Glycopeptide Antibiotic Teicoplanin Research Articles

Characterisation of the selective binding of antibiotics vancomycin and teicoplanin by the VanS receptor regulating type A vancomycin resistance in the enterococci

A-type resistance towards “last-line” glycopeptide antibiotic vancomycin in the leading hospital acquired infectious agent, the enterococci, is the most common in the UK. Resistance is regulated by the VanRASA two-component system, comprising the histidine sensor kinase VanSA and the partner response regulator VanRA. The nature of the activating ligand for VanSA has not been identified, therefore this work sought to identify and characterise ligand(s) for VanSA. In vitro approaches were used to screen the structural and activity effects of a range of potential ligands with purified VanSA protein. Of the screened ligands (glycopeptide antibiotics vancomycin and teicoplanin, and peptidoglycan components N-acetylmuramic acid, D-Ala-D-Ala and Ala-D-y-Glu-Lys-D-Ala-D-Ala) only glycopeptide antibiotics vancomycin and teicoplanin were found to bind VanSA with different affinities (vancomycin 70μM; teicoplanin 30 and 170μM), and were proposed to bind via exposed aromatic residues tryptophan and tyrosine. Furthermore, binding of the antibiotics induced quicker, longer-lived phosphorylation states for VanSA, proposing them as activators of type A vancomycin resistance in the enterococci.

Natural terpene derivatives as new structural task-specific ionic liquids to enhance the enantiorecognition of acidic enantiomers on teicoplanin-based stationary phase by high-performance liquid chromatography.

We present the specific cooperative effect of a semisynthetic glycopeptide antibiotic teicoplanin and chiral ionic liquids containing the (1R,2S,5R)-(-)-menthol moiety on the chiral recognition of enantiomers of mandelic acid, vanilmandelic acid, and phenyllactic acid. Experiments were performed chromatographically on an Astec Chirobiotic T chiral stationary phase applying the mobile phase with the addition of the chiral ionic liquids. The stereoselective binding of enantiomers to teicoplanin in presence of new chiral ionic liquids were evaluated applying thermodynamic measurements and the docking simulations. Both the experimental and theoretical methods revealed that the chiral recognition of enantiomers in the presence of new chiral ionic liquids was enthalpy driven. The changes of the teicoplanin conformation occurring upon binding of the chiral ionic liquids are responsible for the differences in the standard changes in Gibbs energy (ΔG0 ) values obtained for complexes formed by the R and S enantiomers and teicoplanin. Docking simulations revealed the steric adjustment between the chiral ionic liquids cyclohexane ring (chair conformation) and the β-d-glucosamine ring of teicoplanin and additionally hydrophobic interactions between the decanoic aliphatic chain of teicoplanin and the alkyl group of the tested salts. The obtained terpene derivatives can be considered as "structural task-specific ionic liquids" responsible for enhancing the chiral resolution in synergistic systems with two chiral selectors.

VanA-targeted oligonucleotide DNA probe designed to monitor vancomycin- and teicoplanin-resistant bacteria in surface waters.

The glycopeptide antibiotics teicoplanin and vancomycin are common to treat severe Gram-positive bacterial infections. The gene vanA confers high-level resistance to these antibiotics, and these phenomena have been shown to be transferable. Release of vancomycin- and teicoplanin-resistant bacteria to surface waters is, therefore, of particular concern since they might proliferate and spread in different environments. Monitoring of the fate of vanA gene in these waters provides information on the exposure and potential threats of those bacteria for the environment and public health. Therefore, this study aimed at preparing a 25-mer-oligonucleotide DNA probe based on the 909bp BamHI-ClaI fragment from Enterococcus faecium plasmids pVEF1 and pVEF2 through the use of Vector NTI Express Software. The newly designed vanA probe displayed highly specific hybridization with vanA-positive Enterococcus faecalis tested at 46°C, 55% formamide, and 0.020M NaCl stringency conditions. In situ fluorescein hybridizations under the same stringency conditions were also used to monitor river water samples by using fluorescein microscopy. The results showed that the vanA-targeted oligonucleotide DNA probe prepared was not only highly specific but also quantitative tool for monitoring vancomycin- and teicoplanin-resistant bacteria in surface waters.

