Ciprofloxacin vs. temperature: Antibiotic toxicity in the free-floating liverwort Ricciocarpus natans from a climate change perspective

Veterinary antibiotics differ in phytotoxicity on oilseed rape grown over a wide range of concentrations

Residues of veterinary antibiotics are a worldwide problem of increasing concern due to their persistence and diverse negative effects on organisms, including crops, and limited understanding of their phytotoxicity. Therefore, this study aimed to compare the phytotoxic effects of veterinary antibiotics tetracycline (TC) and ciprofloxacin (CIP) applied in a wide range of concentrations on model plant oilseed rape (Brassica napus). Overall phytotoxicity of 1-500 mg kg-1 of TC and CIP was investigated based on morphological, biochemical, and physiological plant response. Photosystem II (PSII) performance was suppressed by TC even under environmentally relevant concentration (1 mg kg-1), with an increasing effect proportionally to TC concentration in soil. In contrast, CIP was found to be more phytotoxic than TC when applied at high concentrations, inducing a powerful oxidative burst, impairment of photosynthetic performance, collapse of antioxidative protection and sugar metabolism, and in turn, complete growth retardation at 250 and 500 mg kg-1 CIP treatments. Results of our study suggest that TC and CIP pollution do not pose a significant risk to oilseed rapes in many little anthropogenically affected agro-environments where TC or CIP concentrations do not exceed 1 mg kg-1; however, intensive application of manure with high CIP concentrations (more than 50 mg kg-1) might be detrimental to plants and, in turn, lead to diminished agricultural production and a potential risk to human health.

The interactions between aquatic plants and antibiotics: Progress and prospects

Antibiotics have emerged as a widespread pollutant in the aquatic environment. Aquatic phytoremediation to remove antibiotic pollution in water has aroused increasing research. Due to complex interaction between aquatic plants and antibiotics in the aquatic environment, it is essential to summarize the present research progress and point out the shortcomings to better use aquatic plants to remediate antibiotic pollution. A growing body of evidence indicates roots are the most important tissues for aquatic plants to absorb and accumulate antibiotics and antibiotics can be transferred in aquatic plants. LogKow value is an important factor to affecting the antibiotic absorption by aquatic plant. The study showed that antibiotics have toxic effects on aquatic plants, including metabolic interference, oxidative damage, damage to photosynthetic system, and inhibition of growth. However, the species sensitivity distribution model indicated that the general environmental concentrations of antibiotics pose no risk to aquatic plant growth. Aquatic plants can significantly reduce the antibiotics concentration in water and the removal efficiency is affected by many factors, such as the type of aquatic plants and antibiotics. Macrolide antibiotics are most easily removed by plants. This study reviewed the current research progress and provides valuable scientific recommendations for further research.

Phytoremediation for antibiotics removal from aqueous solutions: A meta-analysis

Antibiotics are widely used as drugs and enter water bodies through various routes, leading to environmental pollution. As a green in-situ remediation technology, phytoremediation has been proven to be highly effective in removing antibiotics present in the aqueous phase. However, these data are distributed in various studies and lack systematic analysis, which could provide a more comprehensive understanding of the current status and trends in the research field. Based on this, a meta-analysis was conducted from three perspectives in this study: the factors influencing antibiotics removal by phytoremediation, the effect of antibiotics on plant physiological indexes, and the accumulation and translocation of antibiotics in plants. The results showed that plants have a significant effect on antibiotics removal, which is influenced by plant species, running time, biomass, antibiotic types and antibiotic concentration. Although some physiological indexes of plants changed under stress from high antibiotic concentrations, most plant species demonstrated resistance to antibiotic concentrations below 100 μgL-1. Additionally, the amount of antibiotics accumulated in plants was extremely little, so the risk of secondary pollution was minimal during phytoremediation. The results of this study reveal the main factors influencing antibiotics removal by phytoremediation and plant physiological responses to antibiotics, providing a reference for improving the rational application of phytoremediation for antibiotics removal. In addition, it will provide concepts and directions for improving the efficiency of sustainable and environmentally friendly remediation methods for treating antibiotic pollution.

