Tb3+ assisted dithioerythritol stabilized copper nanocluster with AIE behavior for ratiometric fluorescent determination of fluoroquinolones.

BACKGROUND: Fluoroquinolones (FQs) are widely used in livestock and poultry industry because of their satisfactory effects in preventing and treating bacterial infection. However, due to irrational use and poor biodegradability, FQs can easily remain in food animals and further enter the human body through the food chain. Therefore, accurate and sensitive detection of FQs residues in animal-origin food is significant. The traditional methods commonly used for FQs detection have some limitations. Ratiometric fluorescence detection technology has the advantages of fast, sensitive, self-correcting, and easy visualization. However, the reports on the use of ratiometric fluorescence probes for FQs detection are limited. RESULTS: In this work, a novel probe was proposed for ratiometric fluorescent analysis of FQs. In this probe, the fluorescence of dithioerythritol stabilized copper nanoclusters (DTE-Cu NCs) was significantly enhanced due to the Tb3+ triggered aggregation-induced emission effect. FQs bound Tb3+ in Tb3+/DTE-Cu NCs through carboxyl and carbonyl groups, so that Tb3+ was effectively sensitized to emit green fluorescence. However, the red fluorescence of DTE-Cu NCs was not interfered. The fluorescence of the probe transformed from red to green with the increase of FQs concentration. Using norfloxacin (NOR), difloxacin (DIF), and enrofloxacin (ENR) as FQs simulants, this probe showed a sensitive linear response ranged from 0.025 to 22.5 µM, with the limits of detection of 9.6 nM, 9.3 nM, and 7.7 nM. The application potential for FQs detection was verified via a standard addition assay of egg samples with the recovery rate of 90.4 %-114.7 %. SIGNIFICANT: The fluorescence probe based on Tb3+/DTE-Cu NCs is expected to realize the ratiometric fluorescence sensitive detection of FQs. The establishment of this simple, effective, and rapid detection platform opens up a new way for the detection of FQs residues in animal-origin foods, and also provides a new idea for the design of rapid detection platforms for other hazard factors.

Preparation and study of a capillary electrochromatographic column prepared by conjugating ß-CD COFs and gold-poly glycidyl methacrylate nanoparticles.

A new enantioselective open-tubular capillary electrochromatography (OT-CEC) was developed employing ß-cyclodextrin covalent organic frameworks (ß-CD COFs) conjugated gold-poly glycidyl methacrylate nanoparticles (Au-PGMA NPs) as a stationary phase. The resulting coating layer on the inner wall of the fabricated capillary column was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), energy dispersive spectroscopy (EDS), and electroosmotic flow (EOF) experiments. The performance of the fabricated capillary column was evaluated by CEC using enantiomers of seven model analytes, including two proton pump inhibitors (PPIs, omeprazole and tenatoprazole), three amino acids (AAs, tyrosine, phenylalanine, and tryptophan), and two fluoroquinolones (FQs, gatifloxacin and sparfloxacin). The influences of coating time, buffer concentration, buffer pH, and applied voltage on enantioseparation were investigated to obtain satisfactory enantioselectivity. In the optimum conditions, the enantiomers of seven analytes were fully resolved within 10 min with high resolutions of 3.03 to 5.25. The inter- to intra-day and column-to-column repeatabilities of the fabricated capillary column were lower than 4.26% RSD. Furthermore, molecular docking studies were performed based on the chiral fabricated column and as ligand isomers of analytes using Auto Dock Tools. The binding energies and interactions acquired from docking results of analytes supported the experimental data.

Wearable, Biocompatible, and Dual-Emission Ocular Multisensor Patch for Continuous Profiling of Fluoroquinolone Antibiotics in Tears.

