Occurrence and distribution of antibiotic resistant bacteria and genes in the Fuhe urban river and its driving mechanism. - Related Documents




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704901.0000Occurrence and distribution of antibiotic resistant bacteria and genes in the Fuhe urban river and its driving mechanism. Antibiotic resistance genes (ARGs) in urban rivers can affect human health via the food chain and human pathogenic bacteria diffusion. Sediment can be a sink for ARGs, causing second sources of ARG contamination through diffusion. Therefore, we evaluated the effects of total petroleum hydrocarbons (TPHs) and phytoplankton on the distribution of the ARGs in the sediment and water of Fuhe river in Baoding city, China. The ARGs and human pathogenic bacteria in urban river were analyzed, and the phytoplankton and bacterial abundance, TPH, and physicochemical parameters ranked using the partial least squares path modelling (PLS-PM) and aggregated boosted tree (ABT) analysis. The main ARGs in Fuhe river sediment were sulfonamide and tetracycline resistance genes, with sul2 exhibiting the highest level. The main human pathogenic bacteria in the pathogens pool were Clostridium, Bacillus and Burkholderiaceae, with Clostridium demonstrating a positive correlation with SulAfolP01. The PLS-PM analysis confirmed that, among the multiple drivers, water physicochemical factors, TPH, phytoplankton, and heavy metals positively and directly affected the ARG profiles in sediment while sediment heavy metals and bacterial communities did the similar effect. These factors (nutrient factors, heavy metals, and TPH) in water and sediment posed the opposite total effect on ARGs in the sediment, suggesting medium factors should have a conclusive effect on the distribution of ARGs in the sediment. The ABT analysis showed that dissolved oxygen (DO), total nitrogen (TN) and Chlorophyta were the most important factors affecting the ARGs distribution in the water, while TN affected the distribution of the genes in the sediment.202235189229
681010.9997Heavy metals and microbiome are negligible drivers than mobile genetic elements in determining particle-attached and free-living resistomes in the Yellow River. Suspended particles in water can shelter both microorganisms and contaminants. However, the emerging pollutants antibiotic resistance genes (ARGs) in free-living (FL) or particle-attached (PA) bacteria in aquatic environments are less explored. In this study, we compared the free-living and particle-attached ARGs during four seasons in the Yellow River using high-throughput quantitative PCR techniques and 16S rRNA gene sequencing. Our results demonstrated that both the free-living water and particles were dominated by tetracycline and beta-lactamase resistance genes. The PA-ARGs had a higher absolute abundance than FL-ARGs in the Yellow River, regardless of the season. Both PA-ARGs and FL-ARGs had the highest absolute abundance and diversity during winter. Mobile genetic elements (MGEs) were the dominant driver for both size-fractionated ARGs. However, the microbiome had less influence on PA-ARG profiles than the FL-ARG profiles, while the effects of the heavy metals on ARGs were negligible. The community assembly of both FL-ARG and PA-ARG can be explained by neutral processes. Several opportunistic pathogens (e.g., Escherichia coli) associated with human health exhibited a higher relative abundance in the particles than during a free-living lifestyle. Parts of these pathogens were potential ARG hosts. As such, it is important to monitor the ARGs and opportunistic pathogens from size-fractionated bacteria and develop targeted strategies to manage ARG dissemination and opportunistic pathogens to ensure public health.202234736202
699520.9996Insight into the spatiotemporal distribution of antibiotic resistance genes in estuarine sediments during long-term ecological restoration. In this study, we aimed to investigate the long-term spatiotemporal changes in hydrodynamics, antibiotics, nine typical subtypes of antibiotic resistance genes (ARGs), class 1 integron gene (intI1), and microbial communities in the sediments of a semi-enclosed estuary during ecological restoration with four treatment stages (influent (#1), effluent of the biological treatment area (#2), oxic area (#3), and plant treatment area (#4)). Ecological restoration of the estuary reduced common pollutants (nitrogen and phosphorus) in the water, whereas variations in ARGs showed noticeable seasonal and spatial features. The absolute abundance of ARGs at sampling site #2 considerably increased in autumn and winter, while it significantly increased at sampling site #3 in spring and summer. The strong intervention of biological treatment (from #1 to #2) and aerators (from #2 to #3) in the estuary substantially affected the distribution