# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 7073 | 0 | 0.9966 | Fecal Indicator Bacteria and Antibiotic Resistance Genes in Storm Runoff from Dairy Manure and Compost-Amended Vegetable Plots. Given the presence of antibiotics and resistant bacteria in livestock manures, it is important to identify the key pathways by which land-applied manure-derived soil amendments potentially spread resistance. The goal of this field-scale study was to identify the effects of different types of soil amendments (raw manure from cows treated with cephapirin and pirlimycin, compost from antibiotic-treated or antibiotic-free cows, or chemical fertilizer only) and crop type (lettuce [ L.] or radish [ L.]) on the transport of two antibiotic resistance genes (ARGs; 1 and ) via storm runoff from six naturally occurring storms. Concurrent quantification of sediment and fecal indicator bacteria (FIB; and enterococci) in runoff permitted comparison to traditional agricultural water quality targets that may be driving factors of ARG presence. Storm characteristics (total rainfall volume, storm duration, etc.) significantly influenced FIB concentration (two-way ANOVA, < 0.05), although both effects from individual storm events (Kruskal-Wallis, < 0.05) and vegetative cover influenced sediment levels. Composted and raw manure-amended plots both yielded significantly higher 1 and B levels in runoff for early storms, at least 8 wk following initial planting, relative to fertilizer-only or unamended barren plots. There was no significant difference between 1 or B levels in runoff from plots treated with compost derived from antibiotic-treated versus antibiotic-free dairy cattle. Our findings indicate that agricultural fields receiving manure-derived amendments release higher quantities of these two "indicator" ARGs in runoff, particularly during the early stages of the growing season, and that composting did not reduce effects of ARG loading in runoff. | 2019 | 31589689 |
| 7133 | 1 | 0.9965 | Prevalence of antibiotic resistance genes in bacterial communities associated with Cladophora glomerata mats along the nearshore of Lake Ontario. The alga Cladophora glomerata can erupt in nuisance blooms throughout the lower Great Lakes. Since bacterial abundance increases with the emergence and decay of Cladophora, we investigated the prevalence of antibiotic resistance (ABR) in Cladophora-associated bacterial communities up-gradient and down-gradient from a large sewage treatment plant (STP) on Lake Ontario. Although STPs are well-known sources of ABR, we also expected detectable ABR from up-gradient wetland communities, since they receive surface run-off from urban and agricultural sources. Statistically significant differences in aquatic bacterial abundance and ABR were found between down-gradient beach samples and up-gradient coastal wetland samples (ANOVA, Holm-Sidak test, p < 0.05). Decaying and free-floating Cladophora sampled near the STP had the highest bacterial densities overall, including on ampicillin- and vancomycin-treated plates. However, quantitative polymerase chain reaction analysis of the ABR genes ampC, tetA, tetB, and vanA from environmental communities showed a different pattern. Some of the highest ABR gene levels occurred at the 2 coastal wetland sites (vanA). Overall, bacterial ABR profiles from environmental samples were distinguishable between living and decaying Cladophora, inferring that Cladophora may control bacterial ABR depending on its life-cycle stage. Our results also show how spatially and temporally dynamic ABR is in nearshore aquatic bacteria, which warrants further research. | 2017 | 28192677 |
| 6993 | 2 | 0.9963 | Invisible threat: Marine suspended particles mediate delayed decay of antibiotic resistome in coastal effluents. Suspended particles are recognized as hotspots of antibiotic resistance genes (ARGs) in coastal waters. However, the dynamics of ARGs associated with suspended particles during sewage discharge into coastal environments remain poorly understood. This study simulated sewage influx into coastal waters using microcosms to investigate the decay dynamics of particle-associated (PA) and free-living (FL) ARGs. Results showed that four ARGs, including two sulfonamide resistance genes (sul1 and sul2) and two tetracycline resistance genes (tetB and tetG), exhibited significantly lower decay rates in the PA fraction than in the FL fraction. Specifically, bacterial decay (k = 0.96 day⁻¹) and horizontal gene transfer decay (k = 0.62 day⁻¹) were both slower in the PA fraction compared to the FL fraction (1.56 day⁻¹ and 1.98 day⁻¹, respectively). These results indicated that suspended particles slow down the decay of ARGs. Microbial community analysis revealed approximately 80 % similarity between sewage and seawater at day 0, but a marked increase in unique bacterial genera and unknown-source taxa was observed at day 15. These results suggest that sewage discharge rapidly alters the composition of native seawater communities. Furthermore, suspended particles harbored higher abundances of unknown-source bacteria and displayed stronger bacterial community interactions than the surrounding water. These findings advance our understanding of ARG persistence and microbial community dynamics, offering critical insights for understanding ARGs dissemination from wastewater discharge. | 2025 | 40373395 |
| 7081 | 3 | 0.9963 | Seasonal variations in export of antibiotic resistance genes and bacteria in runoff from an agricultural watershed in Iowa. Seasonal variations of antimicrobial resistance (AMR) indicators in runoff water can help improve our understanding of AMR sources and transport within an agricultural watershed. This study aimed to monitor multiple areas throughout the Black Hawk Lake (BHL) watershed (5324 ha) in central Iowa during 2017 and 2018 that consists of both swine and cattle feeding operations as well as known areas with manure application. The measured indicators included plate counts for fecal indicator bacteria (FIB) E. coli, Enterococcus, antibiotic resistant fecal indicator bacteria (ARBs) tylosin resistant Enterococcus, tetracycline resistant Enterococcus, and antibiotic resistance genes (ARGs): ermB, ermF (macrolide), tetA, tetM, tetO, tetW (tetracycline), sul1, sul2 (sulfonamide), aadA2 (aminoglycoside), vgaA, and vgaB (pleuromutilin). Both the plate count and the ARG analyses showed seasonal trends. Plate counts were significantly greater during the growing season, while the ARGs were greater in the pre-planting and post-harvest seasons (Wilcoxon Rank-Sum Test p < 0.05). The ermB gene concentration was significantly correlated (p < 0.05) with E. coli and Enterococcus concentrations in 2017, suggesting a potential use of this ARG as an indicator of environmental AMR and human health risk. Flow rate was not a significant contributor to annual variations in bacteria and AMR indicators. Based on observed seasonal patterns, we concluded that manure application was the likely contributor to elevated ARG indicators observed in the BHL watershed, while the driver of elevated ARB indictors in the growing season can only be speculated. Understanding AMR export patterns in agricultural watersheds provides public health officials knowledge of seasonal periods of higher AMR load to recreational waters. | 2020 | 32806354 |
| 7082 | 4 | 0.9962 | Catchment-scale export of antibiotic resistance genes and bacteria from an agricultural watershed in central Iowa. Antibiotics are administered to livestock in animal feeding operations (AFOs) for the control, prevention, and treatment of disease. Manure from antibiotic treated livestock contains unmetabolized antibiotics that provide selective pressure on bacteria, facilitating the expression of anti-microbial resistance (AMR). Manure application on row crops is an agronomic practice used by growers to meet crop nutrient needs; however, it can be a source of AMR to the soil and water environment. This study in central Iowa aims to directly compare AMR indicators in outlet runoff from two adjacent (221 to 229 ha) manured and non-manured catchments (manure comparison), and among three catchments (600 to 804 ha) with manure influence, no known manure application (control), and urban influences (mixed land use comparison). Monitored AMR indicators included antibiotic resistance genes (ARGs) ermB, ermF (macrolide), tetA, tetM, tetO, tetW (tetracycline), sul1, sul2 (sulfonamide), aadA2 (aminoglycoside), vgaA, and vgaB (pleuromutilin), and tylosin and tetracycline resistant enterococci bacteria. Results of the manure comparison showed significantly higher (p<0.05) tetracycline and tylosin resistant bacteria from the catchment with manure application in 2017, but no differences in 2018, possibly due to changes in antibiotic use resulting from the Veterinary Feed Directive. Moreover, the ARG analysis indicated a larger