A Comprehensive Study to Determine the Residual Elimination Pattern of Major Metabolites of Amoxicillin-Sulbactam Hybrid Molecules in Rats by UPLC-MS/MS.

Amoxicillin and sulbactam are widely used in animal food compounding. Amoxicillin-sulbactam hybrid molecules are bicester compounds made by linking amoxicillin and sulbactam with methylene groups and have good application prospects. However, the residual elimination pattern of these hybrid molecules in animals needs to be explored. In the present study, the amoxicillin-sulbactam hybrid molecule (AS group) and a mixture of amoxicillin and sulbactam (mixture group) were administered to rats by gavage, and the levels of the major metabolites of amoxicillin, amoxicilloic acid, amoxicillin diketopiperazine, and sulbactam were determined by UPLC-MS/MS. The residue elimination patterns of the major metabolites in the liver, kidney, urine, and feces of rats in the AS group and the mixture group were compared. The results showed that the total amount of amoxicillin, amoxicilloic acid, amoxicillin diketopiperazine, and the highest concentration of sulbactam in the liver and kidney samples of the AS group and the mixture group appeared at 1 h after drug withdrawal. Between 1 h and 12 h post discontinuation, the total amount of amoxicillin, amoxicilloic acid, and amoxicillin diketopiperazine in the two tissues decreased rapidly, and the elimination half-life of the AS group was significantly higher than that in the mixture group (p < 0.05); the residual amount of sulbactam also decreased rapidly, and the elimination half-life was not significantly different (p > 0.05). In 72 h urine samples, the total excretion rates were 60.61 ± 2.13% and 62.62 ± 1.73% in the AS group and mixture group, respectively. The total excretion rates of fecal samples (at 72 h) for the AS group and mixture group were 9.54 ± 0.26% and 10.60 ± 0.24%, respectively. These results showed that the total quantity of amoxicillin, amoxicilloic acid, and amoxicillin diketopiperazine was eliminated more slowly in the liver and kidney of the AS group than those of the mixture group and that the excretion rate through urine and feces was essentially the same for both groups. The residual elimination pattern of the hybrid molecule in rats determined in this study provides a theoretical basis for the in-depth development and application of hybrid molecules, as well as guidelines for the development of similar drugs.

Pentacenequinone-Modulated 2D GdSn-PQ Nanosheets as a Fluorescent Probe for the Detection of Enrofloxacin in Biological and Environmental Samples.

The fate and effects of fluoroquinolone antibacterial (FQ) on the environment are important since there appears to be a surge in FQ resistance like enrofloxacin (ENR) in both environmental and clinical organisms. Numerous reports indicate that the sensing capabilities of these antibiotics need to be improved. Here, we have investigated the interaction of ENR with our synthesized pentacenequinone-modulated gadolinium-tin (GdSn-PQ) nanosheets and the formation of intermolecular interactions that caused the occurrence of aggregation-induced emission enhancement. The concept for designing hybrid metallic nanosheets comes from the unique features inherited from the parent organic precursor. Due to the distinct interaction between ENR and GdSn-PQ, the interstate conversion (ISC) between GdSn-PQ and ENR induces a significant wavelength shift in photoluminescence (PL), improving reliability, selectivity, and visibility compared to quenching- or AIEE-based methods without peak shifts, allowing for highly sensitive and visually detectable analyses. The fluorescence signal of GdSn-PQ exhibited a linear relationship (R2 = 0.9911), with the added ENR concentrations ranging from 5 to 90 nM, with a detection limit of 0.10 nM. We have demonstrated its potential and wide use in the detection of ENR in biological samples (human urine and blood serum) and environmental samples (tap water and seawater) with a recovery rate of 98- 108%. The current approach has demonstrated that the 2D GdSn-PQ nanosheet is a novel and powerful platform for future biological and environmental studies.

Spatially confined CuFe2O4 nanosphere in N/O-codoped porous carbon mimetics for triple-mode sensing of antibiotics and visual detection of neurotransmitters in biofluids.

