Levofloxacin in the treatment of complicated urinary tract infections and acute pyelonephritis

Fast, Selective and Sensitive Fluorescence Detection of Levofloxacin, Fe3+ and Cu2+ Ions in 100% Aqueous Solution Via Their Reciprocal Recognition

The fluorescence detection of ions and pharmaceutical effluents by using organic chemosensors is a valuable surrogate to the currently existing expensive analytical methods. In this regard, the design of multi-functional chemosensors to recognize desirable guests is of utmost importance. In this study, we first show that levofloxacin (LVO) is able to use as a fluorescent chemosensor for the detection of biologically important Cu2+ (turn-off) and Fe3+ (turn-on) ions via independent signal outputs in 100% aqueous buffer solutions. Next, using the reciprocal recognition of LVO and Fe3+ provides a unique emission pattern for the detection of LVO. This approach exhibited a high specificity to LVO among various pharmaceutical samples, namely acetaminophen (AC), azithromycin (AZ), gemifloxacin (GEM) and ciprofloxacin (CIP) and also showed great anti-interference property in urine. The attractive features of this sensing system are availability, easy-to-use, high sensitivity (limit of detection = 18 nM for Cu2+, 22 nM for Fe3+ and 0.12 nM for LVO), rapid response (5 s) with an excellent selectivity.

Biological evaluation of levofloxacin and its thionated derivatives: antioxidant activity, aldehyde dehydrogenase enzyme inhibition, and cytotoxicity on A549 cell line

Levofloxacin (LVX) is among the fluoroquinolones antibiotics that has also been studied in vitro and in vivo for its anticancer effects. In this study, we used LVX and novel LVX thionated derivatives; compounds 2 and 3, to evaluate their antioxidant activity, aldehyde dehydrogenase (ALDH) enzymes activity inhibition, and anticancer activity. Combination treatments with doxorubicin (DOX) were investigated as well. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was used to determine the antioxidant activity. The NADH fluorescence spectrophotometric activity assay was used to determine the ALDH inhibitory effects. Resazurin dye method was applied for cell viability assays. Molecular Operating Environment software was used for the molecular docking experiments. Compared to ascorbic acid, DPPH assay showed that compound 3 had the highest antioxidant activity among the tested compounds with approximately 35% scavenging activity. On ALDH enzymes, compound 3 showed a significant ALDH activity inhibition compared to compound 2 at 200 µM. The IC50 values for the tested compounds were approximately 100 µM on A549 cell line, a non-small cell lung cancer (NSCLC) cell line. However, significant enhancement of cytotoxicity and reduction of IC50 values were observed by combining DOX and synergism was achieved with LVX with a combination index value of 0.4. The molecular docking test showed a minimum binding energy with a good affinity for compound 3 towards ALDH enzymes. Thionated LVX derivatives, may be repurposed for NSCLC therapy in combination with DOX, taking into account the antioxidant activity, ALDH activity inhibition, and the molecular docking results of compound 3.

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 24 h in the control compared to the Levo 3.57 treatment. The Pupation in the control was delayed by an average of 48 h 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.

Effects of antibiotics ceftriaxone and levofloxacin on the growth of Lucilia sericata (Diptera: Calliphoridae)

Lucilia sericata is one of the most studied species in forensic entomology due to its widespread distribution, forensic importance as well as medical use. The growth and development stage of maggots is often used to determine the post-mortem interval in forensic cases. L. sericata can cause myiasis in humans who are not able to maintain personal hygiene due to age or medical condition and can therefore be used to determine the time period of neglect. The influence of the temperature on the maggot development has been examined in various studies. Different examinations on the effects of toxic substances on the maggot development and survival have been conducted in order to test the influence and resulting deviations. In this study, the effects of different therapeutical doses of the antibiotics ceftriaxone and levofloxacin were examined on L. sericata in order to determine and compare deviations in maggot development and survival. The used antibiotics did not significantly influence the maggot weight and length. A significant delay in the time of pupation has been determined in the treatments with high concentrations of levofloxacin. The mortality was significantly increased in all treatments with antibiotics compared to the control, whereby the survivability of all treatments remained over 80%. Because of the high doses needed to produce an effect, we concluded that an overestimation of the post-mortem interval is unlikely but higher antibiotic concentrations or possible interactions with other medications could increase the maggot development time.

