Antibiotics In Manure Research Articles

Animal manure in the context of renewable energy and value-added products: A review

Animal manure has a complex structure and can be considered a lignocellulosic material. Manure management generates greenhouse emissions, mainly N2O and CH4. Currently, efforts are being made for the sustainable use of animal manure to obtain bioenergy and value-added products. This work shows thermochemical and biochemical methods for manure valorization and proposes strategies to mitigate the inherent environmental problems, thus helping to meet the Sustainable Development Goals (SDG), particularly SDGs 7, 9, 12, and 13. The physicochemical properties and high heating values (HHV) of different types of manure are presented and discussed. The HHV follows the order of cow≈horse>sheep>poultry>pigmanure. Thermochemical processes such as pyrolysis, gasification, and combustion were studied. The operating conditions of anaerobic digestion were also studied. Physical, chemical, thermochemical, and biochemical (e.g., with microbial consortia and enzymes) pre-treatments were analyzed to improve the performance of the above processes. Limitations and obstacles in technological applications were identified, such as manure distribution, lack of government incentives, or the presence of antibiotics in manure. Animal manure has a clear potential to produce organic acids, biomaterials, biofuels, and bioenergy. So, bioprocesses or biorefineries using this biomass as a feedstock may be promising in the near future in the context of the bio-economy, helping to increase the production of renewable energy, promoting inclusive and sustainable industrialization, fostering innovation that adds value to the main livestock activities that generate manure, and guaranteeing sustainable consumption and production modalities that allow mitigating the effects caused by the current treatment of manure.

Occurrence and ecological risk assessment of antibiotics in manure and the surrounding soil from typical chicken farms in Hangzhou, China

The widespread use of antibiotics in animal and human medication has raised global concerns over environmental contamination caused by antibiotic residues. This research investigated the occurrence of 12 kinds of antibiotics belonging to three groups, sulfonamides (SAs), tetracyclines (TCs), and fluoroquinolones (FQs), in chicken manure and the surrounding soil from different chicken farms in Hangzhou, South China, were detected in the samples via ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) and the contamination characteristics of each type of antibiotic and the correlations between each antibiotic and environmental factors were analyzed to identify the key influencing factors. An ecological risk assessment of antibiotics in the soil environment was conducted using the risk quotient (RQ) method to analyze the potential hazard level. The results indicated that: the total concentration of FQs was much higher than those of SAs and TCs in chicken manures and the soil samples. The mean concentration of FQs (39.17 μg·kg–1), TCs (34.37 μg·kg–1), and SAs (20.24 μg·kg–1) in chicken manure were significantly higher than those in the soil samples. Ciprofloxacin (CIP) was the main antibiotics detected in manure (19.42 μg·kg–1) and the soils samples (near soil: 18.42 μg·kg–1, far soil: 10.29 μg·kg–1), followed by enrofloxacin (ENR), tetracycline (TC), and ofloxacin (OFL). The redundancy analysis (RDA) showed that moisture content (MS), total organic carbon (TOC) and total nitrogen (TN) had a greater influence on the antibiotic concentration in the soil samples. Basis on the calculated risk quotient (RQs) values, the risk assessment indicated Sulfamerazine (SD) and Sulfamethoxazole (SMX) in soil posed a high risk, while trimethoprim (TMP), TC, CIP, and OFL in soils posed a medium or low risk. This research provides control and environmental monitoring data about chicken farms and scientific information that can be used to alleviate antibiotics pollution.

A Critical Overview on Recent Avenues in Co-Composting of Animal Manure with Other Organics of Varying Toxicity

Proper management of livestock invariably includes sustainable methods of reusing their manure. Considering the global scenario of animal manure handling and the need for sustained agricultural production, there is clear lack of a focused approach in achieving the environmental and economical resilience in small-scale farms. Present study reviews the possibility of employing co-composting as a suitable technology for safe and effective handling of animal manure along with other wasted materials of organic nature. The review identifies the scope of effective co-composting using different mixtures of manure, greens and bulking agents to achieve required stability and nutrient content of the product. The study highlights the state of the art in terms of (i) carbon and nitrogen transformation after composting, (ii) challenges in preparing ambient conditions, and (iii) feedstock selection to optimize the mix proportions. The study also highlights the challenges in preparation and application as well as the risks involved in handling emerging contaminants (toxins) such as hormones and antibiotics in manure in producing good quality compost, thereby breaking the chain of their reentry to the food cycles. The results of the study would impart sound technological interventions required to make the best use of animal manure compost in low fertile soils.

