# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 7488 | 0 | 0.9947 | Metagenomic insights into microorganisms and antibiotic resistance genes of waste antibiotic fermentation residues along production, storage and treatment processes. Antibiotic fermentation residue (AFR) is nutrient-rich solid waste generated from fermentative antibiotic production process. It is demonstrated that AFR contains high-concentration of remaining antibiotics, and thus may promote antibiotic resistance development in receiving environment or feeding farmed animals. However, the dominate microorganisms and antibiotic resistance genes (ARGs) in AFRs have not been adequately explored, hampering understanding on the potential antibiotic resistance risk development caused by AFRs. Herein, seven kinds of representative AFRs along their production, storage, and treatment processes were collected, and multiple methods including amplicon sequencing, metagenomic sequencing, and bioinformatic approaches were adopted to explore the biological characteristics of AFRs. As expected, antibiotic fermentation producer was found as the predominant species in raw AFRs, which were collected at the outlet of fermentation tanks. However, except for producer species, more environment-derived species persisted in stored AFRs, which were temporarily stored at a semi-open space. Lactobacillus genus, classified as Firmicutes phylum and Bacilli class, became predominant bacterial taxa in stored AFRs, which might attribute to its tolerance to high concentration of antibiotics. Results from metagenomic sequencing together with assembly and binning approaches showed that these newly-colonizing species (e.g., Lactobacillus genus) tended to carry ARGs conferring resistance to the remaining antibiotic. However, after thermal treatment, remaining antibiotic could be efficiently removed from AFRs, and microorganisms together with DNA could be strongly destroyed. In sum, the main risk from the AFRs was the remaining antibiotic, while environment-derived bacteria which tolerate extreme environment, survived in ARFs with high content antibiotics, and may carry ARGs. Thus, hydrothermal or other harmless treatment technologies are recommended to remove antibiotic content and inactivate bacteria before recycling of AFRs in pharmaceutical industry. | 2024 | 37923454 |
| 7650 | 1 | 0.9947 | Contamination of hay and haylage with enteric bacteria and selected antibiotic resistance genes following fertilization with dairy manure or biosolids. The present study evaluated if enteric bacteria or antibiotic resistance genes carried in fecal amendments contaminate the hay at harvest, representing a potential route of exposure to ruminants that consume the hay. In the field experiments, dairy manure was applied to a hay field for three successive growing seasons, and biosolids were applied to a hay field for one growing season. Various enteric bacteria in the amendments were enumerated by viable plate count, and selected gene targets were quantified by qPCR. Key findings include the following: at harvest, hay receiving dairy manure or biosolids did not carry more viable enteric bacteria than hay from unamended control plots. The fermentation of hay did not result in a detectable increase in viable enteric bacteria. The application of dairy manure or biosolids resulted in a few gene targets being more abundant in hay during the first harvest. Fermentation of hay resulted in an increase in the abundance of gene targets, but this occurred with hay from both the amended and control plots. Overall, the application of fecal amendments resulted in an increase in the abundance of some gene targets associated with antibiotic resistance in the first cut hay. | 2022 | 35020524 |
| 7655 | 2 | 0.9946 | Impact of manure fertilization on the abundance of antibiotic-resistant bacteria and frequency of detection of antibiotic resistance genes in soil and on vegetables at harvest. Consumption of vegetables represents a route of direct human exposure to bacteria found in soil. The present study evaluated the complement of bacteria resistant to various antibiotics on vegetables often eaten raw (tomato, cucumber, pepper, carrot, radish, lettuce) and how this might vary with growth in soil fertilized inorganically or with dairy or swine manure. Vegetables were sown into field plots immediately following fertilization and harvested when of marketable quality. Vegetable and soil samples were evaluated for viable antibiotic-resistant bacteria by plate count on Chromocult medium supplemented with antibiotics at clinical breakpoint concentrations. DNA was extracted from soil and vegetables and evaluated by PCR for the presence of 46 gene targets associated with plasmid incompatibility groups, integrons, or antibiotic resistance genes. Soil receiving manure was enriched in antibiotic-resistant bacteria and various antibiotic resistance determinants. There was no coherent corresponding increase in the abundance of antibiotic-resistant bacteria enumerated from any vegetable grown in manure-fertilized soil. Numerous antibiotic resistance determinants were detected in DNA extracted from vegetables grown in unmanured soil. A smaller number of determinants were additionally detected on vegetables grown only in manured and not in unmanured soil. Overall, consumption of raw vegetables represents a route of human exposure to antibiotic-resistant bacteria and resistance determinants naturally present in soil. However, the detection of some determinants on vegetables grown only in freshly manured soil reinforces the advisability of pretreating manure through composting or other stabilization processes or mandating offset times between manuring and harvesting vegetables for human consumption. | 2013 | 23851089 |