BACKGROUND: Carbon-based nanozymes have recently received enormous concern, however, there is still a huge challenge for inexpensive and large-scale synthesis of magnetic carbon-based "Two-in-One" mimics with both peroxidase (POD)-like and laccase-like activities, especially their potential applications in multi-mode sensing of antibiotics and neurotransmitters in biofluids. Although some progresses have been made in this field, the feasibility of biomass-derived carbon materials with both POD-like and laccase-like activities by polyatomic doping strategy is still unclear. In addition, multi-mode sensing platform can provide a more reliable result because of the self-validation, self-correction and mutual agreement. Nevertheless, the use of magnetic carbon-based nanozyme sensors for the multi-mode detection of antibiotics and neurotransmitters have not been investigated. RESULTS: We herein report a shrimp shell-derived N, O-codoped porous carbon confined magnetic CuFe2O4 nanosphere with outstanding laccase-like and POD-like activities for triple-mode sensing of antibiotic d-penicillamine (D-PA) and chloramphenicol (CPL), as well as colorimetric detection of neurotransmitters in biofluids. The magnetic CuFe2O4/N, O-codoped porous carbon (MCNPC) armored mimetics was successfully fabricated using a combined in-situ coordination and high-temperature crystallization method. The synthesized MCNPC composite with superior POD-like activity can be used for colorimetric/temperature/smartphone-based triple-mode detection of D-PA and CPL in goat serum. Importantly, the MCNPC nanozyme can also be used for colorimetric analysis of dopamine and epinephrine in human urine. SIGNIFICANCE: This work not only offered a novel strategy to large-scale, cheap synthesize magnetic carbon-based "Two-in-One" armored mimetics, but also established the highly sensitive and selective platforms for triple-mode monitoring D-PA and CPL, as well as colorimetric analysis of neurotransmitters in biofluids without any tanglesome sample pretreatment.

Pharmacokinetics, tissue distribution, bioavailability and excretion of the anti-virulence drug Fluorothiazinon in rats and rabbits.

Growing antimicrobial resistance has accelerated the development of anti-virulence drugs to suppress bacterial toxicity without affecting cell viability. Fluorothiazinon (FT), an anti-virulence, type three secretion system and flagella motility inhibitor which has shown promise to suppress drug-resistant pathogens having the potential to enhance the efficacy of commonly prescribed antibiotics when used in combination. In this study we characterized the pharmacokinetics, tissue distribution, bioavailability and excretion of FT in rats and rabbits. FT presented a dose-proportional linear increase in the blood of rats. Tissue distribution profiling confirmed that FT distributes to all organs being substantially higher than in the blood of rats. The bioavailability of FT was higher when administered with starch than with water implying FT should be ideally dosed with food. FT was primarily excreted in the feces in rats and rabbits while negligible amounts are recovered from the urine.

Florfenicol urinary excretion and its potential for treating canine urinary tract infections.

The canine urinary excretion of florfenicol was evaluated to explore its potential for treating urinary tract infections. Nine healthy male intact purpose-bred Beagles and four healthy client-owned dogs each received a single oral dose of florfenicol 20 mg/kg (300 mg/mL parenteral solution) with food. All voluntary urinations were collected for 12 h. Although florfenicol is reportedly bitter tasting, 7/9 Beagles and 4/4 client-owned dogs completely ingested the florfenicol and were enrolled; salivation (n = 1) and headshaking (n = 3) were observed. The last measured urine florfenicol concentrations were variable: Beagles (0.23-3.19 mcg/mL), Pug (3.01 mcg/mL) English Setter (21.29 mcg/mL), Greyhound (32.68 mcg/mL), and Standard Poodle (13.00 mcg/mL). Urine half-life was similar for the Beagles and the Pug, 0.75-1.39 h, whereas the half-life was 1.70-1.82 h for the English Setter, Greyhound, and Standard Poodle. Larger breed dogs exceeded 8 mcg/mL florfenicol (wild-type cutoff) in their urine at 12 h, whereas the Beagles and Pug had <8 mcg/mL; it is unclear if this is an individual, breed, or size difference. These data suggest oral florfenicol may need to be administered q6-12h for canine urinary tract infections, but further data are needed (more enrolled dogs, multiple-dose regimens) before considering clinical trials or breed-specific differences.

