Determination of aminoglycoside antibiotics: Current status and future trends

An exonuclease III-driven dual-mode aptasensor based on Au-Pd@Fc nanozyme and magnetic separation pretreatment for aminoglycoside antibiotics detection

A novel dual-mode aptasensor was constructed for aminoglycoside antibiotics (AAs) detection by using a broad-spectrum aptamer as a biorecognition element, and Au-Pd@Fc functionalized by signal DNA as nanoprobes. In electrochemical mode, the target-induced cyclic amplification reaction run under the action of exonuclease-III, which increased the number of nanoprobes on the electrode surface. AAs could be quantitatively detected with LOD of 0.0355 ± 0.00613 nM. In colorimetric mode, the Au-Pd@Fc nanozyme catalyzed the color reaction of 3,3',5,5'-tetramethylbenzidine. The blue-shifted absorbance will be observed with the change of AAs concentration, and the LOD was 0.0458 ± 0.00572 nM. Furthermore, a magnetic molecular-imprinted material capable of specific adsorption of AAs was prepared on milk sample pretreatment. The aptasensor was used to detect 10 kinds of AAs in milk and the recoveries were 97.19 ± 4.41% ∼ 98.70 ± 4.45% and 96.38 ± 3.53%-97.54 ± 4.13% in electrochemical and colorimetric methods. This work provided a theoretical basis for the application of aptamers in simultaneous detection of antibiotics.

Colorimetric detection of neomycin sulfate in serum based on ultra-small gold nanoparticles with peroxidase-like activity

Neomycin sulfate (NEO) is a kind of aminoglycoside antibiotics. Because of its strong ototoxicity, nephrotoxicity and other side effects, its content in the body should be strictly monitored during use. In this paper, a rapid colorimetric detection method for NEO based on ultrasmall polyvinylpyrrolidone modified gold nanoparticles (PVP/Au NPs) with peroxidase-like activity was developed. Firstly, ultra small PVP/Au NPs with weak peroxidase-like activity were synthetized. When they were mixed with NEO, strong hydrogen bonds were formed between NEO and PVP, resulting in the aggregation of PVP/Au NPs, and the aggregated PVP/Au NPs showed stronger peroxidase-like activity. Therefore, rapid colorimetric detection of NEO was achieved by utilizing the enhanced peroxidase-like activity mechanism caused by the aggregation of ultra small PVP/Au NPs. The naked eye detection limit of this method is 50 nM. Within the range of 1 nM-300 nM, there was a good linear relationship between NEO concentration and the change in absorbance intensity of PVP/Au NPs-H2O2-TMB solution at 652 nm, with the regression curve of y = 0.0045x + 0.0525 (R2 = 0.998), and the detection limit is 1 nM. In addition, this method was successfully applied to the detection of NEO in mouse serum. The recoveries were 104.4 % -107.6 % compared with HPLC assay results, indicating that this method for NEO detection based on PVP/Au NPs has great potential in actual detection of NEO in serum.

Veterinary Drug Residues in Food Products of Animal Origin and Their Public Health Consequences: A Review

Veterinary medications used for disease treatment and prevention may remain in animal-origin foods, such as milk, eggs, honey and meat, which could pose a risk to the public's health. These drugs come from different groups of drugs, mostly with antibiotic, anti-parasitic or anti-inflammatory actions, in a range of food matrices including milk, meat or egg. This review is intended to provide the reader with a general insight about the current status of veterinary drug residues in food products of animal origin, detection methods and their public health consequences. The discovery of antimicrobials has led to the development of antibiotics for treating and preventing cattle illnesses and encouraging growth. However, the rise of drug resistance has led to increased antibiotic consumption and resistance among microbes in the animal habitat. This resistance can be passed to humans directly or indirectly through food consumption and direct or indirect interaction. Improper and illegal use, inadequate withdrawal periods and environmental contamination from veterinary drugs are reported to be the major causes for the formation of residue in food products of animal origin. The use of veterinary products above or below the advised level may also result in short- or long-term public health issues, such as the creation of resistant strains of micro-organisms, toxicity, allergy, mutagenesis, teratogenicity and carcinogenetic effects. To ensure consumer safety, veterinary drug residues in food must be under control.

Fate and mitigation of antibiotics and antibiotic resistance genes in microbial fuel cell and coupled systems

Microbial fuel cells (MFCs), known for their low energy consumption, high efficiency, and environmental friendliness, have been widely utilized for removing antibiotics from wastewater. Compared to conventional wastewater treatment methods, MFCs produce less sludge while exhibiting superior antibiotic removal capacity, effectively reducing the spread of antibiotic resistance genes (ARGs). This study investigates 1) the mechanisms of ARGs generation and proliferation in MFCs; 2) the influencing factors on the fate and removal of antibiotics and ARGs; and 3) the fate and mitigation of ARGs in MFC and MFC-coupled systems. It is indicated that high removal efficiency of antibiotics and minimal amount of sludge production contribute the mitigation of ARGs in MFCs. Influencing factors, such as cathode potential, electrode materials, salinity, initial antibiotic concentration, and additional additives, can lead to the selection of tolerant microbial communities, thereby affecting the abundance of ARGs carried by various microbial hosts. Integrating MFCs with other wastewater treatment systems can synergistically enhance their performance, thereby improving the overall removal efficiency of ARGs. Moreover, challenges and future directions for mitigating the spread of ARGs using MFCs are suggested.

