Fate Of Antibiotics Research Articles

Hypothetical scenarios estimating and simulating the fate of antibiotics: Implications for antibiotic environmental pollution caused by manure application

The application of animal manure containing antibiotic residues as an organic fertilizer to farmlands, poses a major threat to the health of river basin ecosystems. Waste treatment processes can help reduce antibiotic pollution levels in river basins following manure application, but the overall influence of these processes remains unclear. This study evaluates the impact of manure treatment methods on the emission and subsequent river pollution caused by 14 frequently detected antibiotics in a typical pig breeding area in China, by using hypothetical scenarios method. Three scenarios were constructed based on possible fate pathways of antibiotics, representing in 47.0, 55.3, and 81.6 ton·yr−1 antibiotic emissions into the river basin. The soil and water assessment tool (SWAT) model successfully simulated the transport of antibiotics from farmland to surface water, with calibration and verification performed using hydrological station monthly data over 8 consecutive years. Field measured concentrations also verified the reliability of the model and were used to determine the most realistic scenario. In basins applied with manure, environmental antibiotic pollution is most affected by the wastewater treatment process and manure applied patterns, followed by changes in streamflow. The antibiotic pollution in manure applied areas showed significant spatial and temporal differences, resulting from the different manure application patterns. The simulated total outflow of antibiotics in the river basin accounted for 18.1% of the inflow, with the loss of target antibiotics by degradation, volatilization and sedimentation deposition in the river basin being 0.23, 0.01 and 33.2 ton·yr−1, respectively. This study can help to clarify the environmental fate of antibiotics in the basin following manure application, provide guidance for policy makers and help to design the effective corrective interventions for reducing the environmental pollution.

Relevance of sorption in bio-reduction of amoxicillin taking place in forest and crop soils

The fate of antibiotics reaching soils is a matter of concern, given its potential repercussions on public health and the environment. In this work, the potential bio-reduction of the antibiotic amoxicillin (AMX), affected by sorption and desorption, is studied for 17 soils with clearly different characteristics. To carry out these studies, batch-type tests were performed, adding increasing concentrations of AMX (0, 2.5, 5, 10, 20, 30, 40, and 50 μmol L−1) to the soils. For the highest concentration added (50 μmol L−1), the adsorption values for forest soils ranged from 90.97 to 102.54 μmol kg−1 (74.21–82.41% of the amounts of antibiotic added), while the range was 69.96–94.87 μmol kg−1 (68.31–92.56%) for maize soils, and 52.72–85.40 μmol kg−1 (50.96–82.55%) for vineyard soils. When comparing the results for all soils, the highest adsorption corresponded to those more acidic and with high organic matter and non-crystalline minerals contents. The best adjustment to adsorption models corresponded to Freundlich's. AMX desorption was generally <10%; specifically, the maximum was 6.5% in forest soils, and 16.9% in agricultural soils. These results can be considered relevant since they cover agricultural and forest soils with a wide range of pH and organic matter contents, for an antibiotic that, reaching the environment as a contaminant, can pose a potential danger to human and environmental health.

What are the drivers of tetracycline photolysis induced by polystyrene microplastic?

Tetracycline (TC) and polystyrene microplastics (PS MPs), co-occurring in environments inevitably, have been frequently detected in a variety of environmental media. The two major types of emerging pollutants are attracting the global concern due to their potential threat to biota. PS can serve as carriers of TC in aquatic environments, thus dramatically altering environmental behavior of individual PS or TC. However, the photolysis of TC induced by PS remains unknown. In this study, kinetic experiments, quenching experiments, electron paramagnetic resonance analysis (EPR), Two-dimensional correlation Fourier transform infrared spectroscopy (2D-FTIR-COS) and products identification, were conducted to investigate effect and underlying mechanism of PS on photolysis of TC under sunlight irradiation. The corresponding results demonstrated that PS could induce photolysis of TC. The hydroxyl radicals (·OH), singlet oxygen (1O2) and superoxide anion (O2·-) enhanced degradation of TC. Quantitative quenching analysis revealed that both 1O2 and O2·- were main contributors, with contributions of 15.25 ± 2.21% and 11.69 ± 1.84%, respectively. Simultaneously, PS was aged during photolysis of TC, and the intension of O/C was enhanced from 2.07% to 17.92% with increasing aging time. Interestingly, we verified that highly aged PS significantly accelerated the photolysis due to generation of environmentally persistent free radicals (EPFRs), and the degradation pathway of TC induced by PS was firstly proposed. Subsequently, the transformation mainly included five reactions: hydrolysis, hydroxylation, deamination, demethylation and decarbonylation. This work provided a promising strategy for better understanding environmental fate of antibiotics and MPs.

