Hydrogen-Bonded Organic Frameworks for Antibiotic Fluorescent Sensing Artificial Intelligence-Enhanced Anticounterfeiting.

The paramount importance of anticounterfeiting measures in safeguarding consumers from counterfeit products lies in their ability to ensure product safety and reliability. Advanced luminescent anticounterfeiting materials, particularly those responsive to multiple stimuli, afford a dynamic and multilayered security assurance. This study presents the synthesis of a novel material, Eu/Tb@GC-3, via postsynthetic modification, which exhibits notable photoluminescent properties with emission at 544 and 614 nm. The material demonstrates high selectivity and sensitivity in detecting Nitrofural and Enrofloxacin, with limits of detection at 0.0122 and 0.0280 µM, respectively. Furthermore, multistimulus responsive luminescent fibers and inks were developed, facilitating intelligent anticounterfeiting labels. The integration of these labels with back-propagation neural networks (BPNNs) significantly enhances pattern recognition and authentication capabilities, providing an efficacious strategy to combat counterfeit products and ensure consumer safety.

The effect of early administration of antibiotics or feeding a diet containing coccidiostats on the level of their accumulation in liver and the redox status of turkeys.

Early administration of antibiotics may worsen the functioning of the turkeys' antioxidant system. It was also assumed that the longer the time of administration of an antibiotic, e.g. a coccidiostat, the greater the risk of its accumulation in the liver. The study aimed to determine whether early administration of antibiotics or feeding a diet containing coccidiostats causes accumulation in the liver and whether it affects the deterioration of the antioxidant system, and whether preventive vaccinations can intensify it. A total of 3 080 female turkeys were randomly allocated to eight groups. The experiment had a two-factorial design, with four treatments (C, M, E, D) and two groups of birds (vaccinated +, unvaccinated -). The C group did not receive the coccidiostat or antibiotics. Group M was administered monensin at 90 mg/kg feed for 56 days of life. Group E received enrofloxacin at 10 mg/kg BW, and group D received doxycycline at 50 mg/kg BW, added to drinking water, for the first 5 days of life. One-day-old turkeys from groups C+, M+, E+, and D+ were administered live-attenuated vaccines against turkey rhinotracheitis and Newcastle disease by coarse spray; 28-day-old birds were administered a subcutaneously injected inactivated vaccine against Ornithobacterium rhinotracheale. Turkeys from groups C-, M-, E-, and D- were not vaccinated. It was determined that as a result of administration of enrofloxacin or doxycycline until the 5th day of life, biotransformation of these antibiotics occurred in the liver until the 56th day of life of the turkeys, which was confirmed by their lower level than the Maximum Residue Level. Because the concentration of monensin in the liver of turkeys gradually increased with the extension of the time of its administration in the diet, it is probable that discontinuing its addition a day before the slaughter of birds will result in the presence of this coccidiostat in the liver of turkeys. Despite the accumulation of monensin in the liver of turkeys, this coccidiostat did not increase oxidative reactions in the organism of turkeys. Vaccination of turkeys can reduce oxidative reactions and apoptosis in the body. However, the effect of the redox system reaction is different immediately after vaccination, which is due to the mechanism of action of the immune system. If it is necessary to administer an antibiotic in the early rearing period, the effects of doxycycline on the organism's immunity including antioxidant defence will be less severe than those of enrofloxacin.

Swine wastewater co-exposed with veterinary antibiotics enhanced the antibiotic resistance of endophytes in radish (Raphanus sativus L.).

The widespread utilization of antibiotics in livestock has promoted the accumulation and diffusion of antibiotics and antibiotic resistance in agricultural soils and crops. Here we investigated the mechanisms of antibiotic uptake and accumulation in swine wastewater (SW)-treated radish (Raphanus sativus L.) and subsequent impacts on endophyte antibiotic resistance. Under SW treatments, exposure to 500 µg/L sulfamethazine (SMZ) and enrofloxacin (EFX) significantly affected radish biomass, with SMZ causing 63.0% increases and EFX causing 36.3% decreases relative to the untreated control. EFX uptake by radish were from 5 to 100-folds over SMZ. Passive diffusion through anion channel proteins on cell membranes was an important route for SMZ uptake, while both passive diffusion and energy-dependent processes contributed to the uptake of EFX. Bacterial community was time-dependent as a function of both antibiotics and SW, the bacterial alpha diversity in liquid solution co-treated with antibiotics and SW increased over time. The abundance of antibiotic resistance genes (ARGs) in the roots was positively correlated with ARGs in the Hoagland's solution under antibiotic-alone treatments. EFX co-exposure with SW enhanced the dissemination of ARGs from swine wastewater into plant roots, and significant correlations existed between ARGs and integrons in both Hoagland's solution and roots. These findings increased our understanding of the fate of antibiotics in crops and their subsequent impacts on antibiotic resistance of endophytic bacteria.

