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Microorganisms May 2024Pradofloxacin is the newest of the veterinary fluoroquinolones to be approved for use in animals-initially companion animals and most recently food animals. It has a...
Comparative In Vitro Killing by Pradofloxacin in Comparison to Ceftiofur, Enrofloxacin, Florfenicol, Marbofloxacin, Tildipirosin, Tilmicosin and Tulathromycin against Bovine Respiratory Bacterial Pathogens.
Pradofloxacin is the newest of the veterinary fluoroquinolones to be approved for use in animals-initially companion animals and most recently food animals. It has a broad spectrum of in vitro activity, working actively against Gram-positive/negative, atypical and some anaerobic microorganisms. It simultaneously targets DNA gyrase (topoisomerase type II) and topoisomerase type IV, suggesting a lower propensity to select for antimicrobial resistance. The purpose of this study was to determine the rate and extent of bacterial killing by pradofloxacin against bovine strains of and , in comparison with several other agents (ceftiofur, enrofloxacin, florfenicol, marbofloxacin, tildipirosin, tilmicosin and tulathromycin) using four clinically relevant drug concentrations: minimum inhibitory and mutant prevention drug concentration, maximum serum and maximum tissue drug concentrations. At the maximum serum and tissue drug concentrations, pradofloxacin killed 99.99% of cells following 5 min of drug exposure (versus growth to 76% kill rate for the other agents) and 94.1-98.6% of following 60-120 min of drug exposure (versus growth to 98.6% kill rate for the other agents). Statistically significant differences in kill rates were seen between the various drugs tested depending on drug concentration and time of sampling after drug exposure.
PubMed: 38792823
DOI: 10.3390/microorganisms12050996 -
Life (Basel, Switzerland) May 2024Multidrug-resistant bacterial pathogens, such as , represent a major human health threat. Due to the critical need to overcome this dilemma, since the drug efflux pump...
Multidrug-resistant bacterial pathogens, such as , represent a major human health threat. Due to the critical need to overcome this dilemma, since the drug efflux pump has a vital function in the evolution of antimicrobial resistance in bacteria, we have investigated the potential of essential oil major constituents (-) as antimicrobial agents via their ability to inhibit pathogenic DNA gyrase and, in addition, their potential inhibition of the AcrB-TolC efflux pump, a potential target to inhibit MDR pathogens. The ligand docking approach was conducted to analyze the binding interactions of EO constituents with the target receptors. The obtained results proved their antimicrobial activity through the inhibition of DNA gyrase () with binding affinity ΔG values between -4.94 and -6.49 kcal/mol. Moreover, EO constituents demonstrated their activity against MDR by their ability to inhibit AcrB-TolC () with ΔG values ranging between -4.69 and -6.39 kcal/mol. The antimicrobial and MDR activity of EOs was supported via hydrogen bonding and hydrophobic interactions with the key amino acid residues at the binding site of the active pocket of the targeted receptors.
PubMed: 38792631
DOI: 10.3390/life14050610 -
Journal of Chromatography. B,... Jun 2024DNA gyrase and topoisomerase IV play significant role in maintaining the correct structure of DNA during replication and they have been identified as validated targets...
Estimation of passive gastrointestinal absorption of new dual DNA gyrase and topoisomerase IV inhibitors using PAMPA and biopartitioning micellar chromatography and quantitative structure-retention relationship analysis.
DNA gyrase and topoisomerase IV play significant role in maintaining the correct structure of DNA during replication and they have been identified as validated targets in antibacterial drug discovery. Inadequate pharmacokinetic properties are responsible for many failures during drug discovery and their estimation in the early phase of this process maximizes the chance of getting useful drug candidates. Passive gastrointestinal absorption of a selected group of thirteen dual DNA gyrase and topoisomerase IV inhibitors was estimated using two in vitro tests - parallel artificial membrane permeability assay (PAMPA) and biopartitioning micellar chromatography (BMC). Due to good correlation between obtained results, passive gastrointestinal absorption of remaining ten compounds was estimated using only BMC. With this experimental setup, it was possible to identify compounds with high values of retention factors (k) and highest expected passive gastrointestinal absorption, and compounds with low values of k for which low passive gastrointestinal absorption is predicted. Quantitative structure-retention relationship (QSRR) modelling was performed by creating multiple linear regression (MLR), partial least squares (PLS) and support vector machines (SVM) models. Descriptors with the highest influence on retention factor were identified and their interpretation can be used for the design of new compounds with improved passive gastrointestinal absorption.