Residues of veterinary antibiotics in manures from pig and chicken farms in a context of antimicrobial use reduction by implementation of health and welfare plans

The use of antibiotics in food-producing animals can induce the presence of residual substances in manure, which are then released into the environment and may contribute to soil and groundwater contamination. During the on-farm implementation of strategies to improve animal health and welfare in chicken and pig farms, the consequences of antibiotic use were evaluated in terms of the occurrence and levels of antibiotic residues in manure.A set of 35 broiler farms from Cyprus, Greece, the Netherlands and 40 pig farms from France and Italy provided a total of 350 manure samples. The primary objective was to develop a specific LC/MS/MS method capable of quantifying antibiotic residues in both types of manure. The method was able to detect fifteen antibiotics belonging to nine classes, with validated limits of quantification of 10–20 μg/kg, and accuracies ranging from 81% to 138%.With the exception of amoxicillin, which was never detected in any manure, all antibiotics used were detected in manure from treated animals with typical concentrations ranging from 10 to 99198 μg/kg for both chickens and pigs. The occurrence of residual antibiotics was higher in chicken than in pig manure, especially for fluoroquinolones and doxycycline which were detected in 89% and 100% of the chicken manure, respectively, and in 28% of the pig manure. The impact of the health plans on the antibiotic load manure was assessed by measuring for each farm the ratio of the sum of all antibiotic concentrations measured after and before the implementation of the plan. The results showed that, in addition to the frequency of treatments, the class of antibiotic used is an important factor to consider as it strongly influences the stability/instability of the compounds, i.e. their ability to persist in the manure of food-producing animals.

Facultative pathogenic bacteria and antibiotic resistance genes in swine livestock manure and clinical wastewater: A molecular biology comparison

Manure contains vast amounts of biological contaminants of veterinary origin. Only few studies analyse clinically critical resistance genes against reserve antibiotics in manure. In general, resistances against these high priority antibiotics involve a high potential health risk. Therefore, their spread in the soil as well as the aquatic environment has to be prevented.Manures of 29 different swine livestock were analysed. Abundances of facultative pathogenic bacteria including representatives of the clinically critical ESKAPE-pathogens (P. aeruginosa, K. pneumoniae, A. baumannii, E. faecium) and E. coli were investigated via qPCR. Antibiotic resistance genes against commonly used veterinary antibiotics (ermB, tetM, sul1) as well as various resistance genes against important (mecA, vanA) and reserve antibiotics (blaNDM, blaKPC3, mcr-1), which are identified by the WHO, were also obtained by qPCR analysis. The manures of all swine livestock contained facultative pathogenic bacteria and commonly known resistance genes against antibiotics used in veterinary therapies, but more important also a significant amount of clinically critical resistance genes against reserve antibiotics for human medicine. To illustrate the impact the occurrence of these clinically critical resistance genes, comparative measurements were taken of the total wastewater of a large tertiary care hospital (n = 8). Both manure as well as raw hospital wastewaters were contaminated with significant abundances of gene markers for facultative pathogens and with critical resistance genes of reserve antibiotics associated with genetic mobile elements for horizontal gene transfer. Hence, both compartments bear an exceptional potential risk for the dissemination of facultative pathogens and critical antibiotic resistance genes.