Bacterial cellulose-supported dual-layered nanofibrous adsorbent for thin-film micro-solid-phase extraction of antibiotics in municipal wastewaters

In this study, bacterial cellulose was coated with composite nanofibers of polyvinyl alcohol doped with beta cyclodextrin and alginate (PVA-SA-βCD), constructed using the electrospinning technique. This novel material served as an effective adsorbent for thin-film micro-solid-phase extraction (TF-μSPE) of antibiotics from water samples, followed by HPLC-UV analysis. The adsorbent was subjected to a comprehensive characterization using ATR-FTIR, FE-SEM, and BET techniques. These analyses provided valuable insights into its physicochemical structure and properties. Several key parameters that affect the performance of the TF-μSPE method were investigated including electrospinning factors (voltage, flow rate, needle tip-collector distance, and electrospinning time), desorption solvent type and volume, adsorbent dose, adsorption and desorption times, pH value, and salt percentage. Under the optimized conditions, the limits of detections and quantifications for target antibiotics were obtained in the ranges of 0.02-0.03 and 0.07-0.1 μg L⁻1, respectively. The linear range was 0.07-1000 μg L⁻1 with satisfactory determination coefficients (r2) of 0.9944-0.9984. The intra-day and inter-day precisions were obtained as 1.1-1.7 % and 2.2-3.5 %, respectively. The developed method was successfully applied to determine antibiotics in municipal wastewater samples, yielding recoveries within the range of 70-100 % (RSD%<3.7). The green features of the method were also assessed based on AGREE tool. This is the first report on the fabrication of a double-layered nanofibrous adsorbent and its application for the adsorption of antibiotics in wastewater. This robust approach combines efficiency with analytical accuracy, making it a valuable tool for antibiotic analysis in environmental samples.

Microwave Synthesis of Fluorescent Carbon Quantum dots from Araucaria Heterophylla Gum: Application in Drug Detection

This study employed a green microwave synthesis technique to produce carbon quantum dots (CQDs) from araucaria heterophylla gum extract. The produced CQDs emit a distinct blue fluorescent light, contributing a remarkable quantum yield of 14.69%. Their average particle size measures at 1.62 ± 0.39 nm. Furthermore, these CQDs demonstrate excellent water solubility and maintain high fluorescence stability despite ionic strength, pH and time variations. Moreover, we present here for the first time that the synthesized CQDs demonstrate a rapid, exceptionally sensitive, and discerning fluorescence quenching phenomenon (IFE) concerning Cefprozil (CPR). The fluorescent probe was sensitive and specific with good linear relationships for CPR in the 0-18 µM range. The limit of detection for relationships for CPR was 2.51 µM. This study provides novel opportunities for producing high-quality luminescent CQDs that meet the requirements for various biological and environmental applications.

A smartphone-assisted portable dual-mode immunoassay of gentamicin based on curcumin nanoparticles and carbon dots

A smartphone-assisted portable dual-mode immunoassay was constructed based on curcumin nanoparticles (CNPs) and carbon dots (CDs) for gentamicin (GEN) detection. CNPs were labeled with goat anti-mouse IgG (Ab2) to create a conjugation that coupled dual signals to concentrations of GEN antigens. CNPs were introduced to pH 7.4 water and showed insignificant color and optical responses. When exposed to the high pH environment, the structure of CNPs changed and color and optical properties were restored. Because of the inner filter effect (IFE) between CNPs and CDs, the fluorescence of CNPs at 550 nm quenched the fluorescence of CDs at 450 nm. Colorimetry and ratiometric fluorescence (F550 nm/F450 nm) dual-mode immunoassay linearly correlated with GEN ranged from 10-4 to 100 µg/mL with a detection limit (LOD) of 8.98 × 10-5 µg/mL and 4.66 × 10-5 µg/mL, respectively. This work supplied a portable, sensitive, and specific platform to detect GEN.

Determination and Identification of Antibiotic Residues in Fruits Using Liquid Chromatography-High-Resolution Mass Spectrometry (LC-HRMS)

Antibiotic residues may be present in fruit products from trees that were treated to combat bacterial diseases such as citrus greening or blight. A liquid chromatography-high-resolution mass spectrometry (LC-HRMS) method was developed for the simultaneous determination and identification of streptomycin, kasugamycin, penicillin, and oxytetracycline residues in fruit. Samples were extracted with acidic methanol and separation was optimized for a hydrophilic interaction LC column. A Q-Exactive HRMS instrument was used to obtain product ion spectra for analyte identification. Quantitation was performed with matrix-extracted calibration curves and internal standard correction. The method was tested on many different types of fruit. In general, fortified samples demonstrated acceptable recoveries (82-116%) and reproducibility (<15% RSD). Method detection limits for these analytes were well below the established US EPA tolerance levels. It was also possible to analyze the fruit extracts prepared using this method for additional chemical contaminants using LC-HRMS.