The abuse or misuse of antibiotics in clinical and agricultural settings severely endangers human health and ecosystems, which has raised profound concerns for public health worldwide. Trace detection and reliable discrimination of commonly used fluoroquinolone (FQ) antibiotics and their analogues have consequently become urgent to guide the rational use of antibiotic medicines and deliver efficient treatments for associated diseases. Herein, we report a wearable eye patch integrated with a quadruplex nanosensor chip for noninvasive detection and discrimination of primary FQ antibiotics in tears during routine eyedrop treatment. A set of dual-mode fluorescent nanoprobes of red- or green-emitting CdTe quantum dots integrated with lanthanide ions and a sensitizer, adenosine monophosphate, were constructed to provide an enhanced fluorescence up to 45-fold and nanomolar sensitivity toward major FQs owing to the aggregation-regulated antenna effect. The aggregation-driven, CdTe-Ln(III)-based microfluidic sensor chip is highly specific to FQ antibiotics against other non-FQ counterparts or biomolecular interfering species and is able to accurately discriminate nine types of FQ or non-FQ eyedrop suspensions using linear discriminant analysis. The prototyped wearable sensing detector has proven to be biocompatible and nontoxic to human tissues, which integrates the entire optical imaging modules into a miniaturized, smartphone-based platform for field use and reduces the overall assay time to ∼5 min. The practicability of the wearable eye patch was demonstrated through accurate quantification of antibiotics in a bactericidal event and the continuous profiling of FQ residues in tears after using a typical prescription antibiotic eyedrop. This technology provides a useful supplement to the toolbox for on-site and real-time examination and regulation of inappropriate daily drug use that might potentially lead to long-term antibiotic abuse and has great implications in advancing personal healthcare techniques for the regulation of daily medication therapy.

Comparative electrochemical study of veterinary drug danofloxacin at glassy carbon electrode and electrified liquid-liquid interface.

This work compares the electroanalytical performance of two electroanalytical systems based on (1) the glassy carbon electrode (GCE), and (2) the electrified liquid-liquid interface (eLLI), for the detection of fluoroquinolone antibiotic-danofloxacin (DANO). Our aim was to define the optimal conditions to detect the chosen analyte with two employed systems, extract a number of electroanalytical parameters, study the mechanism of the charge transfer reactions (oxidation at GCE and ion transfer across the eLLI), and to provide physicochemical constants for DANO. Detection of the chosen analyte was also performed in the spiked milk samples. To the best of our knowledge, this is the first work that directly compares the electroanalytical parameters obtained with solid electrode (in this case GCE) and eLLI. We have found that for DANO the latter provides better electroanalytical parameters (lower LOD and LOQ) as well as good selectivity when the milk was analyzed.

Low flow-resistance solid phase extraction of fluoroquinolones in water and food samples by high-pressure wet spinning porous polyimide microfibers.

In this work, porous polyimide microfibers (PI-µF) were prepared by high-pressure wet spinning method, and successfully applied as adsorbents for solid phase extraction (SPE) of fluoroquinolones (FQs) in water and food samples. The PI-µFs of ∼10, 25, 50, 100 µm in diameter could be controlled by the inner diameter of quartz capillary nozzles. The flow resistance of SPE cartridges packed with 10 µm PI microfiber (10-PI-µF) and 25-PI-µF was comparable to or even lower than that of commercial SPE cartridges, while the flow resistance of 50-PI-µF and 100-PI-µF SPE cartridges was increased obviously due to tiny broken pieces. The 10-PI-µF and 25-PI-µF have a specific surface area of 102 m2 g-1 and 76 m2 g-1, mesopores of 22-32 nm, and large breakthrough volume of 110 mL/5 mg and 85 mL/5 mg for FQs, while the 50-PI-µF and 100-PI-µF had much lower specific surface area and hardly had retention for FQs. FQs from tap water, egg and milk samples were then extracted by PI-µF SPE, and analyzed by high performance liquid chromatography-fluorescence detector (HPLC-FLD). SPE parameters as type of elution solvent, elution solvent volume, pH value of sample solution, flow rate of sample solution, and breakthrough volume were first optimized in detail. Under the optimal conditions, the PI-µF SPE/HPLC-FLD method showed high recoveries (96.8%-107%), wide linearity (0.05-50 µg L-1, or 0.01-10 µg L-1), high determination coefficients (R2 ≥0.9992), and low limits of detection (LODs, 0.005-0.014 µg L-1). For the real tap water, egg and milk samples, the recoveries and RSDs were 81-119% and 0.8-9.8%, respectively. The results show that porous microfiber up to 25 µm in diameter is a promising solid-phase extraction adsorbent with the lowest flow resistance that can be used for trace organic pollutants in water and food samples.

Distribution pattern analysis of multiple antibiotics in the soil-rice system using a QuEChERS extraction method.