Topics: Quantitative Structure-Activity Relationship; Topoisomerase II Inhibitors; Gastrointestinal Absorption; Micelles; Linear Models; Membranes, Artificial; DNA Gyrase; Humans; DNA Topoisomerase IV
PubMed: 38776787
DOI: 10.1016/j.jchromb.2024.124158 -
Bioorganic Chemistry Jul 2024Aminothiazolyl coumarins as potentially new antimicrobial agents were designed and synthesized in an effort to overcome drug resistance. Biological activity assay...
Aminothiazolyl coumarins as potentially new antimicrobial agents were designed and synthesized in an effort to overcome drug resistance. Biological activity assay revealed that some target compounds exhibited significantly inhibitory efficiencies toward bacteria and fungi including drug-resistant pathogens. Especially, aminothiazolyl 7-propyl coumarin 8b and 4-dichlorobenzyl derivative 11b exhibited bactericidal potential (MBC/MIC = 2) toward clinically drug-resistant Enterococcus faecalis with low cytotoxicity to human lung adenocarcinoma A549 cells, rapidly bactericidal effects and no obvious bacterial resistance development against E. faecalis. The preliminary antibacterial action mechanism studies suggested that compound 11b was able to disturb E. faecalis membrane effectively, and interact with bacterial DNA isolated from resistant E. faecalis through noncovalent bonds to cleave DNA, thus inhibiting the growth of E. faecalis strain. Further molecular modeling indicated that compounds 8b and 11b could bind with SER-1084 and ASP-1083 residues of gyrase-DNA complex through hydrogen bonds and hydrophobic interactions. Moreover, compound 11b showed low hemolysis and in vivo toxicity. These findings of aminothiazolyl coumarins as unique structural scaffolds might hold a large promise for the treatments of drug-resistant bacterial infection.
Topics: Enterococcus faecalis; Coumarins; Humans; Anti-Bacterial Agents; Microbial Sensitivity Tests; Structure-Activity Relationship; Molecular Structure; Dose-Response Relationship, Drug; Thiazoles; DNA, Bacterial; A549 Cells; Hemolysis
PubMed: 38759357
DOI: 10.1016/j.bioorg.2024.107451 -
Biochemistry Jun 2024DNA gyrases catalyze negative supercoiling of DNA, are essential for bacterial DNA replication, transcription, and recombination, and are important antibacterial targets...
DNA gyrases catalyze negative supercoiling of DNA, are essential for bacterial DNA replication, transcription, and recombination, and are important antibacterial targets in multiple pathogens, including , which in 2021 caused >1.5 million deaths worldwide. DNA gyrase is a tetrameric (AB) protein formed from two subunit types: gyrase A (GyrA) carries the breakage-reunion active site, whereas gyrase B (GyrB) catalyzes ATP hydrolysis required for energy transduction and DNA translocation. The GyrB ATPase domains dimerize in the presence of ATP to trap the translocated DNA (T-DNA) segment as a first step in strand passage, for which hydrolysis of one of the two ATPs and release of the resulting inorganic phosphate is rate-limiting. Here, dynamical-nonequilibrium molecular dynamics (D-NEMD) simulations of the dimeric 43 kDa N-terminal fragment of GyrB show how events at the ATPase site (dissociation/hydrolysis of bound nucleotides) are propagated through communication pathways to other functionally important regions of the GyrB ATPase domain. Specifically, our simulations identify two distinct pathways that respectively connect the GyrB ATPase site to the corynebacteria-specific C-loop, thought to interact with GyrA prior to DNA capture, and to the C-terminus of the GyrB transduction domain, which in turn contacts the C-terminal GyrB topoisomerase-primase (TOPRIM) domain responsible for interactions with GyrA and the centrally bound G-segment DNA. The connection between the ATPase site and the C-loop of dimeric GyrB is consistent with the unusual properties of DNA gyrase relative to those from other bacterial species.
