Development Of Antibiotic Resistance Genes Research Articles

Selective enrichment of bacteria and antibiotic resistance genes in microplastic biofilms and their potential hazards in coral reef ecosystems

Microplastics become hotspots for bacteria to trigger a series of ecological effects, but few studies have focused on the potential impacts of microplastic biofilms in coral reef ecosystems. Here, we measured the bacterial communities and antibiotic resistance genes (ARGs) in the seawater and microplastic biofilms. Results showed that microbial biofilms were formed on the surface of microplastics. The alpha diversity of the bacterial community in the microplastic biofilms was lower than that in the seawater, and the bacterial communities were distinct between the two. Further analysis revealed that several bacteria in the microplastic biofilms carried ARGs, and the proportion of which was correlated to the concentration of antibiotics in the seawater. Specifically, Vibrio was positively correlated to sul1 in the microplastic biofilms under higher concentrations of sulfonamides. Pathway analysis reflected significant overrepresentation of human disease related pathways in the bacterial community of microplastic biofilms. These results suggest that the microplastic biofilms could selectively enrich bacteria from the reef environments, causing the development of ARGs under antibiotic driving. This may pose a serious threat to coral reef ecosystems and human health. Our study provides new insights into the ecological impacts of microplastic biofilms in coral reef ecosystems.

Degradation of tetracycline by heat/peroxymonosulfate and ultrasound/peroxymonosulfate systems: performance and kinetics

Abstract In recent decades, water pollution caused by emerging contaminants such as pharmaceuticals, has attracted much attention. Antibiotics are commonly used pharmaceuticals, and their residue in water may accelerate the development of antibiotic resistance genes, which can produce resistance to the treatment of diseases. In this study, two energy-based systems, heat/peroxymonosulfate (PMS) and ultrasound (US)/PMS were chosen to treat the typical antibiotic tetracycline (TC) in water. The influencing factors and kinetic equations of TC degradation by heat/PMS and US/PMS were investigated and the rates of TC degradation by the two systems were compared. The results showed that the optimal PMS concentration required for TC degradation in both systems was 0.3 mM, and neither system was affected by solution pH. The power of the US in the US/PMS system was as important as the temperature in the heat/PMS system because they provided activation energy. Both heat and US could activate PMS to degrade TC, and US was slightly superior with 80% TC removal under the conditions of [TC] = 20 mg/L, [PMS] = 0.3 mM, pH = 6.4, T = 20 °C, and US power = 550 W. US is considered to be more advantageous in activating PMS to degrade TC.

NZnO-based graphene/graphene oxide compounds inhibit methane metabolic pathways and lower the development of antibiotic resistance genes and virulence factors

Ruminant gastrointestinal fermentation produces a large amount of methane (CH4), antibiotic resistance genes (ARGs), and virulence factors (VFs) pose significant risks to human health. This study utilized metagenomic sequencing to investigate the effect of nZnO-based graphene (nZnOG) and nZnO-based graphene oxide (nZnOGO) on the archaeal community, CH4 metabolism, ARGs, VFs, and chemotaxis. Results indicated that the levels of zinc in manure were significantly lower in the nZnOG and nZnOGO groups compared to the nano zinc oxide (nZnO) group. The principal component analysis (PCA) of ARGs antibiotic class showed that there was an 80.13% variation between the three groups, suggesting that different zinc sources could influence ARGs related to various classes of antibiotics. The nZnO group exhibited considerably higher resistance levels to antimicrobial peptides and triclosan, in contrast to the nZnOG and nZnOGO groups. The copy number of ARGs followed the order of nZnO > nZnOG > nZnOGO, with a significant difference observed between the nZnO and nZnOGO groups. Moreover, the nZnOGO group displayed a significantly lower copy number of VFs compared to the nZnO group. Furthermore, the nZnOGO group demonstrated inhibition of CH4 metabolic and chemotaxis pathways, which were associated with reduced transfer of ARGs and VFs. The functional coexistence of ARGs and VFs was driven by the archaeal community, while chemotaxis regulated changes in the archaeal community. These findings suggest that nZnOGO has the potential to inhibit the expression of ARGs and VFs through the inhibition of CH4 metabolism and chemotaxis pathways. Consequently, feed supplementation with nZnOGO may offer a possible solution for mitigating CH4 emission and reducing the transmission of ARGs and VFs.