A Network Pharmacology and Molecular-Docking-Based Approach to Identify the Probable Targets of Short-Chain Fatty-Acid-Producing Microbial Metabolites against Kidney Cancer and Inflammation

(1) Background: A large and diverse microbial population exists in the human intestinal tract, which supports gut homeostasis and the health of the host. Short-chain fatty acid (SCFA)-secreting microbes also generate several metabolites with favorable regulatory effects on various malignancies and immunological inflammations. The involvement of intestinal SCFAs in kidney diseases, such as various kidney malignancies and inflammations, has emerged as a fascinating area of study in recent years. However, the mechanisms of SCFAs and other metabolites produced by SCFA-producing bacteria against kidney cancer and inflammation have not yet been investigated. (2) Methods: We considered 177 different SCFA-producing microbial species and 114 metabolites from the gutMgene database. Further, we used different online-based database platforms to predict 1890 gene targets associated with metabolites. Moreover, DisGeNET, OMIM, and Genecard databases were used to consider 13,104 disease-related gene targets. We used a Venn diagram and various protein-protein interactions (PPIs), KEGG pathways, and GO analyses for the functional analysis of gene targets. Moreover, the subnetwork of protein-protein interactions (through string and cytoscape platforms) was used to select the top 20% of gene targets through degree centrality, betweenness centrality, and closeness centrality. To screen the possible candidate compounds, we performed an analysis of the ADMET (absorption, distribution, metabolism, excretion, and toxicity) properties of metabolites and then found the best binding affinity using molecular docking simulation. (3) Results: Finally, we found the key gene targets that interact with suitable compounds and function against kidney cancer and inflammation, such as MTOR (with glycocholic acid), PIK3CA (with 11-methoxycurvularin, glycocholic acid, and isoquercitrin), IL6 (with isoquercitrin), PTGS2 (with isoquercitrin), and IGF1R (with 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine, isoquercitrin), showed a lower binding affinity. (4) Conclusions: This study provides evidence to support the positive effects of SCFA-producing microbial metabolites that function against kidney cancer and inflammation and makes integrative research proposals that may be used to guide future studies.

Clinical and Translational Pharmacology Considerations for Anti-infectives Approved Under the FDA Animal Rule

The US Food and Drug Administration's Animal Rule provides a pathway for approval of drugs and biologics aimed to treat serious or life-threatening conditions wherein traditional clinical trials are either not ethical or feasible. In such a scenario, determination of safety and efficacy are based on integration of data on drug disposition and drug action collected from in vitro models, infected animals, and healthy volunteer human studies. The demonstration of clinical efficacy and safety in humans based on robust, well-controlled animal studies is filled with challenges. This review elaborates on the challenges in the translation of data from in vitro and animal models to human dosing for antimicrobials. In this context, it discusses precedents of drugs approved under the Animal Rule, along with the approaches and guidance undertaken by sponsors.

Electrochemical monitoring of levofloxacin using a silver nanoparticle-modified disposable device based on a lab-made conductive ink

The emergence of bacteria genetically resistant to first- and second-generation fluoroquinolones has resulted in increased consumption of levofloxacin (LEV) in human and veterinary medicine. In this regard, the development of low cost and good sensitivity electrochemical devices has been highly required. Thus, in this work, we propose the development of a disposable electrochemical device (DED) using a lab-made conductive ink based on graphite powder and nail polish immobilized on a rigid polyvinyl chloride support (transparent sheet). Additionally, a simple and quick protocol for the electrodeposition of silver nanoparticles was used in order to improve the electroanalytical performance of the sensor (2.75-fold). A differential pulse voltammetry (DPV) method was optimized and the sensor was applied for LEV monitoring in pharmaceutical formulation samples, synthetic urine and simulated body fluid. The method showed a wide linear working range ranging from 0.5 to 50 μmol L^-1 and a detection limit of 68.3 nmol L^-1. Furthermore, the precision was adequate (RSD < 4.7%), while the accuracy was evaluated through spiked samples with percent recovery ranging from 93 to 103%. The sensor was also shown to be selective for LEV against other electroactive antibiotic species, thus demonstrating suitable characteristics for electroanalytical applications.

Quinolones as a Potential Drug in Genitourinary Cancer Treatment-A Literature Review

Quinolones, broad-spectrum antibiotics, are frequently prescribed by urologists for many urological disorders. The mechanism of their bactericidal activity is based on the inhibition of topoisomerase II or IV complex with DNA, which consequently leads to cell death. It has been observed that these antibiotics also act against the analogous enzymes present in eukaryotic cells. Due to their higher accumulation in urine and prostate tissue than in serum, these drugs seem to be ideal candidates for application in genitourinary cancer treatment. In this study, an extensive literature review has been performed to collect information about concentrations achievable in urine and prostate tissue together with information about anticancer properties of 15 quinolones. Special attention was paid to the application of cytotoxic properties of quinolones for bladder and prostate cancer cell lines. Data available in the literature showed promising properties of quinolones, especially in the case of urinary bladder cancer treatment. In the case of prostate cancer, due to low concentrations of quinolones achievable in prostate tissue, combination therapy with other chemotherapeutics or another method of drug administration is necessary.