Preconception exposure to environmental antibiotics among childbearing couples in Anhui and health risk assessment: A multicenter population-based representative study.

Only few studies have assessed the health effects due to preconception exposure to antibiotics among childbearing couples. This study investigated the status of preconception exposure to antibiotics among childbearing couples in Anhui, associated with health risks, and influencing factors. Overall, 1500 childbearing couples were randomly selected from the Reproductive Health of Childbearing Couples - Anhui Cohort (RHCC-AC). The urinary levels of 40 antibiotics and 2 metabolites were determined, and specific gravity (SG) adjusted concentrations of antibiotics were measured to assess health risks. Generalized linear models were used to assess the associations of urinary SG-adjusted concentration of antibiotics with demographic parameters and diet frequency. The total detection rates of all antibiotics were 98.9 % and 99.3 % in wives and husbands, respectively. The detection rates of veterinary antibiotics (VAs) and preferred as VAs (PVAs) were above 90 %. Among eight antibiotics, sulfonamides (95.1 %) and fluoroquinolones (87.6 %) had the highest detection rates in couples. Approximately four-fifths of couples were simultaneously exposed to at least three different antibiotics, and more than half of them were exposed to low concentrations of antibiotics. 8.9 % and 9.2 % of wives and husbands had hazard index value of antibiotics exposure greater than 1. Antibiotic concentrations were associated with residence, sampling season, and diet frequency. In Anhui, nearly 98 % of childbearing couples have environmental exposure to antibiotics, and VAs and PVAs are the primary antibiotics. More than 8 % of couples had health risks due to antibiotic exposure. Several potential determinants of urinary antibiotics deserve more attention in future research.

Cyclodextrin-assisted SERS determination of fluoroquinolone antibiotics in urine and blood plasma.

This paper describes the use of cyclodextrins (CDs) to improve the determination of fluoroquinolone antibiotics in human body fluids using surface-enhanced Raman spectroscopy (SERS). CDs were used to (i) prepare the CD-SERS substrate (synthesis and stabilization of silver nanoparticles), (ii) increase the sensitivity of the assay by enhancing the interaction between analyte molecules and the substrate, and (iii) improve the analysis accuracy by reducing the interaction between the substrate and endogenous components of body fluids. Two native CDs (α-CD and ß-CD) and two of their derivatives with hydroxypropyl groups were tested, and the best results were obtained with CD-SERS substrate prepared using native ß-CD. The CD-SERS assay has been developed and optimized for the determination of commonly used and structurally related fluoroquinolones (ciprofloxacin, norfloxacin, pefloxacin, and levofloxacin) in urine and blood plasma samples. Importantly, the non-significant difference in the interaction of the CD-modified SERS substrate with various fluoroquinolones has been successfully used to develop a versatile assay suitable for the analyte-class-specific analysis. Calibration plots were obtained for concentration ranges suitable for the determination of the antibiotics in urine (50-500 µg mL-1) and blood plasma (1-6 µg mL-1). The following figures of merit were obtained (for urine and blood plasma, respectively): RSD values are ≤15% and ≤23%, LOD values are 2.9-5.8 and 0.05-0.34 µg mL-1, recovery ranges are 96-105% and 91-111%. In addition, the influence of excessive concentrations of some main endogenous components of the body fluids on the analytical signal was studied. This step was used to evaluate possible limitations of the assay associated with the deviation of the composition of the body fluid matrix. Therefore, accounting for the short analysis time (≤15 min) and the use of a portable Raman spectrometer, the proposed assay can be suggested for therapeutic drug monitoring in hospitals.

Development and validation of ultra-performance liquid chromatography-tandem mass spectrometric methods for simultaneous and rapid determination of contezolid and its major metabolite M2 in plasma and urine samples and its application to a study in subjects with moderate liver impairment.