Bridging one health and sustainable analysis: enrofloxacin quantification amid combined therapy and its active metabolite in various matrices using green RP-HPLC.

Antibiotics play a crucial role in the treatment of infectious diseases in both humans and animals. However, their extensive utilization has caused significant potential harm to both wildlife and humans. Enrofloxacin (ENR) is a common veterinary antibiotic, which is not approved for human use due to associated toxicities. It is often combined with other antibiotics to expand the antibacterial range. It is crucial to monitor and measure the levels of ENR medication in various matrices. RP-HPLC is highly effective for analyzing antibiotics due to its sensitivity, specificity, and ability to handle complex samples. By adopting eco-friendly solvents, decreasing solvent consumption, and limiting waste we developed a method for determination and quantification of ENR, amoxicillin (AMX), and ENR active metabolite in different matrices. The method utilized a reversed stationary phase and a mobile phase composed of phosphate buffer pH 3.0: ethanol (90:10 v/v) pumped at 1.0 mL/min and UV detection at 254.0 nm. Moreover, a comprehensive assessment of the environmental friendliness of the established method was conducted using various tools including the Green Certificate Classification (GCC) and Analytical Greenness AGREE and RGB12. The method was validated for its accuracy and precision in quantifying ENR, demonstrating its potential for the effective monitoring of ENR and contributing to public health protection.

Rapid transformation of nanobodies affinity based on AlphaFold2's high-accuracy predictions and interaction analysis for enrofloxacin detection in coastal fish.

High-affinity antibodies are crucial in biosensors, disease diagnostics, therapeutic drug development, and immunological analysis, making the enhancement of antibody affinity a key research focus within the field. Computer-aided design is recognized as a time-saving and labor-efficient method for nanobodies in vitro affinity maturation. Compared to experimental mutagenesis techniques, it is advantageous due to the elimination of the need for laborious library construction and screening processes. However, these approaches are constrained by structural prediction since inaccuracy in structure could readily result in maturation failures. Herein, a novel nanobodies modification method for in vitro affinity maturation, utilizing the high accuracy prediction of AlphaFold2, was employed to rapidly transform a low affinity nanobody against enrofloxacin (ENR) into one with high affinity. The molecular docking results revealed a 1.5- to 2.5-fold increase in the number of noncovalent interactions of modified nanobodies, accompanied by a reduction in binding free energy ranging from 14.1 to 62.6%. The evaluation results from ELISA and BLI indicated that the affinity of the modified nanobodies had been enhanced by 6.2-91.6 times compared to the template nanobody. Furthermore, the modified nanobodies were employed for the detection of ENR-spiked coastal fish samples. In summary, this research proposed a nanobodies modification method from a new perspective, endowing its great application potential in biosensors, food safety, and environmental monitoring.

Removal of enrofloxacin as well as nutrients in mariculture water by Sesuvium portulacastrum system: Insights for biodegradation, ecotoxicity of enrofloxacin.

Antibiotic contamination and eutrophication in mariculture have become problems that cannot be ignored, and enrofloxacin (ENR), as an example, is especially widely used in mariculture. This study firstly revealed that Sesuvium portulacastrum, a plant with world-wide distribution in coastal zones, with its rhizosphere microorganisms, could remove ENR as well as nutrients. The S. portulacastrum system could degrade ENR to small-molecule products 1,2,3,4-tetrahydroquinolin-4-ol and (2,4-dihydroxyphenyl)-cyclopropylamine. And there were 81.3-39.2 % removals of ENR with 0.01-100 mg/L. Although ENR significantly influenced functions of rhizosphere microbial community, like decreasing nitrogen fixation, shifting trophic strategies from phototrophy to chemoheterotrophy, nutrients (NH4+-N, NO2--N, NO3--N and total dissolved phosphorus) removal of S. portulacastrum system was essentially unaffected at low ENR concentration (< 1 mg/L). The removal mechanism of S. portulacastrum system was explored. Neither of the isolated root exudates and rhizosphere bacteria could degrade ENR, however, without rhizosphere bacteria, ENR removal rate would decrease. Root proteins including oxidase, decarboxylase, dehydrogenase, such as laccase, isocitrate dehydrogenase, delta-1-pyrroline-5-carboxylate dehydrogenase were overexpressed. Additionally, endocytosis is a pathway for antibiotics to enter S. portulacastrum. This study demonstrated that S. portulacastrum system could be used for remediation of antibiotics-nutrients combined pollution, and deepened understanding the antibiotic removal mechanism of macrophytes in mariculture, moreover, provided new macroplant species and a theoretical basis for antibiotics removal in aquatic systems.