The optimization of enzymatic oxidation of levofloxacin, a fluoroquinolone antibiotic for wastetwater treatment

The global presence of antibiotics in the environment has created concerns about the emergence of antibiotic resistance bacteria and potential hazard to humans and the ecosystem. This work aims to study the removal of levofloxacin, a new generation fluoroquinolone antibiotic from aqueous solutions by enzyme mediated oxidation process and optimization of the conditions thereof by response surface methodology (RSM) using Box-Behnken design (BBD). For this study, experiments were conducted to analyze the effect of independent variables namely, pH, temperature, mediator concentration and antibiotic concentration on the degradation percentage of levofloxacin antibiotic using laccase enzyme derived from Trametes versicolor. The residual levofloxacin concentration was determined using high performance liquid chromatography (HPLC). On applying the quadratic regression analysis, among the main parameters, it was found that the percentage degradation was significantly affected by all the four variables. The predicted values for percentage degradation of levofloxacin were close to the experimental values obtained and the R² (0.95) indicated that the regression was able to give a good prediction of response for the percentage degradation of levofloxacin in the studied range. The optimal conditions for the maximum degradation (99.9%) as predicted by the BBD were: temperature of 37 °C, pH of 4.5, mediator concentration of 0.1 mM and levofloxacin concentration of 5 μg mL^-1. The findings of the study were further extended to study the effect of partially purified enzymes isolated from Pleurotus eryngii, Pleurotus florida and Pleurotus sajor caju on the degradation of levofloxacin at concentrations ranging from as low as 0.1 to as high as 50 µg mL^-1 in synthetic wastewater utilizing the optimized conditions generated by BBD. A maximum degradation of 88.8% was achieved with the partially purified enzyme isolated from Pleurotus eryngii at 1 µg mL^-1 levofloxacin concentration which was at par with the commercial laccase which showed 89% degradation in synthetic wastewater at the optimized conditions. The biodegradation studies were conducted using only 2 units of laccase. Thus, the expensive commercial laccase can be effectively replaced by crude laccase isolated from indigenous macrofungi such as P. eryngii, P. florida and P. sajor caju as a cost effective alternative to degrade levofloxacin present in contaminated wastewater using as low as 2 units of enzyme for a 72 h treatment period.

Absolute Stereochemical Determination of Organic Molecules through Induction of Helicity in Host-Guest Complexes

Stereochemistry is a fundamental molecular property with important ramifications for structure, function, and activity of organic molecules. The basic building blocks of living organisms (amino acids and sugars) exhibit a precisely selected set of molecular handedness that has evolved over millions of years. The absolute stereochemistry of these building blocks is manifested in the structure and function of the cell machinery (e.g., enzymes, proteins, etc.), which are essential components of life. In the many chemical subdisciplines, molecular stereochemistry is exceedingly important and is often a strong determinant of structure and function. Besides its biological implications, the centrally important role of stereochemistry in many disciplines of chemistry and related fields has led to tremendous effort and activity, highlighted by the success in stereoselective syntheses of a host of functionalities. In the present climate, it is often the difficulty of assigning absolute stereochemistry as opposed to synthesis, which has become a nontrivial challenge, requiring the attention of the community. There will not be a general solution to this problem, as each system will have its own unique requirements and challenges; however, the need for rapid, routine, and microscale analysis is apparent. This is especially true with parallel and high-throughput arrays for screening conditions and catalysts, generating a large number of samples that require analysis.In this Account, we summarize our contribution to this field through the development of molecular receptors for sensing molecular asymmetry. These methodologies strive to unambiguously assign the absolute configuration of asymmetric center(s). To accomplish this task, our laboratory has designed a variety of host molecules, bearing various binding elements, to form stable complexes with chiral molecules (guests). During this complexation event, the stereochemistry of a target molecule induces a supramolecular chirality (i.e., helicity) within the host system. The design of the host system is such that the helicity of the host/guest complex can be observed and assigned via Exciton Coupled Circular Dichroism (ECCD), a nonempirical technique for identifying handedness, which is correlated back to the absolute stereochemistry of the bound chiral molecule. Taking advantage of the high sensitivity of chiroptical techniques (in terms of the required amount of sample for analysis) and fast response time, these methodologies offer a microscale, rapid, and nonempirical solution for assignment of absolute stereochemistry.The first part of this Account describes application of porphyrin tweezers as reporters of chirality for the absolute stereochemical determination of various classes of organic molecules. This methodology is suitable to report the absolute configuration of organic molecules that contain two binding elements (nitrogen or oxygen based functionalities). In the second part, host systems that do not require two sites of attachment to form ECCD active complexes will be described. This enables the absolute stereochemical assignment of challenging chiral molecules with functional groups lacking routine techniques for analysis.