of ARGs and dominant antibiotic-resistant bacteria (ARB). The dominant ARB (Thiobacillus) in estuarine sediments may have low abundance but important dissemination roles. Meanwhile, redundancy and network analysis revealed that the microbial communities and intl1 were key factors related to ARG dissemination, which was affected by spatial and seasonal ecological restoration. A positive correlation between low flow velocity and certain ARGs (tetM, tetW, tetA, sul2, and ermC) was observed, implying that flow optimization should also be considered in future ecological restoration to remediate ARGs. Furthermore, the absolute abundance of ARGs can be utilized as an index to evaluate the removal capacity of ARGs by estuarine restoration.202336827800
802530.9996Effect of temperature on sulfonamide antibiotics degradation, and on antibiotic resistance determinants and hosts in animal manures. Animal manure is a main reservoir of antibiotic residues and antibiotic resistance. Here, the effect of temperature on sulfonamide antibiotics (SAs), sulfonamide-resistant (SR) genes/bacteria was investigated by aerobically incubating swine and chicken manures at different temperatures. In swine manure, the SAs concentration declined with increasing temperature, with a minimum at 60°C. In chicken manure, the greatest degradation of SAs was noted at 30°C. The reduction of relative abundance of antibiotic resistance genes (ARGs) and sul-positive hosts in swine manure was more pronounced during thermophilic than mesospheric incubation; neither temperature conditions effectively reduced these parameters in chicken manure. The relationship between the residual levels/distribution profiles of SAs, ARGs (sul1, sul2 and intI1), cultivable SR bacteria and sul-positive hosts was further established. The antibiotic residual profile, rather than antibiotic concentration, acted as an important factor in the prevalence of ARGs and sul-positive hosts in manure. Corynebacterium and Leucobacter from the phylum Actinobacteria tend to be main carriers of sul1 and intI1; the relative abundance of sul2 was significantly correlated with the relative abundance of cultivable SR bacteria. Overall, differences in resistant bacterial communities also constitute a dominant factor affecting ARG variation. This study contributes to management options for reducing the pollution of antibiotics and antibiotic resistance within manure.201728711002
699940.9996Different impacts of manure and chemical fertilizers on bacterial community structure and antibiotic resistance genes in arable soils. Both manure and chemical fertilizers are widely used in modern agriculture. However, the impacts of different fertilizers on bacterial community structure and antibiotic resistance genes (ARGs) in arable soils still remain unclear. In this study, high-throughput sequencing and quantitative PCR were employed to investigate the bacterial community structure, ARGs and mobile genetic elements (MGEs) influenced by the application of different fertilizers, including chemical fertilizers, piggery manure and straw ash. The results showed that the application of fertilizers could significantly change the soil bacterial community and the abundance of Gaiella under phylum Actinobacteria was significantly reduced from 12.9% in unfertilized soil to 4.1%-7.4% in fertilized soil (P < 0.05). It was also found that the application of manure could cause a transient effect on soil resistome composition and the relative abundance of ARGs increased from 7.37 ppm to 32.10 ppm. The abundance of aminoglycoside, sulfonamide and tetracycline resistance genes greatly increased after manure fertilization and then gradually returned to normal levels with the decay of some intestinal bacteria carrying ARGs. In contrast, the application of chemical fertilizers and straw ash significantly changed the bacterial community structure but exerted little effect on soil resistome. Overall, the results of this study illustrated the different effects of different fertilizers on the soil resistome and revealed that the changes of soil resistome induced by manure application mainly resulted from alteration of bacteria community rather than the horizontal gene transfer.201728898777