New insights into the interaction between dissolved organic matter and different types of antibiotics, oxytetracycline and sulfadiazine: Multi-spectroscopic methods and density functional theory calculations

Dissolved organic matter (DOM) is composed of numerous fluorescent components. It is an indispensable parameter to affect the environmental fate of antibiotics in various ways. To assess the migration of antibiotics in environment compartments, it is crucial to understand the binding mechanism between DOM and antibiotics. How a particular component in DOM interacts with coexistence antibiotics is not still fully understood. Therefore, in the present study, interactions of two antibiotics oxytetracycline (OTC) and sulfadiazine (SD) with humic acid (HA) and L-tryptophan (L-Trp) which were representative DOM components, were investigated by multispectral techniques and density functional theory (DFT) calculations. The fluorescence quenching mechanism was static quenching. In the binding process, the quenching ability of OTC was stronger than that of SD in HA, which was the same as in L-Trp. DFT calculations were applied to confirm a stronger interaction between OTC and HA or L-Trp than SD. Meanwhile, analyzing the binding sequence by two-dimensional correlation spectroscopy (2D-COS), a humic-like substance bound antibiotics was earlier than a protein-like substance. In HA system, the combination of two antibiotics had a synergistic effect on HA quenching. In L-Trp system, the quenching relationship between the two antibiotics and L-Trp was antagonistic. The FTIR spectra showed that hydroxyl and amide were involved in the binding process of individual DOM components with OTC and SD. The work will help to further understand the behavior of coexistence antibiotics in the environment.

Shedding Light on the Fate of Antibiotics in Forward Osmosis Through Experimental Investigation and Machine Learning Modeling

Shedding Light on the Fate of Antibiotics in Forward Osmosis Through Experimental Investigation and Machine Learning Modeling

Antibiotic fate in an artificial-constructed urban river planted with the algae Microcystis aeruginosa and emergent hydrophyte.

The behavior and removal of six antibiotics, that is, azithromycin, clarithromycin, sulfathiazole, sulfamethoxazole, ciprofloxacin, and tetracycline, in an artificial-controllable urban river (ACUR) were investigated. The ACUR was constructed to form five artificial eco-systems by planting three emergent hydrophytes and Microcystis aeruginosa: (1) Control; (2) MA: M.aeruginosa only; (3) MA-J-C: M.aeruginosa combined with Juncus effusus and Cyperus alternifolius; (4) MA-C-A: M.aeruginosa combined with C.alternifolius and Acorus calamus L.; (5) MA-A-J: M.aeruginosa combined with A.calamus L. and J.effusus. The MA-C-A system achieved the best removal of azithromycin and clarithromycin after 15-day test with the final concentrations 0.92 and 0.83 μg/L. The contents of ciprofloxacin and tetracycline in sediment were highest, up to 1453 and 1745 ng/g. The antibiotic plant bioaccumulation was higher in roots rather than the shoots (stem and leaves). No target antibiotics were detected in algae cells. The combination of hybrid hydrophytes had a certain effect on the removal of antibiotics, and thus selecting appropriate hydrophytes in urban rivers could greatly improve water quality. The overall removal of six antibiotics was greatly improved by the ACUR containing the hybrid hydrophytes and the algae, indicating a synergistic effect on antibiotic removal. PRACTITIONER POINTS: Controllable-mobile artificial eco-systems were developed with emergent hydrophytes and M.aeruginosa. The M.aeruginosa+ Cyperus alternifolius+ Acorus calamus L. system removed azithromycin and clarithromycin most at the end of tests. Emergent hydrophytes and M.aeruginosa have a synergistic effect on the removal of antibiotics. The combination of emergent hydrophytes did play an important role in the removal of antibiotics. The artificial eco-systems containing the hybrid hydrophytes and the algae could greatly improve the overall removal of antibiotics.

