Concentrations Of Levofloxacin Research Articles

Efficient Adsorptive Removal of Levofloxacin Using Sulfonated Graphene Oxide: Adsorption Behavior, Kinetics, and Thermodynamics

Water pollution by antibiotic residues poses a potential threat to environmental and human health. Graphene-based materials are highly stable, recyclable and effective adsorbents for efficiently removing antibiotics from polluted water. In this study, the adsorption behavior of levofloxacin onto sulfonated graphene oxide (SGO) was investigated by varying the contact period, solution pH, adsorbent quantity, levofloxacin concentration, inorganic ions, and solution temperature. Spectroscopic and microscopic techniques were employed to confirm the adsorptive interaction between levofloxacin and SGO. The adsorption process was most accurately characterized by the pseudo-second-order kinetic model and the Langmuir isotherm model, as indicated by their high correlation coefficients (R2) and low root-mean-square error (RMSE) values. The maximal quantity of levofloxacin that can be adsorbed onto SGO was determined to be 1250 μmol/g at pH 4 and 25 °C using the Langmuir model. Thermodynamic studies reveal that the process of levofloxacin adsorption onto SGO is endothermic and spontaneous in nature. Taking into consideration the results of adsorption, desorption and regeneration studies, it is proposed that SGO can be applied as an economic viable agent for the adsorptive removal of levofloxacin from the aqueous environment.

Levofloxacin degradation in electro-Fenton system with FeMn@GF composite electrode

In this work, a one-step solvent-thermal approach was used to synthesize an Mn-doped Fe3O4 modified graphite felt (GF) composite electrode material (FeMn@GF), which was then used as the cathode in an Electro-Fenton (EF) system. The levofloxacin (LEV) in wastewater can be successfully removed by the EF system, which can produce and activate H2O2 in situ. The successful fabrication of the FeMn@GF composite electrode was confirmed by employing the characterization techniques of Scanning Electron Microscope, X-ray Diffraction, and X-ray Photoelectron Spectroscopy. Additionally, the electrochemical performance test was conducted. The FeMn@GF composite electrode demonstrated a greater electrochemical activity and a more robust electronic transmission ability. The LEV degradation experiment demonstrated reached 98.9 % that under ambient temperature conditions, within 120 minutes, given initial LEV concentration of 20 mg·L −1, Na2SO4 concentration of 50 mM, applied voltage of 3.0 V, initial pH value of 3, and aeration rate of 3.0 L·min −1.The highest leaching quantities of Fe and Mn were 1.294 mg·L−1 and 0.675 mg·L−1, respectively, while the removal effectiveness of LEV remained at 85.2 % after five cycles. Experiments using radical quenching revealed that the main active species were ·OH. The reaction mechanism of the EF system with FeMn@GF as the cathode (FeMn@GF-EF) and the degradation pathway of LEV were investigated.

Comprehensive Pharmacokinetic Evaluation of High Melanin Binder Levofloxacin in Rabbits Shows Potential of Topical Eye Drops for Posterior Segment Treatment.

The purpose of this work was to understand the impact of melanin binding on ocular pharmacokinetics after administration of a high-binder model drug via different administration routes. We applied levofloxacin to pigmented and albino rabbits as eye drops (single and multiple), as well as by intravitreal and intravenous injections. Ocular tissues and plasma were analyzed for levofloxacin concentrations with liquid chromatography-mass spectrometry (LC-MS/MS), and pharmacokinetic parameters were calculated. The data show enrichment of levofloxacin and weeks-long retention in pigmented tissues. Upon intravitreal injection, the area under the curve (AUC) values in pigmented tissues were about 9 to 15 times higher than the respective values in the albino rabbits, but this difference expanded to 255- to 951-fold following topical eye drop administration. Multiple dosing of eye drops led to substantial accumulation of levofloxacin in the pigmented tissues: AUC values were 3 to 12 times higher than after intravitreal injection. The AUCs were much lower after single topical or intravenous drug administrations. High drug levels (0.1-35 µM) were always observed in the neural retinas of pigmented eyes; the highest exposure was seen after intravitreal administration followed by multiple doses of topical drops. Single topical instillation and intravenous injections to the albino rabbits resulted in vitreal bioavailability values of 0.009% and 0.003%, respectively. Melanin binding can be used to achieve targeted drug delivery and extended retention in pigmented ocular tissues. The results from topical multiple dosing experiments suggest that eye drop treatment may yield drug exposures and responses comparable to intravitreal delivery, even in the retinal pigment epithelium and choroid.