Degradation of the antibiotic ciprofloxacin in urine by electrochemical oxidation with a DSA anode

Ciprofloxacin (CIP) is a commonly prescribed fluoroquinolone antibiotic that, even after uptake, remains unmetabolized to a significant extent-over 70%. Unmetabolized CIP is excreted through both urine and feces. This persistent compound manages to evade removal in municipal wastewater facilities, leading to its substantial accumulation in aquatic environments. This accumulation raises concerns about potential risks to the health of various living organisms. Herein, we present a study on the remediation of CIP in synthetic urine by electrochemical oxidation in an undivided cell with a DSA (Ti/IrO2) anode and a stainless-steel cathode. Physisorbed hydroxyl radical formed at the anode surface from water discharge and free chlorine generated from Cl- oxidation were the main oxidizing agents. The effect of pH and current density (j) on CIP degradation was examined, and its total removal was easily achieved at pH ≥ 7.0 and j ≥ 60 mA cm-2 due to the action of free chlorine. The CIP decay always followed a pseudo-first-order kinetics. The components of the synthetic urine were also oxidized. The main nitrogenated species released was NH3. A very small concentration of free chlorine was quantified at the end of the treatment, thus demonstrating the good performance of electrochemical oxidation and its effectiveness to destroy all the organic pollutants. The present study demonstrates the simultaneous oxidation of the organic components of urine during CIP degradation, thus showing a unique perspective for its electrochemical oxidation that enhances the environmental remediation strategies.

The silver lining of antibiotic resistance: Bacterial-mediated reduction of tetracycline plant stress via antibiotrophy

The reuse of water using effluents containing antibiotics from anthropogenic activities has been mainly linked to the development of antibiotic resistance. However, we report that the development of bacterial tolerance promotes plant growth. In the present study, we aimed to evaluate the efficiency of inoculation of a new antibiotic-degrading bacterium, Erwinia strain S9, in augmenting the tolerance of pea (Pisum sativum L.) plants to tetracycline (TET) (10 and 20 mg/L). Physiological parameters such as tissue elongation and biomass, as well as relative water content, were remarkably lower in plants exposed to TET than in the control. The inhibitory effects of TET were associated with reduced CO2 assimilation, stomatal conductance, transpiration, dark respiration, and light saturation point (LSP). High concentrations of TET-induced oxidative stress are attested by the overproduction of superoxide radicals (O2•-), hydrogen peroxide (H2O2), and hydroxyl radicals (HO•), resulting in increased malondialdehyde content and cell death. The high activity of antioxidant enzymes such as catalase, ascorbate peroxidase, and guaiacol peroxidase validated the proposed mechanism. Under TET stress conditions, supplementation with Erwinia strain S9 was beneficial to pea plants through osmotic adjustment, increased nutrient uptake, gas exchange optimization, and increased antioxidant activities. Its presence not only ensures plant survival and growth during antibiotic stress but also degrades TET via significant antibiotrophy. This strategy is a cost-effective environmental chemical engineering tool that can be used to depollute wastewater or to improve crop resistance in rhizofiltration treatment when treated wastewater is reused for irrigation.

Tween 80 assisted washing ciprofloxacin-contaminated soil, and recycled it using active chlorines

Active chlorines (ACs) can selectively oxidize contaminants with benzene rings to recycle surfactants, which greatly facilitates the resource cycle. This paper firstly utilized Tween 80 to assist in ex-situ washing the ciprofloxacin (CI) contaminated soil, including the solubilization experiment, shake washing and soil column washing, all of which showed that 2 g/L of Tween 80 (TW 80) was the most effective in removing CI. Then electrochemically treated the collected soil washing effluent (SWE) at 10 V with an electrolyte of 20 mM NaCl + 10 mM Na₂SO₄; Pre-experiments screened the range of electrode spacing, pH and temperature, based on which an orthogonal design Table L₉ (3⁴) was designed. Visual analysis and ANOVA were performed on the ciprofloxacin removal efficiency and Tween 80 retention efficiency during the orthogonal experiments in 9 groups, and the results showed that CI was usually degraded within 30 min, and 50% of TW 80 was still present at the end of the experiment, and there was no significant effect of all three factors. LC-MS demonstrated that CI was mainly degraded synergistically by ·OH and ACs, and ·OH effectively reduced the biotoxicity of the SWE, so the mixed electrolyte may be more suitable for the electrochemical recycling system of ACs. This paper conducted the washing remediation study of CI-contaminated soil for the first time, and applied the theory of selective oxidation by ACs on benzene ring to treat the SWE, which provides a new treatment idea for antibiotic-contaminated soil.