Determination of Aminoglycosides by Ion-Pair Liquid Chromatography with UV Detection: Application to Pharmaceutical Formulations and Human Serum Samples

Aminoglycosides (AGs) represent a prominent class of antibiotics widely employed for the treatment of various bacterial infections. Their widespread use has led to the emergence of antibiotic-resistant strains of bacteria, highlighting the need for analytical methods that allow the simple and reliable determination of these drugs in pharmaceutical formulations and biological samples. In this study, a simple, robust and easy-to-use analytical method for the simultaneous determination of five common aminoglycosides was developed with the aim to be widely applicable in routine laboratories. With this purpose, different approaches based on liquid chromatography with direct UV spectrophotometric detection methods were investigated: on the one hand, the use of stationary phases based on hydrophilic interactions (HILIC); on the other hand, the use of reversed-phases in the presence of an ion-pairing reagent (IP-LC). The results obtained by HILIC did not allow for an effective separation of aminoglycosides suitable for subsequent spectrophotometric UV detection. However, the use of IP-LC with a C18 stationary phase and a mobile phase based on tetraborate buffer at pH 9.0 in the presence of octanesulfonate, as an ion-pair reagent, provided adequate separation for all five aminoglycosides while facilitating the use of UV spectrophotometric detection. The method thus developed, IP-LC-UV, was optimized and applied to the quality control of pharmaceutical formulations with two or more aminoglycosides. Furthermore, it is demonstrated here that this methodology is also suitable for more complex matrices, such as serum, which expands its field of application to therapeutic drug monitoring, which is crucial for aminoglycosides, with a therapeutic index ca. 50%.

Determination of four aminoglycoside antibiotics and spectinomycin in feed at cross-contamination level: Development and in-house validation of a LC-MS/MS method for enforcing EU Regulation

Combating antimicrobial resistance is a top priority worldwide involving a concerted action by several high-level institutions and organisations in the health sector. To ensure that a meaningful progress is achieved, several campaigns and political initiatives have been launched targeting the health professionals, the industry, the farmers, and the general public. The Regulation (EU) 2019/4 on medicated feed contains provisions for the limitation and control of the contamination of non-target compound feed with 24 antimicrobials. The purpose of this work was to develop a reliable and effective method for the determination of four aminoglycoside antibiotics (apramycin, paromomycin, tobramycin and neomycin) and spectinomycin in feed at cross-contamination level, where an absolute lack of suitable methods was identified. Four candidate methods described in the literature failed to provide adequate recoveries of all analytes. Therefore, an in-depth investigation was carried out to identify the bottleneck variable. The optimised method was then in-house validated and showed performance features appropriate for the intended purpose. The selected compounds could be analysed by LC-MS/MS in five animal feeds with LOQs between 2.6 and 9.2 μg kg-1 for the AGs and between 28 and 86 μg kg-1 for spectinomycin. Using isotopically labelled internal standards, the recovery rates varied from 63 % to 103 % and the intermediate precision (RSDip) varied from 1.1 % to 14 %. This work represents a step forward in the reliable determination of antibiotics in compound feed as the developed method has shown to be precise and sensitive. It is expected that this method gains wide acceptance and can supplement the legislation with effective control tools for antibiotic residues.

A trivalent aptasensor by using DNA tetrahedron as scaffold for label-free determination of antibiotics

Owing to advantage in high sensitivity and fast response, aptamer based electrochemical biosensors have attracted much more attention. However, inappropriate interfacial engineering strategy leads to poor recognition performance, which ascribe to the following factors of immobilized oligonucleotide strand including steric hindrance, interchain entanglement, and unfavorable conformation. In this work, we proposed a DNA tetrahedron based diblock aptamer immobilized strategy for the construction of label-free electrochemical biosensor. The diblock aptamer sequence is composite of T-rich anchor domain and recognition domain, where T-rich domain enabling anchored on the edge of DNA tetrahedron via Hoogsteen hydrogen bond at neutral condition. The DNA tetrahedron scaffold offers an appropriate lateral space for target recognition of diblock aptamer. More importantly, this trivalent aptamer recognition interface can be regenerated by simply adjusting the pH environment to alkaline, resulting in the dissociation of diblock aptamer. Under the optimum condition, proposed electrochemical aptasensor manifested a satisfied sensitivity for aminoglycosides antibiotic, kanamycin with a limit of detection of 0.69 nM, which is 45-fold lower than traditional Au-S immobilization strategy. Moreover, the proposed aptasensor had also successfully been extended to ampicillin detection by changing the sequence of recognition domain in diblock aptamer. This work paves a new way for the rational design of aptamer-based electrochemical sensor.

Dynamic carboxymethyl chitosan prodrug hydrogel precisely mediates robust therapy on wound infection

Dynamic antibacterial polysaccharide prodrug hydrogels are in great demand for treatment of wound infection owing to their unique advantages such as excellent biocompatibility, superior antimicrobial property as well as favorable wound healing capacity. Herein, this work highlights the successful development of a dynamic carboxymethyl chitosan (CMC) prodrug hydrogel, which is facilely constructed through Schiffer base reaction between antibacterial components (amikacin and CMC) and crosslinker (dialdehyde PEG). Moderate dynamic imine linkages endow the hydrogel with excellent injectable and self-healing capability as well as targeted on-demand drug release in slightly alkaline condition at infected wound. All ingredients and their strong intermolecular interactions endow the hydrogel with favorable swelling and moisture retention capability. Moreover, the covalent and non-covalent interactions also endow the hydrogel with superior adhesion and mechanical property. These attractive characteristics enable hydrogel to effectively kill pathogens, promote wound healing and reduce side effects of amikacin. Thereby, such a dynamic CMC prodrug hydrogel may open a new avenue for a robust therapy on wound infection, greatly advancing their use in clinics.

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.