| 7654 | 3 | 0.9944 | Impact of fertilizing with raw or anaerobically digested sewage sludge on the abundance of antibiotic-resistant coliforms, antibiotic resistance genes, and pathogenic bacteria in soil and on vegetables at harvest. The consumption of crops fertilized with human waste represents a potential route of exposure to antibiotic-resistant fecal bacteria. The present study evaluated the abundance of bacteria and antibiotic resistance genes by using both culture-dependent and molecular methods. Various vegetables (lettuce, carrots, radish, and tomatoes) were sown into field plots fertilized inorganically or with class B biosolids or untreated municipal sewage sludge and harvested when of marketable quality. Analysis of viable pathogenic bacteria or antibiotic-resistant coliform bacteria by plate counts did not reveal significant treatment effects of fertilization with class B biosolids or untreated sewage sludge on the vegetables. Numerous targeted genes associated with antibiotic resistance and mobile genetic elements were detected by PCR in soil and on vegetables at harvest from plots that received no organic amendment. However, in the season of application, vegetables harvested from plots treated with either material carried gene targets not detected in the absence of amendment. Several gene targets evaluated by using quantitative PCR (qPCR) were considerably more abundant on vegetables harvested from sewage sludge-treated plots than on vegetables from control plots in the season of application, whereas vegetables harvested the following year revealed no treatment effect. Overall, the results of the present study suggest that producing vegetable crops in ground fertilized with human waste without appropriate delay or pretreatment will result in an additional burden of antibiotic resistance genes on harvested crops. Managing human exposure to antibiotic resistance genes carried in human waste must be undertaken through judicious agricultural practice. | 2014 | 25172864 |
| 7356 | 4 | 0.9944 | Tossed 'good luck' coins as vectors for anthropogenic pollution into aquatic environment. Superstition has it that tossing coins into wells or fountains brings good luck, thereby causing a potential accumulation of microbially contaminated metal particles in the water. Here, we characterized the microbiota and the resistance profile in biofilm on such coins and their surrounding sediments. The study site was a tidal marine lake within a touristic center located in a natural reserve area. Notwithstanding the fact that coin-related biofilms were dominated by typical marine taxa, coin biofilms had specific microbial communities that were different from the communities of the surrounding sediment. Moreover, the communities were different depending on whether the coin were made mainly of steel or of copper. Sequences affiliated with putative pathogens were found on every third coin but were not found in the surrounding sediment. Antibiotic resistance genes (ARGs) were detected on most of the coins, and interestingly, sediments close to the area where coins accumulate had a higher frequency of ARGs. We suggest that the surface of the coins might offer a niche for ARGs and faecal bacteria to survive, and, thus, tossed coins are a potential source and vector for ARGs into the surrounding environment. | 2020 | 31887589 |
| 7652 | 5 | 0.9944 | Safely coupling livestock and crop production systems: how rapidly do antibiotic resistance genes dissipate in soil following a commercial application of swine or dairy manure? Animal manures recycled onto crop production land carry antibiotic-resistant bacteria. The present study evaluated the fate in soil of selected genes associated with antibiotic resistance or genetic mobility in field plots cropped to vegetables and managed according to normal farming practice. Referenced to unmanured soil, fertilization with swine or dairy manure increased the relative abundance of the gene targets sul1, erm(B), str(B), int1, and IncW repA. Following manure application in the spring of 2012, gene copy number decayed exponentially, reaching background levels by the fall of 2012. In contrast, gene copy number following manure application in the fall of 2012 or spring of 2013 increased significantly in the weeks following application and then declined. In both cases, the relative abundance of gene copy numbers had not returned to background levels by the fall of 2013. Overall, these results suggest that under conditions characteristic of agriculture in a humid continental climate, a 1-year period following a commercial application of raw manure is sufficient to ensure that an additional soil burden of antibiotic resistance genes approaches background. The relative abundance of several gene targets exceeded background during the growing season following a spring application or an application done the previous fall. Results from the present study reinforce the advisability of treating manure prior to use in crop production systems. | 2014 | 24632259 |