Antibiotics are commonly released into paddy fields as mixtures via human activities. However, the simultaneous extraction and detection of these chemicals from multiple media are technically challenging due to their different physicochemical properties, resulting in unclear patterns of their transport in the soil-rice system. In this study, a "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) method was developed for the simultaneous analysis of 4 tetracyclines (TCs) and 4 fluoroquinolones (FQs) in the soil and rice tissues from a local poultry farm, and thereby the distribution patterns of the target antibiotics in the soil-rice system and their risk levels to the soil were analyzed. After parameter optimization, the calibration range used for the target antibiotics was 0.1-50 µg/L and each calibration curve was linear with a coefficient of determination (R2 > 0.995); The QuEChERS method achieved satisfactory recovery rates (70.3-124.6%) along with sensitive detection limits (0.005-0.21 ng/g) for TCs and FQs in the soil, root, stem, leaf, and grain. Among the 8 antibiotics, enrofloxacin (ENX), ciprofloxacin (CIP), oxytetracycline (OTC), and doxycycline (DOX) were detected around a poultry farm. The four antibiotics in the collected paddy soils around the poultry farm ranged from 7.1 ng/g to 395.5 ng/g. Notably, ENX and DOX had higher ecological risks (risk quotient values >1) than CIP and OTC in soil. ENX, CIP, and DOX were highly enriched in rice roots with concentrations up to 471.9, 857.3, and 547.4 ng/g, respectively, which were also detected in rice aboveground tissues. The findings may provide both technical and practical guidance for the understanding of antibiotic environmental behavior and risks.

Assessing sorption of fluoroquinolone antibiotics in soils from a Kd compilation based on pure organic and mineral components.

The presence of fluoroquinolone (FQ) antibiotics in soils may cause a threat to human health due to overexposure and the generation of antibiotic resistance genes. Understanding their sorption behavior in soils is important to predict subsequent FQ (bio) availability. Here, FQ sorption in pure soil organic (i.e., humic substances) and mineral (i.e., metal oxides; phyllosilicates) components is evaluated through a solid-liquid distribution coefficient (Kd (FQ)) dataset consisting of 243 entries originated from 80 different studies, to elucidate their respective contribution to the overall Kd (FQ) in bulk soils. First, different factors affecting FQ sorption and desorption in each of these soil phases are critically discussed. The strong role of pH in Kd (FQ), due to the simultaneous effect on both FQ speciation and surface charge changes, encouraged the derivation of normalized sorption coefficients for the cationic, zwitterionic and anionic FQ species in humic substances and in different phyllosilicates. Kd (FQ) in metal oxides revealed a key role of metal nature and material specific surface area due to complexation sorption mechanisms at neutral pH. Cumulative distribution functions (CDF) were applied to each dataset to establish a sorption affinity range for each phase and to derive best estimate Kd (FQ) values for those materials where normalized sorption coefficients to FQ species were unavailable. The data analysis conducted in the different soil phases set the basis for a Kd (FQ) prediction model, which combined the respective sorption affinity of each phase for FQ and phase abundance in soil to estimate Kd (FQ) in bulk soils. The model was subsequently validated with sorption data in well characterized soils compiled from the literature.

Green method by National Environmental Methods Index and Eco-Scale Assessment for evaluation of gatifloxacin-based product by HPLC.

The literature reveals gaps in the availability of green analytical methods for assessing products containing gatifloxacin (GFX), a fluoroquinolone. Presently, method development is supported by tools such as the National Environmental Methods Index (NEMI) and Eco-Scale Assessment (ESA), which offer objective insights into the environmental friendliness of analytical procedures. The objective of this work was to develop and validate a green method by the NEMI and ESA to quantify GFX in eye drops using HPLC. The method utilized a C8 column (4.6 × 150 mm, 5 µm), with a mobile phase of purified water containing 2% acetic acid and ethanol (70:30, v/v). The injection volume was 10 µL and the flow rate was 0.7 mL/min in isocratic mode at 25°C, with detection performed at 292 nm. The method demonstrated linearity in the range of 2-20 µg/mL, and precision at intra-day (relative standard deviation [RSD] 1.44%), inter-day (RSD 3.45%), and inter-analyst (RSD 2.04%) levels. It was selective regarding the adjuvants of the final product (eye drops) and under forced degradation conditions. The method was accurate (recovery 101.07%) and robust. The retention time for GFX was approximately 3.5 min. The greenness of the method, as evaluated by the NEMI, showed four green quadrants, and by ESA, it achieved a score of 88.