Combating Aminoglycoside Resistance: From Structural and Functional Characterisation to Therapeutic Challenges with RKAAT

A comprehensive knowledge of aminoglycoside-modifying enzymes (AMEs) and their role in bacterial resistance mechanisms is urgently required due to the rising incidence of antibiotic resistance, particularly in Klebsiella pneumoniae infections. This study explores the essential features of AMEs, including their structural and functional properties, the processes by which they contribute to antibiotic resistance, and the therapeutic importance of aminoglycosides. The study primarily examines the Recombinant Klebsiella pneumoniae Aminoglycoside Adenylyl Transferase (RKAAT), particularly emphasizing its biophysical characteristics and the sorts of resistance it imparts. Furthermore, this study examines the challenges presented by RKAAT-mediated resistance, an evaluation of treatment methods and constraints, and options for controlling infection. The analysis provides a prospective outlook on strategies to address and reduce antibiotic resistance. This extensive investigation seeks to provide vital insights into the continuing fight against bacterial resistance, directing future research efforts and medicinal approaches.

Dual fluorescence-colorimetric sensor based on silver nanoparticles for determination of tobramycin in its pharmaceutical preparations

The purpose of this study is to develop a dual fluorescence-colorimetric sensor for determination of the non-chromophoric drug, tobramycin using fluorescein-modified silver nanoparticles. Fluorescein is adsorbed on the surface of silver nanoparticles resulting in quenching of the fluorescence intensity of fluorescein at 513 nm. Upon addition of tobramycin to fluorescein-bound silver nanoparticles, tobramycin can displace fluorescein from the surface of nanoparticles resulting in nanoparticles aggregation and liberation of free fluorescein restoring its fluorescence. The interaction of tobramycin with fluorescein-bound silver nanoparticles is manifested by a decrease in the surface plasmon resonance band of silver nanoparticles at 395 nm, an increase in the fluorescence intensity of fluorescein at 513 nm and color change of the colloidal solution from yellow to light pink. These spectral effects are directly proportional to the concentration of tobramycin with a linearity range of 0.10 - 0.45 μg mL-1 and 0.05 - 0.45 μg mL-1 for the spectrophotometric and spectrofluorimetric methods, respectively. The proposed methods were applied for determination of tobramycin in Tobrin® ophthalmic solution with mean %recovery ± standard deviation of 99.036 ± 1.737 for the spectrophotometric method and 101.192 ± 1.315 for the spectrofluorimetric method. The optical sensor is simple, rapid, and cost-effective and can be used for determination of tobramycin in bulk and in its pharmaceutical preparations.

Risk assessment of Enterococcus faecium, Klebsiella pneumoniae, and Pseudomonas aeruginosa in environmental water sources: Development of surrogate models for antibiotic resistance genes

The presence of Enterococcus faecium (E. faecium), Klebsiella pneumoniae (K. pneumoniae), Pseudomonas aeruginosa (P. aeruginosa), and the aminoglycoside resistance genes, aac(6')-Ib and aac(6')-aph(2″), was investigated in environmental water sources obtained from informal settlements in the Western Cape (South Africa). Using ethidium monoazide bromide quantitative polymerase chain reaction (EMA-qPCR) analysis, E. faecium, K. pneumoniae, and P. aeruginosa were detected in 88.9 %, 100 %, and 93.3 % of the samples (n = 45), respectively, with a significantly higher mean concentration recorded for K. pneumoniae (7.83 × 104 cells/100 mL) over the sampling period. The aac(6')-Ib gene was detected in 95.6 % (43/45) of the environmental water samples [mean concentration of 7.07 × 106 gene copies (GC)/100 mL], while the aac(6')-aph(2″) gene was detected in 100 % (n = 45) of the samples [mean concentration of 6.68 × 105 GC/100 mL]. Quantitative microbial risk assessment (QMRA) subsequently indicated that the risks posed by K. pneumoniae and P. aeruginosa were linked to intentional drinking, washing/bathing, cleaning of the home, and swimming, in the samples collected from the various sampling sites. Surrogate risk assessment models were then designed and applied for Gram-positive [aac(6')-aph(2″) gene] and Gram-negative [aac(6')-Ib gene] pathogens that may exhibit aminoglycoside resistance. The results indicated that only the Gram-negative pathogens posed a risk (>10-4) in all the samples for cleaning of the home and intentional drinking, as well as for washing laundry by hand, garden hosing, garden work, washing/bathing, accidental consumption, and swimming at the stream and marsh sites. Thus, while environmental waters may pose a health risk of exposure to pathogenic bacteria, the results obtained indicate that screening for antibiotic resistant genes, associated with multiple genera/species, could serve as a surrogate model for estimating risks with the target group under investigation.

Residue analysis of 10 aminoglycoside antibiotics in aquatic products by multiwalled carbon nanotubes combined with mixed-mode ion exchange liquid chromatography-tandem mass spectrometry

An ultra-high-performance liquid chromatography-tandem mass spectrometry method was developed for simultaneous determination of 10 kinds of aminoglycosides in edible parts of aquatic products. The samples were extracted with 10 mmol/L potassium dihydrogen phosphate buffer solution, then the pH value of the extract was adjusted to neutral by sodium hydroxide. Half volume of the extract was loaded onto multiwalled carbon nanotubes cartridge. All the target compounds were separated on a mixed-mode ion exchange column and detected by ultra-high-performance liquid chromatography-tandem mass spectrometry with electrospray in the positive ionization mode. Under optimized conditions, this method had a good linearity with a squared correlation coefficient > 0.999. For neomycin, the limit of detection and limit of quantification were 5.0 μg/kg and 10.0 μg/kg, respectively; for hygromycin B and apramycin, values were 2.0 μg/kg and 5.0 μg/kg, respectively; for the other seven kinds of aminoglycosides, values were 1.0 μg/kg and 2.0 μg/kg, respectively. The average recoveries presented 75.8%-107.2% with intra- and interday reproducibility ranging between 3.8% and 12.5%. The method was rapid with good separation and sharp peak shapes, had the characteristicsis of high accuracy and good precision, and was suitable for simultaneous determination of 10 kinds of aminoglycosides in aquatic products.