Heavy metals migration and antibiotics removal in anaerobic digestion of swine manure with biochar addition

Anaerobic digestion (AD) is a key technology for the utilization of swine manure, but the complex pollution of heavy metals and antibiotics in manure is catching more attentions. In this study, AD of swine manure loading with four types of biochar was performed in a 1 L-frosted jar with the total fresh weight of 840 g, in which the effects of biochar on the AD stability and methane yields were focused, and the removal of antibiotics and migration of heavy metals were investigated as well. The results showed that the removal efficiencies of sulfadimidine and tylosin were remarkable, which were up to around 70% and 100%, respectively. The maximum methane yield of 146.98 mL/ (g VS) was noted in the digester added with the biochar derived from paper mill sludge (BPMS) which contained 87.35% of ash, having a high pH PZC of 8.95 and more mesopores and macropores. In this reactor, 12.40% of Cu was moved to the solid phase, and 70.26% of Zn and 82.80% of As were migrated to the solid digestate. Compared to the control, the content of the acid soluble Cu in the digester loaded with BPMS was decreased to 7.99%, and no acid soluble Zn was found along with a drop of 29.20% for the reducible Zn, and the residual As content was increased by 16.60%. It revealed that BPMS had a great potentiality to remove As and Zn in wastewater and synchronously mitigate the bioavailability of Cu/Zn/As in the digestate. Herein, applying BPMS in the AD of swine manure could reduce the complex pollution of heavy metals and antibiotics, and obtain a higher methane yield simultaneously. • Paper mill sludge biochar had high pH PZC and was rich of ash, macropores and mesopores. • Around 70% of SDM and 100% of TYL were degraded in AD. • Highest methane yield was noted in the digester loaded with paper mill sludge biochar. • 70.26% Zn and 82.80% As migrated to solid digestate via paper mill sludge biochar adsorption. • Paper mill sludge biochar could reduce the eco-toxicity of Cu, Zn, As in the digestate.

Distribution Characteristics of Antibiotics and Antibiotic Resistance Genes in Manure and Surrounding Soil of Cattle Farms in Ningxia

Livestock breeding intensively uses veterinary antibiotics in concentrated feeding operations to improve growth and control disease. Consequently, livestock and poultry manure is an important repository of antibiotics and antibiotic resistance genes (ARGs). To understanding the distribution of antibiotics and ARGs in manure and surrounding soils of cattle farms in Ningxia, cattle manure from five breeding periods (lactation, calving, growing, pre-fattening, and post-fattening periods) and comparative soil samples were collected from the largest beef-breeding area in Ningxia. The compositions of ARGs in the samples were analyzed by UPLC-MS/MS and HT-qPCR. The results showed that:① Tetracycline, quinolone, and sulfonamide were the dominant antibiotics in cattle manure. The content of antibiotics in the manure varied greatly between different breeding periods. High amounts of antibiotics were detected during the pre-fattening and lactation periods, and the lowest amounts were detected during the calving period. ② Quinolone and tetracycline were the dominant antibiotics in the soils, and the detection rate and content of quinolone were highest. The cattle farms did not affect the distribution of antibiotics in the surrounding soils. The content of quinolone and tetracycline in the soils with cattle manure application were significantly higher than control and surrounding soils. ③ We detected 79-142 ARGs in cattle manure, with aminoglycosides the most common form. The number and relative abundance of ARGs were highest during the growing period and lowest during the calving period. The dominant ARGs were tetQ, ermF, and tetO-01 across all the breeding periods. ④ There were 35-79 ARGs in the tested soils, and multidrug and aminoglycoside ARGs were dominant. The cattle farms did not affect the number and relative abundance of ARGs in the surrounding soils; however, manure application significantly affected the number and relative abundance of ARGs. ⑤ Sulfonamide and chloramphenicol ARGs are at risk of mobilization and horizontal transport. A correlation analysis showed that the relative abundances of aminoglycoside and tetracycline in cattle manure were significantly positively correlated with their contents. ⑥ Aminoglycoside, sulfonamide, chloramphenicol, and mobile genetic elements (MGEs) in manure were significantly or extremely significantly positively correlated with aminoglycosides and sulfonamides in the soils, whereas macrolides were negatively correlated with vancomycin. These results provide baseline data to inform controls on the variety and dosages of feed and veterinary drugs in cattle farms and the application of organic fertilizers in agriculture.