Discovery of clinical isolation of drug-resistant Klebsiella pneumoniae with overexpression of OqxB efflux pump as the decisive drug resistance factor.

Background emergence of multidrug-resistant (MDR) bacterial strains is a public health concern that threatens global and regional security. Efflux pump-overexpressing MDR strains from clinical isolates are the best subjects for studying the mechanisms of MDR caused by bacterial efflux pumps. A Klebsiella pneumoniae strain overexpressing the OqxB-only efflux pump was screened from a clinical strain library to explore reverse OqxB-mediated bacterial resistance strategies. We identified non-repetitive clinical isolated K. pneumoniae strains using a matrix-assisted laser desorption/ionization time-of-flight (TOF) mass spectrometry clinical TOF-II (Clin-TOF-II) and susceptibility test screening against levofloxacin and ciprofloxacin. And the polymorphism analysis was conducted using pulsed-field gel electrophoresis. Efflux pump function of resistant strains is obtained by combined drug sensitivity test of phenylalanine-arginine beta-naphthylamide (PaβN, an efflux pump inhibitor) and detection with ethidium bromide as an indicator. The quantitative reverse transcription PCR was performed to assess whether the oqxB gene was overexpressed in K. pneumoniae isolates. Additional analyses assessed whether the oqxB gene was overexpressed in K. pneumoniae isolates and gene knockout and complementation strains were constructed. The binding mode of PaβN with OqxB was determined using molecular docking modeling. Among the clinical quinolone-resistant K. pneumoniae strains, one mediates resistance almost exclusively through the overexpression of the resistance-nodulation-division efflux pump, OqxB. Crystal structure of OqxB has been reported recently by N. Bharatham, P. Bhowmik, M. Aoki, U. Okada et al. (Nat Commun 12:5400, 2021, https://doi.org/10.1038/s41467-021-25679-0). The discovery of this strain will contribute to a better understanding of the role of the OqxB transporter in K. pneumoniae and builds on the foundation for addressing the threat posed by quinolone resistance.IMPORTANCEThe emergence of antimicrobial resistance is a growing and significant health concern, particularly in the context of K. pneumoniae infections. The upregulation of efflux pump systems is a key factor that contributes to this resistance. Our results indicated that the K. pneumoniae strain GN 172867 exhibited a higher oqxB gene expression compared to the reference strain ATCC 43816. Deletion of oqxB led a decrease in the minimum inhibitory concentration of levofloxacin. Complementation with oqxB rescued antibiotic resistance in the oqxB mutant strain. We demonstrated that the overexpression of the OqxB efflux pump plays an important role in quinolone resistance. The discovery of strain GN 172867 will contribute to a better understanding of the role of the OqxB transporter in K. pneumoniae and promotes further study of antimicrobial resistance.

Carbon Dots Derived from Waste Fish Scale for Enhanced Removal of Levofloxacin Drug: Parametric Optimization, Isotherm and Kinetic Studies

The public health and environmental protection have been facing a great challenge for efficient antibiotics' adsorption from aqueous solution. In this work, a carbon dots nanoparticle from biomass (fish scale) was synthesized and employed for antibiotic adsorption. The synthesized fish scale carbon dots (FCD) were characterized by means of the X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Fourier transform infrared (FTIR) analyses. Experiments on adsorption were performed to examine the capability of the synthesized adsorbent for adsorption of Levofloxacin. The optimum conditions were ascertained through the use of Response Surface Methodology (RSM) design to increase the effectiveness of levofloxacin removal, and there was 96.03% removal efficiency of 60 minutes contact time, 10 mg/L levofloxacin concentration and FCD dosage of 0.2 g/L. Also, the adsorption experiments indicated that at the lowest concentration of 10 mg/L, at time 45 min and 0.15 mg dosage the adsorption rate was high. For the kinetics data, the pseudo-second order model best fit the data. Furthermore, the Redlich-Peterson model fit isothermal data the best.