Quantifying trade-offs between therapeutic efficacy and resistance dissemination for enrofloxacin dose regimens in cattle.

The use of antimicrobial drugs in food-producing animals contributes to the selection pressure on pathogenic and commensal bacteria to become resistant. This study aims to evaluate the existence of trade-offs between treatment effectiveness, cost, and the dynamics of resistance in gut commensal bacteria. We developed a within-host ordinary differential equation model to track the dynamics of antimicrobial drug concentrations and bacterial populations in the site of infection (lung) and the gut. The model was parameterized to represent enrofloxacin treatment for bovine respiratory disease (BRD) caused by Pastereulla multocida in cattle. Three approved enrofloxacin dosing regimens were compared for their effects on resistance on P. multocida and commensal E. coli: 12.5 mg/kg and 7.5 mg/kg as a single dose, and 5 mg/kg as three doses. Additionally, we explored non-FDA-approved regimes. Our results indicated that both 12.5 mg/kg and 7.5 mg/kg as a single dose scenario increased the most the treatment costs and prevalence of P. multocida resistance in the lungs, while 5 mg/kg as three doses increased resistance in commensal E. coli bacteria in the gut the most out of the approved scenarios. A proposed non-FDA-approved scenario (7.5 mg/kg, two doses 24 h apart) showed low economic costs, minimal P. multocida, and moderate effects on resistant E. coli. Overall, the scenarios that decrease P. multocida, including resistant P. multocida did not coincide with those that decrease resistant E. coli the most, suggesting a trade-off between both outcomes. The sensitivity analysis suggests that bacterial populations were the most sensitive to drug conversion factors into plasma ( ß ), elimination of the drug from the colon ( ϑ ), fifty percent sensitive bacteria (P. multocida) killing effect ( L s50 ), fifty percent of bacteria (E. coli) above ECOFF killing effect ( C r50 ), and net drug transfer rate in the lung ( γ ) parameters.

Adsorption/desorption of enrofloxacin in farmland soil as the effect of pH and coexisting ions: implications for enrofloxacin fate and risk in loess soil.

Fluoroquinolone antibiotics have been extensively used in clinical treatments for human and animal diseases. However, their long-term presence in the environment increases the risk of producing resistance genes and creates a potential threat to ecosystems and the health of humans and animals. Batch equilibrium experiments were utilized to investigate the adsorption and retention behavior and mechanism of the quinolone antibiotic enrofloxacin (ENR) in farmland soil in North China. The adsorption and desorption kinetics of ENR in soil were best fitted by pseudo-second-order model (R2 > 0.999). Both the adsorption and desorption processes of ENR in soil reached equilibrium in 1 h. The desorption amounts of ENR were significantly lower than the adsorption amounts, with the hysteresis coefficient (HI) being less than 0.7. The adsorption thermodynamic process of ENR followed the Linear and Freundlich models (0.965 < R2 < 0.985). Hydrophobic distribution and heterogeneous multimolecular layer adsorption were identified as critical factors in the adsorption process. The adsorption amount of ENR gradually decreased with increasing temperature and the initial concentration of ENR. The adsorption rate of ENR was above 80%, while the desorption rate remained below 15%, indicating strong retention ability. The adsorption rate of ENR in soil decreased with increasing pH, the adsorption rate reached 98.3% at pH 3.0 but only 31.5% at pH 11. The influence of coexisting ions on adsorption primarily depended on their properties, such as ion radius, ionic strength, and hydrolysis properties, and the inhibition of adsorption increased with increasing ionic strength. These findings contribute to understanding the fate and risk of veterinary antibiotics in loess soil in North China.

Simultaneous detection of enrofloxacin and florfenicol in animal-derived foods based on fluorescence quenching BELISA and a nanozyme catalytic strategy.