Veterinary antibiotics in soils: Environmental processes, ecotoxicity, and risk mitigation

<p indent=0mm>Concentrated animal feeding operations have long extensively used antibiotics to prevent and treat infectious animal diseases and promote the growth of farmed animals, which have resulted in discharges of large quantities of un-metabolized veterinary antibiotics into agricultural soils along with the land application of animal manure. These veterinary antibiotics in soils could exert a range of ecotoxicological effects and even induce the emergence and development of antimicrobial-resistant microbes and genes, which pose a potential threat to human health. This review provides a systematic overview of the transport and fate processes of antibiotics in the soil environment and the corresponding mechanism, their ecotoxicological effects on crops, soil fauna, and soil microorganisms, and the strategies that can be used to mitigate the risk of antimicrobial pollution and the related mechanism. The major environmental processes of antibiotics in soil, including adsorption/desorption, biodegradation, and abiotic degradation, all strongly depend on the soil’s physical and chemical properties (e.g., pH and organic matter content) and the chemical structures and properties of antibiotics (e.g., functional group and hydrophobicity). The ecotoxicological effects of veterinary antibiotics on crops, soil fauna, and soil microorganisms are mainly determined by their types and concentrations and the soil’s physical and chemical properties. Antibiotic degradation during manure composting and anaerobic digestion primarily occurs through biodegradation and hydrolysis. The antibiotics in manure can be effectively degraded by high-temperature pyrolysis. In addition, biochar and graphene-based composite materials can stabilize the antibiotics in soils through hydrogen bonding, surface complexation, electrostatic interaction, and ion exchange. Important questions that must be addressed and recommendations for future research are proposed herein based on the summary of the recent research progresses on soil pollution by antibiotics.

Veterinary antibiotics and estrogen hormones in manures from concentrated animal feedlots and their potential ecological risks

The spread of pharmaceutically active chemicals (PACs), such as antibiotics and estrogenic hormones from animal manures can pose threats to the ecologic environment. In this work, animal manure samples were collected from 71 concentrated animal feedlots in Northern China and investigated for 24 antibiotics and 4 estrogenic hormones. Results showed that these micropollutants were ubiquitous in manures with the concentration ranges of undetectable (ND)–543,445 μg/kg (mean: 44,568 μg/kg) for antibiotics and ND–249.8 μg/kg (mean: 24.78 μg/kg) for estrogens. There was a significant variation in the amounts of PACs in different animal manures. The amounts of antibiotics in manures had following order: swine (83,177 μg/kg) >chicken (52,932 μg/kg) >beef (37,120 μg/kg) >dairy (305 μg/kg), while the estrogens in dairy (mean: 39.27 μg/kg) and chicken manures (mean: 40.08 μg/kg) were higher than those in beef (2.7 μg/kg) and swine manures (1.8 μg/kg). Based on the estimated farmland application rate of manure, antibiotics and estrogens may cause high ecological risks to terrestrial organisms according to the risk quotient evaluation. Estrogens could pose a relatively higher risk than antibiotics. The toxicological effects of antibiotics and estrogens to the terrestrial environment should receive more intensive study.

Antibiotics in animal manure and manure-based fertilizers: Occurrence and ecological risk assessment

The extensive use of antibiotics globally and their residues in the environment has become a serious concern. Intensive animal farming is considered to be a major contributor to the increased environmental burden of antibiotics. Although some antibiotic investigations have been advancing around the world, as an important agricultural country, the information on these pollutants in animal farms are very limited in China. Previous studies have explored few antibiotic residues in livestock farms, whereas information on some antibiotics has remained unknown. The current study analyzed residues of 32 common veterinary antibiotics in manure and manure-based fertilizers collected from Jiangsu Province, China. In most of the manure and fertilizer samples, sulfamethazine and tetracycline were present, with high concentration up to 5650 and 1920 μg·kg-1, respectively. These detected antibiotics have weak relationships with physicochemical properties. Ciprofloxacin, enrofloxacin, sulfamethazine, and sulfachlorpyridazine, hence pose a high potential risk to crops based on the toxicological data of organisms and plants in the soil environment. However, soil invertebrate, such as earthworms, Planococcus Citri. and Folsomia fimeraria., had low ecological risks. Our results showed the presence of antibiotics in livestock and poultry farms plus the potential risks to the soil ecosystem. Therefore, the findings can provide guidelines for monitoring antibiotic residues in agroecosystems, as well as insights into the associated ecological risks of using the two products.