diversity of ARGs at the manure amended catchment. The mixed land use comparison showed the manure amended catchment had significantly higher (p<0.05) tetracycline resistant bacteria in 2017 and significantly higher tylosin resistant bacteria in 2017 and 2018 than the urban influenced catchment. The urban influenced catchment had significantly higher ermB concentrations in both sampling years, however the manure applied catchment runoff consisted of higher relative abundance of total ARGs. Additionally, both catchments showed higher AMR indicators compared to the control catchment. This study identifies four ARGs that might be specific to AMR as a result of agricultural sources (tetM, tetW, sul1, sul2) and optimal for use in watershed scale monitoring studies for tracking resistance in the environment. | 2020 | 31923233 |
| 7243 | 5 | 0.9962 | Responses and successions of sulfonamides, tetracyclines and fluoroquinolones resistance genes and bacterial community during the short-term storage of biogas residue and organic manure under the incubator and natural conditions. Biogas residue and organic manure are frequently used for crop planting. However, the evaluation of antibiotic resistant bacteria (ARB), antibiotic resistance genes (ARGs) and bacterial community before their applications to fields is still lacking. This study monitored the variations of bacteria resistant to sulfadiazine, tetracycline and norfloxacin, 57 resistance genes for sulfonamides, tetracyclines and fluoroquinolones as well as the bacterial community during the 28-day aerobic storage of biogas residue and organic manure by using viable plate counts, high-throughput qPCR and Illumina MiSeq sequencing methods. Then two storage conditions, incubator (25 °C) and natural environment, were used to assess the responses of ARB and ARGs to the environmental factors. Results showed that a total of 35 and 21 ARGs were detected in biogas residue and organic manure, respectively. ARB and ARGs were enriched up to 8.01-fold in biogas residue after the 28-day storage, but varied in a narrow range during the storage of organic manure. Compared with the incubator condition, the proliferation of ARB and ARGs in biogas residue under the natural condition was relatively inhibited by the varied and complicated environmental factors. However, we found that there was no significant difference of ARB and ARGs in organic manure between the incubator and natural conditions. Bacterial community was also shifted during the storage of biogas residue, especially Bacteroidetes_VC2.1_Bac22, Aequorivita, Luteimonas and Arenimonas. Network analysis revealed that the relationship in biogas residue was much more complicated than that in organic manure, which ultimately resulted in large successions of ARB and ARGs during the short-term storage of biogas residue. Therefore, we suggest that further measures should be taken before the application of biogas residue to fields. | 2018 | 30031308 |
| 3545 | 6 | 0.9961 | Fecal indicators and antibiotic resistance genes exhibit diurnal trends in the Chattahoochee River: Implications for water quality monitoring. Water bodies that serve as sources of drinking or recreational water are routinely monitored for fecal indicator bacteria (FIB) by state and local agencies. Exceedances of monitoring thresholds set by those agencies signal likely elevated human health risk from exposure, but FIB give little information about the potential source of contamination. To improve our understanding of how within-day variation could impact monitoring data interpretation, we conducted a study at two sites along the Chattahoochee River that varied in their recreational usage and adjacent land-use (natural versus urban), collecting samples every 30 min over one 24-h period. We assayed for three types of microbial indicators: FIB (total coliforms and Escherichia coli); human fecal-associated microbial source tracking (MST) markers (crAssphage and HF183/BacR287); and a suite of clinically relevant antibiotic resistance genes (ARGs; blaCTX-M, blaCMY, MCR, KPC, VIM, NDM) and a gene associated with antibiotic resistance (intl1). Mean levels of FIB and clinically relevant ARGs (blaCMY and KPC) were similar across sites, while MST markers and intI1 occurred at higher mean levels at the natural site. The human-associated MST markers positively correlated with antibiotic resistant-associated genes at both sites, but no consistent associations