Interaction of Folk Medicinal Plants with Levofloxacin against Escherichia Coli

The present study was conducted to assess the in vitro activities of folk medicinal plants in combination with levofloxacin against TG1 and mutant KAM3-1(∆acrB-∆tolC) Escherichia coli strains. Plants were chosen based on their traditional use in combination with antibiotics among laymen. Standard protocols were followed to examine the antimicrobial activity of plant extracts and levofloxacin against E. coli in term of their minimum inhibitory concentrations (MICs) and to evaluate the plant extracts-levofloxacin interaction using checkerboard method. Among the twelve plants investigated, Thymus vulgaris, Zingiber officinale, Teucrium polium, Matricaria chamomilla and Curcuma longa had the best antimicrobial activities against E. coli strains with MIC values at 250 μg/ml. It is noteworthy to mention that other folk plants extracts reveled no effects against E coli strains. Furthermore, additive interactions were observed between levofloxacin and T. polium or T. vulgaris against E. coli wild-type TG1 strain. There was no antagonism being observed in this study. The detection of additive interaction between the extracts and levofloxacin demonstrates the prospective of these folk medicinal plants as a source of compounds to modulate antibiotic resistance.

Levofloxacin versus ceftriaxone for treatment of acute pyelonephritis in Iranian adults

INTRODUCTION

Acute pyelonephritis is among the most common bacterial infections. Options for initial treatment of pyelonephritis include an extended-spectrum cephalosporin or a fluoroquinolone. In this study, we aimed to compare the clinical outcomes of patients receiving ceftriaxone to those who received levofloxacin for the treatment of acute pyelone-phritis.

METHODS

In this randomized, open-label trial, hospitalized adults with acute pyelonephritis were treated with ceftriaxone (1g IV every 12 hours) or levofloxacin (750 mg IV daily) for at least 7 days. Clinical and microbiological characteristics were compared among patients treated with ceftriaxone and levofloxacin.

RESULTS

A total of 59 patients were randomized, 30 to the ceftriaxone group and 29 to the levofloxacin group. The clinical response for 68.0% of patients in the ceftriaxone group and 56.0% of patients in the levofloxacin group were cured. The mi-crobiological response (pathogen eradication rates) was 68.7% in the ceftriaxone group and 21.4% in the levofloxacin group.(P value=0.00028) Escherichia coliwas the most common pathogen (n = 31), followed by Klebsiella pneumoniae(n = 21). High resistance rates were detected for cotrimoxazole (55%), ciprofloxacin (48%), and ceftriaxone (34.4%) in isolat-ed E.coli. Likewise, all K. pneumoniaeisolates were resistant to ciprofloxacin.

CONCLUSIONS

Our study indicates that ceftriaxone was more effective than levofloxacin in the treatment of acute pyelone-phritis, on the basis of microbiological response, but there were no statistically significant differences between the treatment groups in the rates of clinical cure.The resistance of uropathogens to the most used antibiotics was relatively high. Choosing the treatment regimen based on susceptibility testing results and shortening the duration of the therapy are now recommend-ed to be the most important approaches to decrease the spread of antibiotic resistance worldwide.

Comparison of single-dose fosfomycin tromethamine and other antibiotics for lower uncomplicated urinary tract infection in women and asymptomatic bacteriuria in pregnant women: A systematic review and meta-analysis

INTRODUCTION

This systematic review and meta-analysis investigated the efficacy and safety of single-dose fosfomycin tromethamine (FT) versus other antibiotic agents in women suffering from lower uncomplicated urinary tract infection (uUTI) and pregnant women with uUTI or asymptomatic bacteriuria (ASB).

METHODS

MEDLINE, EMBASE and the Cochrane library were searched to identify relevant literature. Twenty-one studies were identified. Nine of the 21 studies enrolled 21 22 patients and were used to compare the clinical resolution of uUTI between non-pregnant and pregnant women. Given that uUTI and ASB are assessed using similar microbiological evaluation methods, all 3103 patients in the identified 21 studies were pooled to determine microbiological resolution between uUTI or ASB patients. Safety outcomes of the treatments were analysed in 15 studies.

RESULTS

The results showed that single-dose FT was comparable with other antibiotic agents in clinical resolution of uUTI (OR 0.89; 95% CI 0.71-1.10; P = 0.41) in non-pregnant (P = 0.32) and pregnant women (P = 0.64). Moreover, single-dose FT was equal to other antibiotics in microbiological resolution, and there was no difference in overall microbiological resolution (OR 1.11; 95% CI 0.92-1.34; P = 0.29) among non-pregnant women with uUTI (P = 0.48), pregnant women with uUTI (P = 0.81) and pregnant women with ASB (P = 0.30). There were no serious fosfomycin-related adverse events and most frequent adverse events were mainly gastrointestinal.