Glycopeptide sensitivity patterns in Staphylococci isolated from clinical specimens in a Tertiary Care Hospital

Staphylococci are among the most important and common human pathogens worldwide. Their resistance to antibiotics is increasing. The glycopeptide antibiotics (vancomycin and teicoplanin) are the last resort to treat serious infections caused by these bacteria. During the last decade the strains of staphylococci have developed intermediate levels of resistance to teicoplanin and vancomycin. The objective of this study was to establish the prevalence glycopeptide resistance among clinical isolates of staphylococci in Shaikh Zayed Hospital, Lahore, and comparison of antimicrobial sensitivities of vancomycin and teicoplanin among these isolates. 75 (Seventy five) consecutive staphylococci isolated from clinical specimens received in the laboratory were collected and their sensitivity to antibiotics was tested by National Committee for Clinical Laboratory Standards (NCCLS) disk diffusion method. Results show that all staphylococci were sensitive to the glycopeptide antibiotics. This indicates that no high-level resistance to glycopeptide antibiotics in these organisms is present in our hospital. However, the emerging resistance in staphylococci against these drugs worldwide necessitates strict surveillance of these organisms, institution of effective infection control policies and judicious use of antibiotics.

Characterization of SCO4439, a D-alanyl-D-alanine carboxypeptidase involved in spore cell wall maturation, resistance, and germination in Streptomyces coelicolor.

This work contributes to the understanding of cell wall modifications during sporulation and germination in Streptomyces by assessing the biological function and biochemical properties of SCO4439, a D-alanyl-D-alanine carboxypeptidase (DD-CPase) constitutively expressed during development. SCO4439 harbors a DD-CPase domain and a putative transcriptional regulator domain, separated by a putative transmembrane region. The recombinant protein shows that DD-CPase activity is inhibited by penicillin G. The spores of the SCO4439::Tn5062 mutant are affected in their resistance to heat and acid and showed a dramatic increase in swelling during germination. The mycelium of the SCO4439::Tn5062 mutant is more sensitive to glycopeptide antibiotics (vancomycin and teicoplanin). The DD-CPase domain and the hydrophobic transmembrane region are highly conserved in Streptomyces, and both are essential for complementing the wild type phenotypes in the mutant. A model for the biological mechanism behind the observed phenotypes is proposed, in which SCO4439 DD-CPase releases D-Ala from peptidoglycan (PG) precursors, thereby reducing the substrate pool for PG crosslinking (transpeptidation). PG crosslinking regulates spore physical resistance and germination, and modulates mycelium resistance to glycopeptides. This study is the first demonstration of the role of a DD-CPase in the maturation of the spore cell wall.

Teicoplanin inhibits Ebola pseudovirus infection in cell culture

There is currently no approved antiviral therapy for treatment of Ebola virus disease. To discover readily available approved drugs that can be rapidly repurposed for treatment of Ebola virus infections, we screened 1280 FDA-approved drugs and identified glycopeptide antibiotic teicoplanin inhibiting Ebola pseudovirus infection by blocking virus entry in the low micromolar range. Teicoplanin could be evaluated further and incorporated into ongoing clinical studies.

A few atoms make the difference: Synthetic, CD, NMR and computational studies on antiviral and antibacterial activities of glycopeptide antibiotic aglycon derivatives

Despite the close structural similarity between the heptapeptide cores of the glycopeptide antibiotics teicoplanin and ristocetin, synthetically modified derivatives of their aglycons show significantly different antibacterial and antiviral properties. The teicoplanin aglycon derivatives with one exception proved to be potent antibacterials but they did not exhibit anti-influenza virus activity. In contrast, the aglycoristocetin derivatives generally showed high anti-influenza virus activity and possessed moderate antibacterial activity. A systematic structure-activity relationship study has been carried out on ristocetin and teicoplanin aglycon derivatives, to explore which structural differences are responsible for these markedly different biological activities. According to electronic circular dichroism and in silico conformational studies, it was found that the differences in anti-influenza virus activity are mainly determined by the conformation of the heptapeptide core of the antibiotics controlled by the presence or absence of chloro substituents. Knowledge of the bioactive conformation will help to design new analogs with improved anti-influenza virus activity. For the teicoplanin derivatives, it was shown that derivatization to improve the antiviral efficacy was accompanied by a significant decrease in antibacterial activity.