Synthesis of fluorescent probe based on molecularly imprinted polymers on nitrogen-doped carbon dots for determination of tobramycin in milk

Tobramycin (TOB) plays a considerable role in combating milk spoilage and preventing disease in dairy cows. However, overuse of TOB can lead to nephrotoxicity, ototoxicity, neuromuscular blockade, and hypersensitivity reactions. Here, nitrogen-doped carbon dots (N-CDs) were prepared with ethylenediamine and citric acid, then molecularly imprinted layers were obtained by imprinting of surface on the N-CDs to prepare Nitrogen-doped carbon dot-based molecularly imprinted polymers (N-CDs@MIPs). The fluorescence emission spectrum of this probe showed a linear enhancement with the TOB concentration in the 1-12 μM. Meanwhile, a detection limit of 99.2 nM was obtained. This probe was not affected by the structural analogs of the TOB and can show high sensitivity and selectivity compared to non-imprinted polymers (N-CDs@NIPs). Therefore, it can be successfully used for the trace analysis of TOB in milk with advantages over other reported techniques such as liquid chromatography coupled with tandem mass spectrometry or various aptamer sensors.

Current Trends in Nanomaterials-Based Electrochemiluminescence Aptasensors for the Determination of Antibiotic Residues in Foodstuffs: A Comprehensive Review

Veterinary pharmaceuticals have been recently recognized as newly emerging environmental contaminants. Indeed, because of their uncontrolled or overused disposal, we are now facing undesirable amounts of these constituents in foodstuff and its related human health concerns. In this context, developing a well-organized environmental and foodstuff screening toward antibiotic levels is of paramount importance to ensure the safety of food products as well as human health. In this case, with the development and progress of electric/photo detecting, nanomaterials, and nucleic acid aptamer technology, their incorporation-driven evolving electrochemiluminescence aptasensing strategy has presented the hopeful potentials in identifying the residual amounts of different antibiotics toward sensitivity, economy, and practicality. In this context, we reviewed the up-to-date development of ECL aptasensors with aptamers as recognition elements and nanomaterials as the active elements for quantitative sensing the residual antibiotics in foodstuff and agriculture-related matrices, dissected the unavoidable challenges, and debated the upcoming prospects.

Polyvinyl alcohol electrospun nanofiber membrane based solid-phase extraction for monitoring administered aminoglycoside antibiotics in various animal-derived foods

This work aims to develop a widely applicable method to monitor administered AGs in various animal-derived food samples to ensure food safety. A polyvinyl alcohol electrospun nanofiber membrane (PVA NFsM) was synthesized and employed as solid-phase extraction (SPE) sorbent, in combination with UPLC-MS/MS, for the simultaneous detection of ten AGs in nine types of animal-derived food samples. PVA NFsM exhibited excellent adsorption performance for the targets (with an adsorption rate of over 91.09%), good matrix purification ability (with a reduction of 7.65%-77.47% in matrix effect after SPE), and good recyclability (can be reused 8 times). The method displayed a linear range of 0.1-25000 μg/kg and attained limits of detection for AGs were 0.03-15 μg/kg. Spiked samples demonstrated a recovery of 91.72%-100.04% with a precision of<13.66%. The practicality of the developed method was verified by testing multiple actual samples.

Analysis of Aminoglycoside Antibiotics: A Challenge in Food Control

Aminoglycosides are a widely used group of antibiotics in veterinary medicine. However, misuse and abuse of these drugs can lead to residues in the edible tissues of animals. Due to the toxicity of aminoglycosides and the exposure of consumers to the emergence of drug resistance, new methods are being sought to determine aminoglycosides in food. The method presented in this manuscript describes the determination of twelve aminoglycosides (streptomycin, dihydrostreptomycin, spectinomycin, neomycin, gentamicin, hygromycin, paromomycin, kanamycin, tobramycin, amikacin, apramycin, and sisomycin) in thirteen matrices (muscle, kidney, liver, fat, sausages, shrimps, fish honey, milk, eggs, whey powder, sour cream, and curd). Aminoglycosides were isolated from samples with extraction buffer (10 mM NH₄OOCH₃, 0.4 mM Na₂EDTA, 1% NaCl, 2% TCA). For the clean-up purpose, HLB cartridges were used. Analysis was performed using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) with a Poroshell analytical column and a mobile phase of acetonitrile and heptafluorobutyric acid. The method was validated according to Commission Regulation (EU) 2021/808 requirements. Good performance characteristics were obtained for recovery, linearity, precision, specificity, and decision limits (CCα). This simple and high-sensitivity method can determine multi-aminoglycosides in various food samples for confirmatory analysis.