Development of a new SLE-SPE-HPLC-MS/MS method for the determination of selected antibiotics and their transformation products in anthropogenically altered solid environmental matrices

The presence of antibiotic residues, their bioactive metabolites and other transformation products in the environment may adversely affect the organisms that live in the environment and may also contribute to increasing the antibiotic resistance of bacteria. It is particularly difficult to determine the types of contaminants in solid samples, in particular, those that are anthropogenically changed, e.g., as a result of controlled biochemical processes. Therefore, the aim of this research was to develop of a new method for the determination of twelve antibiotics belonging to different groups, such as penicillins, sulfonamides, tetracyclines, quinolones, imidazoles and cefalosporins, in digested manure and activated sludge samples, which were used as examples of anthropogenically altered environmental solid samples. The analyses were performed using high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). The solid-liquid extraction (SLE) method to isolate analytes from digested manure and activated sludge was developed and optimized, the same as clean-up procedure followed by solid phase extraction (SPE). The recovery ranged from 45 to 85%. Finally, the validated method was applied to the determination of the selected antibiotics in manure and activated sludge samples after an anaerobic digestion process.. An additional aim of the study was to verify whether the developed method allows simultaneous detection of transformation products of the studied antibiotics in solid samples. The study showed that by optimizing the analysis conditions, it is possible to simultaneously determine the selected antibiotics and their transformation products (including their epimeric forms), which can significantly improve the ability to control the efficiency of the biological processes used in this area. In practice, this means that the developed methodology may be particularly useful in the context of research and other works related to the anaerobic digestion of activated sludge, manure or other solid substrates of environmental origin.

Effect of Sulfadimethoxine, Oxytetracycline, and Streptomycin Antibiotics in Three Types of Crop Plants—Root, Leafy, and Fruit

(1) Background: Plants act as the natural sink for a variety of toxins in the environment, including veterinary antibiotics (VAs). The objective of this study was to evaluate the uptake and fate of sulfadimethoxine (SDZ), oxytetracycline (OTC), and streptomycin (STR) in lettuce (Lactuca sativa L.), carrot (Daucus carota), and pepper (Capsicum annum) grown in VAs amended soil. (2) Methods: 0, 50, and 100 mg kg−1 VA laced manure was applied in a sandy clay loam soil. (3) Results: 30-d (lettuce) and 60-d (carrot and pepper) greenhouse experiment showed that SDZ and OTC were taken up by all three plants, with concentrations in plant tissue ranging from 0.1 to 1.2 mg kg−1 dry weight. The concentration of VAs in plant tissues increased with a corresponding increase of antibiotics in manure. The highest plant tissue concentrations were found in carrot and lettuce, followed by pepper. An increase in NADPH P450 reductase and glutathione-s-transferase enzyme activity with increasing SDZ and OTC concentration was evident, signifying the induction of the detoxification process. The activity of plant detoxification enzymes under STR treatment was found not to be significantly different from control. (4) Conclusions: These results raise potential human health concerns of consuming low levels of antibiotics from produce grown on manure-amended soils. The result indicates that SDZ, OTC, and STR antibiotics posed high, medium, and low acute ecological risks in lettuce, carrot, and pepper plants when grown in sandy clay loam soil.

Occurrence and Risk Assessment of Antibiotics in Manure, Soil, Wastewater, Groundwater from Livestock and Poultry Farms in Xuzhou, China.