Contezolid is a novel oxazolidinone antibiotic with good antibacterial activity against gram-positive bacteria including methicillin-resistant Staphylococcus aureus. For the purpose to further characterize the pharmacokinetics of contezolid and its major metabolite M2, accurate and rapid ultra-performance liquid chromatography-tandem mass spectrometric assays (UPLC-MS/MS) were developed and validated for simultaneous quantification of contezolid and M2 in human plasma and urine. The plasma samples were pretreated by liquid-liquid extraction. The automated solid phase extraction method was used to preprocess urine samples. ACQUITY UPLC® BEH C8 (2.1 mm × 100 mm, 1.7 µm) column was used to separate the analytes with a gradient mobile phase of acetonitrile and water at a flow rate of 0.4 mL/min. The calibration curves showed good linearity over the concentration ranges of 0.0100-5.00 µg/mL for contezolid in plasma and urine, 0.00200-1.00 µg/mL in plasma and 0.0200-10.0 µg/mL in urine for M2, respectively. For both plasma and urine assays, the intra- and inter-batch accuracy and precision were within 15% for all quality control levels, including the lower limit of quantitation. The methods were fully validated and successfully applied to a pharmacokinetic study of contezolid tablets in subjects with moderate hepatic impairment.

Amperometric detection of antibiotic drug ciprofloxacin using cobalt-iron Prussian blue analogs capped on carbon nitride.

Ciprofloxacin (CIP) electrochemical sensor was constructed using cobalt-iron Prussian blue analogs decorated on carbon nitride (Co-Fe-PBA@CN). Co-Fe-PBA decorated on CN was fabricated using a simple sonication-assisted hydrothermal method to prepare the composite to obtain a cube-shaped structure decorated on CN sheets. The fabricated Co-Fe-PBA@CN was physically characterized using XRD and SEM analysis. Then, the fabricated composite was electrochemically studied to sense antibiotic drug ciprofloxacin (CIP). The electrochemical behavior was investigated using tools such as cyclic voltammetry (CV) and amperometric I-t studies. The Co-Fe-PBA@CN modified electrode displays a wide linear range (0.005-300 and 325-741 µM) with a low detection limit (0.7389 and 1.0313 nM) and good sensitivity (0.3157 and 0.2263 µA.µM-1cm-2) toward CIP. The Co-Fe-PBA@CN modified electrode also exhibits good selectivity, reproducibility, and repeatability toward CIP. The proposed sensor was validated with real sample analysis, biological samples like urine and blood serum containing commercially available ciprofloxacin tablets were studied, and the results demonstrate good viability.

Electrochemical Technologies to Decrease the Chemical Risk of Hospital Wastewater and Urine.

The inefficiency of conventional biological processes to remove pharmaceutical compounds (PhCs) in wastewater is leading to their accumulation in aquatic environments. These compounds are characterized by high toxicity, high antibiotic activity and low biodegradability, and their presence is causing serious environmental risks. Because much of the PhCs consumed by humans are excreted in the urine, hospital effluents have been considered one of the main routes of entry of PhCs into the environment. In this work, a critical review of the technologies employed for the removal of PhCs in hospital wastewater was carried out. This review provides an overview of the current state of the developed technologies for decreasing the chemical risks associated with the presence of PhCs in hospital wastewater or urine in the last years, including conventional treatments (filtration, adsorption, or biological processes), advanced oxidation processes (AOPs) and electrochemical advanced oxidation processes (EAOPs).

Concentration-dependent photoluminescence carbon dots for visual recognition and detection of three tetracyclines.