Liquid Chromatography-Tandem Mass Spectrometry Analysis of Aminoglycosides in Foods Using an Ethylene-Bridged Hybrid Zwitterionic Stationary Phase and Hydrophilic-Lipophilic-Balanced Solid-Phase Extraction Cartridges

This work aimed to develop an analytical method for the screening of multiple aminoglycoside residues in foods of animal origin using an ethylene-bridged hybrid (BEH) particle-based sulfoalkylbetaine stationary phase. The effects of chromatographic conditions on the separation of 17 aminoglycosides have been systematically investigated. Sample preparation and mass spectrometry detection have also been investigated and optimized. In contrast to high buffer concentrations in the mobile phase required for silica-based sulfoalkylbetaine stationary phases, a moderate buffer concentration (20 mM) provided the optimal separation of 17 aminoglycosides with the BEH sulfoalkylbetaine stationary phase. The developed method has been evaluated in milk, beef, pork, liver, and honey samples with good performance for retention, selectivity, sensitivity, linearity, precision, and accuracy. The majority of the limit of quantitation estimated with the matrix was less than 25 μg/kg. The overall accuracy across five matrices was in the range from 96 to 111%, with standard deviations of less than 19%.

Explainable Deep Learning-Assisted Photochromic Sensor for β-Lactam Antibiotic Identification

Photochromic sensors have the advantages of diverse isomers for multi-analysis, providing more sensing information and possessing more recognition units and more sensitivity to external stimulations, but they present enormous complexity with various stimulations as well. Deep learning (DL) algorithms contribute a huge advantage at analyzing nonlinear and multidimensional data, but they suffer from nontransparent inner networks, "black-boxes". In this work, we employed the explainable DL approach to process and explicate photochromic sensing. Spirooxazine metallic complexes were adopted to prepare a multi-state analysis array for β-Lactams identification and quantitation. A dataset of 2520 unduplicated fluorescence intensity images was collected for convolutional neural network (CNN) operation. The method clearly discriminated six β-Lactams with 97.98% prediction accuracy and allowed rapid quantification with a concentration range from 1 to 100 mg/L. The photochromic sensing mechanism was verified via molecular simulation and class activation mapping, which explicated how the CNN model assesses the importance of photochromic sensor states and makes a discrimination decision. The explainable DL-assisted analysis method establishes an end-to-end strategy to ascertain and verify the complicated sensing mechanism for device optimization and even new scientific discovery.

Multiresidues Multiclass Analytical Methods for Determination of Antibiotics in Animal Origin Food: A Critical Analysis

Veterinary drugs are widely used to prevent and treat diseases. The European Union has forbidden the use of antibiotics as growth promoters since 2006. Its abusive use leads to the presence of antibiotic residues (AR) in foods of animal origin which is associated with antibiotic resistance. The monitoring of AR in food intended for human consumption is of utmost importance to assure Food Safety. A systematic bibliographic review was carried out on the analytical methodologies, published in 2013, for the determination of AR in foods of animal origin. The food processing effect in the AR detected in animal products is also addressed. However, there is a preference for multiresidues multiclass methods, i.e., methodologies that allow determining simultaneously different classes of antibiotics, which is still a challenge for researchers. The wide diversity of physico-chemical properties of these drugs is an obstacle to achieving excellent analytical performance for a vast number of molecules analyzed concurrently. New techniques in sample preparation continue to be developed in order to obtain a compromise between good recoveries and extracts without interferences (clean extracts). The most widely used analytical methodology for the determination of AR is liquid chromatography coupled with mass spectrometry. However, the current trend is focused on the use of powerful high-resolution MS detectors such as Time of Flight and Orbitrap with modern chromatographic systems. Cooking time and temperature control are the key processing conditions influencing the reduction of AR in foods.

Novel Electrochemical Aptasensor Based on Ordered Mesoporous Carbon/2D Ti3C2 MXene as Nanocarrier for Simultaneous Detection of Aminoglycoside Antibiotics in Milk

Herein, a novel electrochemical aptasensor using a broad-spectrum aptamer as a biorecognition element was constructed based on a screen-printed carbon electrode (SPCE) for simultaneous detection of aminoglycoside antibiotics (AAs). The ordered mesoporous carbon (OMC) was firstly modified on 2D Ti₃C₂ MXene. The addition of OMC not only effectively improved the stability of the aptasensor, but also prevented the stacking of Ti₃C₂ sheets, which formed a good current passage for signal amplification. The prepared OMC@Ti₃C₂ MXene functioned as a nanocarrier to accommodate considerable aptamers. In the presence of AAs, the transport of electron charge on SPCE surface was influenced by the bio-chemical reactions of the aptamer and AAs, generating a significant decline in the differential pulse voltammetry (DPV) signals. The proposed aptasensor presented a wide linear range and the detection limit was 3.51 nM. Moreover, the aptasensor, with satisfactory stability, reproducibility and specificity, was successfully employed to detect the multi-residuals of AAs in milk. This work provided a novel strategy for monitoring AAs in milk.