Fabrication of a ß-CD-functionalized magnetic microporous organic network for effective enrichment and detection of fluoroquinolone antibiotics in water samples.

Fluoroquinolone (FQ) antibiotics, one of the leading environmental pollutants, have ecotoxic effects that can accumulate through ecosystems and harm human health. The determination of FQs is still difficult due to the complex matrix, many interfering factors, and low concentration. Hence, a magnetic microporous organic network (MON) composite denoted as Fe3O4@MON-NH2@CM-ß-CD with excellent FQ adsorption performance was prepared by ß-CD covalent modification of a MON. Based on the existence of π-π packing, hydrophobic interaction, and hydrogen bonding between Fe3O4@MON-NH2@CM-ß-CD and FQs, a new magnetic solid phase extraction (MSPE) method for the enrichment of FQs was developed. Under optimized MSPE conditions, five FQs were detected by HPLC-UV with good linearity (R2 ≥ 0.9989) in the range of 0.02-1 µg mL-1, and detection limits (S/N = 3) in the range of 0.0014-0.0023 µg mL-1. The satisfactory recoveries ranged from 93.1 to 116.2% with RSDs lower than 8.39% when applied to actual environmental water samples. These results revealed that Fe3O4@MON-NH2@CM-ß-CD as an adsorbent for MSPE had excellent performance for FQ extraction from real samples, and the MON material types were expanded through the functionalization of MONs, which would have great potential for further application in various analytical methods.

Spectral characterization, degradation behavior, quenching, and semi-quantification of fluoroquinolone antibiotics in the antibiotic-humic mixture using fluorescence spectroscopy.

Antibiotics, one of the significant emerging contaminants, are intensifying their continual spread out into the environment and affecting human health and the ecosystem in the developing country Bangladesh. This study characterizes widely used fluoroquinolone (FQ) antibiotics, formulates the method to spectrally distinguish them from ubiquitous, and important reactive, adsorbent, and altering catalytic macromolecule humic substances (HS), and further quantifies them using fluorescence spectroscopy. The presence of identical fluorophore at Excitation/Emission = 225-230/285-295 nm wavelength, possession of fluorescence spectra at short emission wavelength (<350 nm) during 275 nm excitation, different emission maxima, and various fluorescing components in antibiotics identified through three-dimensional excitation-emission matrix (EEM) and parallel factor analysis (PARAFAC) models distinguished them from the humic substance as well as from each other. Stern-Volmer equation and its modified version were applied to identify quenching and binding capability, and fluorescence intensity quenching rate of antibiotics and humic in their mixture. Unlike poor and inconsistent quenching mechanisms of humic, FQ antibiotics reduced HS intensity throughout the entire photo-irradiation experiment affirming the functioning of the stable quenching methods. Static quenching of fluorophores was identified from the redshift of excited wavelength on the electronic ground state. Temperature differences during daylight and dark conditions played contrasting roles during the fluorescence quenching of FQ. Unique spectral response at emission wavelength < 350 nm during 275 nm excitation in FQ was considered as its least intensity in the antibiotic-humic mixture and was also used to formulate distinct spectral pattern of each FQ antibiotic. The study also identified the traces of FQ antibiotics with various intensities at different lakes in Bangladesh.

Impact of land use-induced soil heterogeneity on the adsorption of fluoroquinolone antibiotics, tested on organic matter pools.

The effects on the adsorption of fluoroquinolone antibiotics of long-term soil heterogeneity induced by land-use were investigated. Three different land use areas with their two organic matter (OM) pools were tested for the adsorption of three antibiotics widely detected in the environment (ciprofloxacin, norfloxacin, ofloxacin). The soils were separated into two size fractions, > 63 µm fraction and < 63 µm fractions for the fast and slow OM pools, respectively. Any effect of land use on adsorption was only observed in the slow pool in the increasing order: arable land, grassland, and forest. The composition of the soil organic matter (SOM) did influence adsorption in the slow pool, but not in the bulk soilsThis was, because: 1) the ratio of the slow pool was low, as in forest, 2) the ratio of the slow pool was high but its adsorption capacity was low due to its SOM composition, as in arable land and grassland. Soils containing a large slow SOM pool fraction with aliphatic dominance were found to be more likely to adsorb micropollutants. It is our contention that the release of contaminated water, sludge, manure or compost into the environment should only be undertaken after taking this into consideration.