Trends in and Future Research Direction of Antimicrobial Resistance in Global Aquaculture Systems: A Review

The accelerated development of antibiotic resistance genes (ARGs) and antimicrobial resistance (AMR) in aquaculture environments due to the overuse of antibiotics is a global concern. To systematically understand the research trends in and key concepts of ARGs and AMR in aquaculture systems, this study employed the bibliometrix R-package to conduct a bibliometric analysis of the publication characteristics of ARGs and AMR in aquaculture systems from the Web of Science, published from 2000 to 2021. The results revealed that China has produced the most papers. China and the northern hemisphere countries work closely together. Collaboration and multidisciplinary research helped to better understand the impact of AMR in aquaculture on food security and human health. Antibiotic-resistant bacteria and ARGs in aquaculture, as well as the relationship between water environmental variables, antibiotic residuals, and ARGs, are the current research focus. One of the future directions is to establish a conclusive link among water environmental variables, antibiotics, and ARGs. Another future direction is the development of new economical and environmentally friendly technologies to treat AMR in aquaculture wastewater. Collectively, our findings investigate the development directions of AMR research in global aquaculture systems and provide future perspectives.

Antibiotics oxytetracycline removal by photocatalyst titanium dioxide and graphitic carbon nitride in aquaculture wastewater

The surge in the use of antibiotics, especially in aquaculture, has led to development of antibiotic resistance genes, which will harm environmental and public health. One of the most commonly used antibiotics in aquaculture is oxytetracycline (OTC). Employing photocatalysis, this study compared OTC degradation efficiency of two different types of common photocatalysts, TiO2 and graphitic carbon nitride (GCN) in terms of their photochemical properties and underlying photocatalytic mechanism. For reference purpose, self-synthesized GCN from urea precursor (GCN-Urea) and commercial GCN (GCN-Commercial) were both examined. OTC adsorption-photocatalysis removal rates in pure OTC solution by TiO2, GCN-Urea and GCN-Commercial were attained at 95%, 60% and 40% respectively. Photochemical properties evaluated included light absorption, band gap, valence and conduction band positions, photoluminescence, cyclic voltammetry, BET surface area and adsorption capability of the photocatalysts. Through the evaluations, this study provides novel insights towards current state-of-the-art heterogeneous photocatalytic processes. The electron-hole recombination examined by photoluminescence is not the key factor influencing the photocatalytic efficacies as commonly discussed. On the contrary, the dominating factors governing the higher OTC degradation efficiency of TiO2 compared to GCN are the high mobility of electrons that leads to high redox capability and the high pollutant-photocatalyst affinity. These claims are proven by 86% and 40% more intense anodic and cathodic cyclic voltammetry curve peaks of TiO2 as compared to both GCNs. OTC also demonstrated 1.7 and 2.3 times higher affinity towards TiO2 than GCN-Urea and GCN-Commercial. OTC removal by TiO2 in real aquaculture wastewater only achieved 50%, due to significant inhibition effect by dissolved solids, dissolved organic matters and high ionic contents in the wastewater.

