# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 6991 | 0 | 0.9934 | Distribution and drivers of antibiotic resistance genes in brackish water aquaculture sediment. Brackish water aquaculture has brought numerous economic benefits, whereas anthropogenic activities in aquaculture may cause the dissemination of antibiotic resistance genes (ARGs) in brackish water sediments. The intricate relationships between environmental factors and microbial communities as well as their role in ARGs dissemination in brackish water aquaculture remain unclear. This study applied PCR and 16S sequencing to identify the variations in ARGs, class 1 integron gene (intI1) and microbial communities in brackish water aquaculture sediment. The distribution of ARGs in brackish water aquaculture sediment was similar to that in freshwater aquaculture, and the sulfonamide resistance gene sul1 was the indicator of ARGs. Proteobacteria and Firmicutes were the dominant phyla, and Paenisporosarcina (p_ Firmicutes) was the dominant genus. The results of correlation, network and redundancy analysis indicated that the microbial community in the brackish water aquaculture sediment was function-driven. The neutral model and variation partitioning analysis were used to verify the ecological processes of the bacterial community. The normalized stochasticity ratio showed that pond bacteria community was dominated by determinacy, which was affected by aquaculture activities. The total nitrogen and organic matter influenced the abundance of ARGs, while Proteobacteria and Thiobacillus (p_Proteobacteria) were the key antibiotic-resistant hosts. Our study provides insight into the prevalence of ARGs in brackish water aquaculture sediments, and indicates that brackish water aquaculture is a reservoir of ARGs. | 2023 | 36436623 |
| 7156 | 1 | 0.9933 | Effect of antibiotics, antibiotic-resistant bacteria, and extracellular antibiotic resistance genes on the fate of ARGs in marine sediments. Surface runoff is a prevalent source via which emerging pollutants (i.e., antibiotics, antibiotic-resistant bacteria (ARB), and antibiotic resistance genes (ARGs)) enter marine sediments. However, few studies have investigated the effect of emerging pollutants on the fate of ARGs in marine sediments. Therefore, three systems were established to measure the relative abundances of four common ARGs (i.e., bla(TEM), tetA, tetC, and aphA) and the integron-integrase gene (intI1) after exposure to emerging pollutants in marine sediments from the Bohai Sea, the Yellow Sea, the East China Sea, and the South China Sea in China. The results revealed that antibiotic exposure could decrease the relative abundance of most ARGs (including bla(TEM), tetA, and tetC) in these marine sediment samples. The exceptions were the relative abundance of bla(TEM) in the Bohai Sea marine sediments under ampicillin exposure and tetC in the Yellow Sea marine sediments under tetracycline exposure, which increased significantly. Among marine sediments challenged with ARB, the relative abundance of aphA in all four marine sediments displayed a decreasing trend, whereas the abundances of bla(TEM) and tetA in the marine sediments from the Bohai Sea and the South China Sea showed an increasing trend. The relative abundance of tetA in the marine sediments from the Yellow Sea and the East China Sea dropped markedly when exposed to extracellular ARG (eARG). Significant changes in bla(TEM) abundance were observed in the four marine sediments under eARG exposure. Gene aphA abundance showed the same trend as the intI1 abundance. IntI1 showed a decreasing trend under the exposure of antibiotic, ARB, or eARG, apart from the East and the South China Sea marine sediments under ampicillin conditions and the South China Sea marine sediments under RP4 plasmid condition. These findings suggest that dosing with emerging pollutants does not increase ARG abundance in marine sediments. | 2023 | 37245825 |
| 3542 | 2 | 0.9932 | 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 |