Topics: Mycobacterium tuberculosis; DNA Gyrase; Molecular Dynamics Simulation; Adenosine Triphosphatases; Protein Domains; Adenosine Triphosphate; Bacterial Proteins; Signal Transduction
PubMed: 38742407
DOI: 10.1021/acs.biochem.4c00161 -
MSphere May 2024Cervimycins A-D are bis-glycosylated polyketide antibiotics produced by HKI 0179 with bactericidal activity against Gram-positive bacteria. In this study, cervimycin C...
Cervimycins A-D are bis-glycosylated polyketide antibiotics produced by HKI 0179 with bactericidal activity against Gram-positive bacteria. In this study, cervimycin C (CmC) treatment caused a spaghetti-like phenotype in 168, with elongated curved cells, which stayed joined after cell division, and exhibited a chromosome segregation defect, resulting in ghost cells without DNA. Electron microscopy of CmC-treated (3 × MIC) revealed swollen cells, misshapen septa, cell wall thickening, and a rough cell wall surface. Incorporation tests in indicated an effect on DNA biosynthesis at high cervimycin concentrations. Indeed, artificial downregulation of the DNA gyrase subunit B gene () increased the activity of cervimycin in agar diffusion tests, and, in high concentrations (starting at 62.5 × MIC), the antibiotic inhibited DNA gyrase supercoiling activity . To obtain a more global view on the mode of action of CmC, transcriptomics and proteomics of cervimycin treated versus untreated cells were performed. Interestingly, 3 × MIC of cervimycin did not induce characteristic responses, which would indicate disturbance of the DNA gyrase activity . Instead, cervimycin induced the expression of the CtsR/HrcA heat shock operon and the expression of autolysins, exhibiting similarity to the ribosome-targeting antibiotic gentamicin. In summary, we identified the DNA gyrase as a target, but at low concentrations, electron microscopy and omics data revealed a more complex mode of action of cervimycin, which comprised induction of the heat shock response, indicating protein stress in the cell.IMPORTANCEAntibiotic resistance of Gram-positive bacteria is an emerging problem in modern medicine, and new antibiotics with novel modes of action are urgently needed. Secondary metabolites from species are an important source of antibiotics, like the cervimycin complex produced by HKI 0179. The phenotypic response of and toward cervimycin C indicated a chromosome segregation and septum formation defect. This effect was at first attributed to an interaction between cervimycin C and the DNA gyrase. However, omics data of cervimycin treated versus untreated cells indicated a different mode of action, because the stress response did not include the SOS response but resembled the response toward antibiotics that induce mistranslation or premature chain termination and cause protein stress. In summary, these results point toward a possibly novel mechanism that generates protein stress in the cells and subsequently leads to defects in cell and chromosome segregation.
Topics: Anti-Bacterial Agents; Staphylococcus aureus; Microbial Sensitivity Tests; Streptomyces; Bacillus subtilis; Polyketides; Glycosides; Cell Wall; Proteomics; Bacterial Proteins; DNA Gyrase
PubMed: 38722162
DOI: 10.1128/msphere.00764-23 -
Frontiers in Chemistry 2024dropped fruits are generally discarded as waste, causing environmental pollution and losses to farmers. In the present study, column chromatography has been used to...
dropped fruits are generally discarded as waste, causing environmental pollution and losses to farmers. In the present study, column chromatography has been used to isolate quinic acid (1,3,4,5-tetrahydroxycyclohexane-1-carboxylic acid) from the ethyl acetate fraction of a methanol extract of citrus fruits dropped in April. Quinic acid is a ubiquitous plant metabolite found in various plants and microorganisms. It is an important precursor in the biosynthesis of aromatic natural compounds. It was further derivatized into 3,4-o-isopropylidenequinic acid 1,5-lactone (QA), 1,3,4,5-tetraacetoxycyclohexylaceticanhydride (QA), and cyclohexane-1,2,3,5-tetraone (QA). These compounds were further tested for their antibacterial potential against the foodborne pathogens , ., , and QA exhibited maximum antibacterial potential (minimum inhibitory concentration; 80-120 μg/mL). QA revealed synergistic behavior with streptomycin against all the tested bacterial strains having a fractional inhibitory concentration index ranging from 0.29 to 0.37. It also caused a significant increase in cell constituent release in all the tested bacteria compared to the control, along with prominent biofilm reduction. The results obtained were further checked with computational studies that revealed the best docking score of QA (-6.30 kcal/mol, -5.8 kcal/mol, and -4.70 kcal/mol) against β-lactamase, DNA gyrase, and transpeptidase, respectively. The absorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis revealed that the drug-like properties of QA had an ideal toxicity profile, making it a suitable candidate for the development of antimicrobial drugs.