Exploring the Biofilm Formation Capacity in S. pseudintermedius and Coagulase-Negative Staphylococci Species

The ability of biofilm formation seems to play an important role in the virulence of staphylococci. However, studies reporting biofilm formation of coagulase-negative staphylococci isolated from animals are still very scarce. Thus, we aimed to evaluate the biofilm-forming capacity of CoNS and S. pseudintermedius isolated from several animal species and to investigate the effect of conventional antimicrobials on biofilm reduction. A total of 35 S. pseudintermedius and 192 CoNS were included. Biofilm formation was accessed by the microtiter plate assay and the biofilms were stained by crystal violet. Association between biofilm formation and staphylococci species and antimicrobial resistance was also performed. Biofilm susceptibility testing was performed with tetracycline and amikacin at the minimum inhibitory concentration (MIC) and 10 × MIC. The metabolic activity of the biofilm cells after antimicrobial treatment was accessed by the XTT assay. All isolates formed biofilm, with S. urealyticus producing the most biofilm biomass and S. pseudintermedius producing the least biomass. There was a positive association between biofilm formation and multidrug resistance as well as resistance to individual antimicrobials. Neither tetracycline nor amikacin were able to eradicate the biofilm, not even at the highest concentration used. This study provides new insights into biofilm formation and the effects of antimicrobials on CoNS species.

Pretreatment Methods for the Determination of Antibiotics Residues in Food Samples and Detected by Liquid Chromatography Coupled with Mass Spectrometry Detectors: A Review

With the increasing use of antibiotics worldwide, antibiotic monitoring has become a topic of concern. After metabolizing of antibiotics in animals, the metabolites enter the environment through excreta or ingested by the human body via food chain that may exacerbate the emergence of antibiotic resistance and then threaten human's life. This article summarized several analytical methods used for the determination of antibiotics in recent 10 years. Due to the complex matrices and low concentration level of antibiotics in the food samples, a reliable analysis method is required to maximize the recovery rate. Several techniques like solid phase extraction (SPE), dispersive liquid-liquid microextraction (DLLME) and QuEChERS have been frequently used in the pretreatment process for analytes extraction and concentration. After the pretreatment, ultra-high performance liquid chromatography combined with mass spectrometry has been a reliable method for quantitative analysis and is able to determine multiple antibiotics simultaneously. This review also gives an overview about analytical conditions for antibiotics residues in different food samples and their method validation parameters.

Direct injection green chromatographic method for simultaneous quantification of amoxicillin and amikacin in maternity hospital wastewater (Sagar, India)

Amoxicillin (AMO) and amikacin (AMK) are broad-spectrum antibiotics that are most preferably given post-delivery (normal and cesarian) in the maternity hospitals located in Sagar city (Madhya Pradesh), India. Both the antibiotics make their way through sewage/drainage systems into the environment in the form of metabolized and unmetabolized compounds. Growing concern about the contamination of wastewater by antibiotics requires fast, sensitive and eco-friendly techniques. Therefore a simple, rapid and environmental friendly chromatographic method has been developed for simultaneous determination of AMO and AMK in maternity hospital wastewater samples. A micellar liquid chromatographic (MLC) method was developed with a C₁₈ column (250 mm × 4.6 mm), sodium dodecyl sulphate (SDS; 0.15 M), 1-butanol (7%) as a modifier, pH 5 and photo diode detector (PDA) at 270 nm and 256 nm for AMO and AMK respectively. The method was fast with analysis time below 9 min. In the present MLC method, linearities (r > 0.998), limits of quantification in the range of 0.02-0.04 μg/mL, repeatabilities, and intermediate precision below 4.9% were adequate for the quantification of AMO and AMK. The proposed method can be utilized to detect and quantify both the antibiotics in various samples by hospitals, pharmaceutical companies, pollution control board, municipal corporations, etc.

Ultrasensitive electrochemical aptasensor based on palindromic sequence mediated bidirectional SDA and a DNAzyme walker for kanamycin detection

An electrochemical biosensing platform for kanamycin analysis based on SDA and a DNA walker.

An Electrochemical Immunosensor Based on SPA and rGO-PEI-Ag-Nf for the Detection of Arsanilic Acid

A sensitive electrochemical immunosensor was prepared for rapid detection of ASA based on arsanilic acid (ASA) monoclonal antibody with high affinity. In the preparation of nanomaterials, polyethyleneimine (PEI) improved the stability of the solution and acted as a reducing agent to generate reduced graphene oxide (rGO) with relatively strong conductivity, thereby promoting the transfer of electrons. The dual conductivity of rGO and silver nanoparticles (AgNPs) improved the sensitivity of the sensor. The synthesis of nanomaterials were confirmed by UV-Vis spectroscopy, X-ray diffraction, transmission electron microscopy and scanning electron microscopy. In the optimal experiment conditions, the sensor could achieve the detection range of 0.50–500 ng mL⁻¹ and the limit of detection (LOD) of 0.38 ng mL⁻¹ (S/N = 3). Moreover, the sensor exhibited excellent specificity and acceptable stability, suggesting that the proposed sensor possessed a good potential in ASA detection. Thus, the as-prepared biosensor may be a potential way for detecting other antibiotics in meat and animal-derived foods.

A novel electrochemical immunosensor for the sensitive detection of tiamulin based on staphylococcal protein A and silver nanoparticle-graphene oxide nanocomposites

Tiamulin (TML) is a pleuromutilin antibiotic and mainly used to treat pulmonary and gastrointestinal infections. However, excessive use of TML can bring health threats to consumers. In this work, a label-free electrochemical immunosensor was proposed for sensitive detection of TML in pork and pork liver. Silver nanoparticles (AgNPs) were synthesized in situ on graphene oxide (GO), in which GO acted as a carrier for loading more AgNPs and AgNPs exhibited both strong conductivity and good redox property. In addition, staphylococcal protein A (SPA) was applied to oriented immobilization of fragment crystallizable (Fc) region of the TML monoclonal antibody. Under the optimal condition, the developed electrochemical immunosensor exhibited a good linear response with a concentration of TML ranging from 0.05 ng mL^-1 to 100 ng mL^-1 and the limit of detection (LOD) was 0.04 ng mL^-1. Furthermore, the designed immunosensor was applied to detect TML in real samples with a good accuracy. Therefore, the label-free electrochemical immunosensor could be used as a potential method to detect TML and other antibiotic residues in animal derived foods.