| 7091 | 3 | 0.9931 | Abundance of Class 1 Integron-Integrase and Sulfonamide Resistance Genes in River Water and Sediment Is Affected by Anthropogenic Pressure and Environmental Factors. In this study, we determined the presence of class 1 integron-integrase gene in culturable heterotrophic bacteria isolated from river water and sediment sampled upstream and downstream of a wastewater treatment plant effluent discharge. Moreover, we quantified intI1 and sulfonamide resistance genes (sul1 and sul2) in the water and sediment using qPCR. There was no correlation between the results from water and sediment samples, which suggests integron-containing bacteria are differentially retained in these two environmental compartments. The discharge of treated wastewater significantly increased the frequency of intI1 among culturable bacteria and the gene copy number in river water, and increased the number of sul1 genes in the sediment. We also observed seasonal differences in the frequency of the class 1 integron-integrase gene among culturable heterotrophs as well as intI1 copy number in water, but not in sediment. The results suggest that the abundance of class 1 integrons in aquatic habitat depends on anthropogenic pressure and environmental factors. | 2016 | 27599709 |
| 7133 | 4 | 0.9931 | 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 |
| 7350 | 5 | 0.9930 | The vertical distribution of tetA and intI1 in a deep lake is rather due to sedimentation than to resuspension. Lakes are exposed to anthropogenic pollution including the release of allochthonous bacteria into their waters. Antibiotic resistance genes (ARGs) stabilize in bacterial communities of temperate lakes, and these environments act as long-term reservoirs of ARGs. Still, it is not clear if the stabilization of the ARGs is caused by a periodical introduction, or by other factors regulated by dynamics within the water column. Here we observed the dynamics of the tetracycline resistance gene (tetA) and of the class 1 integron integrase gene intI1 a proxy of anthropogenic pollution in the water column and in the sediments of subalpine Lake Maggiore, together with several chemical, physical and microbiological variables. Both genes resulted more abundant within the bacterial community of the sediment compared to the water column and the water-sediment interface. Only at the inset of thermal stratification they reached quantifiable abundances in all the water layers, too. Moreover, the bacterial communities of the water-sediment interface were more similar to deep waters than to the sediments. These results suggest that the vertical distribution of tetA and intI1 is mainly due to the deposition of bacteria from the surface water to the sediment, while their resuspension from the sediment is less important. | 2020 | 31926010 |
| 7087 | 6 | 0.9930 | Antibiotic resistance in shellfish and major inland pollution sources in the drainage basin of Kamak Bay, Republic of Korea. Shellfish-growing areas in marine environments are affected by pollutants that mainly originate from land, including streams, domestic wastewater, and the effluents of wastewater treatment plants (WWTPs), which may function as reservoirs of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs). The objective of this study was to identify the occurrence and distribution of antibiotic resistance at five oyster sampling sites and 11 major inland pollution sources in the drainage basin of Kamak Bay, Republic of Korea. Culture-based methods were used to estimate the diversity and abundance of antibiotic-resistant Escherichia coli strains isolated from oysters and major inland pollution sources. The percentages of ARB and multiple antibiotic resistance index values were significantly high in discharge water from small fishing villages without WWTPs. However, the percentages of antibiotic-resistant E. coli isolates from oysters were low, as there was no impact from major inland pollutants. Fourteen ARGs were also quantified from oysters and major inland pollution sources. Although most ARGs except for quinolones were widely distributed in domestic wastewater discharge and effluent from WWTPs, macrolide resistance genes (ermB and msrA) were detected mainly from oysters in Kamak Bay. This study will aid in tracking the sources of antibiotic contamination in shellfish to determine the correlation between shellfish and inland pollution sources. | 2021 | 34226964 |
| 6994 | 7 | 0.9930 | Seasonal variations in antibiotic resistance genes in estuarine sediments and the driving mechanisms. Estuary sediments are chemically contaminated by adjacent coastal industrial cities, but the impact of organic pollutants on antibiotic resistance genes (ARGs) in estuarine sediments is unknown. We comprehensively analyzed the complex interactions between chemical pollutants (heavy metals and organic pollutants), mobile genetic elements (MGEs), and ARGs in estuarine sediments during various seasons. The results indicate that under the effects of the chemically polluted river water, the number of different estuarine sediment ARGs increased by 76.9%-92.3% in summer and 5.9%-35.3% in winter, and the abundance of these ARGs increased by 