CONCLUSION

This meta-analysis suggests that single-dose fosfomycin tromethamine produces equivalent clinical outcomes to comparator antibiotics in terms of clinical efficacy and microbiological efficacy. It is therefore clinically effective and safe for women with uUTI and pregnant women with uUTI or ASB, and has higher patient compliance.

Potential Genes Related to Levofloxacin Resistance in Mycobacterium tuberculosis Based on Transcriptome and Methylome Overlap Analysis

Drug-resistant Mycobacterium tuberculosis (M. tuberculosis) has become an increasingly serious public health problem and has complicated tuberculosis (TB) treatment. Levofloxacin (LOF) is an ideal anti-tuberculosis drug in clinical applications. However, the detailed molecular mechanisms of LOF-resistant M. tuberculosis in TB treatment have not been revealed. Our study performed transcriptome and methylome sequencing to investigate the potential biological characteristics of LOF resistance in M. tuberculosis H37Rv. In the transcriptome analysis, 953 differentially expressed genes (DEGs) were identified; 514 and 439 DEGs were significantly downregulated and upregulated in the LOF-resistant group and control group, respectively. The KEGG pathway analysis revealed that 97 pathways were enriched in this study. In the methylome analysis, 239 differentially methylated genes (DMGs) were identified; 150 and 89 DMGs were hypomethylated and hypermethylated in the LOF-resistant group and control group, respectively. The KEGG pathway analysis revealed that 74 pathways were enriched in this study. The overlap study suggested that 25 genes were obtained. It was notable that nine genes expressed downregulated mRNA and upregulated methylated levels, including pgi, fadE4, php, cyp132, pckA, rpmB1, pfkB, acg, and ctpF, especially cyp132, pckA, and pfkB, which were vital in LOF-resistant M. tuberculosis H37Rv. The overlapping genes between transcriptome and methylome could be essential for studying the molecular mechanisms of LOF-resistant M. tuberculosis H37Rv. These results may provide informative evidence for TB treatment with LOF.

Clinical Benefit of Empiric High-Dose Levofloxacin Therapy for Adults With Community-onset Enterobacteriaceae Bacteremia

PURPOSE

Levofloxacin is commonly prescribed to treat varied community-acquired gram-negative infections; knowledge of the therapeutic efficacies of high-dose (HD) administration is helpful to improve patient care.

METHODS

In this 6-year cohort, adults with community-onset Enterobacteriaceae bacteremia were retrospectively studied in 2 hospitals. To overcome the confounding factors in the dosage choice of empiric administration, patients receiving empiric intravenous HD (750 mg/d) therapy were matched with those receiving the conventional dose (CD; 500 mg/d) by using individual propensity scores, calculated by the independent predictors of 30-day crude mortality.

FINDINGS

Initially, more patients with critical illness (Pitt bacteremia score [PBS] ≥4) at bacteremia onset and comorbid malignancies and the higher 15- and 30-day mortality rate were recorded in 136 patients receiving HD therapy, compared to 103 receiving CD therapy. After appropriate matching, differences in patient demographic and clinical characteristics between the HD (n = 103) and CD (n = 103) groups were nonsignificant. Consequently, crude mortality rates at 3, 15, or 30 days after onset of bacteremia did not differ. However, the period of time to defervescence, total intravenous antimicrobial administration, and hospital stay was shorter in the HD group than in the CD group. Similarly, regardless if patients had more critical illness (PBS ≥2) or stabilized illness (PBS <2), the advantage of empiric HD therapy on defervescence remained significant. Within 60 days after discontinuation of intravenous levofloxacin therapy, the proportion of recurrent bacteremia, posttreatment overall infections, and posttreatment crude mortality was similar between the HD and CD groups.

IMPLICATIONS

For adults with community-onset Enterobacteriaceae bacteremia, empiric administration of HD levofloxacin was as effective as CD levofloxacin in reducing mortality and, notably, led to more rapid defervescence compared with CD administration.

Effects of Lysozyme on the Activity of Ionic of Fluoroquinolone Species

Fluoroquinolones (FQs) constitute an important class of biologically active broad-spectrum antibacterial drugs that are which are in contact with many biological fluids under different acidity conditions. We studied the reactivity of ciprofloxacin (Cpx) and levofloxacin (Lev) and their interaction with lysozyme (Lyz) at different pH values, using UV-visible absorption, fluorescence, infrared spectroscopies supported by DFT calculation and docking. In addition, by antimicrobial assays, the biological consequences of the interaction were evaluated. DFT calculation predicted that the FQ cationic species present at acid pH have lower stabilization energies, with an electric charge rearrangement because of their interactions with solvent molecules. NBO and frontier orbital calculations evidenced the role of two charged centers, NH₂⁺ and COO-, for interactions by electronic delocalization effects. Both FQs bind to Lyz via a static quenching with a higher interaction in neutral medium. The interaction induces a structural rearrangement in β-sheet content while in basic pH a protective effect against the denaturation of Lyz was inferred. The analysis of thermodynamic parameters and docking showed that hydrophobic, electrostatic forces and hydrogen bond are the responsible of Cpx-Lyz and Lev-Lyz associations. Antimicrobial assays evidenced an antagonist effect of Lyz in acid medium while in neutral medium the FQs' activities were not modified by Lyz.