Effect of the residual levofloxacin on hydroponic vegetables with sewage treatment plant tailwater: Microbial community, discharge risk and control strategy

Tailwater-based hydroponic vegetable is a promising strategy for domestic wastewater recycling. However, the effect of residual antibiotics on the hydroponic vegetable system and the relation between hydroponic culture parameters and the residual water quality are still unclear. Here, the typical antibiotic Levofloxacin (LVFX) was employed, and the effect of LVFX (5 mg/L) on the residual water quality, plant growth and microbial community of water spinach hydroponic culture system were investigated under different hydraulic residence times (HRT). Obvious toxic effects on water spinach were observed, and the highest removal rate of LVFX (about 6 %) and TN (25.67±1.43 %) was observed when HRT was 7 days. Hydroponic culture increased the microbial abundance, diversity, and microbial community stability. To optimize the hydroponic culture, actual sewage plant tailwater spiked with 20 μg/L LVFX, along with three common planting substrates (sponge, ceramsite, and activated carbon) were used for the hydroponic culture of lettuce (seasonal reasons). The inhibition effect of LVFX on the removal of NO3--N and TN was observed even as the LVFX concentration decreased significantly (from 14.62 ± 0.44 μg/L to 0.65 ± 0.07 μg/L). The best growth situation of lettuce and removal rates of NH4+-N, NO3--N, TN, especially LVFX (up to 95.65 ± 0.54 %) were observed in the activated carbon treated group. The overall results indicate the negative effect of residual antibiotics on the hydroponic vegetable systems, and adding activated carbon as substrate is an effective strategy for supporting plant growth and controlling discharged risk.

A cost-effective method for the sensitive detection of levofloxacin using a 3D composite electrode composed of nail polish, graphite and aluminium oxide.

The potential impact on human health and the environment has spurred significant interest in detecting and quantifying pharmaceutical compounds across various matrices, from environmental to biological samples. Here, we present an electrochemical approach for determining levofloxacin in drug, synthetic urine, water, and breast milk samples. An affordable sensor was constructed using 3D printing and composite material based on nail polish, graphite, and aluminum oxide. The conductive composite material was characterized spectroscopically, electrochemically, and by imaging techniques. Subsequently, an electrochemical method based on square wave voltammetry was optimized and applied. The method exhibited good sensitivity (5.11 ± 0.0912 μA L μmol-1 cm-2) and enhanced stability (RSD = 7.2%), with electrochemical responses correlating with the concentration of levofloxacin in the samples tested, yielding recovery values in the range of 98 to 111%. The developed method demonstrated a robust linear working range from 2 to 100 μmol L-1 and a nanomolar detection limit of 128 nmol L-1, rendering it suitable for quantitative analysis. The sensor also shows promise as a platform for the sensitive detection of pharmaceutical compounds, contributing to greater safety and sustainability in these domains.

Drug Resistance in Biofilm and Planktonic Cells of Achromobacter spp., Burkholderia spp., and Stenotrophomonas maltophilia Clinical Isolates.