Affinities and in-plane stress forces between glycopeptide antibiotics and biomimetic bacterial membranes

Understanding the molecular basis of interactions between antibiotics affecting bacterial cell wall biosynthesis and cellular membranes is important in rational drug design of new drugs to overcome resistance. However, a precise understanding of how bacteriostatic antibiotics effect action often neglects the effect of biophysical forces involved following antibiotic-receptor binding events. We have employed a combination of a label-free binding biosensor (surface plasmon resonance, SPR) and a force biosensor (in-plane stress cantilever), together with model membrane systems to study the complex interplay between glycopeptide antibiotics, their cognate ligands and different model membranes. Bacterial cell wall precursor analogue N-α-Docosanoyl-ε-acetyl-Lys-d-Alanine-d-Alanine (doc-KAA) was inserted into lipid layers comprised of zwitterionic or anionic lipids then exposed to either vancomycin or the membrane-anchored glycopeptide antibiotic teicoplanin. Binding affinities and kinetics of the antibiotics to these model membranes were influenced by electrostatic interactions with the different lipid backgrounds, in addition to ligand affinities. In addition, cantilever sensors coated with model membranes showed that planar surface stress changes were induced by glycopeptide antibiotics adsorption and caused compressive surface stress generation in a ligand-dependent manner.

Anaphylactic shock secondary to teicoplanin

SummaryWe describe a case of anaphylactic shock secondary to the glycopeptide antibiotic teicoplanin. A 35‐yr‐old female presented for a urological procedure due to complications following a previous gynaecological procedure. She reported an allergy to co‐amoxiclav and was therefore given teicoplanin as per our hospital protocol. This precipitated profound anaphylactic shock requiring admission to the intensive care unit. Subsequent immunological testing confirmed teicoplanin as the precipitant. Teicoplanin is only rarely associated with anaphylaxis, however it should be considered in patients suffering from a life‐threatening allergy.

Evaluation of heterologous promoters for genetic analysis of Actinoplanes teichomyceticus—Producer of teicoplanin, drug of last defense

Actinoplanes teichomyceticus is the only known producer of the valuable glycopeptide antibiotic teicoplanin. Random mutagenesis and selection were extensively applied to teicoplanin producers, while the gene engineering methods were not used, because of the paucity of genetic tools for A. teichomyceticus. Particularly, availability of promoters of different strength that are functional in Actinoplanes would be very useful for overexpression of beneficial genes. Here we report the use of a glucuronidase reporter system (gusA) for studying transcriptional activity in A. teichomyceticus and describe the behavior of a set of heterologous promoters in this strain. We reveal several elements that exceed in their strength the well-established Streptomyces promoter ermEp, underscoring the utility of the gusA reporter for Actinoplanes sp. Remarkable overproduction of teicoplanin was achieved by constructing strains carrying additional copies of the regulatory gene tcp28 under the control of one of the two most active promoters, moeE5p and actp, discovered in this study.

Asymmetric catalysis at a distance: catalytic, site-selective phosphorylation of teicoplanin.

We report three distinct, peptide-based catalysts that enable site-selective phosphorylation of three distinct hydroxyl groups within the complex glycopeptide antibiotic teicoplanin A2-2. Two of the catalysts are based on a design that capitalizes on a catalyst-substrate interaction that mimics the biological mechanism of action for teicoplanin. These catalysts are based on a DXaa-DXaa peptide motif that is known to target the teicoplanin structure in a specific manner. The third was identified through evaluation of a set of catalysts that had been developed for historically distinct projects. Each catalyst contains additional functionality designed to dispose a catalytic moiety (a nucleophilic alkylimidazole) at a different region of the glycopeptide structure. A combination of mass spectrometry and 2D-NMR spectroscopy allowed structural assignment of the distinct phosphorylated teicoplanin derivatives. Mechanistic studies are also reported that support the hypotheses that led to the discovery of the catalysts. In this manner, small molecule catalysts have been achieved that allow rational, catalytic control over reactions at sites that are separated by 11.6, 16.5, and nearly 17.7 Å, based on the X-ray crystal structure of teicoplanin A2-2. Finally, we report the biological activity of the new phosphorylated teicoplanin analogs and compare the results to the natural product itself.