703750.9996Impacts of cadmium addition on the alteration of microbial community and transport of antibiotic resistance genes in oxytetracycline contaminated soil. The large-scale development in livestock feed industry has increased the chances of antibiotics and heavy metals contamination in the soil. The fate of antibiotic resistance genes (ARGs) and microbial community in heavy metals and antibiotic contaminated soil is still unclear. In this study, we investigated the effect of cadmium (Cd) addition on the transport of ARGs, microbial community and human pathogenic bacteria in oxytetracycline (OTC) contaminated soil. Results showed that the addition of OTC significantly increased the abundance of ARGs and intI1 in the soil and lettuce tissues. The addition of Cd to OTC treated soil further increased the abundance and translocation of ARGs and intI1. Moreover, Cd promoted the transfer of potential human pathogenic bacteria (HPB) into lettuce tissues. Compared with O10 treatment, the addition of Cd decreased the concentration of OTC in soil and lettuce tissue, but slightly increased the fresh weight of lettuce tissues. Redundancy analysis indicated that bacterial community succession is a major factor in ARGs variation. Network analysis indicated that the main host bacteria of ARGs were mainly derived from Proteobacteria. Correlation analysis showed that intI1 was significantly correlated with tetG, tetC, sul1, sul2, ermX, and ermQ. Meanwhile, potential HPB (Clostridium, and Burkholderia) was significantly correlated with intI1 and eight ARGs (tetG, tetC, tetW, tetX, sul1, sul2, ermX, and ermQ.). The findings of this study suggest that the addition of heavy metals to agricultural fields must be considered in order to reduce the transfer of ARGs in the soil and crops.202133183716
725760.9996Housefly Larva Vermicomposting Efficiently Attenuates Antibiotic Resistance Genes in Swine Manure, with Concomitant Bacterial Population Changes. Manure from swine treated with antimicrobials as feed additives is a major source for the expansion of the antibiotic resistance gene (ARG) reservoir in the environment. Vermicomposting via housefly larvae (Musca domestica) can be efficiently used to treat manure and regenerate biofertilizer, but few studies have investigated its effect on ARG attenuation. Here, we tracked the abundances of 9 ARGs and the composition and structure of the bacterial communities in manure samples across 6 days of full-scale manure vermicomposting. On day 6, the abundances of genes encoding tetracycline resistance [tet(M), tet(O), tet(Q), and tet(W)] were reduced (P < 0.05), while those of genes encoding sulfonamide resistance (sul1 and sul2) were increased (P < 0.05) when normalized to 16S rRNA. The abundances of tetracycline resistance genes were correlated (P < 0.05) with the changing concentrations of tetracyclines in the manure. The overall diversity and richness of the bacteria significantly decreased during vermicomposting, accompanied by a 100 times increase in the relative abundance of Flavobacteriaceae spp. Variations in the abundances of ARGs were correlated with the changing microbial community structure and the relative abundances of the family Ruminococcaceae, class Bacilli, or phylum Proteobacteria. Vermicomposting, as a waste management practice, can reduce the overall abundance of ARGs. More research is warranted to assess the use of this waste management practice as a measure to attenuate the dissemination of antimicrobial residues and ARGs from livestock production before vermicompost can be safely used as biofertilizer in agroecosystems.201526296728
695070.9996Ceftiofur in swine manure contributes to reducing pathogens and antibiotic resistance genes during composting. Aerobic composting is a common way for the disposal of feces produced in animal husbandry, and can reduce the release of antibiotic resistance genes (ARGs) from feces into the environment. In this study, we collected samples from two distinct treatments of swine manure compost with and without ceftiofur (CEF), and identified the ARGs, mobile genetic elements (MGEs), and bacterial community by metagenomic sequencing. The impacts of CEF on the bacterial community composition and fate of ARGs and MGEs were investigated. With increasing composting temperature and pH, the concentration of CEF in the manure decreased rapidly, with a degradation half-life of 1.12 d and a 100% removal rate after 10 d of aerobic composting. Metagenomics demonstrated that CEF in the manure might inhibit the growth of Firmicutes and Proteobacteria, thereby reducing some ARGs and MGEs hosted by these two bacteria, which was further confirmed by the variations of ARGs and MGEs. A further redundancy analysis suggested that pH and temperature are key environmental factors affecting ARG removal during composting, and intI1 and bacterial communities also have significant influence on ARG abundance. These results are of great significance for promoting the removal of some ARGs from animal manure by controlling some key environmental factors and the type of antibiotics used in animals.202438685300