Background: Biofilm production in nonfermenting Gram-negative bacteria influences drug resistance. The aim of this work was to evaluate the effect of different antibiotics on biofilm eradication of clinical isolates of Achromobacter, Burkholderia, and Stenotrophomonas maltophilia. Methods: Clinical isolates were identified by matrix-assisted laser desorption ionization-time of flightmass spectrometry in a third-level hospital in Monterrey, Mexico. Crystal violet staining was used to determine biofilm production. Drug susceptibility testing was determined by broth microdilution in planktonic cells and biofilm cells. Results: Resistance in planktonic cells was moderate to trimethoprim-sulfamethoxazole, and low to chloramphenicol, minocycline, levofloxacin (S. maltophilia and Burkholderia), ceftazidime, and meropenem (Burkholderia and Achromobacter). Biofilm eradication required higher drug concentrations of ceftazidime, chloramphenicol, levofloxacin, and trimethoprim-sulfamethoxazole than planktonic cells (p < 0.05). Levofloxacin showed biofilm eradication activity in S. maltophilia, minocycline and meropenem in Burkholderia, and meropenem in Achromobacter. Conclusions: Drug resistance increased due to biofilm production for some antibiotics, particularly ceftazidime and trimethoprim-sulfamethoxazole for all three pathogens, chloramphenicol for S. maltophilia and Burkholderia, and levofloxacin for Burkholderia. Some antibiotics could be used for the treatment of biofilm-associated infections in our population, such as levofloxacin for S. maltophilia, minocycline and meropenem for Burkholderia, and meropenem for Achromobacter.

Effect of Salbutamol on the Disposition Kinetics of Levofloxacin in the Plasma and Lung of Rats.

Antibiotics and bronchodilator drugs can be used together in respiratory distress caused by bacterial infections. Levofloxacin (LVX) and Salbutamol (SLB) can be used simultaneously in respiratory distress. However, there have been no investigations on how the concurrent use of SLB can affect the pharmacokinetics of LVX in rats. The purpose of this study was to investigate the influence of SLB on the plasma and lung pharmacokinetics of LVX in rats. A total of 132 rats were randomly assigned to two groups: LVX (n=66) and LVX+SLB (n=66). LVX (intraperitoneal) and SLB (oral) were administered to rats at doses of 50 and 3 mg/kg, respectively. The concentrations of LVX in the plasma and lungs were determined through the utilization of high-performance liquid chromatography along with UV. Pharmacokinetic parameters were assessed by non-compartmental analysis. The area under the curve from 0 to 16 h (AUC0-16), terminal elimination half-life, volume of distribution, total body clearance, and peak concentration of LVX in the plasma were 42.57 h*μg/mL, 2.32 h, 3.91 L/kg, 1.17 L/h/kg, and 23.96 μg/mL, respectively. There were no alterations observed in the plasma and lung pharmacokinetic parameters of LVX when co-administered with SLB. The AUC0-16 lung/AUC0-16 plasma ratios of LVX were 1.60 and 1.39 after administration alone and co-administration with SLB, respectively. The concentration of LVX in lung tissue was higher than that in plasma. SLB administration to rats did not affect the plasma and lung pharmacokinetics and lung penetration ratio of LVX. There is a need to reveal the change in the pharmacokinetics of LVX after multiple administration of both drugs and after administration of SLB by different routes.

Investigation of the Rapid Emergence of Colistin Resistance in a Newborn Infected with KPC-2–Producing Hypervirulent Carbapenem-Resistant Klebsiella pneumoniae

ObjectivesHypervirulent carbapenem-resistant Klebsiella pneumoniae (hv-CRKp) poses a significant threat to public health. This study reports an infection related to hv-CRKp in a premature infant and reveals its colistin resistance and evolutionary mechanisms within the host. MethodsThree KPC-producing CRKp strains were isolated from a patient with sepsis and CRKp osteoarthritis who had been receiving colistin antimicrobial therapy. The minimum inhibitory concentrations (MICs) of ceftazidime, ceftazidime-avibactam (CAZ-AVI), meropenem, imipenem, tigecycline, amikacin, minocycline, sulfamethoxazole/trimethoprim, ciprofloxacin, levofloxacin, aztreonam, cefepime, cefoperazone/sulbactam, piperacillin/tazobactam, and colistin were determined using the microbroth dilution method. The whole-genome sequencing analysis was conducted to determine the sequence types (STs), virulence genes, and antibiotic resistance genes of the three CRKp strains. ResultsWhole-genome sequencing revealed that all three CRKp strains belonged to the ST11 clone and carried a plasmid encoding blaKPC-2. The three strains all possessed the iucABCDiutA virulence cluster, peg-344 gene, and rmpA/rmpA2 genes, defining them as hv-CRKp. Further experiments and whole-genome analysis revealed that a strain of K. pneuomniae had developed resistance to colistin. The mechanism found to be responsible for colistin resistance was a deletion mutation of approximately 9000 bp including the mgrB gene. ConclusionThis study characterizes colistin resistance of the ST11 clone hv-CRKp during colistin treatment and its rapid evolution within the host.