Determination of antibiotics during treatment of hospital wastewater using automated solid-phase extraction followed by UHPLC-MS: occurrence, removal and environmental risks

ABSTRACT The extent of removal of pharmaceuticals by African-based wastewater treatment plants (WWTPs) is relatively unknown with various studies observing high concentrations in effluents. This is mainly due to WWTPs still utilising the traditional treatment methods which are known to be less effective. In this study, 15 selected antibiotics (amoxicillin, ampicillin, azithromycin, ciprofloxacin, doxycycline, erythromycin, gentamicin, metronidazole, norfloxacin, ofloxacin, penicillin, sulfamethoxazole, sulfapyridine, tetracycline and trimethoprim) were monitored in wastewater as it goes through sedimentation (primary and secondary), aeration and chlorination stages of a WWTP. Analytical method involved solid-phase extraction followed by liquid chromatographic determination. Removal efficiencies during sedimentation were generally positive with doxycycline achieving 80–95.8%, while negative removal efficiencies were observed for penicillin V (−46.4 to −17.1%) and trimethoprim (−26.2 to −18.9%). The aeration and agitation stage resulted in concentration enhancement for several antibiotics with seven of them ranging between −273 and −15.5%. This stage was responsible for the relatively low overall removal efficiencies in which only 4 antibiotics (doxycycline, tetracycline, ciprofloxacin, and erythromycin) experienced overall removal efficiencies above 50%. The recorded effluent concentrations ranging between 0.0130 and 0.383 ng/mL were translated to low potential for development of antibiotic resistance genes in the receiving environments while ecotoxicity risk was high for only amoxicillin, ampicillin and sulfapyridine. The study has provided an overview of the performance of common wastewater treatment processes in South Africa and hopes that more monitoring and environmental risk data can be made available towards drafting of antibiotic priority lists that cater for Africa.

Efflux pumps activation caused by mercury contamination prompts antibiotic resistance and pathogen's virulence under ambient and elevated CO2 concentration

The occurrence and development of antibiotic resistance genes (ARGs) in pathogens poses serious threatens to global health. Agricultural soils provide reservoirs for pathogens and ARGs, closely related to public health and food safety. Especially, metals stress provides more long-standing selection pressure for ARGs, and climate change is a “threat multiplier” for the spread of ARGs. However, little is known about the impact of metals contamination on pathogens and ARGs in agricultural soils and their sensitivity to ongoing climate changes. To fill this gap, a pot experiment was conducted in open-top chambers (OTCs) to investigate the influence of mercury (Hg) contamination on the distribution of soil pathogens and ARGs under ambient and elevated CO2 concentration. Results showed that the relative abundance of common plant and human pathogens increased significantly in Hg-contaminated soil under two CO2 concentrations. Hg contamination was a positive effector of the activation of efflux pumps and offensive virulence factors (adhere and secretion system) under two CO2 levels. Activation of efflux pumps caused by Hg contamination might contribute to changes of virulence or fitness of certain pathogens. Overall, our study emphasizes the critical role of efflux pumps as an intersection of antibiotic resistance and pathogen's virulence under Hg stress.

ANTIMICROBIAL RESISTANCE “Ecological features influencing the progress and expansion of antibiotic resistance” (Article Review)

Antibiotic resistance has been one of the main negative reasons for obstructing antibiotic entrance into the human body. This has become the reason for a huge number of illnesses and deaths worldwide. The study has focused on reviewing an article that concerns the topic of Ecological features influencing the progress and expansion of antibiotic resistance. The paper has reviewed a research article that several researchers on the development of antibiotic-resistant genes have executed. The study's main aim is to investigate the microbes that resist the antibiotic to combat the harmful bacteria responsible for resisting antibiotics to fight against harmful bacteria

Investigating the Efficiency of Zirconium Oxide Nanoparticles in Removal of Ciprofoxacin from Aqueous Environments