Enrofloxacin (ENRO) and florfenicol (FF) are animal-specific drugs, but they present great harm to human health. Therefore, it is essential to rapidly and accurately detect ENRO and FF in animal-derived foods simultaneously. Herein, dual-template molecular imprinted polymers (MIPs) with specific recognition of ENRO and FF were prepared, meanwhile, the molar ratios of templates to monomer and cross-linker were optimized and then applied as a bionic antibody to experiment. Based on the principle that the fluorescence of QDs could be efficiently quenched by the enzymatic fabrication of Prussian blue nanoparticles (PBNPs), a novel and sensitive fluorescence quenching biomimetic enzyme-linked immunosorbent assay (BELISA) was established for simultaneous detection of ENRO and FF by the conversion of the absorption signal into fluorescent signals. Under optimal conditions, the detection limit (IC15) was 4.64 ng L-1 for ENRO and 1.33 ng L-1 for FF. Besides, matrix interference of chicken, eggs, milk and shrimp samples, was investigated in our study, and the result indicates that all of the sample matrices had a profound impact on the fluorescence of QDs, especially for milk samples (with Im of 94.10 %). After performing the matrix-elimination experiments, chicken, eggs, milk and shrimp samples spiked with ENRO and FF were extracted and detected by this proposed method, with recoveries ranging from 82.70 to 113.48 %. The results correlated well with those obtained using HPLC. In conclusion, the developed method could be an alternative and sensitive method for the simultaneous detection of ENRO and FF in animal-derived foods.

Pharmacokinetics of Enrofloxacin and Its Metabolite Ciprofloxacin in Nanyang Cattle.

The objective of this study was to determine the pharmacokinetics of enrofloxacin and its metabolite, ciprofloxacin, in Nanyang cattle after a single intravenous (IV), and intramuscular (IM) administration of enrofloxacin at 2.5 mg/kg body weight (BW). Blood samples were collected at predetermined time points. Enrofloxacin and ciprofloxacin concentrations in plasma were simultaneously determined using a high-performance liquid chromatography (HPLC) assay method and subjected to a non-compartmental analysis. After IV administration, enrofloxacin had a mean (±SD) volume of distribution at steady state (VSS) of 1.394 ± 0.349 L/kg, a terminal half-life (t1/2λz) of 3.592 ± 1.205 h, and a total body clearance (Cl) of 0.675 ± 0.16 L/h/kg. After IM administration, enrofloxacin was absorbed relatively slowly but completely, with a mean absorption time (MAT) of 6.051 ± 1.107 h and a bioavailability of 99.225 ± 7.389%. Both compounds were detected simultaneously in most plasma samples following both routes of administration, indicating efficient biotransformation of enrofloxacin to ciprofloxacin. After IV injection, the peak concentration (Cmax) of ciprofloxacin was 0.315 ± 0.017 µg/mL, observed at 0.958 ± 0.102 h. Following IM injection, the corresponding values were 0.071 ± 0.006 µg/mL and 3 ± 1.095 h, respectively. Following IV and IM administration, the conversion ratio of enrofloxacin to ciprofloxacin was calculated as 59.2 ± 9.6% and 31.2 ± 7.7%, respectively. The present results demonstrated favorable pharmacokinetic profiles for enrofloxacin, characterized by complete absorption with relatively slow kinetics, extensive distribution, efficient biotransformation to ciprofloxacin, and prolonged elimination in Nanyang cattle.

A Modified Calculation of the Withdrawal Time and a Risk Assessment of Enrofloxacin in Micropterus salmoides after Its Ad Libitum Administration via Medicated Feed in the Commercial Aquaculture.

The present study investigated the residue depletion and WTs of EF and its main metabolite, ciprofloxacin, in largemouth bass after ad libitum administration in commercial fish farming based on statistical approaches. Samples collected at pre-determined time points were assessed using high-performance liquid chromatography. If the concentrations of medicine were less than the quantitative limit, they were set to be half of the limit of quantitative. The terminal elimination of the target compound was assumed to fit a one-compartment model. The statistical methods of Bartlett's test and Cochran's test were used to inspect the homogeneity of the log-transformed data. The lack-of-fit test and F-test were used to check the linearity of the regression line. Outliers were assessed using standardized residuals. The final WT was estimated using the 95% percentile with a 95% confidence level. The WTs of EF were calculated to be 46, 29, 33, 46, and 20 days for the muscle + skin, plasma, gill, kidney, and liver, respectively. After the risk assessment, the values of the hazard quotient were calculated to be far less than 1, indicating that the risk of residual EF was particularly low in the edible tissues of largemouth bass after medicine depletion for various WTs.