Morphology-transforming AuNPs-based fluorescent probe for ultra-low sensitive detection of levofloxacin in urine samples at pH 7.0 through excimer formation

Fluorescent metal nanoparticles (MNPs) have garnered considerable interest in the realm of healthcare applications. Within this domain, we present a novel fluorescent sensor: Pamoic acid (PA) functionalized excitation-dependent gold nanoparticles (PA@AuNPs), designed to ascertain levofloxacin (LF) concentrations in human urine samples under pH 7.0 conditions. The synthesis of PA@AuNPs was achieved via a chemical reduction method employing PA as both a reducing and stabilizing agent. Validation of the successful synthesis of PA@AuNPs was conducted utilizing a suite of analytical techniques including X-ray diffraction (XRD), ultraviolet–visible absorption spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Microscopic examination via field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM) elucidated the spherical morphology of PA@AuNPs, with an average diameter ranging from 10 to 15 nm. Furthermore, atomic force microscopy (AFM) revealed an average surface roughness of 20.72 nm for PA@AuNPs. Thermal analysis results divulge that PA@AuNPs are highly stable up to 370 °C. The PA@AuNPs have shown more than 10-fold higher selectivity for LF in comparison with other commercially available antibiotics. The fluorescence emission intensity of PA@AuNPs (quantum yield (ΦF) 3.36 %) has shown enhanced redshift (436 → 497 nm; ∼61 nm) (λex 353 nm) upon the sequential addition of LF (0 → 100 µM) and achieved a lower detection limit (LoD = 36 nM; LoQ = 121 nM; Ka = 1.0457 × 104 M−1) with increased ΦF 18.96 %. This radiative process and fluorescence enhancement were confirmed by time-correlated single photon counting (TCSPC) measurement (4.89 → 5.36 ns). Interestingly, upon sensing LF, PA@AuNPs changed their morphology from spherical to octahedron and displayed an excimer formation through intermolecular π-π stacking. Furthermore, the stability of the complex, PA@AuNPs•LF which formed through coordination, by restoring the fluorescence intensity of PA@AuNPs•LF (turn on) in the presence of ethylenediamine tetraacetic acid (EDTA) (turn off) is demonstrated. The formation of the PA@AuNPs•LF complex was further confirmed by XRD analysis and FTIR spectroscopy. The HRTEM and FESEM validate that PA@AuNPs•LF have octahedral morphology with an average size of 20–30 nm, and the obtained moiré fringes in TEM images are due to the overlap of LF on the surface of PA@AuNPs. The AFM analysis divulges that PA@AuNPs•LF had a larger surface roughness (Sa = 26.91 nm). The experimentally attained zeta potential of PA@AuNPs (–12.6 mV) was further decreased (–17.6 mV) in the presence of LF, which confirms the interaction between PA@AuNPs and LF. The cell viability (82 %) in L929 Fibroblast cells augmented the biological applications of PA@AuNPs. The practicability of the fluorescent sensor probe was demonstrated in human urine samples with recovery ranges from 97.56 to 104.38 %.

Development of selective isolation media for detecting the genera Actinomyces and Schaalia from oral specimens containing indigenous bacteria.