Microplastics Influence the Fate of Antibiotics in Freshwater Environments: Biofilm Formation and its Effect on Adsorption Behavior

Microplastics Influence the Fate of Antibiotics in Freshwater Environments: Biofilm Formation and its Effect on Adsorption Behavior

Acute exposure effects of tetracycline, ampicillin, sulfamethoxazole, and their mixture on nutrient removal and microbial communities in the activated sludge of air-scouring and reciprocation membrane bioreactors

The fate of antibiotics, their effects on non-target species, and the spread of antibiotic resistance in wastewater treatment systems have been of concern in recent years. Despite its importance, the effects of these antibiotics on biological nutrient removal in WWTPs have not been completely elucidated. To evaluate the effects of antimicrobial compounds on nutrient removal performance and microbiome, batch experiments were performed using activated sludge samples taken from two distinct membrane bioreactor systems (reciprocation MBR vs. air-scouring MBR). We exposed the activated sludge to 0 mg/L, 0.1 mg/L, and 1.0 mg/L of tetracycline (TET), ampicillin (AMP), sulfamethoxazole (SUL), and their mixture. The mixture of antibiotics significantly decreased ammonia removal efficiency in the reciprocation MBR (rMBR) and air-scouring MBR (AS MBR) by 5% and 12%, respectively. A significant reduction (p < 0.05) in the amoA-AOB gene was observed in AS MBR, while this gene remained unaffected in the rMBR. Interestingly, the gene abundance of amoA from comammox Nitrospira increased from 2.8 × 108 gene copies per gram sludge (0 mg/L) to 5.0 × 108 gene copies per gram sludge (1.0 mg/L) in the setup with antibiotics in the mixture. Correlation analysis of the relative abundance of prevalent taxa and antibiotic concentrations showed that the microbial communities of the AS MBR were more susceptible to TET and MXD antibiotics than the rMBR microbiome.

Transformation of Tetracycline by Manganese Peroxidase from Phanerochaete chrysosporium

The negative impacts on the ecosystem of antibiotic residues in the environment have become a global concern. However, little is known about the transformation mechanism of antibiotics by manganese peroxidase (MnP) from microorganisms. This work investigated the transformation characteristics, the antibacterial activity of byproducts, and the degradation mechanism of tetracycline (TC) by purified MnP from Phanerochaete chrysosporium. The results show that nitrogen-limited and high level of Mn2+ medium could obtain favorable MnP activity and inhibit the expression of lignin peroxidase by Phanerochaete chrysosporium. The purified MnP could transform 80% tetracycline in 3 h, and the threshold of reaction activator (H2O2) was about 0.045 mmol L−1. After the 3rd cyclic run, the transformation rate was almost identical at the low initial concentration of TC (77.05–88.47%), while it decreased when the initial concentration was higher (49.36–60.00%). The antimicrobial potency of the TC transformation products by MnP decreased throughout reaction time. We identified seven possible degradation products and then proposed a potential TC transformation pathway, which included demethylation, oxidation of the dimethyl amino, decarbonylation, hydroxylation, and oxidative dehydrogenation. These findings provide a novel comprehension of the role of MnP on the fate of antibiotics in nature and may develop a potential technology for tetracycline removal.