The challenge of urinary tract infections in renal transplant recipients

Urinary tract infections (UTI) are an important cause of morbidity and mortality in renal transplant patients. These infections are quite common, and the goal of care is to identify and reduce risk factors while providing effective prophylaxis and treatment. Better understanding of long-term outcomes from these infections has led to the distinctions among UTI, recurrent UTI, and asymptomatic bacteriuria (ASB), and that each requires a different therapeutic approach. Specifically, new research has supported the perspective that asymptomatic bacteriuria should not be treated. Symptomatic UTI, on the other hand, requires intervention and remains an ongoing challenge for infectious disease clinicians. Many bacteria species are responsible for UTI in renal transplant patients, and in recent years there has been a global rise in infection caused by bacteria with newly acquired antibacterial resistance genes. Many renal transplant patients who experience UTI will also have multiple recurring episodes, which likely has a distinct pathophysiological mechanism leading to chronic colonization of the urinary tract. In these cases, long-term management includes bacterial suppression, which aims to reduce rather than eliminate bacteria to levels below the threshold for symptomatic infection. This review will address the current understanding of UTI epidemiology, pathogenesis, and risk factors in the renal transplant community, and also focus on current prevention and treatment strategies for patients who face an environment of increasingly antibiotic-resistant bacteria.

Translational Efficacy of Humanized Exposures of Cefepime, Ertapenem, and Levofloxacin against Extended-Spectrum-β-Lactamase-Producing Escherichia coli in a Murine Model of Complicated Urinary Tract Infection

Validated animal models are required as bridging tools to assess the utility of novel therapies and potential microbiologic outcomes. Herein, we utilized uropathogenic extended-spectrum-β-lactamase (ESBL)-producing and non-ESBL-producing Escherichia coli in the neutropenic murine complicated urinary tract infection (cUTI) model with humanized exposures of cefepime, ertapenem, and levofloxacin to assess its translational value to human outcomes. Our data support the translational utility of this murine model to cUTI in humans as humanized exposures produced microbiologic outcomes consistent with the phenotypic profiles of the organisms.

Treatment of complicated urinary tract infection and acute pyelonephritis by short-course intravenous levofloxacin (750 mg/day) or conventional intravenous/oral levofloxacin (500 mg/day): prospective, open-label, randomized, controlled, multicenter, non-inferiority clinical trial

Objective

To compare the efficacy and safety of short-course intravenous levofloxacin (LVFX) 750 mg with a conventional intravenous/oral regimen of LVFX 500 mg in patients from China with complicated urinary tract infections (cUTIs) and acute pyelonephritis (APN).

Methods

This was a prospective, open-label, randomized, controlled, multicenter, non-inferiority clinical trial. Patients with cUTI and APN were randomly assigned to a short-course therapy group (intravenous LVFX at750 mg/day for 5 days) or a conventional therapy group (intravenous/oral regimen of LVFX at 500 mg/day for 7–14 days). The clinical, laboratory, and microbiological results were evaluated for efficacy and safety.

Results

The median dose of LVFX was 3555.4 mg in the short-course therapy group and 4874.2 mg in the conventional therapy group. Intention-to-treat analysis indicated the clinical effectiveness in the short-course therapy group (89.87%, 142/158) was non-inferior to that in the conventional therapy group (89.31%, 142/159). The microbiological effectiveness rates were also similar (short-course therapy: 89.55%, 60/67; conventional therapy: 86.30%, 63/73; p > 0.05). There were no significant differences in other parameters, including clinical and microbiological recurrence rates. The incidence of adverse effects and drug-related adverse effects were also similar for the short-course therapy group (21.95%, 36/164; 18.90%, 31/164) and the conventional therapy group (23.03%, 38/165; 15.76%, 26/165).

Conclusion

Patients with cUTIs and APN who were given short-course LVFX therapy and conventional LVFX therapy had similar outcomes in clinical and microbiological efficacy, tolerance, and safety. The short-course therapy described here is a more convenient alternative to the conventional regimen with potential implication in anti-resistance and cost saving.

Electronic supplementary material

The online version of this article (doi:10.1007/s11255-017-1507-0) contains supplementary material, which is available to authorized users.