Electrochemical methods for the determination of antibiotic residues in milk: A critical review

Several antibiotics have been applied to veterinary medicine due to their broad-spectrum of antibacterial activity and prophylactic power. Residues of these antibiotics can be accumulated in dairy cattle, in addition to promoting contamination of the environment and, in more serious cases, in milk, causing a public health problem. Different regulatory agencies establish maximum residue limits for these antibiotics in milk, so it becomes important to develop sensitive analytical methods for monitoring these compounds. Electrochemical techniques are important analytical tools in analytical chemistry because they present low cost, simplicity, high sensitivity, and adequate analytical frequency (sample throughput) for routine analyses. In this sense, this review summarizes the state of the art of the main electrochemical sensors and biosensors, instrumental techniques, and sample preparation used for the development of analytical methods, published in the last five years, for the monitoring of different classes of antibiotics: aminoglycosides, amphenicols, beta-lactams, fluoroquinolones, sulfonamides, and tetracyclines, in milk samples. The different strategies to develop electrochemical sensors and biosensors are critically compared considering their analytical features. The mechanisms of electrochemical oxidation/reduction of the antibiotics are revised and discussed considering strategies to improve the selectivity of the method. In addition, current challenges and future prospects are discussed.

Aminoglycosides analysis optimization using ion pairing liquid chromatography coupled to tandem mass spectrometry and application on wastewater samples

Aminoglycosides are mostly used as veterinary antibiotics. In France, their consumption accounts for about 10% of all prescribed animal medicine. Due to their high polarity nature (log Kow < -3), they require chromatographic separation by hydrophilic interaction liquid chromatography or ion-pairing chromatography. This study presents the development of an ion pairing liquid chromatography with alkanesulfonates coupled to tandem mass spectrometry for the analysis of 10 aminoglycosides (spectinomycin, streptomycin, dihydrostreptomycin, kanamycin, apramycin, gentamicin, neomycin and sisomicin) in wastewater samples. The novelty of this method lies in the addition of the ion paring salt directly and only into the sample vial and not in the mobile phase, lowering the amount of salt added and consequently reducing signal inhibition. The optimized method was validated and showed satisfactory resolution, performances suitable with the analysis of aminoglycosides in wastewater samples, with limits of quantifications less than 10 ng/mL for most of the compounds, low matrix effects, high accuracy (85%-115% recoveries) and reproducibility (2%-12%RSD). It was then applied successfully to raw and treated wastewater samples.

Electromembrane extraction of streptomycin from biological fluids

In this fundamental study, streptomycin was extracted successfully from urine and plasma using electromembrane extraction (EME). Streptomycin is an aminoglycoside with log P -7.6 and was selected as an extremely polar model analyte. EME is a microextraction technique, where charged analytes are extracted under the influence of an electrical field, from sample, through a supported liquid membrane (SLM), and into an acceptor solution. The SLM comprised 2-nitrophenyl pentyl ether (NPPE) mixed with bis(2-ethylhexyl) phosphate (DEHP). DEHP served as ionic carrier and facilitated transfer of streptomycin across the SLM. For EME from urine and protein precipitated plasma, the optimal DEHP content in the SLM was 45-50% w/w. From untreated plasma, the content of DEHP was increased to 75% w/w in order to suppress interference from plasma proteins. Most endogenous substances with UV absorbance were not extracted into the acceptor. Proteins and phospholipids were also discriminated, with <0.6% of proteins and <0.02% of phospholipids found in the acceptor after EME. Thus, despite the fact that the SLM was permeable to more polar molecules, the EME still provided very efficient sample cleanup. Extraction process efficiencies of 98% and 61% were achieved from urine and plasma, respectively, with linear calibration (R² > 0.9929), absence of significant matrix effects (94-112%), accuracy of 94-125%, and RSD ≤ 15% except at LLOQ. The average current during extractions was 67 µA or less. The findings of this paper demonstrated that EME is feasible for extraction of basic analytes of extreme polarity.

Advances in the Application of Aptamer Biosensors to the Detection of Aminoglycoside Antibiotics

Antibiotic abuse is becoming increasingly serious and the potential for harm to human health and the environment has aroused widespread social concern. Aminoglycoside antibiotics (AGs) are broad-spectrum antibiotics that have been widely used in clinical and animal medicine. Consequently, their residues are commonly found in animal-derived food items and the environment. A simple, rapid, and sensitive detection method for on-site screening and detection of AGs is urgently required. In recent years, with the development of molecular detection technology, nucleic acid aptamers have been successfully used as recognition molecules for the identification and detection of AGs in food and the environment. These aptamers have high affinities, selectivities, and specificities, are inexpensive, and can be produced with small batch-to-batch differences. This paper reviews the applications of aptamers for AG detection in colorimetric, fluorescent, chemiluminescent, surface plasmon resonance, and electrochemical sensors for the analysis in food and environmental samples. This study provides useful references for future research.