680780.9996Rainfall facilitates the transmission and proliferation of antibiotic resistance genes from ambient air to soil. Antibiotic resistance is common in bacterial communities and appears to be correlated with human activities. However, the source of antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) in remote regions remains unclear. In this study, we examined the abundance of ARGs in fine particulate matter (PM(2.5)) as a carrier throughout the rainfall process (4 mm rain/h) to observe the effects of rainfall on the transmission of ARGs. The results suggested that rainwater served as a reservoir that facilitated the spread of ARGs and that wind and particulate matter (PM) concentrations might be meteorological parameters that influence the distribution of ARGs in rainwater. In addition, soil microcosm experiments were performed to investigate the influence of rainfall on antibiotic resistance in soils with different environmental backgrounds. Rainwater facilitated the proliferation of ARGs and mobile genetic elements (MGEs) from ambient air to soil, and this influence was more obvious in heavy metal-contaminated soil. This is the first study to investigate the routes by which rainfall acts as a mobile reservoir to facilitate the transmission and proliferation of ARGs, and the results indicate the potential source of ARGs in remote regions where humans rarely interfere.202134352459
807890.9996Responses of bacterial communities and resistance genes on microplastics to antibiotics and heavy metals in sewage environment. In present study, copper (Cu), zinc (Zn), tetracycline (TC) and ampicillin (AMP) were selected to study the individual and synergistic effects of antibiotics and heavy metals on the microbial communities and resistance genes on polyvinyl chloride microplastics (PVC MPs) and surrounding sewage after 28 and 84 days. The results indicated that PVC MPs enriched many microorganisms from surrounding sewage, especially pathogenic bacteria such as Mycobacterium and Aquabacterium. The resistance gene with the highest abundance enriched on PVC MPs was tnpA (average abundance of 1.0 × 10(7) copies/mL sewage). The single presence of Zn, TC and AMP inhibited these enrichments for a short period of time (28 days). But the single presence of Cu and the co-existence of antibiotics and heavy metals inhibited these enrichments for a long period of time (84 days), resulting in relatively low microbial diversities and resistance genes abundances. Transpose tnpA had significantly positive correlations (p < 0.05) with all other genes. Pathogenic bacteria Mycobacterium and Legionella were potential hosts harboring 5 and 1 resistance genes, respectively. Overall, PVC MPs played important roles in the distribution and transfer of pathogenic bacteria and resistance genes in sewage with the presence of antibiotics or (and) heavy metals.202133254740
7026100.9996Organic fertilizer potentiates the transfer of typical antibiotic resistance gene among special bacterial species. The propagation of antibiotic resistance genes (ARGs) in environments has evoked many attentions, however, how to identify their host pathogenic bacteria in situ remains a great challenge. Here we explored the bacterial host distribution and dissemination of a typical ARG, sul1 gene, in agricultural soils through the simultaneous detection of sul1 and its host 16S rRNA gene by emulsion paired isolation and concatenation PCR (epicPCR). Compared to chemical fertilizer, organic fertilizer (chicken manure) led to a higher prevalence of sul1 gene in the soil, and dominant bacterial hosts of sul1 gene were classified into Proteobacteria and Bacteroidetes phyla. Additionally, significant higher diversity of antibiotic resistance bacteria (ARB), higher rate of horizontal gene transfer (HGT), higher rate of mobile genetic elements (MGE) and higher proportion of pathogens were all observed in the treatment of organic fertilizer. This study alerts potential health risks of manure applications in agricultural soils.202235483268
7003110.9996Vermicompost: In situ retardant of antibiotic resistome accumulation in cropland soils. The dissemination of antibiotic resistance genes (ARGs) in soil has become a global environmental issue. Vermicomposting is gaining prominence in agricultural practices as a soil amendment to improve soil quality. However, its impact on soil ARGs remains unclear when it occurs in farmland. We comprehensively explored the evolution and fate of ARGs and their hosts in the field soil profiles under vermicompost application for more than 3 years. Vermicompost application increased several ARG loads in soil environment but decreased the high-risk bla-ARGs (bla(ampC), bla(NDM), and bla(GES-1)) by log(0.04 - 0.43). ARGs in soil amended with vermicompost primarily occurred in topsoil (approximately 1.04-fold of unfertilized soil), but it is worth noting that their levels in the 40-60 cm soil layer were the same or even less than in the unfertilized soil. The microbial community structure changed in soil profiles after vermicompost application. Vermicompost application altered the microbial community structure in soil profiles, showing that the dominant bacteria (i.e., Proteobacteria, Actinobacteriota, Firmicutes) were decreased 2.62%-5.48% with the increase of soil depth. A network analysis further revealed that most of ARG dominant host bacteria did not migrate from surface soil to deep soil. In particular, those host bacteria harboring high-risk bla-ARGs were primarily concentrated in the surface soil. This study highlights a lower risk of the propagation of ARGs caused by vermicompost application and provides a novel approach to reduce and relieve the dissemination of ARGs derived from animals in agricultural production.202438408828