PubMed: 38698937
DOI: 10.3389/fchem.2024.1372560 -
Journal of Oleo Science 2024Launaea sarmentosa, also known as Sa Sam Nam, is a widely used remedy in Vietnamese traditional medicine and cuisine. However, the chemical composition and bioactivity...
Launaea sarmentosa, also known as Sa Sam Nam, is a widely used remedy in Vietnamese traditional medicine and cuisine. However, the chemical composition and bioactivity of its essential oil have not been elucidated yet. In this study, we identified 40 compounds (98.6% of total peak area) in the essential oil via GC-MS analysis at the first time. Among them, five main compounds including Thymohydroquinone dimethyl ether (52.4%), (E)-α-Atlantone (9.0%), Neryl isovalerate (6.6%), Davanol D2 (isomer 2) (3.9%), and trans-Sesquisabinene hydrate (3.9%) have accounted for 75.8% of total peak area. The anti-bacterial activity of the essential oil against 4 microorganisms including Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa has also investigated via agar well diffusion assay. The results showed that the essential oil exhibited a strong antibacterial activity against Bacillus subtilis with the inhibition zones ranging from 8.2 to 18.7 mm. To elucidate the anti-bacterial effect mechanism of the essential oil, docking study of five main compounds of the essential oil (Thymohydroquinone dimethyl ether, (E)-α-Atlantone, Neryl isovalerate, Davanol D2 (isomer 2), and trans-Sesquisabinene hydrate) against some key proteins for bacterial growth such as DNA gyrase B, penicillin binding protein 2A, tyrosyl-tRNA synthetase, and dihydrofolate reductase were performed. The results showed that the main constituents of essential oil were highly bound with penicillin binding protein 2A with the free energies ranging -27.7 to -44.8 kcal/mol, which suggests the relationship between the antibacterial effect of essential oil and the affinity of main compounds with penicillin binding protein. In addition, the free energies of main compounds of the essential oil with human cyclooxygenase 1, cyclooxygenase 2, and phospholipase A2, the crucial proteins related with inflammatory response were less than diclofenac, a non-steroidal antiinflammatory drug. These findings propose the essential oil as a novel and promising anti-bacterial and anti-inflammatory medicine or cosmetic products.
Topics: Molecular Docking Simulation; Anti-Bacterial Agents; Oils, Volatile; Bacillus subtilis; Staphylococcus aureus; Pseudomonas aeruginosa; Escherichia coli; Tetrahydrofolate Dehydrogenase; DNA Gyrase; Sesquiterpenes; Microbial Sensitivity Tests; Gas Chromatography-Mass Spectrometry; Pentanoic Acids; Hemiterpenes
PubMed: 38692900
DOI: 10.5650/jos.ess23254 -
Microbiology Spectrum Jun 2024This study aims to elucidate additional mutation loci associated with fluoroquinolone (FQ) resistance and evaluate the discriminatory capacity of mutation loci and...