Antibiotics as emerging contaminants are of global concern due to the development of antibiotic resistant genes potentially causing superbugs. The inefficiency of conventional purification processes in the complete removal of antibiotics increases the resistance of microorganisms in humans and the environment, hence new and low-cost technology is needed. Adsorptive materials have been extensively used for the conditioning, remediation and removal of inorganic and organic hazardous materials. Zirconium oxide is a widely used inorganic material which is chemically stable, non-toxic and not soluble in water. Thus it could be an attractive candidate for drinking water puri? cation. In this study, Zirconium Oxide Nanoparticles (ZrO2NP)has been used as the adsorbent for the possibility of removing Cipro? oxacin (CIP) from aqueous solution using the batch adsorption technique under different conditions of initial CIP concentration (25, 50, 75, 100 mg/L), adsorbent dose (0.1, 0.2, 0.3, 0.5, 0.7, 0.9 and 1 g/L) and contact time (10-150 min). The percentage of CIP adsorbed increased with increase in the mass of the adsorbent dose from 0.1 to 1 g/L. Kinetics study for sorption was evaluated using diffusion models, pseudo-first order kinetic and pseudo-second order kinetic. Results show that pseudo second-order kinetic model gave the best description for the adsorption process. The experiments showed that the highest removal rate was 96.5% under optimal conditions. The sorption of CIP on ZrO2NP was rapid during the first 30 min and the equilibrium attained within 75 min. The results suggest that ZrO2NPcould be a good candidate to remove CIP from wastewater containing different amounts of antibiotic.

Sulfonamide antibiotics alter gaseous nitrogen emissions in the soil-plant system: A mesocosm experiment and meta-analysis

Veterinary antibiotics are widely used in many countries worldwide to treat diseases and protect the health of animals. However, the effects of sulfonamide antibiotics introduced via manure and wastewater irrigation on nitrogen (N) loss in the soil-plant system remain poorly understood. Here, we conducted a pot experiment to assess the effects of sulfamethazine (SMZ) and its degradation product (2-amino-4,6-dimethylpyrimidine, ADPD) at four concentration gradients (i.e., 0, 1, 10, 100 mg kg−1) on nitrous oxide (N2O) and ammonia (NH3) emissions, and the abundances of N-cycling functional genes and sulfonamide resistance genes. We also collated 350 observations from 62 published papers and performed a meta-analysis of antibiotic addition effects on N2O emission and soil net nitrification and denitrification. Antibiotics additions showed an inhibitory effect on N2O emissions, which accords with the trend of our meta-analysis showing a significant decrease of 32%. The decreased N2O emissions were attributed to the significant reduction in the abundances of total bacterial communities, ammonia oxidizers, and nir-type denitrifiers and to the resultant changes in soil inorganic N. N2O emissions did not differ between non-environmentally relevant concentrations for SMZ but lowered with increasing ADPD concentrations. This discrepancy can be explained by differential responses of the gene abundances of ammonia oxidizers and nirK-type denitrifiers and the development of antibiotic resistance genes in the highest concentration following antibiotic additions. Antibiotic additions increased soil NH3 volatilization but did not affect vegetable yield. Therefore, these findings provide insight into how the prevalence of antibiotics in soils could alter the N-cycling process and associated gas emissions, with implications for understanding the ecological risks of antibiotics in agriculture.

Trace antibiotics increase the risk of antibiotic resistance genes transmission by regulating the biofilm extracellular polymeric substances and microbial community in the sewer

Sewer is considered a potential hotspot for antibiotic resistance, but the occurrence and proliferation of antibiotic resistance genes (ARGs) under trace antibiotics exposure have received little attention. This work evaluated the effects of tetracycline (TC) and sulfamethoxazole (SMX) individually and in combination in the sewer system and revealed the related mechanisms of ARG proliferation. The relative abundance of tetA and sul1 increased the most under TC and SMX stress, respectively, whereas sul1 increased the most under combined stress. Intl1 was abundant in both the liquid phase and the biofilm, and redundancy analysis confirmed that horizontal gene transfer was the main reason for the proliferation of ARGs. The increase in extracellular polymeric substances (EPS) secretion and the enhancement of the main hydrophobic functional groups facilitated the accumulation of biofilms, which promoted the proliferation of ARGs in biofilms. The relative abundance of most ARGs in the liquid phase was significantly correlated with EPS, protein and tryptophan-like substances. Furthermore, the microbial community structure and diversity affected the proliferation and spread of ARGs in the sewer. These findings contribute to our further understanding of the proliferation and development of ARGs in the sewer and lay the foundation for the front-end control of ARGs.