Insights into removal of sulfonamides in anaerobic activated sludge system: Mechanisms, degradation pathways and stress responses

The fate of antibiotics in activated sludge has attracted increasing interests. However, the focus needs to shift from concerning removal efficiencies to understanding mechanisms and sludge responding to antibiotic toxicity. Herein, we operated two anaerobic sequencing batch reactors (ASBRs) for 200 days with sulfadiazine (SDZ) and sulfamethoxazole (SMX) added. The removal efficiency of SMX was higher than that of SDZ. SDZ was removed via adsorption (9.91–21.18%) and biodegradation (10.20–16.00%), while biodegradation (65.44–86.26%) was dominant for SMX removal. The mechanisms involved in adsorption and biodegradation were investigated, including adsorption strength, adsorption sites and the roles of enzymes. Protein-like substance (tryptophan) functioned vitally in adsorption by forming complexes with sulfonamides. P450 enzymes may catalyze sulfonamides degradation via hydroxylation and desulfurization. Activated sludge showed distinct responses to different sulfonamides, reflected in the changes of microbial communities and functions. These responses were related to sulfonamides removal, corresponding to the stronger adsorption capacity of activated sludge in ASBR-SDZ and degradation capacity in ASBR-SMX. Furthermore, the reasons for different removal efficiencies of sulfonamides were analyzed according to steric and electronic effects. These findings propose insights into antibiotic removal and broaden the knowledge for self-protection mechanisms of activated sludge under chronic toxicities of antibiotics.

Colloid-mediated transport of tetracycline in saturated porous media: Comparison between ferrihydrite and montmorillonite

Given the ubiquitous mineral (e.g., clays and iron oxides) playing critical roles in impacting the fate of antibiotics in the subsurface environment, the effects of two mineral colloids (i.e., ferrihydrite and montmorillonite) on tetracycline (TC, a representative of antibiotic) transport in sand columns were investigated in this study. Interestingly, the results clearly showed that ferrihydrite colloids inhibited TC transport, while montmorillonite colloids enhanced TC mobility under neutral conditions (pH 7.0). This phenomenon resulted from the positively charged ferrihydrite colloids with weak mobility, which assisted TC deposition; besides, providing additional deposition sites for TC by the deposited ferrihydrite colloids was another important mechanism. In contrast, the transport-enhancement effect of montmorillonite on TC was attributed to the strong binding affinity of TC to clay particles as well as the competition between colloids and TC for deposition sites on sand surfaces. Moreover, the transport-inhibition effect of ferrihydrite at pH 7.0 was greater than that at pH 5.0, mainly due to more colloid-associated TC under neutral conditions. Surprisingly, ferrihydrite colloids could act as carriers of antibiotics and enhanced TC transport at pH 9.0. Because the surface charge of colloids was altered to negative and could break through the column. Meanwhile, the transport-enhancement effect of montmorillonite decreased with increasing pH from 5.0 to 9.0, resulting from the decrease of colloid-adsorbed TC. Furthermore, colloid-mediated transport of TC was influenced by ionic strength, which affected the aggregation characteristics of colloids and the binding affinities of TC to minerals. These findings provide critical information for assessing the risks of antibiotics in aquatic ecosystems where abundant natural minerals are present.

Antibiotics along an alpine river and in the receiving lake with a catchment dominated by grazing husbandry

The livestock breeding industries face overuse of antibiotics, which has been intensively studied in recent years. However, the occurrence and fate of antibiotics as well as their potential threats to the aquatic environments in alpine and arid regions remain unclear. This study investigated the relationship of the occurrence and concentrations of antibiotics between the Kaidu River and Bosten Lake in a typical alpine basin in China. Hot spots with antibiotic pollution source were explored. The antibiotic concentrations in river water and suspended sediment (SPS) were 2.20-99.4 ng/L and 1.03-176 ng/g. The dominant antibiotics were tetracyclines, sulphacetamide, and ofloxacin in river water and sulfonamides, clarithromycin, roxithromycin, and ofloxacin in SPS. The apparent differences in pollution sources and landscapes in different reaches led to the obvious spatial patterns of antibiotics in the Kaidu River. Higher partition coefficient of antibiotic between SPS and water phases for sulfonamides than tetracyclines was because that tetracyclines strongly responded to clay contents while sulfonamides significantly responded to organic carbon contents in SPS. There were significant differences in detected antibiotic categories between the river and the lake. Fluoroquinolones (especially ciprofloxacin and enrofloxacin) were detected in the lake while sulphacetamide was only detected in the river. Therefore, the surrounding husbandry and aquaculture around the Bosten Lake was an important antibiotic pollution source in addition to inputs from the Kaidu River. This research suggested that alpine lakes could be an important sink of antibiotics in alpine dry regions, and thus impose greater threats to the aquatic ecosystem.