To isolate specific bacteria from samples constituting the microbiota, it is essential to employ selective media that suppress the growth of resident bacteria other than specific target bacteria. Selective media for clinically important Actinomyces (including Schaalia, which was previously taxonomically classified as part of the genus Actinomyces) have been limited because they have been designed for a limited range of species within the genus and require ingredients which are difficult to prepare and handle. This study aimed to develop a selective medium [referred to as Actinomyces and Schaalia Selective Medium (ASSM)] for the isolation of a broad range of Actinomyces and Schaalia species from samples mixed with resident bacteria. The composition of ASSM includes yeast extract, agar, brain heart infusion (BHI), levofloxacin (LVFX), fosfomycin (FOM), colistin (CL) and metronidazole (MNZ). Evaluation of the medium using 24 swab samples serially collected from the roots of the teeth of a healthy individual for whom metagenome sequencing data of a saliva sample are publicly available revealed that ASSM adjusted to concentrations of LVFX 0.5 mg l-1, FOM 5 mg l-1, CL 1 mg l-1 and MNZ 2 mg l-1 and cultured anaerobically at 35 °C for 7 days enabled the isolation of Actinomyces species from 37.5 % of the samples. The inclusion of CL and MNZ in ASSM can also be useful for samples harbouring other bacterial species. The selective isolation medium is expected to contribute to studies investigating the relationship between these bacteria and their pathogenesis or disease.

Degradation of Levofloxacin by Electroactivated Sodium Persulfate on Carbon Cloth Cathode Modified with Cerium-Based Metal Organic Frameworks (Ce-MOF) Derivatives

Levofloxacin (LFX), which is difficult to degrade effectively due to its molecular stability, has become an problem that needs to be solved urgently. The advanced oxidation technology of persulfate has received increasing attention from researchers. In this study, a Ce-MOF derivative (Ce-MOF-T) was prepared by hydrothermal synthesis and calcination, which synergistically responded to electroactivation to generate sulfate radicals for the efficient degradation of LFX. It has been proven that electrical activation and the Ce-MOF derivatives work together to generate sulfate radicals and effectively degrade LFX. Ce-MOF-550-modified carbon cloth was used as the cathode and a platinum electrode as the anode, the concentration of LFX was 20 mg·L−1, the loading of Ce-MOF-550 was 15 mg, pH = 5, the concentration of sodium persulfate (PMS) was 0.3 g·L−1, the current density was 100 A·m−2, and the degradation rate was 82.05% after 1 h of reaction and 95% after 3 h of reaction. After five cycle tests, the degradation rate was still higher than 75.00%, indicating that the material had good stability. In addition, the degradation of LFX was consistent with a quasi-primary kinetic reaction with apparent rate constants of 2.26 × 10−2 min−1.

Degradation of levofloxacin using electro coagulation residuals-alginate beads as a novel heterogeneous electro-fenton composite

The presence of levofloxacin (LEV) in aqueous solutions can pose health risks to humans, have adverse effects on aquatic organisms and ecosystems, and contribute to the development of antibiotic-resistant bacteria. This study aims to investigate the feasibility of using electrocoagulation residuals (ECRs) as a heterogeneous catalyst in the electro-Fenton process for degrading LEV. By combining electrocoagulation residuals with sodium alginate, ECRs-alginate beads were synthesized as a heterogeneous electro-Fenton composite. The response surface method was employed to investigate the optimization and influence of various operating parameters such as the initial concentration of LEV (10–50 mg/L), voltage (15–35 V), pH (3–9), and catalyst dose (1–9 g/L). The successful incorporation of iron and other metals into the ECRs-alginate beads was confirmed by characterization tests such as EDX and FTIR. By conducting a batch reaction under optimal conditions (initial LEV concentration = 20 mg/L, pH = 4.5, voltage = 30V, and catalyst dose = 7 g/L), a remarkable degradation of 99% for LEV was achieved. Additionally, under these optimal conditions, a high removal efficiency of 92.3% for total organic carbon (TOC) could be attained within 120 min and these findings are remarkable compared to previous studies. The results further indicated that the degradation of levofloxacin (LEV) could be accurately quantified by utilizing the first-order kinetic reaction with a 0.03 min−1 rate constant. The synthesized beads offered notable advantages in terms of being eco-friendly, simple to use, highly efficient, and easily recoverable from the liquid medium after use.

Ratiometric Fluorescence Detection of Levofloxacin Based on a Cube-like Zn(II)-Eu(III) Nanocluster: Functionalized Sodium Alginate Film for the Detection in Serum and Medicine.