Profile of urinary tract infections pathogens and their antimicrobial resistance patterns during three-year period (2009-2011) in the Clinical center Kragujevac

Urinary tract infections are common bacterial diseases and also a frequent reason for prescribing antibiotics. Knowledge about the type of pathogens and their resistance patterns may help the clinician to choose the correct treatment. In this study, the prevalence and the resistance pattern of the main bacteria responsible for urinary tract infections of hospitalized patients in Clinical centar Kragujevac was evaluated throughout a tree-year period. Cross-sectional study in the hospital settings was conducted and urine samples were collected from 662 patients with urinary tract infections and tested using standard procedures. The diskdiffusion method on Mueller-Hinton agar according to Clinical and Laboratory Standards Institute guidelines (CLSI) was performed for assessment of antimicrobial susceptibility. The most frequently isolated pathogen were Klebsiella spp. (219 isolates, i.e. 33.1%), Proteus mirabilis (107 isolates, i.e. 16.2%), Enterobacter (86 isolates, i.e. 13%), Escherichia coli (82 isolates, i.e. 12.4%), Pseudomonas aeruginosa (70 isolates, i.e. 10.6%), Enterococcus spp (39 isolates, i.e. 5.9% ) and Proteus vulgaris (38 isolates, i.e. 5.7%). Group of patients older than 65 years was the largest one 426 (64.4%). Gram negative bacteria showed the highest degree of resistance (92.3% - 100%) to penicillins (ampicillin, amoxicillin, amoxicillin + clavulanic acid) and third-generation cephalosporins (cefotaxime, ceftriaxone and ceftazidime) (88.3% - 98, 4%), while Gram positive Enterococcus spp showed the highest degree of resistance to aminoglycosides (gentamicin and amikacin) (96.8% - 100%) and fluoroquinolone ciprofliksacin (100%). The lowest resistance rate of the studied Gram negative pathogens was to carbapenems (imipenem and meropenem) and piperacillin / tazobactam (6.9% - 35.5%), while the lowest level of resistance of gram positive Enterococcus spp was found to glycopeptide antibiotics (vancomycin and teicoplanin) (3.0% - 3.3%). When choosing antibiotics, the pharmacokinetics and pharmacodynamics, renal and liver function, adverse reactions with other drugs, as well as the results of susceptibility testing should be taken into consideration. According to our data, empiric treatment for Klebsiella spp, Proteus mirabilis, Enterobacter, Escherichia coli, Pseudomonas aeruginosa and Proteus vulgaris should include carbapenems or piperacillin / tazobactam, and when it comes to Enterococcus spp, glycopeptide antibiotics are appropriate choice.

Nano-sized clusters of a teicoplanin ψ-aglycon-fullerene conjugate. Synthesis, antibacterial activity and aggregation studies

Glycopeptide antibiotic derivative teicoplanin ψ-aglycone has been bound covalently to a fullerenopyrrolidine derivative using azide-alkyne 1,3-dipolar cycloaddition reaction. The aggregation of the antibiotic-fullerene conjugate in aqueous solution has been studied. The conjugate exhibited antibacterial activity against enterococci resistant to teicoplanin.