were detected between culturable FIB and any molecular markers. For all microbial indicators, generalized additive mixed models were used to examine diurnal variability and whether this variability was associated with environmental factors (water temperature, turbidity, pH, and sunlight). We found that FIB peaked during morning and early afternoon hours and were not associated with environmental factors. With the exception of HF183/BacR287 at the urban site, molecular MST markers and intI1 exhibited diurnal variability, and water temperature, pH, and turbidity were significantly associated with this variability. For blaCMY and KPC, diurnal variability was present but was not correlated with environmental factors. These results suggest that differences in land use (natural or urban) both adjacent and upstream may impact overall levels of microbial contamination. Monitoring agencies should consider matching sample collection times with peak levels of target microbial indicators, which would be in the morning or early afternoon for the fecal associated indicators. Measuring multiple microbial indicators can lead to clearer interpretations of human health risk associated with exposure to contaminated water. | 2022 | 36439800 |
| 7997 | 7 | 0.9961 | Survival of Antibiotic Resistant Bacteria and Horizontal Gene Transfer Control Antibiotic Resistance Gene Content in Anaerobic Digesters. Understanding fate of antibiotic resistant bacteria (ARB) vs. their antibiotic resistance genes (ARGs) during wastewater sludge treatment is critical in order to reduce the spread of antibiotic resistance through process optimization. Here, we spiked high concentrations of tetracycline-resistant bacteria, isolated from mesophilic (Iso M1-1-a Pseudomonas sp.) and thermophilic (Iso T10-a Bacillus sp.) anaerobic digested sludge, into batch digesters and monitored their fate by plate counts and quantitative polymerase chain reaction (QPCR) of their corresponding tetracycline ARGs. In batch studies, spiked ARB plate counts returned to baseline (thermophilic) or 1-log above baseline (mesophilic) while levels of the ARG present in the spiked isolate [tet(G)] remained high in mesophilic batch reactors. To compare results under semi-continuous flow conditions with natural influent variation, tet(O), tet(W), and sul1 ARGs, along with the intI1 integrase gene, were monitored over a 9-month period in the raw feed sludge and effluent sludge of lab-scale thermophilic and mesophilic anaerobic digesters. sul1 and intI1 in mesophilic and thermophilic digesters correlated positively (Spearman rho = 0.457-0.829, P < 0.05) with the raw feed sludge. There was no correlation in tet(O) or tet(W) ratios in raw sludge and mesophilic digested sludge or thermophilic digested sludge (Spearman rho = 0.130-0.486, P = 0.075-0.612). However, in the thermophilic digester, the tet(O) and tet(W) ratios remained consistently low over the entire monitoring period. We conclude that the influent sludge microbial composition can influence the ARG content of a digester, apparently as a result of differential survival or death of ARBs or horizontal gene transfer of genes between raw sludge ARBs and the digester microbial community. Notably, mesophilic digestion was more susceptible to ARG intrusion than thermophilic digestion, which may be attributed to a higher rate of ARB survival and/or horizontal gene transfer between raw sludge bacteria and the digester microbial community. | 2016 | 27014196 |
| 3516 | 8 | 0.9961 | Presence of microplastic particles increased abundance of pathogens and antimicrobial resistance genes in microbial communities from the Oder river water and sediment. High abundance of microplastic particles (MPs) in the water environment could be a factor in spreading of pathogens and antimicrobial resistance genes (AMR), especially antibiotic resistance genes (ARGs). The aim of our study was to assess changes in the microbial community developing on microplastic surfaces incubated in water from the Oder River-one of Central Europe's major rivers, flowing through three countries (Czechia, Germany, and Poland)-whose diverse, 20,000-km(2) catchment area (encompassing industrial, agricultural, and urban regions) ensures a relatively high abundance of microbial communities.Samples of water and sediment were taken from river in Wroclaw area. Then the water was poured into disinfected glass liquid containers and pre-drained sediment was added. Control