On-site extraction using a 3D printed device coated with Zn/Co-ZIF-derived carbon followed by an on-line SIA-HPLC-FL system for fluoroquinolones determination in wastewater.

A 3D printed device covered with Zn/Co-ZIF-derived carbon allows the on-site extraction of fluoroquinolones (FQs) from wastewater, avoiding the sample transportation to the laboratory, and the subsequent elution, separation and determination using an on-line flow system based on sequential injection analysis (SIA) coupled to HPLC-FL. Several parameters that affect the extraction efficiency and desorption were optimized including the sorption phase immobilization technique on the 3D device, extraction time, pH effect, sample volume as well as the type of eluent, eluent volume, and flow rate. Under optimum conditions, detection limits of 3-9 ng L-1 were achieved for norfloxacin, ciprofloxacin, danofloxacin, enrofloxacin and difloxacin. The precision expressed as relative standard deviation (%RSD, n = 3), showed intraday and interday ranges of 1.5-5.3% and 2.8-5.7%, respectively, demonstrating a good precision of the proposed methodology. To assess matrix effects and accuracy of the proposed method in real samples, recovery studies were performed without and with FQs spiked at different concentrations (0.5-10 µg L-1) to wastewater samples, showing good recoveries in the range of 91-104%. The results allow to confirm the applicability of MOF-derived carbons as adsorbents for on-site extraction, and the satisfactory separation and quantification of FQs by a SIA-HPLC-FL on-line system after their desorption with small eluent volumes.

Hydroxyl-containing triazine-based conjugated microporous polymers for solid phase extraction of fluoroquinolone antibiotics in the environment and food samples.

Fluoroquinolones (FQs) are a category of broadly used antibiotics. Development of an effective and sensitive approach for determination of trace FQs in environmental and food samples is still challenging. Herein, the hydroxyl-containing triazine-based conjugated microporous polymers (CMPs-OH) was constructed and served as SPE absorbent for the efficient enrichment of FQs. Based on DFT simulations, the excellent enrichment capacity between CMPs-OH and FQs was contributed by hydrogen bonding and π-π interactions. In combination with high-performance liquid chromatography-tandem mass spectrometry, the proposed approach exhibited a wide linear range (0.2-400 ng L-1), low detection limits (0.05-0.15 ng L-1), and good intraday and interday precisions under optimal conditions. In addition, the established method was effectively utilized for the determination of FQs in fourteen samples with recoveries between 82.6 % and 109.2 %. This work provided a feasible sample pretreatment method for monitoring FQs in environmental and food matrices.

Mechanistic study of the electrochemical oxidation of fluoroquinolones: Ciprofloxacin, danofloxacin, enoxacin, levofloxacin and lomefloxacin.

The fluoroquinolones ciprofloxacin, danofloxacin, enoxacin, levofloxacin and lomefloxacin, occur in water bodies worldwide and therefore pose a threat to the aquatic environment. Advanced purification procedures, such as electrochemical oxidation, may act as a remedy since they contribute to eliminating contaminants and prevent micropollutants from entering open water bodies. By electrochemical treatment in a micro-flow reactor equipped with a boron-doped diamond (BDD) electrode, the fluoroquinolones were efficiently degraded. A total of 15 new products were identified using high-performance high-resolution chromatography coupled with high-resolution multifragmentation mass spectrometry. The ecotoxicity of the emerging transformation products was estimated through in silico quantitative structure activity relationship analysis. Almost all transformation products were predicted less ecotoxic than the initial compounds. The fluoroquinolone degradation followed three major mechanisms depending on the voltage during the electrochemical oxidation. At approximately 1 V, the reactions started with the elimination of molecular hydrogen from the piperazine moiety. At approx. 1.25 V, methyl and methylene groups were eliminated. At 1.5 V, hydroxyl radicals, generated at the BDD electrode, led to substitution at the piperazine ring. This novel finding of the three reactions depending on voltage contributes to the mechanistic understanding of electrochemical oxidation as potential remedy against fluoroquinolones in the aquatic environment.

Exploring the environmental pathways and challenges of fluoroquinolone antibiotics: A state-of-the-art review.