29-5195 times in summer and 48-239 times in winter. The abundance of sediment ARGs in distinct estuaries showed different seasonal trends. Seasonal changes had a greater impact on the abundance of estuarine sediment ARGs than on their diversity. The diversity of estuarine sediment ARGs was positively correlated with the chemical pollution levels. Furthermore, chemical pollution was positively correlated with MGEs, and MGEs were correlated with ARG abundance. These results indicate that ARGs are enriched in bacteria via horizontal gene transfer triggered by chemical pollution, promoting multi-antibiotic resistance in estuarine sediment bacteria. These findings have implications for our understanding of the distribution and propagation of ARGs in chemically polluted estuarine sediments. | 2020 | 31520936 |
| 6380 | 8 | 0.9930 | Seasonal dynamics of anammox bacteria in estuarial sediment of the Mai Po Nature Reserve revealed by analyzing the 16S rRNA and hydrazine oxidoreductase (hzo) genes. The community and population dynamics of anammox bacteria in summer (wet) and winter (dry) seasons in estuarial mudflat sediment of the Mai Po Nature Reserve were investigated by 16S rRNA and hydrazine oxidoreductase (hzo) genes. 16S rRNA phylogenetic diversity showed that sequences related to 'Kuenenia' anammox bacteria were presented in summer but not winter while 'Scalindua' anammox bacteria occurred in both seasons and could be divided into six different clusters. Compared to the 16S rRNA genes, the hzo genes revealed a relatively uniform seasonal diversity, with sequences relating to 'Scalindua', 'Anammoxoglobus', and planctomycete KSU-1 found in both seasons. The seasonal specific bacterial groups and diversity based on the 16S rRNA and hzo genes indicated strong seasonal community structures in estuary sediment of this site. Furthermore, the higher abundance of hzo genes in summer than winter indicates clear seasonal population dynamics. Combining the physicochemical characteristics of estuary sediment in the two seasons and their correlations with anammox bacteria community structure, we proposed the strong seasonal dynamics in estuary sediment of Mai Po to be due to the anthropogenic and terrestrial inputs, especially in summer, which brings in freshwater anammox bacteria, such as 'Kuenenia', interacting with the coastal marine anammox bacteria 'Scalindua'. | 2011 | 21487198 |
| 3498 | 9 | 0.9929 | Comparative study on the bacterial diversity and antibiotic resistance genes of urban landscape waters replenished by reclaimed water and surface water in Xi'an, China. Pathogenic bacteria and antibiotic resistance genes (ARGs) in urban landscape waters may pose a potential threat to human health. However, the investigation of their occurrence in the urban landscape waters replenished by reclaimed water (RW) and surface water (SW) is still insufficient. The water samples collected from six urban landscape waters replenished by RW or SW were used to analyze bacterial diversity using high-throughput sequencing of 16S rRNA gene and to detect 18 ARGs and 2 integron-integrase genes by means of quantitative PCR array. Results indicated that Proteobacteria was the dominant phylum in all six urban landscape waters. The bacterial species richness was lower in urban landscape waters replenished by RW than that by SW. Sulfonamide resistance genes (sulI and sulIII) were the major ARGs in these urban landscape waters. No significant difference in the relative abundance of sulfonamide resistance genes, tetracycline resistance genes, and most of beta-lactam resistance genes was observed between RW-replenished and SW-replenished urban landscape waters. By contrast, the relative abundance of bla(ampC) gene and qnrA gene in RW-replenished urban landscape waters was significantly higher than that in SW-replenished urban landscape waters (p < 0.05), which suggested that use of RW may increase the amount of specific ARGs to urban landscape waters. Interestingly, among six urban landscape waters, RW-replenished urban landscape waters had a relatively rich variety of ARGs (12-15 of 18 ARGs) but a low relative abundance of ARGs (458.90-1944.67 copies/16S × 10(6)). The RW replenishment was found to have a certain impact on the bacterial diversity and prevalence of ARGs in urban landscape waters, which provide new insight into the effect of RW replenishment on urban landscape waters. | 2021 | 33786766 |