ОЦЕНКА ЧАСТОТЫ И СПЕКТРА АНТИБИОТИКОРЕЗИСТЕНТНОСТИ У E. COLI И ENTEROCOCCUS SPP., ВЫДЕЛЕННЫХ ИЗ ПИЩЕВОЙ ПРОДУКЦИИ

Antibiotic resistance is considered one of the most important problem for global health. Antibiotics are widely used in traditional medicine and in animal husbandry, but not only for the treatment of diseases of bacterial etiology and for preventive purposes, as well as to increase meat productivity. Uncontrolled use of antimicrobial veterinary drugs favors the emergence of resistant strains and the rapid growth and development of antibiotic resistance genes that are transmitted to pathogens. The purpose of the research work was to study and evaluate the purity and spectrum of antibiotic sensitivity of enterobacteria and enterococci strains isolated from benign food products presented on the markets of the Moscow region. Based on the screening of sensitivity profiles to 17 modern bactericidal drugs, among non-clinical isolates of enterococci and enterobacteria, it was found that resistance to antibiotics of the groups of quinolone and the aminoglycoside prevails. Food isolates of the Enterobacteriaceae and Enterococcus spp families isolated from raw cottage cheese and poultry meat with multiresistance occur with a frequency of 27%.

Minimizing Risks of Antimicrobial Resistance Development in the Environment from a Public One Health Perspective.

Antimicrobial resistance (AMR) is a globally recognized crisis with meaningful engagement across humans, animals, and the environment as in the One Health approach. The environment is the potential source, reservoir, and transmission route of AMR, and it plays a key role in AMR development from the One Health perspective. Animal farming, hospitals, and the pharmaceutical industry are identified as the main emission sources in the environment. Minimizing emissions and determining antimicrobial emission limits are priorities in the containment of environmental AMR development. From the perspectives of environmental management and environmental engineering, some important actions to minimize risks of AMR development are summarized, including the recent progress in enhanced hydrolysis pre-treatment technology to control the development of antibiotic resistance genes (ARGs) during biological wastewater treatment. It is desirable to establish a holistic framework to coordinate international actions on the containment of environmental AMR development. To establish a community with a shared future for humanity, China should and could play an important role in international cooperation to cope with AMR challenges.

Enhancement of antibiotic resistance dissemination by artificial sweetener acesulfame potassium: Insights from cell membrane, enzyme, energy supply and transcriptomics

The abuse of antibiotics on animals could induce the development of antibiotic resistant genes (ARGs) and antibiotic resistant bacteria (ARB), and acesulfame potassium (ACE) is the widely used artificial sweetener in animal feed. Generally speaking, ACE and ARB often coexist in livestock wastewater, however, the impact of the co-occurrence of ACE and ARB on the transmission of ARGs is still unknown. In this study, the effects of ACE on vertical gene transfer (VGT) and horizontal gene transfer (HGT) were both evaluated. For VGT, ACE may hinder the spread of sul gene in Pseudomonas HLS-6 by blocking ARB growth. As for HGT (from Escherichia coli DH5α to Pseudomonas HLS-6), environmentally relevant ACE concentration could facilitate the conjugative transfer. The underlying mechanisms of HGT were characterized by enhanced cell membrane permeability, reactive oxygen species overproduction, SOS response, energy supply, which were all further verified by the changes in transcription levels of related genes. Interestingly, intracellular Mg2+ in donor strain was found for the first time as an indicator for the conjugation occurrence in ACE treated mating system. This study may provide new insights into the role of ACE on ARGs proliferation and highlight its potential environmental impacts.

