Pesticide contamination and antimicrobial resistance: Two threats to the Neotropical Otter (Lontra longicaudis) in the Peñas Blancas River Basin, Costa Rica. - Related Documents




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812901.0000Pesticide contamination and antimicrobial resistance: Two threats to the Neotropical Otter (Lontra longicaudis) in the Peñas Blancas River Basin, Costa Rica. The effects of synthetic pesticides on antibiotic-resistance genes (ARGs) in bacterial communities from contaminated waters are unclear. Otters in the Peñas Blancas basin encounter various anthropogenic residues, including pesticides. In 2022, we analyzed the presence of pesticides in six water samples and ARGs in eight otter fecal samples. Thirteen pesticides (herbicides, insecticides, fungicides, and multi-target) and seven ARGs (qnrS, tetA, tetB, tetQ, tetW, sulI, sulII) were detected. Regulated pesticides such as chlorpyrifos and ethoprophos, along with diazinon, diuron, imidacloprid, and terbutryn were found. These pesticides have been implicated in promoting antimicrobial resistance (AMR) in bacteria, particularly when combined with sub-lethal doses of antibiotics. Elevated levels of ethoprophos (0.67 ng/L) and a fecal sample containing four ARGs (tetA, tetB, sulI, and sulII) came from the upper basin. Our findings reveal pesticide application practices in the region, and highlight the potential risk of pesticide exposure to wildlife, including development of AMR.202540473152
687510.9977Metagenomic analysis of antibiotic resistance genes in coastal industrial mariculture systems. The overuse of antibiotics has posed a propagation of antibiotic resistance genes (ARGs) in aquaculture systems. This study firstly explored the ARGs profiles of the typical mariculture farms including conventional and recirculating systems using metagenomics approach. Fifty ARGs subtypes belonging to 21 ARGs types were identified, showing the wide-spectrum profiles of ARGs in the coastal industrial mariculture systems. ARGs with multiple antibiotics resistance have emerged in the mariculure systems. The co-occurrence pattern between ARGs and microbial taxa showed that Proteobacteria and Bacteroidetes were potential dominant hosts of ARGs in the industrial mariculture systems. Typical nitrifying bacteria such as Nitrospinae in mariculture systems also carried with some resistance genes. Relative abundance of ARGs in fish ponds and wastewater treatment units was relatively high. The investigation showed that industrial mariculture systems were important ARGs reservoirs in coastal area, indicating the critical role of recirculating systems in the terms of ARGs pollution control.201829353751
755720.9977Sulfadiazine degradation in soils: Dynamics, functional gene, antibiotic resistance genes and microbial community. Sulfonamides and their corresponding antibiotic resistance genes (ARGs) are widespread in the environment, which leads to a major threat to global health crisis. Biodegradation plays a major role in sulfonamides removal in soil ecosystem, but the degradation dynamics and the associated functional bacteria in situ remain unclear. In this study, aerobic degradation of sulfadiazine (SDZ) at two dosages (1 and 10 mg/kg) was explored for up to 70 days in two different agricultural soils. The removal of SDZ in all treatments followed first-order multi-compartment model with half-life times of 0.96-2.57 days, and DT50 prolonged with the increase of initial dosage. A total of seven bacterial genera, namely Gaiella, Clostrium_sensu_stricto_1, Tumebacillus, Roseiflexus, Variocorax, Nocardioide and Bacillus, were proposed as the potential SDZ-degraders. sadA gene was for the first time detected in soil samples, but other functional genes might also participate in SDZ degradation. The enrichment of sulfonamide resistance genes was found after 70 days' incubation, which might result in the spread of ARGs in soil. This study can add some new insights towards SDZ degradation in soil ecosystem and provide a potential resource for the bioremediation of SDZ-contaminated soil.201931466189
367230.9977Multiple antibiotic resistance of heterotrophic bacteria in the littoral zone of Lake Shira as an indicator of human impact on the ecosystem. Resistance to Ampicillin and Kanamycin displayed by heterotrophic bacteria isolated in Summer and in Spring from the littoral and the central parts of Lake Shira (a therapeutic lake in the Khakasia Republic, Russia) has been investigated. It has been found that in Summer, human and animal microflora featuring multiple antibiotic resistance (to Ampicillin and Kanamycin) predominates in all the studied stations of the littoral zone of the lake. In Spring, concentrations of bacteria featuring multiple antibiotic resistance decrease significantly and bacteria sensitive to antibiotics predominate in the lake. Emergence of multiple antibiotic resistance in bacteria of Lake Shira is caused by the input of allochthonous bacteria into the lake; this feature of heterotrophic bacteria of Lake Shira can be used to monitor the impact on the ecosystem made by health resorts.200816762536