| 3500 | 10 | 0.9929 | Shifts in bacterial communities and antibiotic resistance genes in surface water and gut microbiota of guppies (Poecilia reticulata) in the upper Rio Uberabinha, Brazil. Anthropogenic activities especially water pollution can affect the diversity and composition of microbial communities and promote the spread of antibiotic resistance genes (ARGs). In this study, water samples and guppies (Poecilia reticulata) were sampled from six sampling sites along the Uberabinha River in southeastern Brazil, both microbial communities and ARGs of surface waters and intestinal microbiota of guppies (Poecilia reticulata) were detected. According to the results of 16S rRNA amplicon sequencing, Proteobacteria, Bacteroidetes, Firmicutes and Actinobacteria were dominant phyla in both water and intestinal microbiota, but the abundance of putative pathogens was higher at heavily polluted sites. Up to 83% of bacteria in intestinal microbiota originated from water microbiota; this proportion was relatively higher in less polluted compared to polluted environments. ARGs providing resistance of tetracyclines and quinolones were dominant in both water and gut microbiota. The relative abundances of class I integrons and ARGs were as high as 1.74 × 10(-1)/16S rRNA copies and 3.61 × 10(-1)/16S rRNA copies, respectively, at heavily polluted sites. Correlation analysis suggests that integrons and bacteria play key roles in explaining the widespread occurrence of ARGs in the surface, but not in intestinal microbiota. We could rule out the class I integrons a potential intermediary bridge for ARGs between both types of microbiomes. Our results highlight the tight link in microbial communities and ARGs between ambient microbiota of stream ecosystems and intestinal microbiota of fish. Our study could have far-reaching consequences for fisheries and consumer safety and calls for investigations of gut microbiota of target species of both commercial fisheries and recreational (hobby) angling. | 2021 | 33497859 |
| 7096 | 11 | 0.9928 | Sulfonamide and tetracycline resistance genes in total- and culturable-bacterial assemblages in South African aquatic environments. Antibiotic resistant bacteria are ubiquitous in the natural environment. The introduction of effluent derived antibiotic resistance genes (ARGs) into aquatic environments is of concern in the spreading of genetic risk. This study showed the prevalence of sulfonamide and tetracycline resistance genes, sul1, sul2, sul3, and tet(M), in the total bacterial assemblage and colony forming bacterial assemblage in river and estuarine water and sewage treatment plants (STP) in South Africa. There was no correlation between antibiotic concentrations and ARGs, suggesting the targeted ARGs are spread in a wide area without connection to selection pressure. Among sul genes, sul1 and sul2 were major genes in the total (over 10(-2) copies/16S) and colony forming bacteria assemblages (∼10(-1) copies/16S). In urban waters, the sul3 gene was mostly not detectable in total and culturable assemblages, suggesting sul3 is not abundant. tet(M) was found in natural assemblages with 10(-3) copies/16S level in STP, but was not detected in colony forming bacteria, suggesting the non-culturable (yet-to-be cultured) bacterial community in urban surface waters and STP effluent possess the tet(M) gene. Sulfamethoxazole (SMX) resistant (SMX(r)) and oxytetracycline (OTC) resistant (OTC(r)) bacterial communities in urban waters possessed not only sul1 and sul2 but also sul3 and tet(M) genes. These genes are widely distributed in SMX(r) and OTC(r) bacteria. In conclusion, urban river and estuarine water and STP effluent in the Durban area were highly contaminated with ARGs, and the yet-to-be cultured bacterial community may act as a non-visible ARG reservoir in certain situations. | 2015 | 26300864 |
| 7276 | 12 | 0.9927 | 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 |
| 7360 | 13 | 0.9927 | Antibiotic resistance gene levels within a highly urbanised estuary. Antibiotic resistant bacteria are increasingly being found in aquatic environments, representing a potential threat to public health. To examine the dynamics and potential sources of antibiotic-resistant genes (ARGs) in urbanised waterways, we performed a six-month temporal study at six locations within the Sydney Harbour estuary. These locations spanned a salinity gradient from seawater at the mouth of the harbour to freshwater at the more urbanised western sites. We quantified the abundances of three ARGs (sulI, tetA, and dfrA1) and an anthropogenic pollution marker (intI1). To assess potential sources of environmental ARGs, we also quantified levels of the sewage marker (Lachnospiraceae), bird-associated faecal pollution markers (GFD), and a common wastewater