Concentration-dependent photoluminescence carbon dots (CDs) have been successfully synthesized through the one-step hydrothermal treatment of o-phthalic acid and ethylenediamine. The CDs possessed higher fluorescence quantum yield, up to 39.22%, exhibiting distinguished optical property, water solubility, and stability. The CDs that emit strong blue-green fluorescence can visually identify and determine tetracycline (TC), oxytetracycline (OTC), and chlortetracycline (CTC). TC quenched the fluorescence of CDs at 500 nm owing to the inner filter effect; OTC behaved similarly, but the emission wavelength of CDs was red-shifted to 515 nm. Inversely, once CTC was introduced to CDs solution, the fluorescence increased and the emission peak was blue-shifted to 450 nm. Bandgap transition and electrostatic interaction were proposed to be the mechanisms for the detection of OTC and CTC by CDs. Wide linear relationships were established for TC, OTC, and CTC with the limits of detection to be 50 nM, 36 nM, and 373 nM, respectively. Furthermore, the nanoscale probe constructed by this system has been applied to detect tetracyclines (TCs) in complex samples with satisfying recoveries (93.2-114%) and was designed as a portable test strip sensor for visually on-site TCs of honey sample screening. Accordingly, the preparation process of the nano fluorescent probe is simple and environmentally friendly, and the probe has a specific recognition ability for tetracyclines. The synthesized CDs in this work provide a new orientation for fast, effective, and visual real-time detection of tetracycline in actual samples.

Antibiotics biomonitored in urine and obesogenic risk in a community-dwelling elderly population.

BACKGROUND: Experimental and epidemiological studies have linked antibiotics use to gut dysbiosis-mediated risk of chronic metabolic diseases. However, whether adiposity is linked to antibiotic exposure in elderly remains inadequately understood. OBJECTIVE: To investigate the association between internal exposure of antibiotics and adiposity in elderly by using a biomonitoring method. METHODS: We included 990 participants (≥60 years) from the baseline survey of the Cohort of Elderly Health and Environment Controllable Factors in Lu'an city, China, from June to September 2016. Forty-five antibiotics and two metabolites in urine were monitored through liquid chromatography-electrospray tandem mass spectrometry (HPLC-MS/MS). Creatinine-corrected urinary concentrations were used to assess antibiotic exposure levels. Body mass index (BMI), waist circumference (WC) and body fat percentage (BFP) were used as indicators of adiposity. Multiple linear regression and binary logistic regression analyses were used to analyze the association of antibiotic concentrations with obesity-related indices. Subsequently, a gender-stratified analysis was performed. RESULTS: Of the included elderly, 50.7% were defined as having overweight/ obesity, 59.8% as having central preobesity/obesity, and 37.5% as having slightly high/high BFP. Linear regression analysis revealed that a 1-unit increase in the logarithmic transformation of norfloxacin concentrations was related with an increase of 0.29 kg/m2 (95% CI: 0.02-0.04), 0.99 cm (95% CI：0.24-1.75), and 0.69% (95% CI：0.21-1.17) in BMI, WC, and BFP, respectively. Compared with the control group, exposure to doxycycline (tertile 2: odds ratio, 2.06 [95% CI: 1.12-3.76]) and norfloxacin (tertile 2: 2.13 [1.05-4.29]; tertile 3: 2.07 [1.03-4.17]) had BMI-based overweight/obesity risk. Additionally, ciprofloxacin (tertile 2: 2.06 [1.12-3.76]), norfloxacin (tertile 3: 2.95 [1.34-6.49]), and florfenicol (tertile 3: 1.84 [1.07-3.14]) were related to WC-based central preobesity/obesity risk. Norfloxacin (tertile 3: 2.54 [1.23-5.24]) was positively associated with a slightly high/high BFP risk. Gender-stratified analysis demonstrated an increased adiposity risk in women compared with men. CONCLUSIONS: Our research provided an evidence that exposure to specific types of antibiotics (tetracyclines and fluoroquinolones) probably from the food chain contributed to obesity in elderly. Prospective cohort studies with larger sample size are warrented to explore the causation.

The search for a microbiological inhibition method for the rapid, broad-spectrum and high-throughput screening of six kinds of antibiotic residues in swine urine.