Salvinia molesta phytoremediation capacity as a nature-based solution to prevent harmful effects and accumulation of ciprofloxacin in Neotropical catfish

Phytoremediation has been a potential solution for the removal of pharmaceuticals from water. Here, we evaluated the toxicological safety of ciprofloxacin-contaminated water treated by 96 h with Salvinia molesta. The Neotropical catfish Rhamdia quelen was used as a model, and the potential of the phytoremediation technique for mitigating the drug accumulation in the fishes was also studied. Fish exposed to Cipro (1 and 10 µg·L^-1) in untreated water showed toxic responses (alteration of hematological, genotoxicity, biochemical, and histopathological biomarkers) and accumulated Cipro in their muscles at concentrations high for human consumption (target hazardous quotient > 1). Fish exposed to water treated with S. molesta showed no toxic effect and no accumulation of Cipro in their tissues. This must be related to the fact that S. molesta removed up to 97% of Cipro from the water. The decrease in Cipro concentrations after water treatment with S. molesta not only prevented the toxic effects of Cipro on R. quelen fish but also prevented the antimicrobial accumulation in fish flesh, favouring safe consumption by humans. For the very first time, we showed the potential of phytoremediation as an efficiently nature-based solution to prevent environmental toxicological effects of antimicrobials to nontarget organisms such as fish and humans. The use of S. molesta for Cipro-removal from water is a green technology to be considered in the combat against antimicrobial resistance.

Microplastics and co-pollutant with ciprofloxacin affect interactions between free-floating macrophytes

Microplastic and antibiotic contamination are considered an increasing environmental problem in aquatic systems, while little is known about the impact of microplastics and co-pollutant with antibiotics on freshwater vascular plants, particularly the effects of interactions between macrophytes. Here, we performed a mesocosm experiment to evaluate the impact of polyethylene-microplastics and their co-pollutants with ciprofloxacin on the growth and physiological characteristics of Spirodela polyrhiza and Lemna minor and the interactions between these two macrophytes. Our results showed that microplastics alone cannot significantly influence fresh weight and specific leaf area of the two test free-floating macrophytes, but the effects on photosynthetic pigments, malondialdehyde, catalase and soluble sugar contents were species-specific. Ciprofloxacin can significant adverse effects on the growth and physiological traits of the two test macrophytes and microplastic mitigated the toxicity of ciprofloxacin on the two free-floating plants to a certain extent. In addition, our studies showed that microplastics and co-pollutants can influence relative yield and competitiveness of S. polyrhiza and L. minor by directly or indirectly influencing their physiology and growth. Therefore our findings suggest that species-specific sensibility to microplastic and its co-pollutant among free-floating macrophytes may influence macrophyte population dynamics and thereby community structure and ecosystem functioning. And microplastics altered other contaminant behaviours and toxicity, and may directly or indirectly influence macrophytes interactions and community structure. The present study is the first experimental study exploring the effects of microplastics alone and with their co-pollutants on interactions between free-floating macrophytes, which can provide basic theoretical guidance for improving the stability of freshwater ecosystems.