Antibiotics in manure, soil, wastewater, and groundwater samples from the livestock and poultry farms in Xuzhou City were investigated in the present study. The concentrations of antibiotics in all matrices varied greatly among farms. Total concentrations of fluoroquinolones and macrolides were much higher than those of sulfonamides in manures and soil samples. Total concentrations of antibiotics in wastewater of livestock farms were higher than those of poultry farm. Josamycin (JM) and tilmicosin (TIL) accounted for more than 74% of the nine macrolides in all groundwater samples. Sulfamethizole (SMT), fleroxacin (FLE), cinoxacin (CIN) and JM were the main antibiotics detected in manure and soil samples, while sulfamethoxypyridazine (SMP), sulfameter (SME), SMT, FLE, JM and TIL accounted for a large proportion of antibiotics in surface and groundwater. The risk assessment of target antibiotics revealed that JM in wastewater showed relatively high RQs for aquatic organisms.

Pretreatment of swine manure containing β-lactam antibiotics with whole-cell biocatalyst to improve biogas production

Abstract Biogas is one of the most popular renewable alternatives. Large quantities of antibiotics are used for rearing livestock resulting in the presence of high levels of antibiotics in manure, inhibiting biogas production during anaerobic digestion. In this study, a novel whole-cell biocatalyst that can accelerate degradation of antibiotics was developed by displaying β-lactamase on the cell surface of Escherichia coli. This biocatalyst showed high enzyme activity (4.93 ± 0.77 U/g dry weight of cells) in degrading β-lactam antibiotics and higher stability at room temperature than free β-lactamase. Penicillin, cefamezin, and amoxicillin were completely degraded in solution by the biocatalyst within 1 h. Pretreatment of swine manure containing 50 mg/kg and 100 mg/kg of penicillin, cefamezin, and amoxicillin with the new biocatalyst enhanced methane production by 37.1% and 93.2%, respectively during anaerobic digestion. The engineered biocatalyst protected the microbial community from antibiotic inhibition and hence is conducive for the growth of methanogens. This new strategy eliminates the inhibiting effects of antibiotics on manure, increasing the methane production and therefore achieving maximum utilization of renewable energy during anaerobic digestion. This pretreatment technology provides a new idea to treat manure containing antibiotics and improve energy efficiency.

Effect of sulfonamide pollution on the growth of manure management candidate Hermetia illucens.

Antibiotics are commonly used in livestock and poultry farming. Residual antibiotics in manure may lead to antibiotic pollution of soil, surface water, and groundwater through land application and run-off rainfall. The black soldier fly (BSF) Hermetia illucens is a good candidate for manure management. We evaluated the effect of sulfonamide pollution on the growth of H. illucens. Four treatments were considered with a sulfonamide content in the feed of 0 (control group), 0.1, 1, and 10 mg/kg. The control larvae were fed without sulfonamide. Survival and development status of the individuals were recorded daily. The weights of the fifth instar larvae, prepupae, and pupae were checked. Antioxidant enzyme activity was determined with the fifth instar larvae. The results showed that a low (0.1 and 1 mg/kg) concentration of sulfonamides had no effects on larval survival, pupation, and eclosion of BSFs. A high sulfonamide concentration of 10 mg/kg had a significant effect on the survival of larvae and pupae and on the body weight of larvae, prepupae and pupae. Peak of the cumulated pupation rate and eclosion rate in the sulfonamide treatment of 10 mg/kg was very low. Pupation and eclosion in this group peaked later than that of the control and low sulfonamide concentration treatment groups (0.1 mg/kg and 1 mg/kg). Larvae from the sulfonamides group showed lower antioxidase activities than that of the control. In sulfonamide groups, the activity of peroxidase and superoxide dismutase was reduced in a concentration-dependent manner. Sulfamonomethoxine, sulfamethoxazole, and sulfamethazine were not detected in the harvested prepupae. Only sulfadiazine was discovered in the sulfonamide treatments of 1 and 10 mg/kg. In conclusion, BSFs can tolerate certain concentrations of sulfonamide contamination.