A Novel Membrane Protein, VanJ, Conferring Resistance to Teicoplanin

Bacterial resistance to the glycopeptide antibiotic teicoplanin shows some important differences from the closely related compound vancomycin. They are currently poorly understood but may reflect significant differences in the mode of action of each antibiotic. Streptomyces coelicolor possesses a vanRSJKHAX gene cluster that when expressed confers resistance to both vancomycin and teicoplanin. The resistance to vancomycin is mediated by the enzymes encoded by vanKHAX, but not by vanJ. vanHAX effect a reprogramming of peptidoglycan biosynthesis, which is considered to be generic, conferring resistance to all glycopeptide antibiotics. Here, we show that vanKHAX are not in fact required for teicoplanin resistance in S. coelicolor, which instead is mediated solely by vanJ. vanJ is shown to encode a membrane protein oriented with its C-terminal active site exposed to the extracytoplasmic space. VanJ also confers resistance to the teicoplanin-like antibiotics ristocetin and A47934 and to a broad range of semisynthetic teicoplanin derivatives, but not generally to antibiotics or semisynthetic derivatives with vancomycin-like structures. vanJ homologues are found ubiquitously in streptomycetes and include staP from the Streptomyces toyocaensis A47934 biosynthetic gene cluster. While overexpression of staP also conferred resistance to teicoplanin, similar expression of other vanJ homologues (SCO2255, SCO7017, and SAV5946) did not. The vanJ and staP orthologues, therefore, appear to represent a subset of a larger protein family whose members have acquired specialist roles in antibiotic resistance. Future characterization of the divergent enzymatic activity within this new family will contribute to defining the molecular mechanisms important for teicoplanin activity and resistance.

High-performance liquid chromatographic enantioseparation of unusual isoxazoline-fused 2-aminocyclopentanecarboxylic acids on macrocyclic glycopeptide-based chiral stationary phases

The enantiomers of four unusual isoxazoline-fused 2-aminocyclopentanecarboxylic acids were directly separated on chiral stationary phases containing macrocyclic glycopeptide antibiotics teicoplanin (Astec Chirobiotic T and T2), teicoplanin aglycone (Chirobiotic TAG), vancomycin (Chirobiotic V) and vancomycin aglycone (Chirobiotic VAG) as chiral selectors. The effects of the mobile phase composition, the structure of the analytes and temperature on the separations were investigated. Experiments were performed at constant mobile phase compositions in the temperature range 5–45°C to study the effects of temperature, and thermodynamic parameters were calculated from plots of lnk or lnα versus 1/T. Some mechanistic aspects of the chiral recognition process are discussed with respect to the structures of the analytes. It was found that the enantiomeric separations were in most cases enthalpy-driven. The sequence of elution of the enantiomers was determined in all cases.

Linezolid vs Glycopeptide Antibiotics for the Treatment of Suspected Methicillin-Resistant Staphylococcus aureus Nosocomial Pneumonia: A Meta-analysis of Randomized Controlled Trials

Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of nosocomial pneumonia. Societal guidelines suggest linezolid may be the preferred treatment of MRSA nosocomial pneumonia. We investigated the efficacy of linezolid compared with glycopeptide antibiotics (vancomycin or teicoplanin) for nosocomial pneumonia. This was a systematic review and meta-analysis of English language, randomized, controlled trials comparing linezolid to glycopeptide antibiotics for suspected MRSA pneumonia in subjects > 12 years of age. A highly sensitive search of PubMed MEDLINE and Cochrane Central Register of Controlled Trials databases identified relevant studies. Eight trials encompassing 1,641 subjects met entry criteria. Linezolid was not superior to glycopeptide antibiotics for end points of clinical success (relative risk [RR] linezolid vs glycopeptide, 1.04; 95% CI, 0.97-1.11; P = .28), microbiologic success (RR, 1.13; 95% CI, 0.97-1.31; P = .12), or mortality (RR, 0.91; 95% CI, 0.69-1.18; P = .47). In addition, clinical success in the subgroup of subjects with MRSA-positive respiratory tract culture (RR, 1.23; 95% CI, 0.97-1.57; P = .09) was not significantly different from those without MRSA (RR, 0.95; 95% CI, 0.83-1.09; P = .48), P for interaction, 0.07. The risk for adverse events was not different between the two antibiotic classes (RR, 0.96; 95% CI, 0.86-1.07; P = .48). Randomized controlled trials do not support superiority of linezolid over glycopeptide antibiotics for the treatment of nosocomial pneumonia. We recommend that decisions between linezolid or glycopeptide antibiotics for empirical or MRSA-directed therapy of nosocomial pneumonia depend on local availability, antibiotic resistance patterns, preferred routes of delivery, and cost, rather than presumed differences in efficacy.