Contamination of antibiotics and sul and tet(M) genes in veterinary wastewater, river, and coastal sea in Thailand

Water systems in Southeast Asia accumulate antibiotics and antibiotic resistance genes (ARGs) from multiple origins, notably including human clinics and animal farms. To ascertain the fate of antibiotics and ARGs in natural water environments, we monitored the concentrations of these items in Thailand. Here, we show high concentrations of tetracyclines (72,156.9 ng/L) and lincomycin (23,968.0 ng/L) in pig farms, followed by nalidixic acid in city canals. The city canals and rivers contained diverse distributions of antibiotics and ARGs. Assessments of targeted ARGs, including sul1, sul2, sul3, and tet(M), showed that freshwater (pig farm wastewater, rivers, and canals) consistently contained these ARGs, but these genes were less abundant in seawater. Although sulfonamides were low concentrations (<170 ng/mL), sul1 and sul2 genes were abundant in freshwater (minimum 4.4 × 10−3–maximum 1.0 × 100 copies/16S), suggesting that sul genes have disseminated over a long period, despite cessation of use of this class of antibiotics. Ubiquitous distribution of sul genes in freshwater appeared to be independent of selection pressure. In contrast, water of the coastal sea in the monitored area was not contaminated by these antibiotics or ARGs. The density of Enterobacteriales was lower in seawater than in freshwater, suggesting that the number of ARG-possessing Enterobacteriales falls after entering seawater. From the pig farms, through rivers/canals, to the coastal sea, the occurrence of tetracyclines and tet(M) exhibited some correlation, although not a strong one. However, no correlations were found between concentrations of total antibiotics and ARGs, nor between sulfonamides and sul genes. This is the first comprehensive study showing Thai features of antibiotics and ARGs contaminations. The pig farm is hot spot of antibiotics and ARGs, and sul genes ubiquitously distribute in freshwater environments, which become less abundant in seawater.

Transport and fate of antibiotics in a typical aqua-agricultural catchment explained by rainfall events: Implications for catchment management

Antibiotics receive many concerns since their negative environmental impacts are being revealed, especially in aqua-agricultural areas. Rainfall events are responsible for transferring excess contaminants to receiving waters. However, the understanding of antibiotics transport and fate responding to rainfall events was constrained by limited event-based data and lacking integrated consideration of dissolved and particulate forms. We developed an intensive monitoring strategy to capture responses of fourteen antibiotics to different types of rainfall events and inter-event low flow periods. Pollutant-rich suspended particles, as high as 1471 ng/g, were found in low flow periods while the very heavy rainfall events and consecutive rainfall events stimulated the release of antibiotics from eroded soil particles to river water. Therefore, these rainfall events drove radical increase of dissolved antibiotic concentration up to 592 ng/L and total flux up to 25.0 g/d. Sulfonamides were particularly sensitive to rainfall events because of their residues in manure-applied agricultural lands. Transport dynamics of most antibiotics were accretion whereas only clarithromycin exhibited a dilution pattern by concentration-discharge relationships. Aquaculture ponds were inferred to significantly contribute tetracycline, oxytetracycline, and clarithromycin. Conventional contaminants were compared to discriminate potential sources of antibiotics and imply effective catchment management. The results provided novel insights into event-based drivers and dynamics of antibiotics and could lead to appropriate management strategy.