pipe-dwelling genus of bacteria (Arcobacter). We assessed the impact of a major rainfall event on ARG levels during this period. The strong rainfall event led to increases in intI1 and ARGs (sulI and dfrA) across sites, but the potential source for ARGs was different. Some sites experienced sewage intrusions, as defined using the human-faecal marker Lachnospiraceae, which were clearly correlated with ARG levels. However, at the two sites furthest from the ocean, links between ARG levels and sewage were less evident, with correlations to other contaminants, including heavy metals, apparent. These results highlight the potential complexities associated with identifying, and ultimately remediating, the causes and sources of antimicrobial resistance within natural aquatic ecosystems. | 2025 | 39823941 |
| 6993 | 14 | 0.9927 | 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 |
| 7357 | 15 | 0.9926 | Metagenomic surveys show a widespread diffusion of antibiotic resistance genes in a transect from urbanized to marine protected area. Ports are hot spots of pollution; they receive pollution from land-based sources, marine traffic and port infrastructures. Marine ecosystems of nearby areas can be strongly affected by pollution from port-related activities. Here, we investigated the microbiomes present in sea floor sediments along a transect from the harbour of Livorno (Central Italy) to a nearby marine protected area. Results of 16S rRNA amplicon sequencing and metagenome assembled genomes (MAGs) analyses indicated the presence of different trends of specific bacterial groups (e.g. phyla NB1-j, Acidobacteriota and Desulfobulbales) along the transect, correlating with the measured pollution levels. Human pathogenic bacteria and antibiotic resistance genes (ARGs) were also found. These results demonstrate a pervasive impact of human port activities and highlight the importance of microbiological surveillance of marine sediments, which may constitute a reservoir of ARGs and pathogenic bacteria. | 2025 | 39908950 |
| 7351 | 16 | 0.9926 | Dynamics of integron structures across a wastewater network - Implications to resistance gene transfer. Class 1 and other integrons are common in wastewater networks, often being associated with antibiotic resistance genes (ARGs). However, the importance of different integron structures in ARG transfer within wastewater systems has only been implied, especially between community and hospital sources, among wastewater treatment plant compartments, and in receiving waters. This uncertainty is partly because current clinical class 1 integron qPCR assays (i.e., that target human-impacted structures, i.e., clintI1) poorly delineate clintI1 from non-impacted class 1 integron structures. They also say nothing about their ARG content. To fill these technical gaps, new real-time qPCR assays were developed for "impacted" class 1 structures (called aint1; i.e., anthropogenic class 1 integrons) and empty aint1 structures (i.e., carry no ARGs; called eaint1). The new assays and other integron assays then were used to examine integron dynamics across a wastewater network. 16S metagenomic sequencing also was performed to characterise associated microbiomes. aint1 abundances per bacterial cell were about 10 times greater in hospital wastewaters compared with other compartments, suggesting aint1 enrichment with ARGs in hospital sources. Conversely, the relative abundance of eaint1 structures were over double in recycled activated sludge compared with other compartments, except receiving waters (RAS; ∼30% of RAS class 1 structures did not carry ARGs). Microbiome analysis showed that human-associated bacterial taxa with mobile integrons also differed in RAS and river sediments. Further, class 1 integrons in RAS bacteria appear to have released ARGs, whereas hospital bacteria have accumulated ARGs. Results show that quantifying integron dynamics can help explain where ARG transfer occurs in wastewater networks, and should be considered in future studies on antibiotic resistance in the environment. | 2021 | 34673462 |