Personalized therapeutics for levofloxacin: a focus on pharmacokinetic concerns

Background

Personalized medicine should be encouraged because patients are complex, and this complexity results from biological, medical (eg, demographics, genetics, polypharmacy, and multimorbidities), socioeconomic, and cultural factors. Levofloxacin (LVX) is a broad-spectrum fluoroquinolone antibiotic. Awareness of personalized therapeutics for LVX seems to be poor in clinical practice, and is reflected in prescribing patterns. Pharmacokinetic–pharmacodynamic studies have raised concerns about suboptimal patient outcomes with the use of LVX for some Gram-negative infections. Meanwhile, new findings in LVX therapeutics have only been sporadically reported in recent years. Therefore, an updated review on personalized LVX treatment with a focus on pharmacokinetic concerns is necessary.

Methods

Relevant literature was identified by performing a PubMed search covering the period from January 1993 to December 2013. We included studies describing dosage adjustment and factors determining LVX pharmacokinetics, or pharmacokinetic–pharmacodynamic studies exploring how best to prevent the emergence of resistance to LVX. The full text of each included article was critically reviewed, and data interpretation was performed.

Results

In addition to limiting the use of fluoroquinolones, measures such as reducing the breakpoints for antimicrobial susceptibility testing, choice of high-dose short-course of once-daily LVX regimen, and tailoring LVX dose in special patient populations help to achieve the validated pharmacokinetic–pharmacodynamic target and combat the increasing LVX resistance. Obese individuals with normal renal function cleared LVX more efficiently than normal-weight individuals. Compared with the scenario in healthy subjects, standard 2-hour spacing of calcium formulations and oral LVX was insufficient to prevent a chelation interaction in cystic fibrosis patients. Inconsistent conclusions were derived from studies of the influence of sex on the pharmacokinetics of LVX, which might be associated with sample size and administration route. Children younger than 5 years cleared LVX nearly twice as fast as adults. Patients in intensive care receiving LVX therapy showed significant pharmacokinetic differences compared with healthy subjects. Creatinine clearance explained most of the population variance in the plasma clearance of LVX. Switching from intravenous to oral delivery of LVX had economic benefits. Addition of tamsulosin to the LVX regimen was beneficial for patients with bacterial prostatitis because tamsulosin could increase the maximal concentration of LVX in prostatic tissue. Coadministration of multivalent cation-containing drugs and LVX should be avoided. For patients receiving warfarin and LVX concomitantly, caution is needed regarding potential changes in the international normalized ratio; however, it is unnecessary to seek alternatives to LVX for the sake of avoiding drug interaction with warfarin. It is unnecessary to proactively reduce the dose of cyclosporin or tacrolimus when comedicated with LVX. Transporters such as organic anion-transporting polypeptide 1A2, P-glycoprotein, human organic cation transporter 1, and multidrug and toxin extrusion protein 1 are involved in the pharmacokinetics of LVX.

Conclusion

Personalized LVX therapeutics are necessary for the sake of better safety, clinical success, and avoidance of resistance. New findings regarding individual dosing of LVX in special patient populations and active transport mechanisms in vivo are opening up new horizons in clinical practice.

Cu(ii) and Co(ii) ternary complexes of quinolone antimicrobial drug enoxacin and levofloxacin: structure and biological evaluation

Four novel metal–quinolone complexes tightly binded to calf-thymus DNA and exhibited good binding propensity to albumin protein.

Comparative pharmacokinetics of levofloxacin in healthy volunteers and in patients suffering from typhoid Fever

The aim of this study was to characterize the effect of typhoid fever on pharmacokinetic parameters of levofloxacin (LF) and compare the pharmacokinetic parameters of the said antibiotic in healthy human volunteers and patients with typhoid fever. Total of 12 subjects were divided into two groups "A" (healthy volunteers) and "B" (typhoid patients). Single oral dose of LF 500 mg was given and 5 mL of blood was collected from each subject at 0, 0.25, 0.5, 1, 2, 3, 6, 12, 24, 36 and 72 h. Plasma concentrations of LF were measured by HPLC. Pharmacokinetic parameters were calculated from plasma concentration-time data by using MW/PHARM pharmacological analysis. In healthy volunteers, the average pharmacokinetic parameters were as Cmax (6.79 μg/mL), Tmax (1.84 h), T(½) (10.03 h), Ka (2.23 h(-1)), AUC (110.09 μgh/mL), Vd (85.84 L), Cl (4.57 L/h) and in typhoid patients were Cmax (6.90 μg/mL), Tmax (1.82 h), T(½) (9.42 h), Ka (2.21 h(-1)), AUC (105.55 μgh/mL), Vd (64.31 L), Cl (4.75 L/h). The difference between pharmacokinetic parameters of LF in healthy human volunteers and typhoid patients was calculated by using unpaired t-test. As the p-value in case of all pharmacokinetic parameters was more than 0.05, the difference between pharmacokinetic parameters in both healthy human volunteers and typhoid patients was insignificant. It is concluded that there is no need to adjust the dose of LF in typhoid patients.