A cube-like Zn(II)-Eu(III) nanocluster 1 (molecular sizes: 1.8 × 2.0 × 2.0 nm) was constructed by the use of a new long-chain Schiff base ligand. It shows a ratiometric fluorescence response to levofloxacin (LFX) with high sensitivity and selectivity, which can be expressed as I615nm/I550nm = A*[LFX]2 + B*[LFX] + C. It is used to quantitatively detect the LFX concentrations in fetal calf serum (FCS) and tablets sold in pharmacy. Filter paper strips bearing 1 can be used to qualitatively detect LFX by a color change to red under a UV lamp. 1 and its hybrid with sodium alginate (SA), 1@SA, display potential applications in the qualitative detection of LFX in FCS and the medicine. The limit of detection of 1 to LFX is as low as 2.1 × 10-2 nM.

Fabrication of Carbon Paste Sensor Activated with Electropolymerized DL‐Phenylalanine for the analysis of Levofloxacin

AbstractVoltammetric analysis of Levofloxacin (LF) using an electrochemically polymerized composite of DL‐phenylalanine (DLP) alongside a bare carbon paste electrode. The constructed electrodes are polymerized DL‐phenylalanine modified carbon paste electrodes P(DLP/MCPE) and bare carbon paste electrodes (BCPE). Cyclic voltammetry (CV), differential pulse voltammetry (DPV), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and other electrochemical techniques used for characterization of P(DLP/MCPE) and BCPE in 0.2 M phosphate buffer solution (PBS) with pH 4.5 were conformed using the P(DLP/MCPE), and it shows the highest current responses compared to the BCPE. This research work examines the effect of pH in PBS, scan rate, and LF concentration on the surface of P(DLP/MCPE). The outcome result shows that the oxidation reaction of LF pH is an adsorption‐controlled path. The detection limit of LF ranges from 0.2 μM to 7.0 μM, and the lower limits of detection (LOD) is 0.613x10−7 M and the lower limits of quantification (LOQ) is 2.051X10−7 M. The electrochemical P(DLP/MCPE) shows good repeatability, reproducibility, and stability. Finally, by analyzing LF in a pharmacological sample, the real time application of the sensor was assessed, and significant recoveries were observed.

Effects of antibiotics ceftriaxone and levofloxacin on the growth of Protophormia terraenovae (Diptera: Calliphoridae).

Protophormia terraenovae is a colonizer of decomposing bodies and is known to cause pre-mortem myiasis as the female flies lay eggs in uncleaned wounds. In this study the effects of different concentrations of antibiotics levofloxacin and ceftriaxone on maggot development, weight, length, and mortality were examined. The maggot length and weight were significantly increased by therapeutical doses of levofloxacin and ceftriaxone. The maggot development time was significantly decreased in every levofloxacin treatment compared to the control. The time to start pupation was significantly increased in the control compared to the antibiotic treatments. Levofloxacin significantly increased the survivability of the maggots. Every levofloxacin treatment significantly improved the rearing conditions for the maggots. Reaching the third instar was delayed by 24h in the control compared to the Levo 3.57 treatment. The Pupation in the control was delayed by an average of 48h compared to the Levo 3.57 treatment. The significantly reduced development time of the maggots in the antibiotic treatments might lead to an overestimation of the post-mortem interval and therefore an incorrect time of death determination. The improved rearing conditions may be an indication of the potential of a combined application of antibiotics and maggot therapy.

Pharmacokinetics and Optimal Dosing of Levofloxacin in Children for Drug-Resistant Tuberculosis: An Individual Patient Data Meta-Analysis.