A modified withdrawal time estimation and risk assessment of enrofloxacin in grass carp (Ctenopharyngodon idella) after ad libitum medicated feed based on statistical approaches in natural cultured environments.

Enrofloxacin (EF) is a broad-spectrum and highly efficient antibiotic commonly used for treating diseases in aquatic animals. However, its abuse in aquaculture applications often leads to excess residue in tissues of grass carp (Ctenopharyngodon idella). Hence, this study aimed to estimate the withdrawal time (WT) of EF and its metabolite of ciprofloxacin (CF) administered medicated feed in natural culture environments and conduct a risk assessment. Plasma and tissue samples were gathered at appropriate time points and detected by high-performance liquid chromatography. The data homogeneity was evaluated by Bartlett's test and Cochran's test. The linearity of the regressed line was evaluated by visual inspection and F test. Outliers were estimated on a normal probability scale by plotting the standardized residual versus their cumulative frequency distribution. Finally, the WT was calculated to be 51 days in muscle + skin based on the maximum residue limit of 100 µg/kg. After 51 days, the concentration of EF and CF fell below 10 µg/kg. The estimated daily intake was calculated to be 0.009 µg/kg/d. Hazard quotient was computed to be 0.002, which was far below one. These results suggested that calculated WT of EF could ensure the safety of products from grass carp for humans.

Enrofloxacin Pharmaceutical Formulations through the Polymer-Free Electrospinning of ß-Cyclodextrin-oligolactide Derivatives.

Enrofloxacin (ENR), a member of the fluoroquinolone class of antibiotics, is widely used in veterinary medicine to treat bacterial infections. Like many antibiotics, ENR has limited water solubility and low bioavailability. To address these challenges, drug formulations using solid dispersions, nanosuspensions, surfactants, cocrystal/salt formation, and inclusion complexes with cyclodextrins may be employed. The approach described herein proposes the development of ENR formulations by co-electrospinning ENR with custom-prepared cyclodextrin-oligolactide (CDLA) derivatives. This method benefits from the high solubility of these derivatives, enabling polymer-free electrospinning. The electrospinning parameters were optimized to incorporate significant amounts of ENR into the CDLA nanofibrous webs, reaching up to 15.6% by weight. The obtained formulations were characterized by FTIR and NMR spectroscopy methods and evaluated for their antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. This study indicates that the presence of CDLA derivative does not inhibit the antibacterial activity of ENR, recommending these formulations for further development.

Intra-species differences shape differences of enrofloxacin residues and its degradation products in tilapia: A precise risk assessment.

The increasing use and abuse of antibiotics in agriculture and aquaculture necessitates a more thorough risk assessment. We first advocate a precise assessment that subdivides the assessment scope from interspecies to intraspecific levels. Differences in ENR residues and degradation within the intraspecific category were simultaneously explored. This study chose red and GIFT tilapia, both belonging to the intra-specific category of tilapia, for an enrofloxacin (ENR) exposure experiment. Red tilapia had a lower area under the curve (AUC) representing drug accumulation, indicating a notably shorter withdrawal period (7 days) compared to GIFT tilapia (31.4 days) in the edible parts. While four potential transformation pathways were proposed for ENR in tilapia, red tilapia had fewer detected degradation products (6 items) than GIFT tilapia (10 items), indicating a simpler transformation pathway in red tilapia. Predictive assessments using the Toxtree model revealed that of the four extra degradation products in GIFT tilapia, two may possess carcinogenic and mutagenic properties. Overall, differences were observed in ENR residues and degradation within the intraspecific category, with red tilapia presenting lower risks than GIFT tilapia. This work suggests a new strategy to perfect the methodology for antibiotic risk assessment and facilitate systematic antibiotic administration management in the future.

Linking the removal of enrofloxacin to the extracellular polymers of microalgae in water bodies: A case study focusing on the shifts in microbial communities.