807740.9977Effects of coexistence of tetracycline, copper and microplastics on the fate of antibiotic resistance genes in manured soil. The coexistence of antibiotics, heavy metals and microplastics is becoming commonplace and may affect antibiotic resistance in manured soil. The current understanding of the role of microplastics in soil with combined pollution of antibiotics, heavy metals and antibiotic resistance genes (ARGs) is limited. Here, the effects of the coexistence of tetracycline (TC), Cu and environmental microplastics (EM) on the fate of nine ARGs and three heavy metal resistance genes in agricultural soil were investigated by batch and microcosm experiments. EM were obtained by exposing virgin microplastics to soil environments for 80 days, which exhibited higher adsorption affinity for Cu and TC than soil particles and virgin microplastics. 1% EM in soil increased bioavailable concentrations of TC and Cu by 79-138% and 88-135%, respectively, and decreased TC dissipation from 11.79 mg kg(-1) to 3.08 mg kg(-1). Correspondingly, the total relative abundances of target ARGs increased by 219-348%. The significant correlations of tetG, tetB, tetQ, sul2, sul1 and intl1 with bioavailable fractions of TC and Cu in soil environments were revealed by network analysis. Moreover, scanning electron micrographs showed the special plastisphere around EM. Attributed to the biofilm generation and higher pollutant accumulation in the plastisphere, EM could be the source of antibiotic-resistant bacteria and ARGs in soil environments. Structure equation models further identified that indirect effects of EM acted a major role in the propagation of ARGs by altering soil properties, soil microbial diversity and intl1 abundance. This study revealed that EM could increase the stimulative effects of Cu and TC on antibiotic resistance and magnify the environmental risk of manure application in soil environments.202134091329
699750.9976Linkage of antibiotic resistance genes, associated bacteria communities and metabolites in the wheat rhizosphere from chlorpyrifos-contaminated soil. Rhizosphere is a crucial site for the proliferation of antibiotic resistance genes (ARGs) in agricultural soil. Pesticide contamination is ubiquitous in soil, such as chlorpyrifos as one of the most commonly used pesticides. However, limited knowledge is reported about ARGs profiles changes and the driving mechanism of ARGs prevalence in rhizosphere soil after adding pesticide. In this study, irrespective of chlorpyrifos presence, the abundances of ARGs (tetM, tetO, tetQ, tetW, tetX, sul1 and sul2) and intI1 in rhizosphere soil of wheat were obviously higher than those in bulk soil. 20.0 mg·kg(-1) chlorpyrifos significantly increased the abundance of total ARGs and intI1 in bulk soil, respectively, at day 50 and 100, but not in rhizosphere soil. Rhizosphere influence on ARGs was far greater than chlorpyrifos. ARGs and intI1 abundances were higher at day 50 than ones at day 100. C/N ratio and NO(3)(-)-N content, which were affected by rhizosphere and cultivation time, significantly explained the increased ARGs. Compared to bulk soil, rhizosphere shifted host bacteria of tetracycline resistance genes (TRGs), intI1 at genus level, and host bacteria of sul1, sul2 at phylum level. Rhizosphere simplified the linkage of ARGs, host bacteria and metabolites. Bacterial communities played important roles in the variation of ARGs and intI1, and the difference in the distribution of potential hosts between bulk and rhizosphere soil was related to metabolites abundance and composition. These results provide valuable information for understanding the linkage of ARGs, associated bacteria communities and metabolites in the wheat rhizosphere soil.202032615437