Physiological responses and phytoremediation capacity of floating and submerged aquatic macrophytes exposed to ciprofloxacin

Ciprofloxacin (Cipro) water contamination is a global concern, having reached disturbing concentrations and threatening the aquatic ecosystems. We investigated the physiological responses and Cipro-phytoremediation capacity of one floating (Salvinia molesta D.S. Mitchell) and one submerged (Egeria densa Planch.) species of aquatic macrophytes. The plants were exposed to increased concentrations of Cipro (0, 1, 10, and 100 µg.Cipro.L^-1) in artificially contaminated water for 96 and 168 h. Although the antibiotic affected the activities of mitochondrial electron transport chain enzymes, the resulting increases in H₂O₂ concentrations were not associated with oxidative damage or growth reductions, mainly due to the activation of antioxidant systems for both species. In addition to being tolerant to Cipro, after only 96 h, plants were able to reclaim more than 58% of that from the media. The phytoremediation capacity did not differ between the species, however, while S. molesta bioaccumulate, E. densa appears to metabolize Cipro in their tissues. Both macrophytes are indicated for Cipro-phytoremediation projects.

Growth and physiological responses in a submerged clonal aquatic plant and multiple-endpoint assessment under prolonged exposure to ciprofloxacin

Ciprofloxacin is ubiquitous and poses a potential threat to aquatic ecosystems. However, the comprehensive effect of prolonged ciprofloxacin exposure on the submerged clonal plant Vallisneria natans (Lour.) Hara remains unknown. Growth and physiological responses in V. natans exposed to ciprofloxacin at concentrations of 0, 0.05, 0.25, 1.25, 2.5, 5 and 10 mg/L were repeatedly evaluated on Days 7, 14, 28, 42 and 56. V. natans maintained good growth properties under 0.05-0.25 mg/L ciprofloxacin treatments, while the inhibition effect on plant growth induced by higher-concentration treatments increased over time. The IC50 values of ciprofloxacin for growth endpoints ranged from 1.6 mg/L to 5.3 mg/L and displayed time-dependent decreases. Pigment contents were significantly stimulated by ciprofloxacin on Day 7 but decreased to varying degrees as the exposure time was extended. Soluble protein and hydrogen peroxide content rose significantly over the first 14 days of treatment with 0.25-10 mg/L ciprofloxacin but decreased under 1.25-10 mg/L ciprofloxacin treatments since Day 28. Antioxidants including superoxide dismutase, catalase, guaiacol peroxidase, ascorbate peroxidase and proline functioned well in mitigating oxidative stress under different ciprofloxacin concentrations, lowering the comprehensive toxic effects of ciprofloxacin on V. natans during the period from Day 14 to Day 42, as evidenced by decreased IBR (integrated biomarker response) values. However, the toxic pressure of ciprofloxacin on V. natans peaked on Day 56. These findings suggest that exposure time can influence the responses of V. natans exposed to ciprofloxacin and that IBR can be employed to evaluate the integrated impacts of prolonged ciprofloxacin contamination in aquatic settings.

Toxicity assessment and microbial response to soil antibiotic exposure: differences between individual and mixed antibiotics

Increasing amounts of antibiotics are introduced into soils, raising great concerns on their ecotoxicological impacts on the soil environment. This work investigated the individual and joint toxicity of three antibiotics, tetracycline (TC), sulfonamide (SD) and erythromycin (EM) via a whole-cell bioreporter assay. TC, SD and EM in aqueous solution demonstrated cytotoxicity, whilst soil exposure showed genotoxicity, indicating that soil particles possibly affected the bioavailability of antibiotics. Toxicity of soils exposed to TC, SD and EM changed over time, demonstrating cytotoxic effects within 14-d exposure and genotoxic effects after 30 days. Joint toxicity of TC, SD and EM in soils instead showed cytotoxicity, suggesting a synergetic effect. High-throughput sequencing suggested that the soil microbial response to individual antibiotics and their mixtures showed a different pattern. Soil microbial community composition was more sensitive to TC, in which the abundance of Pseudomonas, Pirellula, Subdivision3_genera_incertae_sedis and Gemmata varied significantly. Microbial community functions were significantly shifted by EM amendments, including signal transduction mechanisms, cytoskeleton, cell wall/membrane/envelope biogenesis, transcription, chromatin structure and dynamics, and carbohydrate transport and metabolism. This work contributes to a better understanding of the ecological effects and potential risks of individual and joint antibiotics on the soil environment.