Microalgae can promote antibiotic removal, which has attracted growing attention. However, its synergistic removal performance with bacteria in antibiotic pollutants is still poorly understood. In this study, firstly, we selected two green algae (Dictyosphaerium sp. and Chlorella sp.) and exposed them to Enrofloxacin (ENR) to observe their extracellular polysaccharides (EPS) concentration dynamic and the removal of antibiotics. Secondly, EPS was extracted and added to in situ lake water (no algae) to investigate its combined effect with bacteria. The results indicate that both Dictyosphaerium sp. and Chlorella sp. exhibited high tolerance to ENR stress. When the biomass of microalgae was low, ENR could significantly stimulate algae to produce EPS. The removal rates of Dictyosphaerium sp. and Chlorella sp. were 15.8% and 10.5%, respectively. The addition of EPS can both alter the microbial community structure in the lake water and promote the removal of ENR. The LEfSe analysis showed that there were significant differences in the microbial marker taxa, which promoted the increase of special functional bacteria for decomposing ENR, between the EPS-added group and the control group. The EPS of Dictyosphaerium sp. increased the abundance of Moraxellaceae and Spirosomaceae, while the EPS of Chlorella sp. increased the abundance of Sphingomonadaceae and Microbacteriaceae. Under the synergistic effect, Chlorella sp. achieved a maximum removal rate of 24.2%, while Dictyosphaerium sp. achieved a maximum removal rate of 28.9%. Our study provides new insights into the removal performance and mechanism of antibiotics by freshwater microalgae in water bodies and contribute to the development of more effective water treatment strategies.

Exposure to blue light reduces antimicrobial resistant Pseudomonas aeruginosa isolated from dog ear infections.

Introduction: Pseudomonas aeruginosa is a leading cause of canine otitis externa. Enrofloxacin is often applied topically to treat this condition, although recalcitrant and recurring infections are common. There is evidence that exposure to blue light (400-470 nm) has a bactericidal effect on P. aeruginosa and other microorganisms. Methods: In the present study, we tested the biocidal effect of blue light (375-450 nm), alone or in combination with enrofloxacin, against six isolates of P. aeruginosa from dogs with otitis externa (5 of which were resistant to enrofloxacin). Results: Treatment of planktonic cell cultures with blue light resulted in significant (p < 0.5) reductions in Colony Forming Units (CFU) for all seven strains tested, in some cases below the limit of detection. The greatest bactericidal effect was observed following exposure to light at 405 nm wavelength (p < 0.05). Exposure to blue light for 20 min usually resulted in a greater reduction in Pseudomonas aeruginosa than enrofloxacin treatment, and combination treatment typically resulted in the largest reductions in CFU. Analysis of the genome sequences of these strains established that enrofloxacin resistance was likely the result of a S466F substitution in GyrB. However, there was no clear association between genotype and susceptibility to blue light treatment. Discussion: These results suggest that blue light treatment, particularly at 405 nm wavelength, and especially in combination with enrofloxacin therapy, could be an effective treatment for otherwise recalcitrant canine otitis externa caused by Pseudomonas aeruginosa. It may also provide a way of extending the usefulness of enrofloxacin therapy which would otherwise be ineffective as a sole therapeutic agent.

Development and validation of rapid screening of 192 veterinary drug residues in aquatic products using HPLC-HRMS coupled with QuEChERS.

The presence of veterinary drug residues in aquatic products represents a significant challenge to food safety. The current detection methods, limited in both scope and sensitivity, underscore the urgent need for more advanced techniques. This research introduces a swift and potent screening technique using high-performance liquid chromatography-high-resolution mass spectrometry (HPLC-HRMS) and a refined QuEChERS protocol, allowing simultaneous qualitative and semi-quantitative analysis of 192 residues. A comprehensive database, employing full scan mode and data-dependent secondary mass spectroscopy, enhances screening accuracy. The method involves efficient extraction using 90% acetonitrile, dehydration with Na2SO4, and acetic acid, followed by cleanup using dispersive solid-phase extract sorbent primary secondary amine. It is suitable for samples with varying fat content, offering detection limits ranging from 0.5 to 10 µg/kg, high recovery rates (60-120%), and low relative standard deviations (<20%). Practical application has validated its effectiveness for multi-residue screening, marking a significant advancement in food safety evaluation.

Pharmacokinetic/pharmacodynamic relationships of enrofloxacin against Klebsiella pneumoniae in an in vivo infection model in young chicks.