Application of Photocatalytic Process Using UV/TiO2 for Degradation of Cefepime: A Comparison between Photocatalytic and Photolytic

Cephalosporin is a group of β-lactam antibiotics that has a wide antibacterial ability, so its therapeutic use is high. Although much research has been conducted about the fate of antibiotics in an aquatic environment, little investigation has been done about the removal of cephalosporin. In this study, Cefepime, a fourth-generation cephalosporin antibiotic was selected and different tests such as UV/TiO2, UV, TiO2 under darkness, and TiO2 under sunlight were applied to determine whether these methods are effective ways to remove Cefepime from aqueous solutions or not. Different amounts of catalyst and different pHs were used as effective parameters on degradation efficiency and were optimized. The Cefepime removal was measured by HPLC. The mobile phase was comprised of 10:90 Acetonitrile: water with a flow rate of 1 mL/min. The detected wavelength was 212 nm. Maximum removal efficiency (92.9%) for 20 mg/L Cefepime in neutral pH and catalyst dose of 70 mg/L after 120 min irradiation was observed. At the same conditions, the degradation efficiencies for UV, TiO2 under sunlight, and TiO2 under darkness were determined 77.65%, 53.24%, and 15.12% respectively. Also, the reaction rate constant was increased from 0.0054 to 0.0279 (1/min) for photolysis and photocatalysis, respectively. This work was economically compared with photolysis and the result showed that the EEO for the UV/TiO2 process was five times lower than UV processes.UV/TiO2 process could be an efficient method to successfully remove the Cefepime antibiotic from aqueous solutions.

The fate of tetracycline in vegetated mesocosmic wetlands and its impact on the water quality and epiphytic microbes

The fate of antibiotics and their impact on antibiotic resistance genes (ARGs) and microbial communities are far from clear in wetlands. The fate and impact of tetracycline (TC) on the nutrient degradation of wetlands and epiphytic microbes were investigated. This study showed that after TC spiking, 99.7% of TC were removed from the surface water of wetlands containing Vallisneria spiralis within 4 days post-treatment. TC spiking impaired the nutrient removal capacity and disrupted epiphytic microbial community structure while enhancing the abundance of 11 ARGs subtypes, including tetracycline resistance genes, tetX, tetM, tetO, tetQ, tetS, and tet36. TC decreased bacterial biodiversity but amplified the relative abundance of Proteobacteria and Firmicutes by 4% and 61%, respectively, and increased eukaryotic diversity. 16 metabolic pathways including Carbohydrate, Energy, Amino acid, ‘cofactor and vitamins’ metabolisms were significantly (p < 0.01) increased in TC treatment. Phylogenetic, functional prediction analysis indicated that Flavobacterium was positively related with xenobiotics, cell motility, ‘terpenoids and polyketides’ metabolism but negatively related to nucleotide metabolism, while Rhodobacter showed a reverse trend but positively related with nucleotide and ‘glycan biosynthesis’ and metabolism. These data highlighted that TC has negative impacts on epiphytic microbial community and nutrients removal in wetlands.

Towards more Sustainable Peptide- based Antibiotics: Stable in Human Blood, Enzymatically Hydrolyzed in Wastewater?

The emergence and spread of antibiotic resistance is a major societal challenge and new antibiotics are needed to successfully fight bacterial infections. Because the release of antibiotics into wastewater and downstream environments is expected to contribute to the problem of antibiotic resistance, it would be beneficial to consider the environmental fate of antibiotics in the development of novel antibiotics. In this article, we discuss the possibility of designing peptide-based antibiotics that are stable during treatment (e.g. in human blood), but rapidly inactivated through hydrolysis by peptidases after their secretion into wastewater. In the first part, we review studies on the biotransformation of peptide-based antibiotics during biological wastewater treatment and on the specificity of dissolved extracellular peptidases derived from wastewater. In the second part, we present first results of our endeavour to identify peptide bonds that are stable in human blood plasma and susceptible to hydrolysis by the industrially produced peptidase Subtilisin A.