This study aims to elucidate additional mutation loci associated with fluoroquinolone (FQ) resistance and evaluate the discriminatory capacity of mutation loci and allele mutation frequencies in identifying FQ-resistant (MTB) isolates. A random selection of isolates was extracted from an ongoing collection. Drug resistance was determined using the resazurin microtiter assay (REMA) as the gold standard. Mutation loci and the burden of mutations in the quinolone resistance-determining region (QRDR) were elucidated through whole-genome sequencing (WGS). Novel amino acid mutations, namely, G520D and G520T, were identified in the gyrB and associated with FQ resistance. In the context of distinguishing FQ-resistant isolates, the AUC for the QRDR mutation frequency burden (0.969) surpassed that of the mutation locus (0.929), and this difference was statistically significant ( = 0.03). Furthermore, using the resistance mutation locus as a reference, setting the QRDR mutation frequency burden threshold at 1.31% resulted in a 3.60% increase in the accuracy of classifying FQ-resistant isolates (NRI = 3.60%, < 0.001). The QRDR mutation frequency burden appears to offer superior diagnostic efficacy in discriminating FQ-resistant isolates compared to qualitative detection of mutant loci.IMPORTANCEFluoroquinolone (FQ) drugs are recommended as second-line drugs for the treatment of multidrug-resistant tuberculosis. With the massive use of FQ drugs in the clinical treatment of tuberculosis (TB), there is an increasing rate of drug resistance to FQ drugs. In this study, we identified and demonstrated novel amino acid mutations associated with FQ resistance in (MTB), and we quantified the mutation sites and identified the quinolone resistance-determining region (QRDR) mutation frequency burden as a novel diagnostic method for FQ resistance. We hope that the results of this study will provide data support and a theoretical basis for the rapid diagnosis of FQ-resistant MTB.
Topics: Mycobacterium tuberculosis; Fluoroquinolones; Whole Genome Sequencing; Humans; Mutation; Microbial Sensitivity Tests; Antitubercular Agents; Tuberculosis, Multidrug-Resistant; Drug Resistance, Bacterial; Genome, Bacterial; DNA Gyrase
PubMed: 38687077
DOI: 10.1128/spectrum.03930-23 -
Environmental Research Jul 2024Andrographis echioides has been extensively utilized in traditional Indian folk medicines for several skin disorders and other biological actions such as diuretic,...
Andrographis echioides has been extensively utilized in traditional Indian folk medicines for several skin disorders and other biological actions such as diuretic, antimicrobial, anthelmintic, anti-ulcer, and hepatoprotective properties. Different crude extracts were extracted from A. echioides leaves using various solvents such as methanol and water. The prepared crude extracts were utilized to formulate different herbal ointments. Further, the prepared ointments were examined against wounds and bacterial pathogens. The wound healing ability of the prepared formulations was observed for F, F, and F, to be (89.84%, 95.11%, and 95.75%) respectively. Moreover, wound healing capabilities were compared with standard Betadine which exhibits 98.12%, those results indicating that the prepared herbal ointment also has a promising wound healing ability. The F formulations outperform the other two formulations (F and F) in terms of their antibacterial ability to combat Staphylococcus aureus, Klebsiella pneumoniae Bacillus subtilis, and Escherichia coli. Moreover, there are two compounds were successfully isolated and identified from methanolic extract, which are 2-(3,4-dihydroxyphenyl)-3,4-dihydro-2H-chromene-3,5,7-triol and 3-(3,4-Dihydroxyphenyl)-2-propenoic acid. Meanwhile, the molecular docking investigation exposed high binding energy Staphylococcus aureus TyrRS (-8.9 kcal/mol), Isoleucyl-tRNA synthetase (-7.5 kcal/mol), Penicillin-binding protein 2a (-8.0 kcal/mol), S. aureus DNA Gyrase (-7.2 kcal/mol), GSK-3beta (Glycogen synthase kinase-3 beta) (-8.3 kcal/mol) and TGF - Beta Receptor Type 1 Kinase Domain (-8.7 kcal/mol) indicating high degree of interaction between Compound-1 2-(3,4-dihydroxyphenyl)-3,4-dihydro-2H-chromene-3,5,7-triol (DHPDHC) and 7 clinically important skin infective pathogen Staphylococcus aureus proteins at the active sites. Additionally, the standard drug Povidone iodine, Sulphothiazole, and Nitrofurazone (<-8 kcal/mol), displayed low binding affinity on targeted proteins. A molecular dynamics simulation research with high free energy showed stable interaction between the ligand and protein. Which endorses the capabilities of A. echioides derived compounds as a potential wound healer and antibacterial therapeutic candidate for drug development in the future.
Topics: Molecular Docking Simulation; Anti-Bacterial Agents; Wound Healing; Plant Extracts; Animals; Microbial Sensitivity Tests
PubMed: 38685295
DOI: 10.1016/j.envres.2024.119023