6931120.9996What role does organic fertilizer actually play in the fate of antibiotic resistome and pathogenic bacteria in planting soil? Organic fertilizer increase antibiotic resistance genes (ARGs) and bacterial pathogens have widely documented. However, how organic fertilizer is involved in changing soil ARGs and pathogenic bacteria after long-term (≥5 years) application remains unclear. Herein, the ARGs and pathogenic bacteria were compared in organic fertilized soils (AF) and non-fertilized soils (NF), and the contribution of input sources (organic fertilizer, irrigation water, air and background soil) on soil ARGs also was determined in this study. Results showed that the abundances of some ARGs, such as vanR and aac(6')-I in AF, were significantly higher than these of NF (p < 0.05). And a relatively higher abundance of potential pathogens, especially, Salmonella enterica and Stenotrophomonas maltophilia, in AF was observed. This indicated that organic fertilizer application can maintain a high level of some soil ARGs and pathogenic bacteria for at least 5 years. Traceability analysis unearthed that organic fertilizer application mainly increased its own contribution to soil ARGs from 1.16% to 9.05%, as well reduced the contribution of background soil, suggesting that the increase in soil ARGs may be partly attributable to organic fertilizer inputs. Notably, organic fertilizer application did not significantly alter the contribution ratio of input sources to microorganisms, but there was a clear change in the composition of soil microorganisms, which meant that the effect of the input source on the microorganism may emanate from other factors, rather than direct inputs. Subsequent structural equation demonstrated that organic fertilizer application significantly enhanced the effect of environmental factors on ARGs, and also indirectly increased the influence of communities on ARGs. Collectively, under the long-term fertilization, the role of organic fertilizers on soil ARGs not just stems from its own input, and also dominates the influence of environmental factors on ARGs. This study elucidates main causes for the difference in ARGs in AF vs. NF and enlightens actual role of organic fertilizer in them.202235623127
6948130.9996Fate of antibiotic resistance genes and metal resistance genes during the thermophilic fermentation of solid and liquid swine manures in an ectopic fermentation system. Environmental pollution due to resistance genes from livestock manure has become a serious issue that needs to be resolved. However, little studies focused on the removal of resistance genes in simultaneous processing of livestock feces and urine. This study investigated the fate of antibiotic resistance genes (ARGs), metal resistance genes (MRGs), and class 1 integron-integrase gene (intI1) during thermophilic fermentation of swine manure in an ectopic fermentation system (EFS), which has been regarded as a novel system for efficiently treating both feces and urine. The abundances of MRGs and tetracycline resistance genes were 34.44-97.71% lower in the EFS. The supplementation of heavy metals significantly increased the abundance of intI1, with the enhancement effect of copper being more prominent than that of zinc. The highest abundances of resistance genes and intI1 were observed at high Cu levels (A2), indicating that Cu can increase the spreading of resistance genes through integrons. Network analysis revealed the co-occurrence of ARGs, MRGs, and intI1, and these genes potentially shared the same host bacteria. Redundancy analysis showed that the bacterial community explained most of the variations in ARGs, and environmental factors had influences on ARGs abundances by modulating the bacterial community composition. The decreased Sphingomonas, Comamonas, Acinetobacter, Lactobacillus, Bartonella, Rhizobium, and Bacteroides were mainly responsible for the reduced resistance genes. These results demonstrate that EFS can reduce resistance genes in simultaneous processing of livestock feces and urine.202133592372
6847140.9996Nutrients, 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