| 3506 | 17 | 0.9926 | Occurrence and distribution of antibiotic resistance genes in sediments in a semi-enclosed continental shelf sea. Extensive and improper overuse of antibiotics resulted in the prevalence of antibiotic resistance genes (ARGs). As the typical semi-enclosed continental shelf sea, the Bohai Sea has been considered as one of the most polluted marine areas in China. However, no comprehensive investigation on the spatial distribution of ARGs in sediments from the Bohai Sea has been reported. A large-scale sampling was performed in the Bohai Sea areas. The abundances of ARGs (6 classes, 29 ARG subtypes), class 1 integron-integrase gene (intI1), hmt-DNA and 16S rRNA gene were evaluated. IntI1 was detected with higher abundances in coastal areas ranging from 2.8 × 10(5) to 2.5 × 10(8) copies/g. The total ARGs abundances varied over 3 orders of magnitude in different sampling sites with the maximum at 4.9 × 10(8) copies/g. Sulfonamides resistance genes were ubiquitous and abundant with the abundances ranging from 5.7 × 10(4) to 1.8 × 10(7) copies/g, and quinolones resistance genes varied greatly in different samples. The contour map demonstrated that ARGs were more abundant in the Laizhou Bay, the south of Bohai Bay and the eastern of central sea basin. Most of the target ARG subtypes were detected with 100% detection frequencies. The genes of sul1, sul2 and tetX were detected with both higher absolute and relative abundance, while the abundance of β-lactams ARG subtypes was lower. Principal component analysis (PCA) and redundancy analysis (RDA) indicated that no significant differences in the ARGs abundance existed in different samples, and the sediment qualities played important roles in the distribution of ARGs. Bacterial communities were investigated and 768 strong and significant connections between ARGs and bacteria were identified. The possible hosts of ARGs were revealed by network analysis with higher relative abundance in coastal areas than the sea. | 2020 | 32325606 |
| 3517 | 18 | 0.9925 | Characterization of the bacterioplankton community and its antibiotic resistance genes in the Baltic Sea. The residues from human environments often contain antibiotics and antibiotic resistance genes (ARGs) that can contaminate natural environments; the clearest consequence of that is the selection of antibiotic-resistant bacteria. The Baltic Sea is the second largest isolated brackish water reservoir on Earth, serving as a drainage area for people in 14 countries, which differ from one another in antibiotic use and sewage treatment policies. The aim of this study was to characterize the bacterioplankton structure and quantify ARGs (tetA, tetB, tetM, ermB, sul1, blaSHV, and ampC) within the bacterioplankton community of the Baltic Sea. Quantitative polymerase chain reaction was applied to quantify ARGs from four different sampling sites of the Baltic Sea over 2 years, and the bacterial communities were profiled sequencing the V6 region of the 16S rRNA gene on Illumina HiSeq2000. The results revealed that all the resistance genes targeted in the study were detectable from the Baltic Sea bacterioplankton. The percentage of tetA, tetB, tetM, ermB, and sul1 genes in the sea bacterial community varied between 0.0077% and 0.1089%, 0.0003% and 0.0019%, 0.0001% and 0.0105%, 0% and 0.0136%, and 0.0001% and 0.0438%, respectively. The most numerous ARG detected was the tetA gene and this gene also had the highest proportion in the whole microbial community. A strong association between bacterioplankton ARGs' abundance data and community phylogenetic composition was found, implying that the abundance of most of the studied ARGs in the Baltic Sea is determined by fluctuations in its bacterial community structure. | 2014 | 23941523 |
| 3505 | 19 | 0.9925 | Temporal variation and sharing of antibiotic resistance genes between water and wild fish gut in a peri-urban river. Antibiotic resistance genes (ARGs) as emergence contaminations have spread widely in the water environment. Wild fish may be recipients and communicators of ARGs in the water environment, however, the distribution and transmission of ARGs in the wild fish and relevant water environment were rarely reported. Here, we have profiled ARGs and bacterial communities in wild freshwater fish and relevant water in a peri-urban river using high-throughput qPCR and 16S rRNA gene sequence. A total of 80 and 220 unique ARG subtypes were identified in fish and water samples. Fish and water both showed significant ARG seasonal variations (P < 0.05). The highest absolute abundance of ARGs in fish and water occurred in summer (1.32 × 10(9) copies per g, on average) and autumn (9.04 × 10(6) copies per mL), respectively. In addition, the bipartite network analysis showed that 9 ARGs and 1 mobile genetic element continuously shared in fish and water. Furthermore, bacteria shared in fish and water were found to significantly correlate with shard ARGs. The findings demonstrate that bacteria and ARGs in fish and water could interconnect and ARGs might transfer between fish and water using bacteria as a spreading medium. | 2021 | 33743895 |