Application of pharmaceutical waste sludge compost alters the antibiotic resistome in soil under the Chinese cabbage system

Antibiotic resistance is a global threat posing risks to public health. China, as the largest consumer and producer of antibiotics, is generating a large amount of pharmaceutical waste sludge from the antibiotic manufacturing industry, which has the potential to be released into the environments by anthropogenic activities. Land application of pharmaceutical waste sludge compost (PWSC) is a popular way of PWSC disposal, with large amount of antibiotics might hence be introduced into the soil environments and result in the development of antibiotic resistance genes (ARGs). ARGs in PWSC amended soil-plant systems, their transmission routes and potential ecological risks are still unknown. A high-throughput qPCR chip was used to profile ARGs in Chinese cabbage (Shanghaiqing, Brassica chinensis L.) and soils (including phyllosphere, root endosphere, rhizosphere soil, and bulk soil) with PWSC amendment, aiming to study the effect of PWSC application on ARGs soil-plant systems. A total of 249 ARGs and 12 mobile genetic elements (MGEs) were detected in all collected samples. The highest number of detected ARGs was in the soil samples (up to 181) compared to the above and below-ground components of Chinese cabbage. Our results demonstrated the PWSC amendment increased the diversity and normalized abundance of ARGs in the amended soil-Chinese cabbage system. Mantel test and Procrustes analysis revealed the connection between ARG profiles and microbial communities (fungal and bacterial communities). Shared ARGs were identified among the Chinese cabbage phyllosphere, Chinese cabbage root, and rhizosphere soils, demonstrating a potential link between antibiotic resistome in Chinese cabbage and soils, with the amended soil as a key source of ARGs in the phyllosphere of Chinese cabbage. In summary, our findings provided novel evidence for a transmission route shared Zero-radius operational taxonomic units (ZOTUs) and ARGs were passed between the soil-Chinese cabbage system elements (i.e., amended soil, root, and phyllosphere) of ARGs from the PWSC amended soils to common green vegetables, highlighting a potential safety hazard of antibiotic resistome transfer from soils to the human food chain.

Paradigm shift in antibiotic-resistome of petroleum hydrocarbon contaminated soil

The increasing prevalence of antibiotic-resistant microorganisms in both clinical and environmental samples is of great concern for public health. In the present study, environmental samples from seven different sites, heavily contaminated with petroleum hydrocarbons has been examined for the antimicrobial resistome through metagenomic approach. The soil samples were found to be contaminated with high concentration of total petroleum hydrocarbons (average 45 g/kg), polyaromatic hydrocarbons (average ∑16PAH = 280 mg/kg), and heavy metals, which shapes the microbial community and their function. Proteobacteria was found to be predominant phylum in the contaminated habitat with the highest diversity (55.91%) followed by Actinobacteria (9.86%). Although the taxonomical abundance of the non-contaminated sample was not significantly different from contaminated samples, the functional abundance of genes related to antibiotic resistance was found to be higher up to 2 fold in contaminated samples. The comparative metagenomic analysis revealed a higher abundance of different antibiotic resistance genes, especially genes for fluoroquinolones was found to be higher up to 10 fold in contaminated samples. Moreover, the study has shown a significant difference in total functional diversity and abundance, mainly genes for aromatic compound metabolism and genes for phages, mobile genetic elements. These higher abundances of well recognized antibiotic resistance genes, multidrug efflux pumps, and integrons, suggest that the petroleum hydrocarbon contaminated sites can act as reservoirs for development of antibiotic resistance genes (ARGs). From this study, a significant link between the presence of petroleum hydrocarbon and the development of antibiotic resistance in the microbiome of contaminated habitat has been established.

Antibiotics in Food Chain: The Consequences for Antibiotic Resistance.

Antibiotics have been used as essential therapeutics for nearly 100 years and, increasingly, as a preventive agent in the agricultural and animal industry. Continuous use and misuse of antibiotics have provoked the development of antibiotic resistant bacteria that progressively increased mortality from multidrug-resistant bacterial infections, thereby posing a tremendous threat to public health. The goal of our review is to advance the understanding of mechanisms of dissemination and the development of antibiotic resistance genes in the context of nutrition and related clinical, agricultural, veterinary, and environmental settings. We conclude with an overview of alternative strategies, including probiotics, essential oils, vaccines, and antibodies, as primary or adjunct preventive antimicrobial measures or therapies against multidrug-resistant bacterial infections. The solution for antibiotic resistance will require comprehensive and incessant efforts of policymakers in agriculture along with the development of alternative therapeutics by experts in diverse fields of microbiology, biochemistry, clinical research, genetic, and computational engineering.