The Role of H2O2-Scavenging Enzymes (Ascorbate Peroxidase and Catalase) in the Tolerance of Lemna minor to Antibiotics: Implications for Phytoremediation

We investigated the individual and combined contributions of two distinct heme proteins namely, ascorbate peroxidase (APX) and catalase (CAT) on the tolerance of Lemna minor plants to antibiotics. For our investigation, we used specific inhibitors of these two H₂O₂-scavenging enzymes (p-aminophenol, 3-amino,1,2,4-triazole, and salicylic acid). APX activity was central for the tolerance of this aquatic plant to amoxicillin (AMX), whereas CAT activity was important for avoiding oxidative damage when exposed to ciprofloxacin (CIP). Both monitored enzymes had important roles in the tolerance of Lemna minor to erythromycin (ERY). The use of molecular kinetic approaches to detect and increase APX and/or CAT scavenging activities could enhance tolerance, and, therefore, improve the use of L. minor plants to reclaim antibiotics from water bodies.

Veterinary antibiotics and plant physiology: An overview

Antibiotics are considered one of the greatest advances of medicine and, in addition to their use in treating a wide spectrum of illnesses, they have been widely employed to promote animal growth. As many of those pharmaceuticals are only partially absorbed by the digestive system, a considerable fraction is excreted in its original active form or only partially metabolized. Therefore, the use of animal excrement in agriculture represents one of the principal routes of insertion of antibiotics into the environment. Within that context, plants, principally those of agricultural interest, will be exposed to those compounds when present in the soil or when irrigated with contaminated water. Although not yet fully understood, there are reports of phytotoxic effects of antibiotics that can diminish agricultural production. This review is designed to provide a general and integrative overview of physiological alterations observed in plants caused by environmental exposures to veterinary-use antibiotics. This text principally focuses on the processes involved in antibody absorption and accumulation, and their effects on the primary (photosynthesis, respiration, nitrogen assimilation) and oxidative metabolisms of plants. We also bring attention to germinative and plant establishment processes under conditions of antibiotic contamination. The different effects of different antibiotics on plant physiology are listed here to provide a better understanding of their phytotoxicities.

Crop irrigation (soybean, bean, and corn) with enrofloxacin-contaminated water leads to yield reductions and antibiotic accumulation

The increasing use of antibiotics in animal production has become an emergent environmental problem. The large percentages of applied antibiotic doses eliminated in animal excrement often end up contaminating water resources, which are then used for irrigation - compromising agricultural production and/or food security. Here, we evaluated the effects of crop irrigation with water artificially contaminated by enrofloxacin (10 μg l-1) and its accumulation in soybean, bean, and corn tissues. Grain production was evaluated on the basis of grain dry weight plant-1, while enrofloxacin and ciprofloxacin (its breakdown metabolite) concentrations in plant tissues were evaluated by HPLC after harvesting. Diminished production was observed only in soybean plants irrigated with antibiotic-contaminated water. Enrofloxacin [1.68 ng g fresh weight (FW)-1 to 26.17 µg g FW-1] and ciprofloxacin (8.23 ng g FW-1 to 51.05 ng g FW-1), were found in all of the plant tissues (roots, leaves, and seeds) of the three species. Regardless of the species, the highest enrofloxacin concentrations were observed in their roots, followed by the leaves and seeds, while ciprofloxacin concentrations varied among the different plant tissues of the different species. The presence of enrofloxacin in the water used for irrigating soybeans can result in productivity losses and, as that antibiotic was encountered in plant tissues (leaves and seeds) of all of the three species analyzed that are consumed in the diets of both humans and animals, it can interfere with food security.