Electrodes boost microbial metabolism to mineralize antibiotics in manure

Livestock manures are potential sources of antibiotics in the environment. Sulfamethazine (SMZ), frequently used in veterinary medicine, can enter the environment by using manure as soil fertilizer due to its incomplete absorption in the animal gut and its unmetabolized excretion. The objective of this study was to evaluate the mineralization of 14C-labelled SMZ in manure under a new redox scenario provided by microbial electrochemical reactors, termed microbial electroremediating cells (MERC). These devices aim to overcome the electron acceptor limitation in bacterial oxidative metabolism by means of using electrodes to enhance the biodegradation of pollutants in the environment. Our results revealed that the total degradation of 14C-SMZ reached 43.5% in short term batch laboratory scale experiments under reducing conditions (−400 mV vs. Ag/AgCl). Actually, SMZ mineralization was enhanced up to 10-fold in the early stages (after 2 weeks) in comparison with an electrode-free natural attenuation assay. Moreover, mineralization showed a dependence on electrode potential, with negligible results for conditions set to +400 mV vs Ag/AgCl. The impact of merging electrodes and microorganisms for manure bioremediation suggests a promising future for this emerging technology to treat polluted livestock wastes and prevent soil and groundwater pollution.

Higher Temperatures Do Not Always Achieve Better Antibiotic Resistance Gene Removal in Anaerobic Digestion of Swine Manure.

This study employed high-throughput quantitative PCR and 16S rRNA sequencing to evaluate the effect of temperature and residual antibiotics on the dynamics of antibiotic resistance genes (ARGs) and microbial communities during anaerobic digestion of swine manure. The abundances of total ARGs and 16S rRNA genes significantly decreased in all of four treatments (25°C, 37°C, and 37°C with 50 mg of wet weight antibiotics of body weight, and 55°C). The abundances of most ARG types were significantly correlated with those of the 16S rRNA gene and transposase gene (P < 0.01). However, the abundances of total ARGs at 55°C were much higher than those of other treatments. Meanwhile, the microbial communities at 55°C, where the Streptococcus pathogen remained at a relatively high abundance and cellulose degraders and hydrogen producers, such as Ethanoligenens and Coprococcus bacteria, increased, were markedly different from those of other treatments. Redundancy analysis indicates that temperature, pH, and the genus Streptococcus had the highest explanation for ARG variation among experimental factors, chemical properties, and representative genera, respectively. Network analysis further showed that the genus Streptococcus contributed greatly to the higher ARG abundance at 55°C. The moderate antibiotic residue only caused a slight and transitory inhibition for microbially diverse populations and promotion for ARG abundance, probably due to the degradation of antibiotics and microbial adaptability. Our results clarify the cooperativity of gene transfer-related items on ARG variation and intensively prove that higher temperature cannot always achieve better ARG removal in anaerobic digestion unless pathogens and gene transfer elements are more efficiently inhibited.IMPORTANCE Antibiotic resistance genes (ARGs) are frequently detected with high abundance in manure-applied soils. Anaerobic digestion is one of widely used processes for animal waste treatment. Thus, it is critical to understand the potential of anaerobic digestion to attenuate ARGs. Although some previous studies recommended thermophilic digestion for ARG removal, they did not get sufficient evidence to support this view. The antibiotics applied to animals are mostly excreted through feces and urine because of incomplete metabolism. It is indispensable to know whether residual antibiotics in manure will hinder ARG attenuation in anaerobic digesters. The significance of our research is in comprehensively understanding the evolution and mechanism of ARGs in anaerobic digestion of swine manure affected by temperature and residual antibiotics, which will allow the development of an ARG elimination strategy before their release into the environment.

Veterinary pharmaceuticals and antibiotics in manure and slurry and their fate in amended agricultural soils: Findings from an experimental field site (Baix Empordà, NE Catalonia)

