harmful algal blooms (cyanoHABs), which are a form of microbial dysbiosis in freshwater environments, are an emerging environmental and public health concern. Additionally, the freshwater environment serves as a reservoir of antibiotic resistance genes (ARGs), which pose a risk of transmission during microbial dysbiosis, such as cyanoHABs. However, the interactions between potential synergistic pollutants, cyanoHABs, and ARGs remain poorly understood. During cyanoHABs, Microcystis and high microcystin levels were dominant in all the nine regions of the river sampled. The resistome, mobilome, and microbiome were interrelated and linked to the physicochemical properties of freshwater. Planktothrix and Pseudanabaena competed with Actinobacteriota and Proteobacteria during cyanoHABs. Forty two ARG carriers were identified, most of which belonged to Actinobacteriota and Proteobacteria. ARG carriers showed a strong correlation with ARGs density, which decreased with the severity of cyanoHAB. Although ARGs decreased due to a reduction of ARG carriers during cyanoHABs, mobile gene elements (MGEs) and virulence factors (VFs) genes increased. We explored the relationship between cyanoHABs and ARGs for potential synergistic interaction. Our findings demonstrated that cyanobacteria compete with freshwater commensal bacteria such as Actinobacteriota and Proteobacteria, which carry ARGs in freshwater, resulting in a reduction of ARGs levels. Moreover, cyanoHABs generate biotic and abiotic stress in the freshwater microbiome, which may lead to an increase in MGEs and VFs. Exploration of the intricate interplays between microbiome, resistome, mobilome, and pathobiome during cyanoHABs not only revealed that the mechanisms underlying the dynamics of microbial dysbiosis but also emphasizes the need to prioritize the prevention of microbial dysbiosis in the risk management of ARGs.202337897871
6926120.9747Insights into the driving factors of vertical distribution of antibiotic resistance genes in long-term fertilized soils. The prevalence of antibiotic resistance genes (ARGs) in soils has aroused wide attention. However, the influence of long-term fertilization on the distribution of ARGs in different soil layers and its dominant drivers remain largely unknown. In this study, a total of 203 ARGs were analyzed in greenhouse vegetable soils (0-100 cm from a 13-year field experiment applied with different fertilizers (control, chemical fertilizer, organic manure, and mixed fertilizer). Compared with unfertilized and chemically fertilized soils, manure application significantly increased the abundance and alpha diversity of soil ARGs, where the assembly of ARG communities was strongly driven by stochastic processes. The distribution of ARGs was significantly driven by manure application within 60 cm, while it was insignificantly changed in soil below 60 cm under different fertilization regimes. The inter-correlations of ARGs with mobile genetic elements (MGEs) and microbiota were strengthened in manured soil, indicating manure application posed a higher risk for ARGs diffusion in subsurface soil. Bacteria abundance and MGEs directly influenced ARG abundance and composition, whereas soil depth and manure application indirectly influenced ARG abundance and composition by affecting antibiotics. These results strengthen our understanding of the long-term anthropogenic influence on the vertical distribution of soil ARGs and highlight the ecological risk of ARGs in subsurface soil induced by long-term manure application.202337247491
7007130.9747Tracking resistomes, virulence genes, and bacterial pathogens in long-term manure-amended greenhouse soils. Organic manure has been implicated as an important source of antibiotic resistance genes (ARGs) in agricultural soils. However, the profiles of biocide resistance genes (BRGs), metal resistance genes (MRGs) and virulence genes (VGs) and their bacterial hosts in manure-amended soils remain largely unknown. Herein, a systematic metagenome-based survey was conducted to comprehensively explore the changes in resistomes, VGs and their bacterial hosts, mobile genetic elements (MGEs), and pathogenic bacteria in manure-amended greenhouse soils. Many manure-borne ARGs, BRGs, MRGs, VGs, and bacterial pathogens could be transferred into soils by applying manures, and their abundance and diversity were markedly positively correlated with greenhouse planting years (manure amendment years). The main ARGs transferred from manures to soils conferred resistance to tetracycline, aminoglycoside, and macrolide-lincosamide-streptogramin. Both statistical analysis and gene arrangements showed a good positive co-occurrence pattern of ARGs/BRGs/MRGs/VGs and MGEs. Furthermore, bacterial hosts of resistomes and VGs were significantly changed in the greenhouse soils in comparison with the field soils. Our findings confirmed the migration and dissemination of resistomes, VGs, and bacterial pathogens, and their accumulation and persistence were correlated with the continuous application of manures.202032298867