In this study, a microbiological inhibition method for rapidly screening antibiotics in swine urine was established with an easy sample pre-treatment. The microbiological system consisted of an agar medium mixed with nutrients, sensitizers, a test bacterium (Geobacillus stearothermophilus ATCC12980) and pH indicator (bromocresol purple). It was observed that the detection limits of the test kit for twenty-eight common antimicrobial residues in urine, including ß-lactams, aminoglycosides, tetracyclines, sulfonamides, macrolides, and lincosamides, were less than or equal to the maximum residue limits of the kidney, as determined by the EU and China. Moreover, the false negative rate and the false positive rate, along with other performance indexes such as interassay coefficients of variation and shelf life of the kit, all met the standard requirements of the ISO13969:2003 guidelines. Additionally, our results were consistent with those using the gold-standard physical chemistry method, which suggest the proposed method is suitable for screening antibiotic residues.

Antibiotic use and prescription and its effects on Enterobacteriaceae in the gut in children with mild respiratory infections in Ho Chi Minh City, Vietnam. A prospective observational outpatient study.

BACKGROUND AND OBJECTIVES: Treatment guidelines do not recommend antibiotic use for acute respiratory infections (ARI), except for streptococcal pharyngitis/tonsillitis and pneumonia. However, antibiotics are prescribed frequently for children with ARI, often in absence of evidence for bacterial infection. The objectives of this study were 1) to assess the appropriateness of antibiotic prescriptions for mild ARI in paediatric outpatients in relation to available guidelines and detected pathogens, 2) to assess antibiotic use on presentation using questionnaires and detection in urine 3) to assess the carriage rates and proportions of resistant intestinal Enterobacteriaceae before, during and after consultation. MATERIALS AND METHODS: Patients were prospectively enrolled in Children's Hospital 1, Ho Chi Minh City, Vietnam and diagnoses, prescribed therapy and outcome were recorded on first visit and on follow-up after 7 days. Respiratory bacterial and viral pathogens were detected using molecular assays. Antibiotic use before presentation was assessed using questionnaires and urine HPLC. The impact of antibiotic usage on intestinal Enterobacteriaceae was assessed with semi-quantitative culture on agar with and without antibiotics on presentation and after 7 and 28 days. RESULTS: A total of 563 patients were enrolled between February 2009 and February 2010. Antibiotics were prescribed for all except 2 of 563 patients. The majority were 2nd and 3rd generation oral cephalosporins and amoxicillin with or without clavulanic acid. Respiratory viruses were detected in respiratory specimens of 72.5% of patients. Antibiotic use was considered inappropriate in 90.1% and 67.5%, based on guidelines and detected pathogens, respectively. On presentation parents reported antibiotic use for 22% of patients, 41% of parents did not know and 37% denied antibiotic use. Among these three groups, six commonly used antibiotics were detected with HPLC in patients' urine in 49%, 40% and 14%, respectively. Temporary selection of 3rd generation cephalosporin resistant intestinal Enterobacteriaceae during antibiotic use was observed, with co-selection of resistance to aminoglycosides and fluoroquinolones. CONCLUSIONS: We report overuse and overprescription of antibiotics for uncomplicated ARI with selection of resistant intestinal Enterobacteriaceae, posing a risk for community transmission and persistence in a setting of a highly granular healthcare system and unrestricted access to antibiotics through private pharmacies. REGISTRATION: This study was registered at the International Standard Randomised Controlled Trials Number registry under number ISRCTN32862422: http://www.isrctn.com/ISRCTN32862422.

An enzyme-free fluorometric nanoprobe for chloramphenicol based on signal amplification using graphene oxide sheets.

A sensitive and selective method for the determination of the antibiotic chloramphenicol (CAP) is described, which is based on double signal amplification and GO as an efficient fluorescence quencher. The nucleic acid probe is composed of three well-defined regions, viz. the signal probe I, the signal probe II, and the capture probe. The capture probe will bind to CAP specifically and the signal probes produce a significant fluorescence signal. One end of the signal probes is labeled with the fluorophore 6-carboxyfluorescein (FAM). The labeled probes can be adsorbed on graphene oxide (GO) via π-stacking interactions, upon which the green fluorescence of FAM (measured at excitation/emission wavelengths of 490/514 nm) is quenched. On addition of CAP, the aptamer/CAP complexes are formed, and this leads to the restoration of fluorescence due to the removal of the probes from GO. The double signal probes, together with GO as quencher, improve the fluorescence signal significantly and lower the detection limit. Under optimized conditions, the assay works in the 20- to 200-ppb CAP concentration range and has a 0.3-ppb detection limit. It is also successfully applied to the determination of CAP in spiked swine urine samples. The recoveries from spiked swine urine samples are between 97.73 and 108.56%, and the repeatability (expressed as the RSD) is between 4.66 and 8.90%. Graphical abstract The constructed DNA probes form a stable structure and bind to chloramphenicol specifically. One end of signal probes was labeled with the fluorophore 6-carboxyfluorescein (FAM). The detection sensitivity of chloramphenicol was significantly enhanced by using double signal amplification, which was superior to the traditional methods. The quantities of CAP can be achieved by fluorescence increment.