The fate and transport of 34 veterinary pharmaceuticals (PhACs) is investigated in swine slurry and dairy cattle manure-amended agricultural soils, from an experimental field site, by using both analytical and modelled data. Potential differences on PhACs fate, attributed to the application of distinct swine slurry fractions (total, solid, and liquid), are herein assessed for the first time. Surface and deep soil layers, up to a depth of 120 cm, were analyzed at different periods after an annual fertilization event. Using input data representing typical agricultural soil conditions and the PhACs concentration measured in organic fertilizers the transport of these pollutants was modelled for a period of 10 years, including the monitored annual fertilization event. Fluoroquinolone, tetracycline and pleuromutilin antibiotics, together with anti-helmintics and analgesic and anti-inflammatories, were detected in manure-amended soils, at average concentrations ranging from 0.078 to 150 μg/kg dw in surface layers, with the highest levels found in the fields fertilized with the swine slurry solid fraction. Even though severe disagreements were observed between experimental and simulated PhACs concentrations along the soil column, both approaches pointed out that target compounds strongly adsorb onto surface layers, showing limited mobility along the soil profile. Thus, repeated manure and slurry fertilizations will contribute in building up persistent PhACs residues in the uppermost layers of the soil, while leaching will be a minor process governing their fate towards the subsurface. The ecotoxicological risks posed by the occurrence of PhACs in soils were estimated to be low for terrestrial organisms. Nevertheless the antibiotic enrofloxacin showed some potential to induce negative effects to crops.

Biochar-mediated sorption of antibiotics in pig manure.

Using manure contaminated with antibiotics as fertilizer is a primary source of soil pollution with antibiotics and concomitantly with antibiotic resistance genes (ARG). Bioavailable antibiotics trigger further ARG amplification during manure storage. Consequently it is aimed to facilitate the immobilization of antibiotics in manure. To this end, five biochars derived from pine cone (BCP), rice husk, sewage sludge, digestate and Miscanthus were tested as additional sorbents in liquid pig manure for sulfamethazine, ciprofloxacin, oxytetracycline and florfenicol. Non-linear sorption was best-fit using the Freundlich isotherm (R2 > 0.82) and the pseudo-second-order model best described sorption kinetics (R2 > 0.94). Antibiotics' sorption onto manure increased in the order sulfamethazine < florfenicol < ciprofloxacin < oxytetracycline. Admixtures of BCP to manure changed the order to sulfamethazine < oxytetracycline < florfenicol = ciprofloxacin. Generally, with the addition of biochar, sorption coefficients of florfenicol increased most (by factors>2.7) followed by sulfamethazine and ciprofloxacin. Yet, oxytetracycline was mostly mobilized probably due to competitive adsorption. Effects depended on the proportion of biochar added and the type of biochar, whereby plant-derived biochar exhibited better immobilization of antibiotics. Depending on the type and portion of biochar, admixtures to manure can be used to lower the mobility and hence bioavailability of fenicols, fluoroquinolones and sulfonamides.

Quantification of multi-class antibiotics by UHPLC–MS/MS analysis combined with salt-assisted acetonitrile extraction: comparative evaluation of dairy and poultry manure

ABSTRACTA comprehensive multiresidue method for the analysis of 33 antibiotics from 7 prevalent classes was comparably investigated for both dairy and poultry manure samples, which can be important pollution sources for the release of antibiotics into the environment. Following salting-out-assisted extraction with acetonitrile, the antibiotics were quantified with ultrahigh-performance liquid chromatography tandem mass spectrometry without a clean-up step. By changing the composition of the mobile phase for chromatography, a pronounced signal enhancement was achieved not only for tetracyclines (TCs) but also for other groups of antibiotics in the manure samples. Although the physicochemical properties of selected antibiotics were quite different, the apparent recovery values from dairy and poultry manure samples by using an extraction solvent comprising McIlvaine buffer and ethylenediaminetetraacetic solution at pH 3 were 86–121% and 89–113%, respectively. Apparent recovery of the antibiotics was not remarkably affected by the extraction solvent over a wide range of pH values, with the exception of the recovery of TC antibiotics from poultry manure, which was in the 53–55% range at pH 8. Furthermore, the poor performance of the analytical method for a few of the antibiotics in poultry manure was correlated with high metal and organic contents of the complicated matrix. The high suppression effects of co-eluted matrix components were compensated by constructing matrix-matched calibration curves and by using internal standards. Simultaneous quantification of seven different antibiotic classes with low limit of detection values varying from 0.38 to 31 μg kg−1 for dairy manure and from 0.32 to 5.85 μg kg−1 for poultry manure facilitated their monitoring. The application of the developed analytical method to dairy, broiler and layer-hen manure samples from confined animal feeding operations showed that a wide variety of antibiotics at high concentrations were found in broiler manure.