Aquatic Macrophytes in Constructed Wetlands: A Fight against Water Pollution

There is growing concern among health institutions worldwide to supply clean water to their populations, especially to more vulnerable communities. Although sewage treatment systems can remove most contaminants, they are not efficient at removing certain substances that can be detected in significant quantities even after standard treatments. Considering the necessity of perfecting techniques that can remove waterborne contaminants, constructed wetland systems have emerged as an effective bioremediation solution for degrading and removing contaminants. In spite of their environmentally friendly appearance and efficiency in treating residual waters, one of the limiting factors to structure efficient artificial wetlands is the choice of plant species that can both tolerate and remove contaminants. For sometimes, the chosen plants composing a system were not shown to increase wetland performance and became a problem since the biomass produced must have appropriated destination. We provide here an overview of the use and role of aquatic macrophytes in constructed wetland systems. The ability of plants to remove metals, pharmaceutical products, pesticides, cyanotoxins and nanoparticles in constructed wetlands were compared with the removal efficiency of non-planted systems, aiming to evaluate the capacity of plants to increase the removal efficiency of the systems. Moreover, this review also focuses on the management and destination of the biomass produced through natural processes of water filtration. The use of macrophytes in constructed wetlands represents a promising technology, mainly due to their efficiency of removal and the cost advantages of their implantation. However, the choice of plant species composing constructed wetlands should not be only based on the plant removal capacity since the introduction of invasive species can become an ecological problem.

Emerging contaminants in water used for maize irrigation: Economic and food safety losses associated with ciprofloxacin and glyphosate

Chemicals used to assure agricultural production and the feasibility of planting sites often end up in bodies of water used for crop irrigation. In a pot study, we investigated the consequences associated with the irrigation of maize with water contaminated by ciprofloxacin (Cipro; 0, 0.2, 0.8, 1.4 and 2.0 μg l-1) and/or glyphosate (0, 5, 25 and 50 mg l-1) on yields and food safety. Glyphosate in concentrations ≥25 mg l-1 prevented plant establishment, regardless of Cipro presence. Evaluations made at the V5 stage of plants reveal that Cipro concentrations ≥0.8 μg l-1 and glyphosate decreased photosynthesis and induced changes in leaf anatomy and stem biophysical properties that may contribute to decreased kernel yields. When those chemicals were applied together, kernel yield reductions were accentuated, evidencing their interactive effects. Irrigation with contaminated water resulted in accumulations of Cipro and glyphosate (as well as its metabolite, aminomethylphosphonic acid) in plant tissues. Accumulation of these chemicals in plant tissues such as leaves and kernels is a problem, since they are used to feed animals and humans. Moreover, these chemicals are of potential toxicological concern, principally due to residue accumulations in the food chain. Specially, the antibiotic residue accumulations in maize tissues can assist the induction of antibiotic resistance in dangerous bacteria. Therefore, we point out the urgency of monitoring the quality of water used for crop irrigation to avoid economic and food-quality losses.

Effects of Ciprofloxacin and Roundup on seed germination and root development of maize

Their continuous release into the environment, associated with their inherent biological activity, has motivated investigations into the detrimental effects of antibiotics and herbicides in natural and agricultural ecosystems. In this study, the interactive effects of the antibiotic ciprofloxacin (Cipro) and the herbicide Roundup on seed germination and root development were investigated. Although both compounds act as inhibitors of the mitochondrial electron transport chain in seeds, neither Cipro nor Roundup disrupted germinability of maize seeds. However, Cipro accelerated germination by promoting ROS accumulation in seeds, while the stimulatory effect of Roundup on ROS-scavenging enzymes (catalase and ascorbate peroxidase) seems to prevent ROS-signaling, delaying the germination process. Roundup reduced root elongation, possibly due to its interference with auxin production, thereby preventing cell division, while Cipro stimulated root elongation by increasing root oxidative status. Cipro and Roundup showed antagonistic effects on maize seeds and root physiology. The presence of the antibiotic is likely not to disturb plant development; however, its stimulatory effects were not sufficient to overcome the deleterious effects of Roundup. According to our results, glyphosate-based herbicides must be carefully used during maize cropping and although antibiotics such as Cipro may not negatively impact agricultural production, their accumulation by crops must be investigated since this can be a pathway of antibiotic-insertion into the food chain.