Structural studies in the biosynthesis of the glycopeptide antibiotic teicoplanin

Teicoplanin is a glycopeptide antibiotic that has proven efficacy against Gram‐positive bacteria and is in clinical trials. It is distinguished from vancomycin‐type glycopeptides antibiotics by side chain modifications, which have been shown to contribute to its improved efficacy and superior pharmacokinetic profile. Our research aims to study the biosynthetic mechanisms of teicoplanin, which will likely lead to the development of new glycopeptide derivatives. Here we present high resolution crystal structures of several enzymes that modify teicoplanin side chains during its biosynthesis. The structures provide insights into the active residues of these enzymes and suggest possible mechanisms of modifying glycopeptides antibiotics.

Development of Microfluidic Chips for Heterogeneous Receptor−Ligand Interaction Studies

A simple microfluidic-based technique to quantitate the binding affinity between the glycopeptide antibiotics teicoplanin from Actinoplanes teicomyceticus and vancomycin from Streptomyces orientalis and 5-carboxyfluorescein-D-Ala-D-Ala-D-Ala (5-FAM-(DA)(3)) is described. In this work, (3-aminopropyl)triethoxysilane is used to modify the surfaces of a series of microchannels, and each channel is subsequently exposed to a solution of antibiotic for a few minutes. The antibiotic is retained after washing through electrostatic interactions, and the series of channels are subsequently exposed to an increasing concentration of 5-FAM-(DA)(3) followed by washing to exclude any nonspecific binding. The extent of fluorescence is quantified using a microscope fitted with a CCD camera. The binding constants for the interaction of teicoplanin and vancomycin with the fluorescent peptide were determined to be 6.03 +/- 0.97 x 10(4) and 4.93 +/- 1.13 x 10(4) M(-1), respectively, in good agreement with previous data. The ease of quantifying the extent of interaction in this microchip technique may prove powerful for exploration of a myriad of receptor-ligand pairs.

Frontal analysis microchip capillary electrophoresis to study the binding of ligands to receptors derivatized on magnetic beads

The model binding of the glycopeptide antibiotic teicoplanin (Teic) from Actinoplanes teichomyceticus, immobilized on magnetic microspheres, to D-Ala-D-Ala terminus peptides was assessed using microchip capillary electrophoresis (MCE) with continuous frontal analysis (FA). Teic is closely related to vancomycin (Van), historically, the drug of last resort used to treat many gram-positive bacterial infections. Glycopeptide antibiotics inhibit bacterial growth by binding to the D-Ala-D-Ala terminus on the cell wall of gram-positive bacteria via hydrogen bonds, thereby preventing the enzyme-mediated cross-linking of peptidoglycan and eventual cell death. In this work direct and competitive bead-based assays in a microfluidic chip are demonstrated. The binding constants obtained using the technique are comparable with values reported in the literature.

Comparison of performance of Chirobiotic T, T2 and TAG columns in the separation of β2‐ and β3‐homoamino acids

The enantiomers of eight unusual beta(2)- and beta(3)-homoamino acids were separated on chiral stationary phases containing the macrocyclic glycopeptide antibiotic teicoplanin (Chirobiotic T or T2) or teicoplanin aglycone (Chirobiotic TAG) as chiral selectors. The effects of the organic modifier, the mobile phase composition, and temperature on the separations were investigated. Linear van't Hoff plots were observed in the studied temperature range, 280-318 K, and the changes in enthalpy, Delta(DeltaH(o)), entropy, Delta(DeltaS(o)), and free energy, Delta(DeltaG(o)) were calculated. The values of the thermodynamic parameters depended on the nature of the selectors, the structures of the analytes, and especially the positions of the substituents on the analytes. A comparison of the separation performances of the macrocyclic glycopeptide stationary phases revealed that the Chirobiotic TAG column exhibited much better selectivity for beta(2)-homoamino acids, while the separation of beta(3)-homoamino acid enantiomers was better on Chirobiotic T or T2. The elution sequence was determined in some cases and was observed to be R < S.