samples of water and sediment were collected on day 0. Then microplastic particles were added (500 mg; ~ 1 mm). Subsequent sampling was performed after incubation on 7(th) and 14(th) day. From each group, samples of sediment and water were collected after the incubation period (n = 5/group), for extraction of microbial DNA and library preparation. Sequencing was performed, using MinION sequencer with 10.4.1 Flow cell. Galaxy Europe platform and R program (v 4.3.3), alpha diversity and PERMANOVA with Benjamini-Hochberg p-value correction for multiple comparisons were used. For identification of biomarker taxa being different between groups, ANCOMBC (Analysis of Compositions of Microbiomes with Bias Correction) was performed. Obtained results shown higher abundance of pathogenic bacteria such as Aeromonas salmonicida Vibrio spp., Escherichia coli or Salmonella after 7 days of incubation in water and sediment. Additionally, after 7 days of incubation numbers of ARGs was higher compared to control group. | 2025 | 40348784 |
| 7275 | 9 | 0.9961 | Bacterial lineages putatively associated with the dissemination of antibiotic resistance genes in a full-scale urban wastewater treatment plant. Urban wastewater treatment plants (UWTPs) are reservoirs of antibiotic resistance. Wastewater treatment changes the bacterial community and inevitably impacts the fate of antibiotic resistant bacteria and antibiotic resistance genes (ARGs). Some bacterial groups are major carriers of ARGs and hence, their elimination during wastewater treatment may contribute to increasing resistance removal efficiency. This study, conducted at a full-scale UWTP, evaluated variations in the bacterial community and ARGs loads and explored possible associations among them. With that aim, the bacterial community composition (16S rRNA gene Illumina sequencing) and ARGs abundance (real-time PCR) were characterized in samples of raw wastewater (RWW), secondary effluent (sTWW), after UV disinfection (tTWW), and after a period of 3 days storage to monitoring possible bacterial regrowth (tTWW-RE). Culturable enterobacteria were also enumerated. Secondary treatment was associated with the most dramatic bacterial community variations and coincided with reductions of ~2 log-units in the ARGs abundance. In contrast, no significant changes in the bacterial community composition and ARGs abundance were observed after UV disinfection of sTWW. Nevertheless, after UV treatment, viability losses were indicated ~2 log-units reductions of culturable enterobacteria. The analysed ARGs (qnrS, bla(CTX-M), bla(OXA-A), bla(TEM), bla(SHV), sul1, sul2, and intI1) were strongly correlated with taxa more abundant in RWW than in the other types of water, and which associated with humans and animals, such as members of the families Campylobacteraceae, Comamonadaceae, Aeromonadaceae, Moraxellaceae, and Bacteroidaceae. Further knowledge of the dynamics of the bacterial community during wastewater treatment and its relationship with ARGs variations may contribute with information useful for wastewater treatment optimization, aiming at a more effective resistance control. | 2018 | 29883764 |
| 7239 | 10 | 0.9961 | Full-scale mesophilic biogas plants using manure as C-source: bacterial community shifts along the process cause changes in the abundance of resistance genes and mobile genetic elements. The application of manure, typically harboring bacteria carrying resistance genes (RGs) and mobile genetic elements (MGEs), as co-substrate in biogas plants (BGPs) might be critical when digestates are used as fertilizers. In the present study, the relative abundance of RGs and MGEs in total community (TC-) DNA from manure, fermenters and digestate samples taken at eight full-scale BGPs co-fermenting manure were determined by real-time PCR. In addition, the bacterial community composition of all digestates as well as manure and fermenter material from one BGP (BGP3) was characterized by 454-pyrosequencing of 16S rRNA amplicons from TC-DNA. Compared to respective input manures, relative abundances determined for sul1, sul2, tet(M), tet(Q), intI1, qacEΔ1, korB and traN were significantly lower in fermenters, whereas relative abundances of tet(W) were often higher in fermenters. The bacterial communities in all digestates were dominated by Firmicutes and Bacteroidetes while Proteobacteria were low in abundance and no Enterobacteriaceae were detected. High-throughput sequencing revealed shifts in bacterial communities during treatment for BGP3. Although in comparison to manure, digestate bacteria had lower relative abundances of RGs and MGEs except for tet(W), mesophilic BGPs seem not to be effective for prevention of the spread of RGs and MGEs via digestates into arable soils. | 2016 | 26772986 |