684760.9976Nutrients, heavy metals and microbial communities co-driven distribution of antibiotic resistance genes in adjacent environment of mariculture. With the rapid development of aquaculture, the large amounts of pollutants were discharged into the aquatic environment, where the detected antibiotic resistance genes (ARGs) have drawn increasing attention due to their potential threats to ecological environment and human health. Thus, the impact of mariculture on ARGs was assessed and the underlying mechanism of their propagation was explained. Sediments from eight sampling sites were collected along a mariculture drainage ditch, and the sediment in Yellow River Delta National Park was used as a non-mariculture control. Microbial ARGs qPCR array and illumina sequencing of 16S rRNA gene were applied to examine the changing patterns of ARGs and bacterial communities. Results showed that 18 ARGs (3 fluoroquinolone, 1 aminoglycoside, 3 macrolide-lincosamide-streptogramin B, 2 tetracycline, and 9 beta-lactam resistance genes) were influenced by mariculture, and ARGs abundance and diversity were significantly increased in mariculture sediments (p < 0.05). A remarkable shift in bacterial community structure and composition was also observed. The abundance of most of ARGs were significantly decreased in the estuary samples, implying that seawater had a significant dilution effect on the ARGs emission from the mariculture sites. Partial redundancy analysis showed that nutrients, heavy metals, and bacteria communities might directly and indirectly contribute to ARGs propagation, suggesting that the profile and dissemination of ARGs were driven by the combined effects of multiple factors in mariculture-impacted sites.201727814984
696570.9976Metaphire guillelmi gut as hospitable micro-environment for the potential transmission of antibiotic resistance genes. Earthworm gut played an important role in the transformation of various contaminants in the soil environments. With the increasing application of organic fertilizer recently, the ingestion of antibiotics, antibiotic resistance bacteria (ARB), and antibiotic resistance genes (ARGs) made the earthworm gut a potential favorable micro-environment for the transmission of ARGs in the soil. In this work, the conventional plate incubation and high-throughput sequencing methods were both employed to investigate the composition of the cultivable and overall ARB/ARGs in the Metaphire guillelmi earthworm gut. A total of 87 cultivable isolates that resisted tetracycline (TC) and/or sulfadiazine (SD) were obtained, most of which belonged to phylum Firmicutes, genus Bacillus. Meanwhile, the counts of isolates with TC-SD dual resistance were higher than those with sole SD or TC resistance. Moreover, higher ARB counts and diversity were detected in the earthworm gut by high-throughput sequencing technique than those by the classical plate cultivation. Overall, the combination of conventional cultivable bacteria isolation and high-throughput sequencing methods provided a comprehensive understanding of the ARB composition in the earthworm gut. The results demonstrate that the earthworm gut is a hospitable micro-environment for ARB colonization. The potential role of earthworm intestinal ARB and ARGs proliferation in soil environments warrants further research.201930884260
704880.9976Airborne antibiotics, antimicrobial resistance, and bacterial pathogens in a commercial composting facility: Transmission and exposure risk. Multiple elements associated with antimicrobial resistance in compost may escape into the air during the composting process, including antibiotic resistance genes (ARGs), human pathogenic bacteria (HPBs), and even antibiotics. Although antibiotics play a critical role in the evolution of resistance in HPBs, no information is available on airborne antibiotics in composting facilities. In this study, we systematically quantified airborne antibiotics, ARGs, and HPBs in comparison with those in compost. The burden of antibiotics in the air reached 4.17 ± 2.71 × 10(2) ng/g, significantly higher than that in compost. The concentration of ARGs (10(2) copies/g) in air also increased compared with that in compost. Concentrations of target contaminants in air were affected by temperature, organic matter, and heavy metals. Co-occurrence network analysis revealed the connectivity and complexity of antibiotics, ARGs, and HPBs were greater in air than in compost. The maximum daily antibiotic intake dose was up to 1.18 × 10(-1)ng/d/kg, accompanied by considerable inhalation levels of ARGs and HPBs. Our results reveal the severity of airborne antimicrobial resistance (AMR) elements in composting facilities, highlight the non-negligible amount of antibiotics and their co-existence with ARGs and HPBs, and shed light on the potential role of airborne antibiotics in the evolution of environmental AMR.202439442303