| 7458 | 6 | 0.9942 | Hidden Resistome: Enrichment Reveals the Presence of Clinically Relevant Antibiotic Resistance Determinants in Treated Wastewater-Irrigated Soils. Treated-wastewater (TW) irrigation transfers antibiotic-resistant bacteria (ARB) to soil, but persistence of these bacteria is generally low due to resilience of the soil microbiome. Nonetheless, wastewater-derived bacteria and associated antibiotic resistance genes (ARGs) may persist below detection levels and potentially proliferate under copiotrophic conditions. To test this hypothesis, we exposed soils from microcosm, lysimeter, and field experiments to short-term enrichment in copiotroph-stimulating media. In microcosms, enrichment stimulated growth of multidrug-resistant Escherichia coli up to 2 weeks after falling below detection limits. Lysimeter and orchard soils irrigated in-tandem with either freshwater or TW were subjected to culture-based, qPCR and shotgun metagenomic analyses prior, and subsequent, to enrichment. Although native TW- and freshwater-irrigated soil microbiomes and resistomes were similar to each other, enrichment resulted in higher abundances of cephalosporin- and carbapenem-resistant Enterobacteriaceae and in substantial differences in the composition of microbial communities and ARGs. Enrichment stimulated ARG-harboring Bacillaceae in the freshwater-irrigated soils, whereas in TWW-irrigated soils, ARG-harboring γ-proteobacterial families Enterobacteriaceae and Moraxellaceae were more profuse. We demonstrate that TW-derived ARB and associated ARGs can persist at below detection levels in irrigated soils and believe that similar short-term enrichment strategies can be applied for environmental antimicrobial risk assessment in the future. | 2021 | 33904706 |
| 7453 | 7 | 0.9942 | Long-term application of Swedish sewage sludge on farmland does not cause clear changes in the soil bacterial resistome. The widespread practice of applying sewage sludge to arable land makes use of nutrients indispensable for crops and reduces the need for inorganic fertilizer, however this application also provides a potential route for human exposure to chemical contaminants and microbial pathogens in the sludge. A recent concern is that such practice could promote environmental selection and dissemination of antibiotic resistant bacteria or resistance genes. Understanding the risks of sludge amendment in relation to antibiotic resistance development is important for sustainable agriculture, waste treatment and infectious disease management. To assess such risks, we took advantage of an agricultural field trial in southern Sweden, where land used for growing different crops has been amended with sludge every four years since 1981. We sampled raw, semi-digested and digested and stored sludge together with soils from the experimental plots before and two weeks after the most recent amendment in 2017. Levels of selected antimicrobials and bioavailable metals were determined and microbial effects were evaluated using both culture-independent metagenome sequencing and conventional culturing. Antimicrobials or bioavailable metals (Cu and Zn) did not accumulate to levels of concern for environmental selection of antibiotic resistance, and no coherent signs, neither on short or long time scales, of enrichment of antibiotic-resistant bacteria or resistance genes were found in soils amended with digested and stored sewage sludge in doses up to 12 metric tons per hectare. Likewise, only very few and slight differences in microbial community composition were observed after sludge amendment. Taken together, the current study does not indicate risks of sludge amendment related to antibiotic resistance development under the given conditions. Extrapolations should however be done with care as sludge quality and application practices vary between regions. Hence, the antibiotic concentrations and resistance load of the sludge are likely to be higher in regions with larger antibiotic consumption and resistance burden than Sweden. | 2020 | 32036119 |