| 8028 | 11 | 0.9960 | The 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. | 2022 | 35780677 |
| 3542 | 12 | 0.9960 | Fecal indicators, pathogens, antibiotic resistance genes, and ecotoxicity in Galveston Bay after Hurricane Harvey. Unprecedented rainfall after Hurricane Harvey caused a catastrophic flood in the southern coast of Texas, and flushed significant floodwater and sediments into Galveston Bay, the largest estuary along the Texas Gulf Coast. This study investigated the immediate and long-term (6 months post-Harvey) fecal indicators, pathogenic bacteria, antibiotic resistance genes (ARGs), and ecotoxicity in the Galveston Bay. Dramatic decrease of salinity profile to zero, increased levels of fecal indicator bacteria and pathogenic bacteria, and detection of various ARGs were observed in the water and sediment samples collected 2 weeks post-Harvey. High levels of Bla(TEM) and cytotoxicity measured by yeast bioluminescent assay (BLYR) were also observed especially near the river mouths. While Vibrio spp. was dominant in water, much higher abundance of fecal indicator bacteria and pathogen were detected in the sediments. A decreasing trend of Bla(TEM) and cytotoxicity was observed in March 2018 samples, suggesting the Bay has returned to its pre-hurricane conditions 6 months post-Harvey. Interestingly, the abundance of fecal indicator bacteria and pathogens were shifted dramatically according to high-streamflow and low-streamflow seasons in the Bay. The data are useful to construct the model of risk assessment in coastal estuaries system and predict the effects of extreme flooding events in the future. | 2021 | 33445049 |
| 7143 | 13 | 0.9960 | Simulated discharge of treated landfill leachates reveals a fueled development of antibiotic resistance in receiving tidal river. Around 350 million tons of solid waste is disposed of in landfills every year globally, with millions of cubic meters of landfill leachates released into neighboring environment. However, to date, little is known about the variations of antimicrobial resistance (AMR) in on-site leachate treatment systems and its development in leachate-receiving water environment. Here, we quantified 7 subtypes of antibiotic resistance genes (ARGs), 3 types of culturable antibiotic resistant bacteria (ARB) and 6 subtypes of mobile genetic elements (MGEs) in the effluents from a combined leachate treatment process, including biological treatment (MBR), physical separation (UF), ultraviolet (UV) disinfection and advanced oxidation process (AOP). The contents of ARGs, ARB and MGEs were generally enriched by the MBR, but then decreased significantly along with the tertiary treatment process. However, in the effluent-receiving water samples, the abundance of dominant ARGs (i.e. ermB, sul1, bla(TEM)) increased by 1.5 orders of magnitude within 96 h, alongside a general increase of MGEs (~10.0 log(10)(copies/mL) and total ARB (~1100 CFU/mL). Structural correlation analyses reveal that target ARGs were closely associated with MGEs, particularly in effluent-receiving samples (Procrustes test; M(2) = 0.49, R = 0.71, P = 0.001); and occurrences of ARB were majorly affected by ARG's distribution and environmental conditions (e.g. nitrogen speciation) in effluent and recipient groups, respectively. This study indicates that current treatment technologies and operation protocols are not feasible in countering the development of AMR in effluent-receiving water environment, particularly in tidal rivers that are capable of retaining contaminants for a long residence time. | 2018 | 29501852 |