An electrochemical membrane biofilm reactor for removing sulfonamides from wastewater and suppressing antibiotic resistance development: Performance and mechanisms

Sulfonamides, such as sulfadiazine (SDZ), are frequently detected in water and wastewater with their toxic and persistent nature arousing much concern. In this work, a novel electrochemical membrane biofilm reactor (EMBfR) was constructed for the removal of SDZ whilst suppressing the development of antibiotic resistance genes (ARGs). Results showed that the EMBfR achieved 94.9% removal of SDZ, significantly higher than that of a control membrane biofilm reactor (MBfR) without electric field applied (44.3%) or an electrolytic reactor without biofilm (77.3%). Moreover, the relative abundance of ARGs in the EMBfR was only 32.0% of that in MBfR, suggesting that the production of ARGs was significantly suppressed in the EMBfR. The underlying mechanisms relate to (i) the change of the microbial community structure in the presence of the electric field, leading to the enrichment of potential aromatic-degrading microorganisms (e.g., Rhodococcus accounting for 51.0% of the total in the EMBfR compared to 10.0% in the MBfR) and (ii) the unique degradation pathway of SDZ in the EMBfR attributed to the synergistic effect between the electrochemical and biological processes. Our study highlights the benefits of EMBfR in removing pharmaceuticals from contaminated waters and suppressing the development (and transfer) of ARGs in the environment.

Toxic Effects of Single Antibiotics and Antibiotics in Combination on Germination and Growth of Sinapis alba L.

Antibiotics enter agro-ecosystems via the application of farmyard manure, sewage sludge, animal by-products, or digestates. There are many open questions regarding the behavior of such compounds in the soil like their adsorption, degradation, half-life, and their effects on soil organisms and plants. The impact of antibiotics on the development of antibiotic resistance genes in the environment is regarded as the most important effect that endangers the environment as well as human health. Nevertheless, direct plant toxicity, especially of different antibiotics and heavy metals at the same time, can be of importance as well. In the current study, commercially available phytotoxkits were tested with regard to the toxicity of single antibiotics and antibiotics in combination with the root growth of Sinapis alba L. Additionally, a pot trial was conducted to study the transfer of the observed phytotoxkits results in more complex systems. The phytotoxkits revealed direct toxicity of antibiotics on root development only at high concentrations. The highest toxicity was determined for sulfadiazine, followed by tetracycline and enrofloxacin, showing the least toxicity. When two antibiotics were tested at the same time in the phytotoxkit, synergistic effects were detected. The pot trial indicated lower effect concentrations for enrofloxacin than determined in the phytotoxkit and, therefore, to higher toxicity on plant growth.

Removal of veterinary antibiotics from swine wastewater using anaerobic and aerobic biodegradation

High amounts of antibiotics, used in animal farms for the prevention of diseases, are released back into the natural environment with a possible risk of chronic toxicity to other organisms and the development of antibiotic-resistant genes. The antibiotics, including sulfonamides and β-lactams, detected in swine wastewater were between 99.2 and 339.3 μg/L. The typical on-site swine wastewater treatment process turned out to be inadequate, reflected by the high conventional contaminant and antibiotic residuals even under a long hydraulic residence time (HRT, around 2–3 months). The lab-scale combined anaerobic and aerobic biological process showed that anaerobic digestion was mainly responsible for chemical oxygen demand (COD) reduction and aerobic biodegradation contributed significantly to antibiotic removal, with overall removal efficiencies of 95% for COD and 92% for antibiotics under a short HRT of 3.3 days. The removal of selected antibiotics could be a combined result of biodegradation, the balance between adsorption and desorption, and the transformation between antibiotic metabolites and their parent antibiotics. The current work provides valuable insights into the appropriate selection and optimisation of biological processes for the treatment of typical wastewater with high COD and trace antibiotics.