799090.9976Calcined Eggshell Waste for Mitigating Soil Antibiotic-Resistant Bacteria/Antibiotic Resistance Gene Dissemination and Accumulation in Bell Pepper. The combined accumulation of antibiotics, heavy metals, antibiotic-resistant bacteria (ARB)/antibiotic resistance genes (ARGs) in vegetables has become a new threat to human health. This is the first study to investigate the feasibility of calcined eggshells modified by aluminum sulfate as novel agricultural wastes to impede mixed contaminants from transferring to bell pepper (Capsicum annuum L.). In this work, calcined eggshell amendment mitigated mixed pollutant accumulation in bell pepper significantly, enhanced the dissipation of soil tetracycline, sulfadiazine, roxithromycin, and chloramphenicol, decreased the water-soluble fractions of antibiotics, and declined the diversity of ARB/ARGs inside the vegetable. Moreover, quantitative polymerase chain reaction analysis detected that ARG levels in the bell pepper fruits significantly decreased to 10(-10) copies/16S copies, indicating limited risk of ARGs transferring along the food chain. Furthermore, the restoration of soil microbial biological function suggests that calcined eggshell is an environmentally friendly amendment to control the dissemination of soil ARB/ARGs in the soil-vegetable system.201627333280
7259100.9976Practical survey on antibiotic-resistant bacterial communities in livestock manure and manure-amended soil. Through livestock manure fertilization, antibiotics, antibiotic-resistant bacteria and genes are transferred to agricultural soils, resulting in a high prevalence of antibiotic-resistant bacteria in the soil. It is not clear, however, whether a correlation exists between resistant bacterial populations in manure and manure-amended soil. In this work, we demonstrate that the prevalence of cephalexin-, amoxicillin-, kanamycin- and gentamicin-resistant bacteria as well as bacteria simultaneously resistant to all four antibiotics was much higher in manure-amended soils than in manure-free soil. 454-pyrosequencing indicated that the ARB and multiple antibiotic-resistant bacteria (MARB) in swine or chicken manure and manure-amended soil were mainly distributed among Sphingobacterium, Myroides, Enterococcus, Comamonas and unclassified Flavobacteriaceae. The genus Sphingobacterium was highly prevalent among ARB from swine manure and manure-amended soil, and was also the most dominant genus among MARB from chicken manure and manure-amended soil. Other dominant genera among ARB or MARB populations in manure samples, including Myroides, Enterococcus and Comamonas, could not be detected or were detected at very low relative abundance in manure-amended soil. The present study suggests the possibility of transfer of ARBs from livestock manures to soils and persistence of ARB in these environments.201626513264
6848110.9976Swine farming elevated the proliferation of Acinetobacter with the prevalence of antibiotic resistance genes in the groundwater. Swine farming generates a large amount of wastes containing various contaminants, resulting in environmental contamination and human health problems. Here we investigated the contamination profiles of antibiotics and antibiotic resistance genes (ARGs) as well as microbial community in groundwater of the two villages with or without swine farms, and then assessed the human exposure risks of antibiotics, ARGs and indicator bacteria through drinking groundwater. The results showed that swine farming could lead to enhanced concentration levels of various veterinary antibiotics and ARGs in the groundwater in comparison to the reference village without swine farming. The microbial diversity of groundwater was significantly decreased with predominance of conditional pathogens Acinetobacter (up to 90%) in some wells of the swine farming village. Meanwhile, the abundance of Acinetobacter was significantly correlated to bacterial abundance, ARGs and integrons. The local residents could ingest various antibiotic residues and ARGs as well as pathogens, with daily intake of Acinetobacter up to approximately 10 billion CFU/resident through drinking groundwater contaminated by swine farming. The findings from this study suggest potential health risks of changing gut microbial community and resistome by drinking contaminated groundwater.202031999967