| 7246 | 14 | 0.9960 | Tetracycline resistance genes are more prevalent in wet soils than in dry soils. This study aimed to reveal the effects of water content on the spread of tetracycline resistance genes (TRGs) in the soil. Amendments of four samples with different soil water contents, namely 16% (dry soil) and 25% (wet soil), and with or without pig manures (PM) were conducted under laboratory conditions. Quantitative polymerase chain reaction (q-PCR) results showed that the relative abundance of TRGs (tetB, tetC, tetM, tetO, tetT, and tetZ) in the wet soils was significantly higher than that in the dry soils whether under fertilization or non-fertilization conditions. Moreover, PM application enhanced the relative abundance of TRGs. The absolute copies of TRGs did not decline with the decrease in 16S rRNA genes in wet soils, implying that most TRGs were probably located in facultative anaerobic bacteria. However, cultivable tetracycline-resistant bacteria (TRB) in the wet soils were not in line with the q-PCR results, further indicating that aerobes might not account for the increases in the relative abundance of TRGs. Diversities of aerobic TRB were significantly higher in the wet soils than in the dry soils, especially on days 14 and 28. The patterns of community structures of aerobic TRB in the wet soils or dry soils containing PM were different from those in the dry soils. Together, this study showed that the variations in bacterial communities between the wet and dry soils, especially reflected in the diversity of aerobic TRB and/or community structure of facultative anaerobic TRB, might be an important reason behind the changes in the abundance of TRGs. | 2018 | 29573724 |
| 7265 | 15 | 0.9960 | Airborne 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. | 2020 | 31726367 |
| 7234 | 16 | 0.9960 | Urban and agriculturally influenced water contribute differently to the spread of antibiotic resistance genes in a mega-city river network. The widespread of water borne antibiotic resistance genes (ARGs) represents a growing threat to the health of millions of people. Our study detected the relative abundances of 10 ARG subtypes in the Shanghai river network, where the major ARG components were strB, sul1, and ermB. These ARGs were significantly enriched by the combined sewage, tail water from urban wastewater treatment plant and runoff from agricultural areas, which reached the Suzhou (SZ), Dianpu (DP), and Huangpu (HP) River, respectively (one-way ANOVA, P < 0.01). The target ARGs were distributed in varying patterns across different rivers. bla(CTX-M) and bla(TEM) contributed to the increase of total ARGs in the rivers influenced by urban sources, particularly in the SZ River, whose distribution of ARGs was significantly related to that of the confluence of the whole river network (Mantel test, P < 0.01). The bacterial community was closely structured with ARGs and potential pathogenic bacteria's association with target ARGs became significant in downstream samples (Procrustes test, P = 0.03). Water near urban wastewater fallouts was observed to have the highest content of intl1 in the DP River, whose downstream samples' intl -ARG relationship fitted the same regression model as that of the network confluence (R = 0.84, P < 0.001). The amelioration of river water quality does not reduce ARGs, but may affect their distributional patterns in the river network in Shanghai. | 2019 | 31009830 |
| 7276 | 17 | 0.9960 | Antibiotic resistance in urban and hospital wastewaters and their impact on a receiving freshwater ecosystem. The main objective of this study was to investigate the antibiotic resistance (AR) levels in wastewater (WW) and the impact on the receiving river. Samples were collected once per season over one year in the WW of a hospital, in the raw and treated WW of two wastewater treatment plants (WWTPs), as well as upstream and downstream from the release of WWTPs effluents into the Zenne River (Belgium). Culture-dependent methods were used to quantify Escherichia coli and heterotrophic bacteria resistant to amoxicillin, sulfamethoxazole, nalidixic acid and tetracycline. Six antibiotic resistance genes (ARGs) were quantified in both particle-attached (PAB) and free-living (FLB) bacteria. Our results showed that WWTPs efficiently removed antibiotic resistant bacteria (ARB) regardless of its AR profile. The ARGs levels were the highest in the hospital WW and were significantly reduced in both WWTPs. However, ARB and ARGs abundances significantly increased into the Zenne River downstream from the WWTPs outfalls. The variation in the relative abundance of ARGs through WW treatment differed depending on the WWTP, fraction, and gene considered. The sul1 and sul2 genes in PAB fraction showed significantly higher relative abundances in the effluent compared to the influent of both WWTPs. This study demonstrated that WWTPs could be hotspots for AR spread with significant impacts on receiving freshwater ecosystems. This was the first comprehensive study investigating at the same time antibiotics occurrence, fecal bacteria indicators, heterotrophic bacterial communities, and ARGs (distinguishing PAB and FLB) to assess AR levels in WW and impacts on the receiving river. | 2018 | 29730567 |