Ultrasound supported synthesis of tantalum carbide integrated functionalized carbon composite for the voltammetric determination of the antibacterial drug nitrofurantoin in pharmaceutical samples.

The synthesis and fabrication of oval-shaped tantalum carbide (Ta-C) integrated functionalized-multiwalled carbon nanotube (Ta-C/f-MWCNT) as an electrocatalyst for the electrochemical determination of nitrofurantoin (NFT) is described. The Ta-C/f-MWCNT composite was prepared using the soft-template method followed by the ultrasonication process. The as-prepared Ta-C/f-MWCNT composite was characterized using powder X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), scanning transmission electron microscopy (STEM), and X-ray photoelectron spectroscopy (XPS) analysis. The electrochemical properties of Ta-C/f-MWCNT were investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and linear sweep voltammetry (LSV). The Ta-C/f-MWCNT-modified glassy carbon electrode (Ta-C/f-MWCNT/GCE) was successfully utilized as an active electrocatalyst for the detection of NFT in the presence of 0.384 mM NFT containing 0.05 M phosphate buffer (pH 7) at a scan rate of 50 mV/s. The Ta-C/f-MWCNT/GCE exhibited a wide linear response range (0.04-1047 µM) and a low detection limit (0.0011 µM). Further, the Ta-C/f-MWCNT/GCE showed appreciable results for repeatability, reproducibility, and long-term cyclic stability towards NFT sensing. The Ta-C/f-MWCNT/GCE was applied to real sample analysis such as a commercial tablet and human urine samples. The Ta-C/f-MWCNT/GCE exhibited good recovery values for the tablet (105 to 115%) and urine (101-107%) samples. The above electrochemical results suggest that the Ta-C/f-MWCNT is a promising electrocatalyst for the electrochemical sensing of NFT drug. Graphical abstract .

Determination of amphenicol antibiotics and their glucuronide metabolites in urine samples using liquid chromatography with quadrupole time-of-flight mass spectrometry.

A rapid procedure for the determination of amphenicol antibiotics in human urine by liquid chromatography with quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) is proposed. The presence of thiamphenicol (TAP), florfenicol (FF) and chloramphenicol (CAP) in the human body can be attributed to their administration to treat certain diseases or by eating food of animal origin. The TAP, FF and CAP excreted in urine is mainly in the form of glucuronide conjugates, although their free forms may also be excreted to a lesser extent. In the procedure described, the enzymatic hydrolysis of amphenicol glucuronide forms in urine was carried out using ß-glucuronidase and sulfatase at pH 5 (37 °C, overnight) in order to discriminate the free and conjugated forms. Then, amphenicol antibiotics were submitted to dispersive liquid-liquid microextraction (DLLME) for preconcentration. All the parameters affecting DLLME efficiency were optimized, and the following conditions were selected: 0.9 g NaCl in 10 mL of urine, to which 1.2 mL methanol (as dispersant solvent) and 1 mL of 4-methyl-2-pentanone (as extractant solvent) were added. The absence of a matrix effect allowed quantification of the samples against aqueous standards. Detection limits were 29, 6 and 3 pg mL-1 for TAP, FF and CAP, respectively. Relative standard deviations were calculated to evaluate the intra- and inter-day precision and values lower than 10% were obtained in all cases. The trueness of the method was tested through recovery studies, obtaining satisfactory values (83-104%). Ten urine samples obtained from volunteers were analysed and all of them were free of the studied antibiotics.