8083150.9996Alteration of the migration trajectory of antibiotic resistance genes by microplastics in a leachate activated sludge system. The environmental behavior of emerging contaminants of microplastics (MPs), antibiotics and antibiotic resistance genes (ARGs) in the leachate activated sludge system has been monitored and analyzed comprehensively. The results suggested that MPs could effectively alter the migration trajectory of tetracycline resistance genes (tet genes) in the leachate activated sludge system under intermittent and continuous influent conditions. After adding MPs, the total average abundance of tet genes in leachate increased from 0.74 ± 0.07 to 0.78 ± 0.07 (log(10)tet genes/log(10) 16S rRNA) and that in sludge increased from 0.65 ± 0.08 to 0.70 ± 0.06 (log(10)tet genes/log(10) 16S rRNA). Except for tetA, the abundance of tetB, tetO, tetM and tetQ on MPs increased with increasing TC concentration under both aerobic and anaerobic conditions. MPs not only significantly affect the abundance level and migration trajectory of ARGs in the leachate activated sludge system, but also remarkably improve the level of heavy metals in the ambient environment, indirectly promoting the selective effect of antibiotic-resistant bacteria (ARB) and promoting the development of antibiotic resistance (AR). In addition, MPs changed their physicochemical properties and released hazardous substances with aging to force tet genes to migrate from the leachate activated sludge system to the MPs, making AR more difficult to eliminate and persisted in wastewater treatment plants. Meanwhile, microorganisms played a driving role, making MPs serve as a niche for ARGs and ARB colonization. The co-occurrence network analysis indicated the specific distribution pattern of tet genes and microorganisms in different media, and the potential host was speculated. This study improves the understanding of the environmental behavior of emerging contaminants in leachate activated sludge system and lays a theoretical for protecting the ecological environment.202337321316
7047160.9996Characteristics of airborne bacterial communities and antibiotic resistance genes under different air quality levels. Pathogenic bacteria and antibiotic resistance genes (ARGs) in bioaerosols are major threats to human health. In this study, the microbial community structure and ARG distribution characteristics of airborne bacteria in total suspended particulates (TSP) and PM(2.5) were investigated under different air quality levels in Xinxiang, Central China. The results revealed that with the deterioration of air quality, the concentrations of airborne bacteria in both TSP and PM(2.5) decreased; however, the relative amounts of pathogenic bacteria increased. The predominant genera in pathogenic bacteria of Bacillus, Sphingomonas, Corynebacterium, Rhodococcus, and Staphylococcus were identified in both TSP and PM(2.5). Although the airborne bacteria concentrations and absolute abundances of ARGs in TSP were higher than those in PM(2.5) under identical air quality conditions, the bacterial community structure and relative amounts of pathogenic bacteria were similar. In addition, the relationship between environmental factors of ions, metal elements, and meteorological parameters and the community structures of airborne bacteria and pathogenic bacteria were also analyzed. The effects of soluble ions and metal elements on several dominant genera of total bacteria and pathogenic bacteria differed, probably due to the strong tolerance of pathogenic bacteria to harsh atmospheric environments Different subtypes of ARGs showed various distribution characteristics with variations in air quality. The deterioration of air quality can inhibit the dissemination of ARGs, as the minimum values of all ARGs and class 1 integrase intI1 were observed under Severely Polluted conditions. This study provides a comprehensive understanding of the effect of air pollution levels on the airborne bacteria community composition and ARG distribution.202235180669
7255170.9996Distribution of quinolone and macrolide resistance genes and their co-occurrence with heavy metal resistance genes in vegetable soils with long-term application of manure. The spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) has become an increasingly serious global public health issue. This study investigated the distribution characteristics and influencing factors of ARB and ARGs in greenhouse vegetable soils with long-term application of manure. Five typical ARGs, four heavy metal resistance genes (MRGs), and two mobile genetic elements (MGEs) were quantified by real-time quantitative polymerase chain reaction (qPCR). The amount of ARB in manure-improved soil greatly exceeded that in control soil, and the bacterial resistance rate decreased significantly with increases in antibiotic concentrations. In addition, the resistance rate of ARB to enrofloxacin (ENR) was lower than that of tylosin (TYL). Real-time qPCR results