8028120.9976The fate of antibiotic resistance genes, microbial community, and potential pathogens in the maricultural sediment by live seaweeds and oxytetracycline. Three common seaweeds including Ulva fasciata, Codium cylindricum and Ishige okamurai were used for the remediation of maricultural wastewater and sediment in the presence/absence of trace level of oxytetracycline (OTC) in lab-scale experiments. Higher NO(3)(-)-N and PO(4)(3-)-P removal rates were achieved due to the presence of seaweeds, and trace OTC also had a positive effect on NO(3)(-)-N removal. A slight variation of 2.10-2.15% were observed in the total relative abundances of antibiotic resistance genes (ARGs) of different sediment samples after one-month operation. However, the variation of ARGs profiles by the co-existence of different seaweeds and OTC was in the descending order of Ishige okamurai > Codium cylindricum > Ulva fasciata, which was in accordance with the variation of microbial hosts at genus level. The abundance of dominant tetracycline resistance genes promoted by the co-existence of different seaweeds and OTC in compared with the presence of single seaweed or OTC via metagenomic sequencing and qPCR analysis, and the co-existence of Ishige okamurai and OTC exhibited the largest impact. The potential pathogens were more sensitive to the co-existence of seaweed and OTC than single seaweeds. Meanwhile, a variety of ARGs were enriched in the pathogens, and the dominant pathogenic bacteria of Vibrio had 133 Vibrio species with 28 subtypes of ARGs. The variation of ARGs profiles in the sediment were strongly related with the dominant phyla Proteobacteria, Actinobacteria, Firmicutes, Planctomycetes and Cyanobacteria. Besides, Nitrate level exhibited more significant effect on ∑ARGs, ARGs resistant to vancomycin and streptogramin_a, while phosphate level exhibited more positively significant effect on ARGs resistant to fosmidomycin, ATFBT and cephalosporin.202235780677
6956130.9976Fertilizing drug resistance: Dissemination of antibiotic resistance genes in soil and plant bacteria under bovine and swine slurry fertilization. The increasing global demand for food production emphasizes the use of organic animal fertilizers, such as manure and slurry, to support sustainable agricultural practices. However, recent studies highlight concerns about antibiotic resistance determinants in animal excrements, posing a potential risk of spreading antibiotic resistance genes (ARGs) in agricultural soil and, consequently, in food products. This study examines the dissemination of ARGs within the soil and plant-associated microbiomes in cherry radish following the application of swine and bovine slurry. In a 45-day pot experiment, slurry-amended soil, rhizospheric bacteria, and endophytic bacteria in radish roots and leaves were sampled and analyzed for 21 ARGs belonging to 7 Antibiotic Resistance Phenotypes (ARPs). The study also assessed slurry's impact on soil microbiome functional diversity, enzymatic activity, physicochemical soil parameters, and the concentration of 22 selected antimicrobials in soil and plant tissues. Tetracyclines and β-lactams were the most frequently identified ARGs in bovine and swine slurry, aligning with similar studies worldwide. Swine slurry showed a higher prevalence of ARGs in soil and plant-associated bacteria, particularly TET genes, reflecting pig antibiotic treatments. The persistent dominance of TET genes across slurry, soil, and plant microbiomes highlights significant influence of slurry application on gene occurrence in plant bacteria. The presence of ARGs in edible plant parts underscores health risks associated with raw vegetable consumption. Time-dependent dynamics of ARG occurrence highlighted their persistent presence throughout the experiment duration, influenced by the environmental factors and antibiotic residuals. Notably, ciprofloxacin, which was the only one antimicrobial detected in fertilized soil, significantly impacted bovine-amended variants. Soil salinity modifications induced by slurry application correlated with changes in ARG occurrence. Overall, the research underscores the complex relationships between agricultural practices, microbial activity, and antibiotic resistance dissemination, emphasizing the need for a more sustainable and health-conscious farming approaches.202438969119
7645140.9976Antibiotic Resistance in the Collembolan Gut Microbiome Accelerated by the Nonantibiotic Drug Carbamazepine. The effects of pharmaceuticals as emerging contaminants in soil on the gut microbiome and antibiotic resistome in nontarget soil fauna are largely elusive. In this study, we explored the composition of the bacterial community and the presence of antibiotic resistance genes (ARGs) in the gut of the model soil collembolan (Folsomia candida) upon antiepileptic drug carbamazepine (CBZ) and antibiotic tetracycline (TC) exposure. Results showed that, individually or in combination, exposure to TC or CBZ significantly altered the gut community structure of F. candida, causing some enrichment of the bacteria associated with xenobiotic metabolism, such as Arthrobacter, Achromobacter, Gordonia, and Shinella. More importantly, oral exposure to the nonantibiotic drug CBZ enhanced the abundance and diversity of ARGs in the gut of F. candida, especially for the beta-lactams and multidrug resistance genes. Our results revealed that the most likely hosts of ARGs in the gut of F. candida were Proteobacteria and Actinobacteria. The significant positive correlation between mobile genetic elements (MGEs) and ARGs indicated the potential risk of ARGs transmission in the gut of F. candida. Overall, the nonantibiotic CBZ is likely to disturb the gut microbiota of nontarget soil fauna such as collembolans, thereby enhancing the dissemination of ARGs.202032816468