Fluoroquinolone (FQ) antibiotics have become a subject of growing concern due to their increasing presence in the environment, particularly in the soil and groundwater. This review provides a comprehensive examination of the attributes, prevalence, ecotoxicity, and remediation approaches associated with FQs in environmental matrices. The paper discusses the physicochemical properties that influence the fate and transport of FQs in soil and groundwater, exploring the factors contributing to their prevalence in these environments. Furthermore, the ecotoxicological implications of FQ contamination in soil and aquatic ecosystems are reviewed, shedding light on the potential risks to environmental and human health. The latter part of the review is dedicated to an extensive analysis of remediation approaches, encompassing both in-situ and ex-situ methods employed to mitigate FQ contamination. The critical evaluation of these remediation strategies provides insights into their efficacy, limitations, and environmental implications. In this investigation, a correlation between FQ antibiotics and climate change is established, underlining its significance in addressing the Sustainable Development Goals (SDGs). The study further identifies and delineates multiple research gaps, proposing them as key areas for future investigational directions. Overall, this review aims to consolidate current knowledge on FQs in soil and groundwater, offering a valuable resource for researchers, policymakers, and practitioners engaged in environmental management and public health.

Quantum dot-based fluorescence-linked immunosorbent assay for the rapid detection of lomefloxacin in animal-derived foods.

Lomefloxacin (LMF), a third-generation fluoroquinolone antibacterial agent, is often used to treat bacterial and mycoplasma infections. However, due to its prolonged half-life and slow metabolism, it is prone to residues in animal-derived foods, posing a potential food safety risk. Therefore, it is particularly urgent and important to establish a method for detecting lomefloxacin. In this study, direct and indirect competitive fluorescence-linked immunosorbent assay (dc-FLISA and ic-FLISA) based on quantum dots (QDs) was established for the detection of LMF. As for dc-FLISA, the half-maximal inhibitory concentration (IC50) and limit of detection (LOD) were 0.84 ng/mL, 0.04 ng/mL, respectively, the detection ranges from 0.08 to 9.11 ng/mL. The IC50 and LOD of ic-FLISA were 0.43 ng/mL and 0.03 ng/mL, respectively, meanwhile the detection ranges from 0.05 to 3.49 ng/mL. The recoveries of dc-FLISA and ic-FLISA in animal-derived foods (milk, fish, chicken, and honey), ranged from 95.8% to 105.2% and from 96.3% to 103.4%, respectively, with the coefficients of variation less than 8%. These results suggest that the dc-FLISA and ic-FLISA methods, which are based on QD labelling, are highly sensitive and cost-effective, and can be effectively used to detect LMF in animal-derived foods.

An immunochromatographic strip sensor for marbofloxacin residues.

Marbofloxacin (MBF) was once widely used as a veterinary drug to control diseases in animals. MBF residues in animal food endanger human health. In the present study, an immunochromatographic strip assay (ICSA) utilizing a competitive principle was developed to rapidly detect MBF in beef samples. The 50% inhibitory concentration (IC50) and the limit of detection (LOD) of the ICSAs were 2.5 ng/mL and 0.5 ng/mL, respectively. The cross-reactivity (CR) of the MBF ICSAs to Ofloxacin (OFL), enrofloxacin (ENR), norfloxacin (NOR), and Ciprofloxacin (CIP) were 60.98%, 32.05%, 22.94%, and 23.58%, respectively. The CR for difloxacin (DIF) and sarafloxacin (SAR) was less than 0.1%. The recovery rates of MBF in spiked beef samples ranged from 82.0% to 90.4%. The intra-assay and interassay coefficients of variation (CVs) were below 10%. In addition, when the same authentic beef samples were detected in a side-by-side comparison between the ICSAs and HPLC‒MS, no statistically significant difference was observed. Therefore, the proposed ICSAs can be a useful tool for monitoring MBF residues in beef samples in a qualitative and quantitative manner.

Fate of fluoroquinolones in field soil environment after incorporation of poultry litter from a farm with enrofloxacin administration via drinking water.