Each year 25 000-32 000 children develop rifampicin- or multidrug-resistant tuberculosis (RR/MDR-TB), and many more require preventive treatment. Levofloxacin is a key component of RR/MDR-TB treatment and prevention, but the existing pharmacokinetic data in children have not yet been comprehensively summarized. We aimed to characterize levofloxacin pharmacokinetics through an individual patient data meta-analysis of available studies and to determine optimal dosing in children. Levofloxacin concentration and demographic data were pooled from 5 studies and analyzed using nonlinear mixed effects modeling. Simulations were performed using current World Health Organization (WHO)-recommended and model-informed optimized doses. Optimal levofloxacin doses were identified to target median adult area under the time-concentration curve (AUC)24 of 101 mg·h/L given current standard adult doses. Data from 242 children (2.8 years [0.2-16.8] was used). Apparent clearance was 3.16 L/h for a 13-kg child. Age affected clearance, reaching 50% maturation at birth and 90% maturation at 8 months. Nondispersible tablets had 29% lower apparent oral bioavailability compared to dispersible tablets. Median exposures at current WHO-recommended doses were below the AUC target for children weighing <24 kg and under <10 years, resulting in approximately half of the exposure in adults. Model-informed doses of 16-33 mg/kg for dispersible tablets or 16-50 mg/kg for nondispersible tablets were required to meet the AUC target without significantly exceeding the median adult Cmax. Revised weight-band dosing guidelines with doses of >20 mg/kg are required to ensure adequate exposure. Further studies are needed to determine safety and tolerability of these higher doses.

Levofloxacin susceptibility of Staphylococci from conjunctiva in patients with atopic dermatitis.

The ocular surface in patients with atopic dermatitis (AD) is known to harbor an abundance of gram-positive cocci, particularly Staphylococcus aureus (S. aureus). This study reviewed the results of microbial cultures from the conjunctiva in AD patients, with special attention to the levofloxacin susceptibility of Staphylococci. Retrospective, single-center study. This study involved 131 eyes of 112 Japanese patients with AD (87 men and 25 women, mean age: 40.4 ± 12.2 years) who underwent ocular surgery at Kyorin University Hospital. Bacterial isolates were collected from the conjunctival sacs in the preoperative period. Drug resistance to methicillin and levofloxacin was judged using the minimal inhibitory concentrations of oxacillin and levofloxacin determined by the broth dilution method. One hundred and fifty-seven strains were identified in 103 of the 131 eyes examined. S. aureus was isolated from 74 eyes (56.5%), followed by Staphylococcus epidermidis (S. epidermidis). In S. aureus, 11 strains (14.9%) were methicillin-resistant, and 18 (24.3%) were levofloxacin-resistant. In S. epidermidis, 15 strains (26.8%) were methicillin-resistant, and 17 (30.4%) were levofloxacin-resistant. No significant differences were observed in levofloxacin susceptibility with age, sex, previous ocular surgery, or duration of previous surgery. However, logistic multivariate analysis revealed that levofloxacin-resistant Staphylococci were concurrently resistant to methicillin, suggesting multidrug resistance. Distinctive bacterial distribution and drug resistance need consideration in the managing of ocular disorders among patients with AD.

Population pharmacokinetics and dose optimization of levofloxacin in elderly patients with pneumonia.

Levofloxacin is a quinolone antibiotic with a broad antibacterial spectrum. It is frequently used in elderly patients with pneumonia. The pharmacokinetic profile of elderly patients changes with age, but data on the pharmacokinetics of levofloxacin in these patients are limited. The aim of this study was to establish a population pharmacokinetic model of levofloxacin in elderly patients with pneumonia and to optimize individualized dosing regimens based on this newly developed model. This is a prospective, open-label pharmacokinetic study in elderly patients with pneumonia. Blood samples were collected using an opportunistic approach. The plasma concentrations of levofloxacin were determined by high-performance liquid chromatography. A population pharmacokinetic model was established using nonlinear mixed-effect model software. Monte Carlo simulations were used for dose simulation and dose optimization. Data from 51 elderly patients with pneumonia were used for the population pharmacokinetic analysis. A one-compartment model with first-order elimination was most suitable for describing the data, and the estimated glomerular filtration rate was the only covariate that had a significant impact on the model. The final model estimated that the mean clearance of levofloxacin in elderly patients with pneumonia was 5.26 L/h. Monte Carlo simulation results showed that the optimal dosing regimen for levofloxacin was 750 mg once a day in elderly patients with pneumonia, with a minimum inhibitory concentration of 2 mg/L. The population pharmacokinetic model of levofloxacin in elderly patients with pneumonia was established, and the dose optimization of levofloxacin was completed through Monte Carlo simulation.