| 7063 | 8 | 0.9942 | Impact of dairy manure pre-application treatment on manure composition, soil dynamics of antibiotic resistance genes, and abundance of antibiotic-resistance genes on vegetables at harvest. Manuring ground used for crop production is an important agricultural practice. Should antibiotic-resistant enteric bacteria carried in the manure be transferred to crops that are consumed raw, their consumption by humans or animals will represent a route of exposure to antibiotic resistance genes. Treatment of manures prior to land application is a potential management option to reduce the abundance of antibiotic resistance genes entrained with manure application. In this study, dairy manure that was untreated, anaerobically digested, mechanically dewatered or composted was applied to field plots that were then cropped to lettuce, carrots and radishes. The impact of treatment on manure composition, persistence of antibiotic resistance gene targets in soil following application, and distribution of antibiotic resistance genes and bacteria on vegetables at harvest was determined. Composted manure had the lowest abundance of antibiotic resistance gene targets compared to the other manures. There was no significant difference in the persistence characteristics of antibiotic resistance genes following land application of the various manures. Compared to unmanured soil, antibiotic resistance genes were detected more frequently in soil receiving raw or digested manure, whereas they were not in soil receiving composted manure. The present study suggests that vegetables grown in ground receiving raw or digested manure are at risk of contamination with manure-borne antibiotic resistant bacteria, whereas vegetables grown in ground receiving composted manure are less so. | 2017 | 28076772 |
| 7731 | 9 | 0.9942 | Biochemical Recurrence in Prostate Cancer Is Associated with the Composition of Lactobacillus: Microbiome Analysis of Prostatic Tissue. Many human pathologies, such as malignancy, are linked with specific bacteria and changes in the constituents of the microbiome. In order to examine the association between an imbalance of bacteria and prostate carcinoma, a comparison of the microbiomes present in patients with biochemical recurrence (BCR) or NO BCR (NBCR) was performed. Additionally, 16S rRNA-based next-generation sequencing was applied to identify the bacterial profiles within these tumors in terms of the bacteria and operational genes present. The percentage average taxonomic composition between the taxa indicated no difference between BCR and NBCR. In addition, alpha and beta diversity indices presented no distinction between the cohorts in any statistical method. However, taxonomic biomarker discovery indicated a relatively higher population of Lactobacillus in the NBCR group, and this finding was supported by PCR data. Along with that, differences in the operational activity of the bacterial genes were also determined. It is proposed that the biochemical recurrence was linked to the quantity of Lactobacillus present. The aim of this study was to investigate the microbiome involved in prostate carcinoma and the potential association between them. | 2023 | 37445601 |
| 7489 | 10 | 0.9942 | Rethinking water treatment targets: Bacteria regrowth under unprovable conditions. Ozonation is among the currently used technologies to remove chemical and biological contaminants from secondary treated urban wastewater (UWW). Despite its effectiveness on the abatement of organic micropollutants (OMPs) and disinfection, previous studies have shown that regrow of bacteria may occur upon storage of the ozonated UWW. This reactivation has been attributed to the high content of assimilable organic carbon after treatment. In order to investigate if ozonation by-products are the main biological regrowth drivers in stored ozonated UWW, the ozonation surviving cells were resuspended in sterile bottled mineral water (MW), simulating a pristine oligotrophic environment. After 7 days storage, organisms such as Acinetobacter, Methylobacterium, Cupriavidus, Massilia, Acidovorax and Pseudomonas were dominant in both ozonated UWW and pristine MW, demonstrating that bacterial regrowth is not strictly related to the eventual presence of ozonation by-products, but instead with the ability of the surviving cells to cope with nutrient-poor environments. The resistome of UWW before and after ozonation was analysed by metagenomic techniques. Draft metagenome assembled genomes (dMAGs), recovered from both ozonated UWW and after cell resuspension in MW, harboured genes conferring resistance to diverse antibiotics classes. Some of these antibiotic resistance genes (ARGs) were located in the vicinity of mobile genetic elements, suggesting their potential to be mobilized. Among these, dMAGs affiliated to taxa with high relative abundance in stored water, such as P. aeruginosa and Acinetobacter spp., harboured ARGs conferring resistance to 12 and 4 families of antibiotics, respectively, including those encoding carbapenem hydrolysing oxacillinases. The results herein obtained point out that the design and development of new wastewater treatment technologies should include measures to attenuate the imbalance of the bacterial communities promoted by storage of the final treated wastewater, even when applying processes with high mineralization rates. | 2021 | 34214892 |