Fate of antibiotics and antibiotic resistance genes during aerobic co-composting of food waste with sewage sludge

Aerobic composting is widely used on transforming organic solid waste into proliferating products. However, the removal of antibiotics and antibiotic resistance genes (ARGs) in the process of co-composting of food waste with sewage sludge has been rarely reported to date. Therefore, we investigated a laboratory-scale composting using food waste and sewage sludge as substrates to study changes in antibiotics and ARGs during composting. Varying dose of antibiotics were added to allow the evaluation of changes in antibiotics, the microbial community and ARGs. The results revealed that composting effectively removed fluoroquinolones and macrolides, while showed poor efficiency in removing sulfonamides. Results from the 16S rRNA sequencing revealed that Firmicutes dominated on D0, while Proteobacteria and Actinomycetes dominated on D28, and a high concentration of antibiotics affected the microbial succession. The quantitative PCR demonstrated that the abundance of sul3, sulA, qnrB, qnrS, and ermB was reduced after 28 days composting, while an increase in the abundance of sul1, sul2, qnrD, ermC, and ermF was induced by high concentrations of antibiotics. Redundancy analysis revealed that total organic matter was the most important factor for the variation in the ARGs abundance. Overall, our findings indicated that the aerobic co-composting of food waste with sewage sludge can effectively remove antibiotics and ARGs. Our study sheds a new idea light on the strategy for the removal of antibiotics and ARGs from organic solid waste.

English

Veterinary antibiotics (VAs) are widely used in Pakistan for growth enhancement, production, and in the prevention and treatment of infectious diseases in the livestock and poultry industry. Their emergence into the agro-environment began during the resource utilization of farmyard and poultry manure. However, these bioactive organic pollutants are non-degradable in the natural environment and can be uptaken by plants, eventually ending up in the human food chain. Despite the danger these antibiotics pose, unfortunately, it is an issue that still remains underreported, especially in Pakistan. As such, this review critically summarizes the current consumption, exposure pathways, strategies for controlling dissemination, and serious environmental concerns associated with VAs. Additionally, the fate of antibiotics in the dry arid climate of Pakistan is thoroughly explained along with the lack of monitoring and strict legislation in developing countries. It is reported that antibiotic consumption negatively impacts raw manure, hence suggestions such as limiting the consumption of antibiotics from the source, proper disposal of farmyard manure with effective technologies, and remediation techniques are introduced. Finally, the authors highlight the importance of farmer's education and awareness campaigns in the pollution control of antibiotics, as the problem can only be properly addressed with the cooperation of government agencies, companies, and involved stakeholders. © 2021 Friends Science Publishers

Antibiotic resistance in the environment: a critical insight on its occurrence, fate, and eco-toxicity.

The overuse, misuse, and underuse of antibiotics tend to increase the antibiotic burden in the environment resulting into the evolution in microbial community to possess resistance that renders antibiotics ineffective against them. The current review recapitulates the present state of knowledge about the occurrence and fate of antibiotics in various environmental matrices. Also, the prevalence of antibiotic-resistant bacteria/antibiotic-resistant genes (ARB/ARGs) in various biological and non-biological systems, eco-toxicity of antibiotics on non-target organisms, and remediation methods for antibiotics and ARB/ARGs removal were critically reviewed. Furthermore, a comparison of various technologies for their efficiency to eliminate antibiotic residues and ARB/ARGs is made. The study identified gaps in the investigation of toxic effects of low concentration of antibiotics and the mixture of multiple antibiotics on non-target organisms. The study of antibiotics' phytotoxicity and toxicity towards sediment and soil-dwelling organisms are also recognized as a knowledge gap. The review also details policies implemented across the globe to fight against antibiotic resistance, and the scarcity of data on lab to land transferred remediation technology was identified. The present study entails a critical review of literature providing guidelines for the articulation of policies for prudent use of antibiotics, limits on the amount of antibiotics in pharmaceutical formulations, and regular surveillance in the Indian context.