| 7216 | 18 | 0.9960 | Tracking antibiotic resistance through the environment near a biosolid spreading ground: Resistome changes, distribution, and metal(loid) co-selection. The application of urban wastewater treatment plants (WWTPs) products to agricultural lands has contributed to the rising level of antibiotic resistance and drawn a critical public health concern. It has not been thoroughly investigated at which spatial scales a biosolid applied area as a potentially predominant source affects surrounding soil resistomes. This study investigated distribution and impact of WWTP biosolids treated with anaerobic digestion on an agricultural area. Heterotrophic plate counts (HPCs) and quantitative polymerase chain reaction (qPCR) were performed for detection of selected antibiotic-resistant bacteria (ARB), selected antibiotic resistance genes (ARGs), intI1 genes, and 16S rRNA genes. Biosolid samples contained significantly higher levels of selected ARGs than the raw agricultural soils (p < 0.05). The average relative abundances of intI1, sul1, bla(SHV), and ermB genes were significantly higher in biosolid-amended soils than nearby agricultural soils (p < 0.05). Spatial interpolation analysis of relative gene abundances of intI1, sul1, sul2, and tetW across the studied area further indicated directional trends towards the northwest and southeast directions, highlighting possible airborne spread. Concentrations of Co, Cu, Ni, and Fe were found to be significantly and positively correlated with relative abundances of intI1, sul1, and tetW genes (p < 0.05). The resistance ratios of culturable antibiotic-resistant bacteria in agricultural soils with biosolid amendments were generally identical to those without biosolid amendments. This study will advance the understanding of the antibiotic resistome in agricultural soils impacted by long-term waste reuse and inform the evaluation strategies for future biosolids application and management. | 2022 | 35121038 |
| 6925 | 19 | 0.9960 | Multiple driving factors contribute to the variations of typical antibiotic resistance genes in different parts of soil-lettuce system. The application of manure compost may cause the transmission of antibiotic resistance genes (ARGs) in agroecological environment, which poses a global threat to public health. However, the driving factors for the transmission of ARGs from animal manure to agroecological systems remains poorly understood. Here, we explored the spatiotemporal variation in ARG abundance and bacterial community composition as well as relative driving factors in a soil-lettuce system amended with swine manure compost. The results showed that ARGs abundance had different variation trends in soil, lettuce phylloplane and endophyere after the application of swine manure compost. The temporal variations of total ARGs abundance had no significant different in soil and lettuce phylloplane, while lettuce endosphere enriched half of ARGs to the highest level at harvest. There was a significant linear correlation between ARGs and integrase genes (IGs). In contrast to the ARGs variation trend, the alpha diversity of soil and phylloplane bacteria showed increasing trends over planting time, and endosphere bacteria remained stable. Correlation analysis showed no identical ARG-related genera in the three parts, but the shared Proteobacteria, Pseudomonas, Halomonas and Chelativorans, from manure compost dominated ARG profile in the soil-lettuce system. Moreover, redundancy analysis and structural equation modelling showed the variations of ARGs may have resulted from the combination of multiple driving factors in soil-lettuce system. ARGs in soil were more affected by the IGs, antibiotic and heavy metals, and bacterial community structure and IGs were the major influencing factors of ARG profiles in the lettuce. The study provided insight into the multiple driving factors contribute to the variations of typical ARGs in different parts of soil-lettuce system, which was conducive to the risk assessment of ARGs in agroecosystem and the development of effective prevention and control measures for ARGs spread in the environment. | 2021 | 34562788 |