| 7377 | 11 | 0.9942 | Impact of treated wastewater irrigation on antibiotic resistance in agricultural soils. Antibiotic resistance (AR) is a global phenomenon with severe epidemiological ramifications. Anthropogenically impacted natural aquatic and terrestrial environments can serve as reservoirs of antibiotic resistance genes (ARG), which can be horizontally transferred to human-associated bacteria through water and food webs, and thus contribute to AR proliferation. Treated-wastewater (TWW) irrigation is becoming increasingly prevalent in arid regions of the world, due to growing demand and decline in freshwater supplies. The release of residual antibiotic compounds, AR bacteria, and ARGs from wastewater effluent may result in proliferation of AR in irrigated soil microcosms. The aim of this study was to assess the impact of TWW-irrigation on soil AR bacterial and ARG reservoirs. Tetracycline, erythromycin, sulfonamide, and ciprofloxacin resistance in soil was assessed using standard culture-based isolation methods and culture-independent molecular analysis using quantitative real-time PCR (qPCR). High levels of bacterial antibiotic resistance were detected in both freshwater- and TWW-irrigated soils. Nonetheless, in most of the soils analyzed, AR bacteria and ARG levels in TWW-irrigated soils were on the whole identical (or sometimes even lower) than in the freshwater-irrigated soils, indicating that the high number of resistant bacteria that enter the soils from the TWW are not able to compete or survive in the soil environment and that they do not significantly contribute ARG to soil bacteria. This strongly suggests that the impact of the TWW-associated bacteria on the soil microbiome is on the whole negligible, and that the high levels of AR bacteria and ARGs in both the freshwater- and the TWW-irrigated soils are indicative of native AR associated with the natural soil microbiome. | 2012 | 22494147 |
| 7653 | 12 | 0.9941 | The impact of municipal sewage sludge stabilization processes on the abundance, field persistence, and transmission of antibiotic resistant bacteria and antibiotic resistance genes to vegetables at harvest. Biosolids were obtained from four Ontario municipalities that vary in how the sewage sludge is treated. These included a Class B biosolids that was anaerobically digested, a Class A biosolids that were heat treated and pelletized (Propell), and two Class A biosolids that were stabilized using either the N-Viro (N-Rich) or Lystek (LysteGro) processes. Viable enteric indicator or pathogenic bacteria in the biosolids were enumerated by plate count, gene targets associated with antibiotic resistance or horizontal gene transfer were detected by PCR, and a subset of these gene targets were quantified by qPCR. Following application at commercial rates to field plots, the persistence of enteric bacteria and gene targets in soil was followed during the growing season. Carrots, radishes and lettuce were sown into the amended and unamended control plots, and the diversity and abundance of gene targets they carried at harvest determined. All three Class A biosolids carried fewer and less abundant antibiotic resistance genes than did the Class B biosolids, in particular the very alkaline N-Viro product (N-Rich). Following application, some gene targets (e.g. int1, sul1, strA/B, aadA) that are typically associated with mobile gene cassettes remained detectable throughout the growing season, whereas others (e.g. ermB, ermF, bla(OXA20)) that are not associated with cassettes became undetectable within three weeks or less. At harvest a larger number of gene targets were detected on the carrots and radishes than in the lettuce. Overall, land application of Class A biosolids will entrain fewer viable bacteria and genes associated with antibiotic resistance into crop ground than will amendment with Class B biosolids. | 2019 | 30316087 |
| 6052 | 13 | 0.9941 | Safety and technological application of autochthonous Streptococcus thermophilus cultures in the buffalo Mozzarella cheese. Thermophilic and mesophilic lactic acid bacteria (LAB), such as Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus helveticus, and Lactococcus lactis, play a crucial role in the technological and sensory quality of Mozzarella cheese. In this study, the safety (genes encoding virulence factors and antibiotic resistance) and acidifying activity of autochthonous S. thermophilus cultures were evaluated in order to choose the most suitable strain for industrial application. The safe and good acidifying culture was tested in two buffalo Mozzarella cheese batches: Mozzarella cheeses produced with autochthonous culture (SJRP107) and commercial culture (STM5). The cultivable LAB was evaluated by culture-dependent method (plate counting) and the quantification of S. thermophilus cultures (commercial and autochthonous) were evaluated by culture-independent method RealT-qPCR (real-time quantitative polymerase chain reaction). The texture, physicochemical and proteolytic properties of the Mozzarella cheeses were similar for both batches. The nonstarter LAB count was higher during manufacture than in the storage, and the RealT-qPCR indicated the presence of S. thermophilus culture until the end of storage. S. thermophilus SJRP107 presented high potential for safety application in the production of Mozzarella cheese. Furthermore, considering the culture characteristics and their relationship with product quality, further studies could be helpful to determine their effect on the sensory characteristics of the cheese. | 2020 | 31948624 |