showed that long-term application of manure enhanced the relative abundance of ARGs in vegetable soils, and the content and proportion of quinolone resistance genes were higher than those of macrolide resistance genes. Redundancy analysis (RDA) showed that qepA and qnrS significantly correlated with total and available amounts of Cu and Zn, highlighting that certain heavy metals can influence persistence of ARGs. Integrase gene intI1 correlated significantly with the relative abundance of qepA, qnrS, and ermF, suggesting that intI1 played an important role in the horizontal transfer of ARGs. Furthermore, there was a weakly but not significantly positive correlation between specific detected MRGs and ARGs and MGEs. The results of this study enhance understanding the potential for increasing ARGs in manure-applied soil, assessing ecological risk and reducing the spread of ARGs.202234559332
6902180.9996Antibiotic resistance genes in surface water and groundwater from mining affected environments. Mining activities are known to generate a large amount of mine tailings and acid mine drainage which contain varieties of heavy metals. Heavy metals play an important role in co-selection for bacterial antibiotic resistance. However, the characteristics of antibiotic resistance genes (ARGs) in mining-affected water environments are still unclear. Here we investigated the pollution of metals, profiles of ARGs, mobile genetic elements (MGEs) and microbial community in mining-affected surface water and groundwater. The results showed that in the tested water samples, the concentrations of Zn and Mn were the highest, and Ni was the lowest. Higher abundances of ARGs with great proportion of sulfonamides, chloramphenicols and tetracyclines resistance genes were found in mining-affected water when compared with those without mining activities. Additionally, there were positive correlations between heavy metals (especially Ni, Zn and Mn) and these ARGs. Linear regression analysis suggested that MGEs were positively correlated with ARGs. In addition, total phosphorus was correlated with ARGs (p < 0.05). The microbial community was different between the mining-affected water and the reference (p < 0.05). Proteobacteria, Bacteroidetes and Actinobacteria were dominant phyla in the surface water and groundwater. Network analysis showed that many ARGs were significantly associated with these dominant bacteria, which suggested they might be potential hosts for these ARGs. These findings provide a clear evidence that the mining activities in the study area had a significant impact on surface water and groundwater to different degrees.202133571766
7265190.9996Airborne bacterial communities and antibiotic resistance gene dynamics in PM(2.5) during rainfall. The biotoxicity and public health effects of airborne bacteria and antibiotic resistance genes (ARGs) in fine particulate matter (PM(2.5)) are being increasingly recognized. The characteristics of bacterial community composition and ARGs in PM(2.5) under different rainfall conditions were studied based on the on-site synchronous measurements in downtown Beijing. Marked differences were evident in the bacterial community characteristics of PM(2.5) before, during, and after rain events (p < 0.05). The rain intensities affected the bacterial community abundance in PM(2.5) and heavy rain had greater washing effects. The Proteobacteria (phylum level), α-Proteobacteria (class level), Pseudomonadales (order level), Pseudomonadaceae (family level), and Cyanobacteria (genus level) were the dominant bacterial taxa associated with PM(2.5) in Beijing during rain events. However, the bacteria at each level that displayed the biggest percentage variance was not the dominant type under different rain intensities. The ermB, tetW, and mphE genes were the primary ARGs, with abundances of 18 to 30 copies/m(3), which was a relatively smaller value than other observations. Real-time monitoring of the meteorological condition of rain events and physicochemical properties of PM(2.5) were used to identify the main factors during rainfall. The bacterial community was sensitive to the ionic and metal element components of PM(2.5) during rainfall. The abundance of ARGs was closely correlated with some groups of the bacterial community, which were also close to the initial value before the rain. Statistical analysis demonstrated that temperature, relative humidity, and duration of rain were the primary meteorological factors for the biological characteristics. The ionic species, rather than metal elements, in PM(2.5) were the sensitive factors for the bacteria community and ARGs, which varied at the phylum, class, order, family, and genus levels. The observations provide insights for the biological risk assessment in an urban rainfall water and the potential health impact on citizens.202031726367