Change of antimicrobial susceptibility among Escherichia coli strains isolated from female patients with community-onset acute pyelonephritis

PURPOSE

There is a concern on which antimicrobials are appropriate as empirical agents for community-onset acute pyelonephritis (APN) in regions where the fluoroquinolone resistance rate is high, such as in Korea.

MATERIALS AND METHODS

Three hundred and two strains of E. coli in 2001-2002 and 349 strains in 2008-2009 were isolated from the urine cultures of female adult APN patients, and the antimicrobial susceptibility was compared according to each study period. All the patients were classified as uncomplicated or complicated APN, and a subgroup analysis was done thereafter.

RESULTS

The E. coli strains isolated in 2008-2009 showed improved susceptibility to trimethoprim-sulfamethoxazole compared to those isolated in 2001-2002. However, the third generation cephalosporin and gentamicin susceptibility was worsened. Of the 232 isolates from the uncomplicated APN patients, there was no difference between the two different time periods. On the other hand, of the 419 isolates from the complicated APN patients, the susceptibility to third generation cephalosporin, gentamicin and ciprofloxacin was significantly worsened.

CONCLUSION

The antimicrobial susceptibility of E. coli changed over the study period, however, this change occurred mainly in the complicated APN patients. In Korea, ciprofloxacin is still useful as an empirical agent for uncomplicated APN patients, but this is not the case for patients with complicated APN because of high resistance rate to ciprofloxacin in these patients. For the complicated APN patients, the rate of resistance to ciprofloxacin is already more than 30%.

Cumulative clinical experience from over a decade of use of levofloxacin in urinary tract infections: critical appraisal and role in therapy

The treatment of urinary tract infections (UTIs) continues to evolve as common uropathogens increasingly become resistant to previously active antimicrobial agents. In addition, bacterial isolates, which were once considered to be either colonizers or contaminants, have emerged as true pathogens, likely related to the more complex array of settings where health care is now delivered. Even though the reliability of many antimicrobial agents has become less predictable, the fluoroquinolone group of agents has remained a frequent, if not the most often prescribed, antimicrobial therapy for almost all types of UTIs. Levofloxacin has taken its position at the top of the list as one of the most regularly administered fluoroquinolone agents given to patients with a suspected or proven UTI. The authors review the clinical experience of the use of levofloxacin over the past decade and suggest that the use of levofloxacin for the treatment of UTIs, although still fairly dependable, is perhaps not the best use of this important antimicrobial agent.

Management of complicated urinary tract infections in the era of antimicrobial resistance

Complicated urinary tract infections (cUTIs) are a major cause of hospital admissions and are associated with significant morbidity and health care costs. Patients presenting with a suspected UTI should be screened for the presence of complicating factors, such as anatomic and functional abnormalities of the genitourinary tract. In the setting of cUTIs, the etiology and susceptibility of the causative organism is not predictable; therefore, when infection is suspected, patients should undergo a urinalysis in addition to culture and sensitivity testing. Although not warranted in all cases of complicated pyelonephritis, blood cultures are appropriate in some clinical settings. With the increased prevalence of antimicrobial resistance, and the lack of well-designed clinical trials, treatment of cUTIs can be challenging for clinicians. Although resistant organisms are not always implicated as the causative agent, all patients with cUTIs should be assessed for predisposing risk factors. Consideration of an optimal antimicrobial agent should be based on local resistance patterns, patient-specific factors, including anatomic site of infection and severity of disease, pharmacokinetic and pharmacodynamic principles, and cost. Resistance to first-line antimicrobial agents, including fluoroquinolones, has become increasingly common in Escherichia coli. Fluoroquinolones should not be used as a first-line option for empiric treatment of serious cUTIs, especially when patients exhibit risk factors for harboring a resistant organism, such as previous or recent use of fluoroquinolones. Fluoroquinolones, trimethoprim-sulfamethoxazole, and nitrofurantoin are still appropriate empiric options for mild lower cUTIs. However, empiric treatment for serious cUTIs, where risk factors for resistant organisms exist, should include broad-spectrum antibiotics such as carbapenems or piperacillin-tazobactam. Once organisms and susceptibilities are identified, treatment should be targeted accordingly. Nitrofurantoin and fosfomycin have limited utility in the setting of cUTIs and should be reserved as alternative treatment options for lower cUTIs following confirmation of the causative organism. Aminoglycosides, tigecycline, and polymyxins can be used for the treatment of serious cUTIs when first-line options are deemed to be inappropriate or patients fail therapy. The duration of treatment for cUTIs has not been well established; however, treatment durations can range from 1 to 4 weeks based on the clinical situation.