The practice of incorporating animal manure into soil is supported within the European Circular economy as a possible substitute for mineral fertilizers and will become crucial for the sustainability of agriculture. However, this practice may indirectly contribute to the dissemination of antibiotics, resistance bacteria, and resistance genes. In this study, medicated drinking water and poultry litter samples were obtained from a broiler-chick farm. The obtained poultry litter was incorporated into the soil at the experimental field site. The objectives of this research project were first to develop analytical methods able to quantify fluoroquinolones (FQs) in medicated drinking water, poultry litter, and soil samples by LC-MS; second to study the fate of these FQs in the soil environment after incorporation of poultry litter from flock medicated by enrofloxacin (ENR); and third to screen the occurrence of selected fluoroquinolone resistance encoding genes in poultry litter and soil samples (PCR analysis). FQs were quantified in the broiler farm's medicated drinking water (41.0 ± 0.3 mg∙L-1 of ENR) and poultry litter (up to 70 mg∙kg-1 of FQs). The persistence of FQs in the soil environment over 112 days was monitored and evaluated (ENR concentrations ranged from 36 µg∙kg-1 to 9 µg∙kg-1 after 100 days). The presence of resistance genes was confirmed in both poultry litter and soil samples, in agreement with the risk assessment for the selection of AMR in soil based on ENR concentrations. This work provides a new, comprehensive perspective on the entry and long-term fate of antimicrobials in the terrestrial environment and their consequences after the incorporation of poultry litter into agricultural fields.

Long-term exposure of Allonais inaequalis to a mixture of antibiotics in freshwater and synthetic wastewater matrices: Reproduction, recovery, and swimming responses.

Antibiotics from sulfonamide, fluoroquinolone, and diaminopyrimidine classes are widely used in human and veterinary medicine, and their combined occurrence in the aquatic environment is increasing around the world. In parallel, the understanding of how mixtures of these compounds affect non-target species from tropical freshwaters is scarce. Thus, this work aimed to study the long-term reproductive, recovery, and swimming effects of mixtures of 12 antibiotics from three different classes (up to 10 µg L-1 ) added to freshwater (FWM) and synthetic wastewater (SWM) matrices on freshwater worm Allonais inaequalis. Results revealed that at the reproduction level, the exposure to antibiotics in the SWM matrix does not cause a significant toxic effect on species after 10 days. On the other hand, exposures to initial dose mixtures (10 µg L-1 each) in FWM caused a significant reduction of offspring by 19.2%. In addition, recovery bioassays (10 days in an antibiotic-free environment) suggested that A. inaequalis has reduced offspring production due to previous exposure to antibiotic mixtures in both matrices. Furthermore, despite slight variation in swimming speed over treatments, no significant differences were pointed out. Regarding antibiotics in the water matrices after 10-day exposures, the highest concentrations were up to 2.7, 7.8, and 4.2 µg L-1 for antibiotics from sulfonamide, fluoroquinolone, and diaminopyrimidine classes, respectively. These findings suggest that a species positioned between primary producers and secondary consumers may experience late reproductive damage even in an antibiotic-free zone, after previous 10-day exposure to antibiotic mixtures. PRACTITIONER POINTS: A mixture of sulfonamide, fluoroquinolone, and diaminopyrimidine antibiotics in freshwater affects the offspring production of A. inaequalis after 10 days. After the 10-day antibiotic exposure, the reproduction of A. inaequalis remains affected in an antibiotic-free environment over the recovery period. The swimming speed of the worms does not change after 10 days of exposure to the antibiotic mixture. The concentration of dissolved solids can limit the natural degradation of sulfonamide, fluoroquinolone, and diaminopyrimidine antibiotics in the aquatic environment.

Sensitive immunoenzyme assay for the detection of antibiotic flumequine in honey.

Fluoroquinolone antibiotics are used to cure and protect bees and apiaries from infections. Consequently, they may contaminate honey and other products of beekeeping. In this study, a highly sensitive immunoenzyme assay (EIA) was for the first time developed for the determination of a fluoroquinolone flumequine (FLU) in honey. The EIA was carried out in an indirect competitive format with colorimetric detection. The analysis was characterized by a low limit of detection of 30 pg mL-1. The polyclonal antibodies used showed no cross-reactivity with 24 other (fluoro)quinolones; the assay was highly specific only toward FLU. Different coating FLU-protein conjugates were tested to achieve the most sensitive competitive immunodetection. A highly simplified and rapid (3-5 min) sample preparation was proposed based on the 100-300 times dilution of honey by a buffer. The developed EIA has been tested to detect FLU in honey of different origins, namely acacia, flower, buckwheat, chestnut, and linden honey. It has been demonstrated that 76.2-115.9% of FLU could be determined by the assay. The versatility, simplicity, and rapidity of the EIA enable us to propose this method as an effective tool to control the contamination of honey.