8030150.9976Application of manure containing tetracyclines slowed down the dissipation of tet resistance genes and caused changes in the composition of soil bacteria. Manure application contributes to the increased environmental burden of antibiotic resistance genes (ARGs). We investigated the response of tetracycline (tet) resistance genes and bacterial taxa to manure application amended with tetracyclines over two months. Representative tetracyclines (oxytetracycline, chlorotetracycline and doxycycline), tet resistance genes (tet(M), tet(O), tet(W), tet(S), tet(Q) and tet(X)) and bacterial taxa in the untreated soil, +manure, and +manure+tetracyclines groups were analyzed. The abundances of all tet resistance genes in the +manure group were significantly higher than those in the untreated soil group on day 1. The abundances of all tet resistance genes (except tet(Q) and tet(X)) were significantly lower in the +manure group than those in the +manure+tetracyclines group on day 30 and 60. The dissipation rates were higher in the +manure group than those in the +manure+tetracyclines group. Disturbance of soil bacterial community composition imposed by tetracyclines was also observed. The results indicated that tetracyclines slowed down the dissipation of tet resistance genes in arable soil after manure application. Application of manure amended with tetracyclines may provide a significant selective advantage for species affiliated to the taxonomical families of Micromonosporaceae, Propionibacteriaceae, Streptomycetaceae, Nitrospiraceae and Clostridiaceae.201828898804
7260160.9976Vertical Distribution and Drivers of Antibiotic Resistance Genes in Agricultural Soil Irrigated with Livestock Wastewater. Livestock wastewater reuse could be a potential source for the distribution of antibiotics, antibiotic resistance bacteria (ARB), and antibiotic resistance genes (ARGs) in agricultural soil. In this study, soil samples were collected from different depths (0-60 cm) of farmland that has been subjected to long-term application of livestock wastewater. The vertical distribution of antibiotics, bacterial communities, and ARGs were assessed to identify the driving factors that could potentially influence the distribution of ARB and ARGs. The results demonstrated distinguished distributions of antibiotics along the soil depths, with tetracyclines (TCs) mainly found in the top 10 cm of the soil (0.11-0.31 μg/kg), while quinolones (QNs), sulfonamides (SAs), and macrolides (MLs) were detected in all 60 cm of soil depth (0.01-0.22 μg/kg). The selection pressure of antibiotics to microorganisms led to the proliferation of ARB, especially tetracycline-resistant bacteria and erythromycin-resistant bacteria. In terms of the distribution/abundance of ARGs, novA and tetA (58) were relatively higher in 0-10 cm surface soil, while vanRM and vanRF were mainly detected in the deeper soil. Different ARGs may have the same host bacteria, which lead to the emergence of multidrug resistant bacteria, such as Ilumatobacter sp., Aggregatilinea sp., Rhabdothermincola sp., and Ornithinimicrobium sp. Soil pH, electrical conductivity (EC), and moisture content (MC) could affect the distribution and proliferation of ARB and were found negatively correlated with most of the ARGs except macB. Therefore, it is potentially possible to eliminate/inhibit the spread of ARGs by adjusting these soil parameters. These findings provide insights into the distribution and dissemination of antibiotics, ARB, and ARGs in agricultural practices of livestock wastewater irrigation and provide effective mitigation strategies to ensure the safe use of livestock wastewater in agriculture.202540142503