Antiadhesive natural products against uropathogenic E. coli: What can we learn from cranberry extract?

ETHNOPHARMACOLOGICAL RELEVANCE: Extracts from Cranberry fruits (Vaccinium macrocarpon) are traditionally used against urinary tract infections, mainly due to antiadhesive activity against uropathogenic E. coli (UPEC), but the exact mode of action and compounds, responsible for the activity, are unknown. AIM OF THE STUDY: i. To investigate if cranberry extract acts only by a single component or must be assessed as a multi-active-compound preparation; ii to screen isolated cranberry-related natural products under in vitro conditions to pinpoint natural products with antiadhesive effects against UPEC, followed by in silico calculations (QSAR) to predict potential antiadhesive compounds; iii. investigations by using urine samples from cranberry treated volunteers for evaluation on the bacterial transcriptome and the mannose-binding side of FimH, iv. to investigate if besides Tamm Horsfall Protein induction in the kidney, the extract acts also directly against UPEC. MATERIAL AND METHODS: Antiadhesive activity of 105 compounds was determined by flow cytometric adhesion assay (UPEC UTI89 on T24 bladder cells). Urine samples from 16 volunteers treated with cranberry extract (p.o., 7 days, 900 mg/day) were used for ex vivo testing concerning influence on the bacterial transcriptome (Illumina RNA-seq) and interaction with the mannose binding domain of type-1 fimbriae. RESULTS: i. The antiadhesive effect of cranberry extract cannot be attributed to a single compound or to a single fraction. ii. Unglycosylated flavones and flavonols with bulky substitution of the B ring contribute to the antiadhesive activity. 3'-8″-biflavones and flavolignans (not related to cranberry fruits) were identified as potent antiadhesive compounds against UPEC. iii. QSAR yielded a model with good statistical performance and sufficient internal and external predictive ability. iv. Urine samples from male cranberry-treated volunteers indicated significant interaction with the mannose binding domain of type-1 fimbriae, which correlated with the amount of Tamm-Horsfall Protein in the test samples. v Cranberry extract did not influence the UPEC transcriptome; gene expression of bacterial adhesins (P-, S-fimbrae, curli) was not influenced by the urine samples, while a slight, but non-significant upregulation of type 1 fimbriae was observed. CONCLUSIONS: B-ring substituted flavones and flavonols from cranberry contribute to the antiadhesive activity against UPEC by inhibition of the FimH-mediated interaction with the host cell bladder epithelium.

Liquid-liquid extraction-assisted SERS-based determination of sulfamethoxazole in spiked human urine.

The determination of antibiotic levels in body fluids is of great importance in the field of personalized medicine and therapeutic drug monitoring. We report on the determination of sulfamethoxazole (SMX), an antibacterial drug of the sulfanilamide class, in spiked human urine. The protocol is based on the combination of surface-enhanced Raman spectroscopy (SERS) and liquid-liquid extraction (LLE-SERS analysis). First, the urine was diluted to reduce its buffer properties and the influence of the intrinsic urine components on the background SERS signal. Second, the acidification of the diluted urine and SMX extracts was performed to facilitate SMX extraction by chloroform and suppress the background signal, respectively. Finally, the SMX determination process was performed using hydroxylamine-stabilized silver nanoparticles as the SERS substrate. The efficiency and reliability of the LLE-SERS analysis were studied using spiked urine samples obtained from healthy volunteers with an SMX content within the therapeutically relevant concentration range (10-200 µg mL-1). Additionally, the verification of the analysis protocol was done using spiked urine samples obtained from oncology patients. The results of the verification demonstrate the applicability of the analysis for quantitative therapeutic drug monitoring due to the (i) strong suppression of the background SERS signal, which occurs as the result of LLE, dilution, and pH adjusting, (ii) satisfactory limit of detection of 1.7 µg mL-1, and (iii) simple, relatively fast (∼30 min), and cost-effective sample pretreatment.