| 7649 | 14 | 0.9941 | Pathogenic bacteria in biogas plants using cattle, swine, and poultry manure. Fugate, a waste product from biogas production, regularly used in agriculture as a fertiliser, may contain bacterial pathogens that cause zoonoses. Anaerobic digestion (AD) can inactivate viable pathogens, including parasites, viruses, and pathogens containing antibiotic resistance genes. This study aimed to compare the numbers of pathogenic bacteria and diversity of potential bacterial pathogens in the fugate using three different types of slurry: cattle, swine, and poultry manure. The swine fugate showed higher numbers of Clostridium perfringens and Campylobacter sp. than the poultry and cattle fugate. In the cattle fugate, the lowest total number of pathogenic bacteria and a low number of coliforms were detected after the AD. The use of cattle manure in biogas plants presents a lower potential for soil contamination with pathogens. The fugate produced using poultry or swine manure can be used carefully to avoid possibility of contamination of aquifers or surface waters. Also fugate produced from manure of cows suffering from chronic botulism can be used only with carefulness because of the presence of Clostridium botulinum spores in biogas waste of diseased cows. | 2025 | 40735305 |
| 7128 | 15 | 0.9940 | Composting of chicken litter from commercial broiler farms reduces the abundance of viable enteric bacteria, Firmicutes, and selected antibiotic resistance genes. We examined the ability of composting to remove ARGs and enteric bacteria in litter obtained from broiler chickens fed with a diet supplemented with Bacitracin methylene disalicylate (BDM) (conventional chicken litter), or an antibiotic-free diet (raised without antibiotic (RWA) chicken litter). This was done by evaluating the litter before and after composting for the abundance of ten gene targets associated with antibiotic resistance or horizontal gene transfer, the composition of the bacterial communities, and the abundance of viable enteric bacteria. The abundance of gene targets was determined by qPCR and the microbial community composition of chicken litter determined by 16S rRNA gene amplicon sequencing. Enteric bacteria were enumerated by viable plate count. A majority of the gene targets were more abundant in conventional than in RWA litter. In both litter types, the absolute abundance of all of the target genes decreased after composting except sul1, intI1, incW and erm(F) that remained stable. Composting significantly reduced the abundance of enteric bacteria, including those carrying antibiotic resistance. The major difference in bacterial community composition between conventional and RWA litter was due to members affiliated to the genus Pseudomonas, which were 28% more abundant in conventional than in RWA litter. Composting favoured the presence of thermophilic bacteria, such as those affiliated with the genus Truepera, but decreased the abundance of those bacterial genera associated with cold-adapted species, such as Carnobacterium, Psychrobacter and Oceanisphaera. The present study shows that chicken litter from broilers fed with a diet supplemented with antibiotic has an increased abundance of some ARGs, even after composting. However, we can conclude that fertilization with composted litter represents a reduced risk of transmission of antibiotic resistance genes and enteric bacteria of poultry origin to soil and crops than will fertilization with raw litter. | 2020 | 32768779 |
| 7065 | 16 | 0.9940 | Exploring the immediate and long-term impact on bacterial communities in soil amended with animal and urban organic waste fertilizers using pyrosequencing and screening for horizontal transfer of antibiotic resistance. We investigated immediate and long-term effects on bacterial populations of soil amended with cattle manure, sewage sludge or municipal solid waste compost in an ongoing agricultural field trial. Soils were sampled in weeks 0, 3, 9 and 29 after fertilizer application. Pseudomonas isolates were enumerated, and the impact on soil bacterial community structure was investigated using 16S rRNA amplicon pyrosequencing. Bacterial community structure at phylum level remained mostly unaffected. Actinobacteria, Proteobacteria and Chloroflexi were the most prevalent phyla significantly responding to sampling time. Seasonal changes seemed to prevail with decreasing bacterial richness in week 9 followed by a significant increase in week 29 (springtime). The Pseudomonas population richness seemed temporarily affected by fertilizer treatments, especially in sludge- and compost-amended soils. To explain these changes, prevalence of antibiotic- and mercury-resistant pseudomonads was investigated. Fertilizer amendment had a transient impact on the resistance profile of the soil community; abundance of resistant isolates decreased with time after fertilizer application, but persistent strains appeared multiresistant, also in unfertilized soil. Finally, the ability of a P. putida strain to take up resistance genes from indigenous soil bacteria by horizontal gene transfer was present only in week 0, indicating a temporary increase in prevalence of transferable antibiotic resistance genes. | 2014 | 25087596 |