6849170.9976Antibiotic resistance genes and their links with bacteria and environmental factors in three predominant freshwater aquaculture modes. Rapid development of aquaculture industry and increasing demand of various inputs (especially antibiotics), are suspected to promote the occurrence and spread of ARGs in aquaculture related environments. However, the occurrences of ARGs under different freshwater aquaculture practices are rarely known. Here, we investigated the seasonal profiles of the main ARGs, intI1 and bacteria in waters from three kinds of predominant freshwater aquaculture practices around the Honghu Lake (China), as well as their co-occurrences and interrelationships with antibiotics, heavy metals and general water quality. The results indicate that quinolone resistance genes (qnrB), tetracycline resistance genes (tetB and tetX) and sulfonamide resistance genes (sul1 and sul2) were the top five predominant ARGs with seasonal variations of abundance. Fish ponds were of the highest absolute abundances of tested ARGs than the other two modes. Crayfish ponds and their adjacent ditches shared similar ARGs profile. Different subtypes of ARGs belonging to the same class of resistance were varied in abundances. Some bacteria were predicted to carry different ARGs, which indicating multi-antibiotic resistances. Moreover, the combined environmental factors (antibiotics, heavy metals and water quality) partially shaped the profiles of ARGs and bacteria composition. Overall, this study provides new comprehensive understanding on the characterization of ARGs contamination in different freshwater aquaculture practices from the perspectives of environmental chemistry, microbiology and ecology. The results would benefit the optimization of aquaculture practices toward environmental integrity and sustainability.202236068758
7149180.9976Municipal Solid Waste Treatment System Increases Ambient Airborne Bacteria and Antibiotic Resistance Genes. Landfill and incineration are the primary disposal practices for municipal solid waste (MSW) and have been considered as the critical reservoir of antibiotic resistance genes (ARGs). However, the possible transmission of ARGs from the municipal solid waste treatment system (MSWT system) to ambient air is still unclear. In this study, we collected inside and ambient air samples (PM(10) and PM(2.5)) and potential source samples (leachate and solid waste) in the MSWT system. The results showed that the MSWT system contributed to the increased ambient airborne bacteria and associated ARGs. Forty-one antibiotic-resistant bacteria (ARB) harboring bla(TEM-1) were isolated, and the full-length nucleotide sequences of the bla(TEM-1) gene (harbored by identical bacillus) from air (downwind samples) were 100% identical with those in the leachate and solid waste, indicating that the MSWT system was the important source of disperse bacteria and associated ARGs in the ambient air. The daily intake (DI) burden level of ARGs via PM inhalation was comparable with that via ingestion of drinking water but lower than the DI level via ingestion of raw vegetables. The antibiotic-resistant opportunistic pathogen Bacillus cereus was isolated from air, with a relatively high DI level of Bacillus via inhalation (10(4)-10(6) copies/day) in the MSWT system. This study highlights the key pathway of airborne ARGs to human exposure.202032208626
6983190.9976Deciphering Potential Roles of Earthworms in Mitigation of Antibiotic Resistance in the Soils from Diverse Ecosystems. Earthworms are capable of redistributing bacteria and antibiotic resistance genes (ARGs) through soil profiles. However, our understanding of the earthworm gut microbiome and its interaction with the antibiotic resistome is still lacking. Here, we characterized the earthworm gut and soil microbiome and antibiotic resistome in natural and agricultural ecosystems at a national scale, and microcosm studies and field experiments were also employed to test the potential role of earthworms in dynamics of soil ARGs. The diversity and structure of bacterial communities were different between the earthworm gut and soil. A significant correlation between bacterial community dissimilarity and spatial distance between sites was identified in the earthworm gut. The earthworm gut consistently had lower ARGs than the surrounding soil. A significant reduction in the relative abundance of mobile genetic elements and dominant bacterial phylotypes that are the likely hosts of ARGs was observed in the earthworm gut compared to the surrounding soil, which might contribute to the decrease of ARGs in the earthworm gut. The microcosm studies and field experiments further confirmed that the presence of earthworms significantly reduced the number and abundance of ARGs in soils. Our study implies that earthworm-based bioremediation may be a method to reduce risks associated with the presence of ARGs in soils.202133977709