8648140.9747Host-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
6933150.9746Enantioselective effect of the chiral fungicide tebuconazole on the microbiota community and antibiotic resistance genes in the soil and earthworm gut. Tebuconazole, consisting of two enantiomers, has a high detectable rate in the soil. The residue of tebuconazole in the soil may cause risk to microbiota community. Antibiotic resistance genes (ARGs) are considered as emerging environmental contaminants, and they can be transferred vertically and horizontally between microbiota community in the soil. Until now, the enantioselective effect of tebuconazole on the microbiota community and ARGs in the soil and earthworm gut has remained largely unknown. Tebuconazole enantiomers showed different bioconcentration behaviors in earthworms. The relative abundances of bacteria belonging to Actinobacteriota, Crenarchaeota and Chloroflexi in R-(-)-tebuconazole-treated soil were higher than those in S-(+)-tebuconazole-treated soil at same concentrations. In the earthworm gut, bacteria belonging to Proteobacteria and Bacteroidota exhibited different relative abundances between the S-(+)-tebuconazole and R-(-)-tebuconazole treatments. The numbers and abundances of ARGs in the soil treated with fungicides were higher than those in the control. In earthworm gut, the diversities of ARGs in all treatments were higher than that in the control, and the relative abundances of Aminoglycoside, Chloramphenicol, Multidrug resistance genes and mobile genetic elements (MGEs) in R-(-)-tebuconazole-treated earthworm gut were higher than those in S-(+)-tebuconazole-treated earthworm gut. Most of ARGs showed a significantly positive correlation with MGEs. Based on network analysis, many ARGs may be carried by bacteria belonging to Bacteroidota and Proteobacteria. These results provide valuable information for understanding the enantioselective effect of tebuconazole on the microbiota community and ARGs.202337422227
8128160.9746Recognize and assessment of key host humic-reducing microorganisms of antibiotic resistance genes in different biowastes composts. Humic-reducing microorganisms (HRMs) can utilize humic substance as terminal electron mediator promoting the bioremediation of contaminate, which is ubiquitous in composts. However, the impacts of HRMs on antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) in composts and different HRMs community composition following the types of biowastes effected the spread of ARGs have not been investigated. Herein, the dynamics and mobility of ARGs and HRMs during protein-, lignocellulose- and lignin-rich composting were investigated. Result show that ARGs change significantly at the thermophilic phase, and the relative abundance of most ARGs increase during composting. Seven groups of HRMs communities are classified as primary host HRMs of ARGs, and most host HRMs groups from protein-rich composts. Conclusively, regulating methods for inhibiting ARGs spread for different composts are proposed. HRMs show a higher ARGs dissemination capacity in protein-rich composts than lignocellulose- and lignin-rich composts, but the spread of ARGs can be inhibited by regulate physicochemical parameters in protein-rich composts. In contrary, most HRMs have inhibitory effects on ARGs spread in lignocellulose- and lignin-rich composts, and those HRMs can be used as a new agent that inhibits the spread of ARGs. Our results can help in understanding the potential risk spread of ARGs by inoculating functional bacteria derived from different biowastes composts for environmental remediation, given their expected importance to developing a classification-oriented approach for composting different biowastes.202234600985