Klebsiella pneumoniae is a serious pathogenic bacterium that poses a significant threat to young poultry and the cause of significant chick mortality and economic loss. We investigated the therapeutic efficacy of enrofloxacin in treating K. pneumoniae infections in chicks and employed an in vivo pharmacokinetic/pharmacodynamic (PK/PD) model. In vivo efficacy was evaluated using 6 multiple-dose groups (oral administration once a day for 3 d) and 2 single-dose groups (oral administration once only). The PK and PD parameters of plasma and lung were analyzed using PK/PD fitting analysis. K. pneumoniae administered intratracheally (108 CFU/mL in 0.4 mL saline) was used to establish a model for pulmonary infection. The plasma protein binding of enrofloxacin was 20.18%. Enrofloxacin displayed T1/2ß values of 4.78 ± 0.69 h and 4.78 ± 1.02 h in plasma and lung of infected chicks, respectively. When the dosage in the multiple-dose group was > 10 mg/kg, bactericidal activity was found and complete eradication was not achieved when the dosage was ≤ 40 mg/kg. When TMSW was set at 20%, the calculated dosage and bacterial reduction (E) based on plasma free drug data were 4.03 mg/kg and -1.982 Log10 CFU/mL, respectively. In the calculation of PK/PD parameters for reducing 3 Log10 CFU/mL and using Cmax/MIC, AUC72h/MIC and TMSW of free drug in plasma values at 9.479, 379.691, and 44.395%, respectively, the value of AUC72h/MIC based on the concentration of drug in lung was 530.800. According to the fitting correlation R2, the PK/PD fitting results of free drug in plasma were better. The corresponding enrofloxacin dosage for AUC72h/MIC of the plasma free drug concentration was 14.16 mg/kg. The administration regimen corresponding to these dosages was once daily for 3 d. This dosage regimen (14.16 mg/kg) was relatively high compared to the clinically recommended dosage in China (7.5 mg/kg) when treating infections caused by K. pneumoniae with MIC ≥ 0.125 µg/mL, so careful consideration is needed.

Combining GC-MS/MS with a LLE-SPE sample pretreatment step to simultaneously analyse enrofloxacin and ofloxacin residues in chicken tissues and pork.

A widely applicable original gas chromatography-tandem mass spectrometry (GC-MS/MS) method was explored to qualitatively and quantitatively measure enrofloxacin and ofloxacin residues in chicken tissues and pork. The experimental samples were processed based on liquid-liquid extraction (LLE) and solid-phase extraction (SPE). Trimethylsilyl diazomethane (TMSD) was chosen to react derivatively with enrofloxacin and ofloxacin. In total, 78.25% âˆ¼ 90.56% enrofloxacin and 78.43% âˆ¼ 91.86% ofloxacin was recovered from the blank fortified samples. The limits of detection (LODs) were 0.7-1.0 µg/kg and 0.1-0.2 µg/kg, respectively. The limits of quantitation (LOQs) were 1.6-1.9 µg/kg and 0.3-0.4 µg/kg, respectively. It was verified that various experimental data met the requirements of the FAO & WHO (2014) for the detection of veterinary drug residues. Real samples obtained from local markets were analysed using the established method, and no residues of enrofloxacin or ofloxacin were detected in the samples.

Exo â ¢-assisted amplification signal strategy synergized with Au@Pt NFs/CoSe2 for sensitive detection of enrofloxacin.

Overuse of enrofloxacin (ENR) has posed a potential threat to ecosystems and public health, so it is critical to sensitive and accurate determination of ENR residues. In this work, a novel ultra-sensitive and specific electrochemical aptasensor was fabricated based on the cobalt diselenide loaded gold and platinum nanoflowers (Au@Pt NFs/ CoSe2) and Exonuclease III (Exo III)-assisted cycle amplification strategy for the detection of ENR. Au@Pt NFs/ CoSe2 nanosheets as the substrate material, with large surface area, accelerate electron transfer and attach more DNA probes on the electrode substrate, have effectively enhanced the electrochemical performance of the electrode. With the existence of Enrofloxacin (ENR), the aptamer recognizes and binds to ENR, thus the signal probe cDNA was released and immobilized onto the electrode surface to hybridized with methylene blue (MB) labelled DNA (MB-DNA), thereby triggering the Exo III-assisted cycle for further signal amplification. As expected, the prepared aptasensor demonstrated excellent sensitivity and selectivity, with a wide linear range from 5.0 × 10-6 ng/mL to 1.0 × 10-2 ng/mL for ENR, a low detection limit of 1.59 × 10-6 ng/mL. Consequently, this strategy provided a promising avenue for ultrasensitive and accurate detection of ENR in milk samples.