| 7062 | 17 | 0.9940 | Impact of chicken litter pre-application treatment on the abundance, field persistence, and transfer of antibiotic resistant bacteria and antibiotic resistance genes to vegetables. Treatment of manures prior to land application can potentially reduce the abundance of antibiotic resistance genes and thus the risk of contaminating crops or water resources. In this study, raw and composted chicken litter were applied to field plots that were cropped to carrots, lettuce and radishes. Vegetables were washed per normal culinary practice before downstream analysis. The impact of composting on manure microbial composition, persistence of antibiotic resistant bacteria in soil following application, and distribution of antibiotic resistance genes and bacteria on washed vegetables were determined. A subset of samples that were thought likely to reveal the most significant effects were chosen for shotgun sequencing. The absolute abundance of all target genes detected by qPCR decreased after composting except sul1, intI1, incW and erm(F) that remained stable. The shotgun sequencing revealed that some integron integrases were enriched by composting. Composting significantly reduced the abundance of enteric bacteria, including those carrying antibiotic resistance. Manure-amended soil showed significantly higher abundances of sul1, str(A), str(B), erm(B), aad(A), intI1 and incW compared to unmanured soil. At harvest, those genes that were detected in soil samples before the application of manure (intI1, sul1, strA and strB) were quantifiable by qPCR on vegetables, with a larger number of gene targets detected on the radishes than in the carrots or lettuce. Shotgun metagenomic sequencing suggested that the increase of antibiotic resistance genes on radishes produced in soil receiving raw manure may be due to changes to soil microbial communities following manure application, rather than transfer to the radishes of enteric bacteria. Overall, under field conditions there was limited evidence for transfer of antibiotic resistance genes from composted or raw manure to vegetables that then persisted through washing. | 2021 | 34425441 |
| 7446 | 18 | 0.9940 | Overgrowth control of potentially hazardous bacteria during storage of ozone treated wastewater through natural competition. Improving the chemical and biological quality of treated wastewater is particularly important in world regions under water stress. In these regions, reutilization of wastewater is seen as an alternative to reduce water demand, particularly for agriculture irrigation. In a reuse scenario, the treated wastewater must have enough quality to avoid chemical and biological contamination of the receiving environment. Ozonation is among the technologies available to efficiently remove organic micropollutants and disinfect secondary effluents, being implemented in full-scale urban wastewater treatment plants worldwide. However, previous studies demonstrated that storage of ozone treated wastewater promoted the overgrowth of potentially harmful bacteria, putting at risk its reutilization, given for instance the possibility of contaminating the food-chain. Therefore, this study was designed to assess the potential beneficial role of inoculation of ozone treated wastewater with a diverse bacterial community during storage, for the control of the overgrowth of potentially hazardous bacteria, through bacterial competition. To achieve this goal, ozone treated wastewater (TWW) was diluted with river water (RW) in the same proportion, and the resulting bacterial community (RW+TWW) was compared to that of undiluted TWW over 7 days storage. As hypothesized, in contrast to TWW, where dominance of Beta- and Gammaproteobacteria, namely Pseudomonas spp. and Acinetobacter spp., was observed upon storage for 7 days, the bacterial communities of the diluted samples (RW+TWW) were diverse, resembling those of RW. Moreover, given the high abundance of antibiotic resistance genes in RW, the concentration of these genes in RW+TWW did not differ from that of the non-ozonated controls (WW, RW and RW+WW) over the storage period. These results highlight the necessity of finding a suitable pristine diverse bacterial community to be used in the future to compete with bacteria surviving ozonation, to prevent reactivation of undesirable bacteria during storage of treated wastewater. | 2022 | 34902759 |
| 7073 | 19 | 0.9940 | 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 |