7674170.9746Insights into gut microbiomes in stem cell transplantation by comprehensive shotgun long-read sequencing. The gut microbiome is a diverse ecosystem, dominated by bacteria; however, fungi, phages/viruses, archaea, and protozoa are also important members of the gut microbiota. Exploration of taxonomic compositions beyond bacteria as well as an understanding of the interaction between the bacteriome with the other members is limited using 16S rDNA sequencing. Here, we developed a pipeline enabling the simultaneous interrogation of the gut microbiome (bacteriome, mycobiome, archaeome, eukaryome, DNA virome) and of antibiotic resistance genes based on optimized long-read shotgun metagenomics protocols and custom bioinformatics. Using our pipeline we investigated the longitudinal composition of the gut microbiome in an exploratory clinical study in patients undergoing allogeneic hematopoietic stem cell transplantation (alloHSCT; n = 31). Pre-transplantation microbiomes exhibited a 3-cluster structure, characterized by Bacteroides spp. /Phocaeicola spp., mixed composition and Enterococcus abundances. We revealed substantial inter-individual and temporal variabilities of microbial domain compositions, human DNA, and antibiotic resistance genes during the course of alloHSCT. Interestingly, viruses and fungi accounted for substantial proportions of microbiome content in individual samples. In the course of HSCT, bacterial strains were stable or newly acquired. Our results demonstrate the disruptive potential of alloHSCTon the gut microbiome and pave the way for future comprehensive microbiome studies based on long-read metagenomics.202438374282
6973180.9746Carbendazim shapes microbiome and enhances resistome in the earthworm gut. BACKGROUND: It is worrisome that several pollutants can enhance the abundance of antibiotic resistance genes (ARGs) in the environment, including agricultural fungicides. As an important bioindicator for environmental risk assessment, earthworm is still a neglected focus that the effects of the fungicide carbendazim (CBD) residues on the gut microbiome and resistome are largely unknown. In this study, Eisenia fetida was selected to investigate the effects of CBD in the soil-earthworm systems using shotgun metagenomics and qPCR methods. RESULTS: CBD could significantly perturb bacterial community and enrich specific bacteria mainly belonging to the phylum Actinobacteria. More importantly, CBD could serve as a co-selective agent to elevate the abundance and diversity of ARGs, particularly for some specific types (e.g., multidrug, glycopeptide, tetracycline, and rifamycin resistance genes) in the earthworm gut. Additionally, host tracking analysis suggested that ARGs were mainly carried in some genera of the phyla Actinobacteria and Proteobacteria. Meanwhile, the level of ARGs was positively relevant to the abundance of mobile genetic elements (MGEs) and some representative co-occurrence patterns of ARGs and MGEs (e.g., cmx-transposase and sul1-integrase) were further found on the metagenome-assembled contigs in the CBD treatments. CONCLUSIONS: It can be concluded that the enhancement effect of CBD on the resistome in the earthworm gut may be attributed to its stress on the gut microbiome and facilitation on the ARGs dissemination mediated by MGEs, which may provide a novel insight into the neglected ecotoxicological risk of the widely used agrochemicals on the gut resistome of earthworm dwelling in soil. Video abstract.202235436900
8661190.9746Differential priority effects impact taxonomy and functionality of host-associated microbiomes. Most multicellular eukaryotes host complex communities of microorganisms, but the factors that govern their assembly are poorly understood. The settlement of specific microorganisms may have a lasting impact on community composition, a phenomenon known as the priority effect. Priority effects of individual bacterial strains on a host's microbiome are, however, rarely studied and their impact on microbiome functionality remains unknown. We experimentally tested the effect of two bacterial strains (Pseudoalteromonas tunicata D2 and Pseudovibrio sp. D323) on the assembly and succession of the microbial communities associated with the green macroalga Ulva australis. Using 16S rRNA gene sequencing and qPCR, we found that both strains exert a priority effect, with strain D2 causing initially strong but temporary taxonomic changes and strain D323 causing weaker but consistent changes. Consistent changes were predominately facilitatory and included taxa that may benefit the algal host. Metagenome analyses revealed that the strains elicited both shared (e.g., depletion of type III secretion system genes) and unique (e.g., enrichment of antibiotic resistance genes) effects on the predicted microbiome functionality. These findings indicate strong idiosyncratic effects of colonizing bacteria on the structure and function of host-associated microbial communities. Understanding the idiosyncrasies in priority effects is key for the development of novel probiotics to improve host condition.202334995388