A retrospective analysis to estimate trough concentrations of teicoplanin in patients with suspected or documented Gram-positive infections

Abstract Teicoplanin is a glycopeptide antibiotic commonly used to treat Gram-positive bacterial infections in the clinic. The aim of this study was to provide a therapeutic reference for the clinical application and dosage regimen adjustment of teicoplanin by identifying factors associated with its plasma trough concentration (Ctrough). A retrospective study was performed on patients with suspected or documented Gram-positive infections who were hospitalized from November 2017 to January 2020 and treated with teicoplanin while undergoing routine therapeutic drug monitoring (TDM). A total of 112 Ctrough trough measurements were obtained from 72 patients were included in this study. SPSS software was used for correlation analysis and receiver operator characteristic curve (ROC) analysis. The Ctrough for teicoplanin showed statistically significant relationships (P<0.05) with PLT, Scr, CLcr, eGFR, BUN and Cys-C. ROC curve analysis revealed that CLcr and eGFR were more sensitive and specific for Ctrough compared to the other factors. These findings should be considered in the clinical application of teicoplanin and for its dosage adjustment.

Immunohistochemical localization and pharmacokinetics of the anti-MRSA drug teicoplanin in rat kidney using a newly developed specific antibody.

We prepared a polyclonal antibody against a teicoplanin (TEIC)-bovine serum albumin conjugate that was specific to both conjugated and free forms of TEIC. We demonstrated that this antibody could be used to detect the time-dependent localization of TEIC in rat kidneys. Immunohistochemistry revealed immunoreactivity specifically in the microvilli and apical cytoplasm of epithelial cells in proximal tubule segments S1 and S2, 1 h after intravenous TEIC injection, with higher staining intensity in the S2 segments. The epithelial cells of S3 segments showed moderate immunostaining with a few cells exhibiting nuclear staining. Furthermore, we found that the distal tubules and collecting ducts contained both TEIC-positive and -negative cells. TEIC immunoreactivity decreased rapidly over time; only weak staining remained in the S3 segments, distal tubules, and collecting ducts 24 h after administration. No staining was detected 7 days after injection. These results were significantly different from those of our previous study obtained using vancomycin, which showed moderate staining in the proximal tubule segments S1 and S2, distal tubules, and the collecting ducts 8 days after administration. The lower TEIC accumulation in tissues may account for a lower risk of adverse events compared to that using vancomycin.

LC-HRMS based on mixed-mode chromatography for the separation of teicoplanin and the unravelment of its composition.

Liquid chromatography - high resolution mass spectrometry (LC-HRMS) based on mixed-mode chromatography has proven to be a useful tool in pharmaceutical analysis for the characterization of very polar antibiotics such as teicoplanin. This compound is a semisynthetic glycopeptide antibiotic thought to be a mixture of five major compounds (named A2-1 through A2-5) and four minor ones (RS-1 to RS-4), all sharing the same glycopeptide core structure (dubbed A3-1) and differing only on the length of a hydrocarbon side chain. These nine compounds have been fully characterized in the past thirty years by means of HPLC coupled to UV and MS detectors. However, HPLC separations were all based on octadecylsilica columns (C18), which nowadays may not be the best choice for the chromatographic separation of such polar and charged compounds. In this work, several different chromatographic alternatives are tested for the separation of teicoplanin, including mixed-mode chemistries. It has been demonstrated that a C18-PFP mixed-mode column provides the best chromatographic resolution, furthermore, confirming the existence of several minor compounds in the composition of teicoplanin. Up to fourteen minor components were characterized by means of High-resolution MS/MS and confirmed by the analysis of a commercial teicoplanin product (Targocid®).

Binding modes identification through molecular dynamic simulations: A case study with carnosine enantiomers and the Teicoplanin A2-2-based chiral stationary phase.

In the present study, an in silico methodology able to define the binding modes adopted by carnosine enantiomers in the setting of the chiral recognition process is described. The inter- and intramolecular forces involved in the enantioseparation process with the Teicoplanin A2-2 chiral selector and carnosine as model compound are successfully identified. This approach fully rationalizes, at a molecular level, the (S) < (R) enantiomeric elution order obtained under reversed-phase conditions. Consistent explanations were achieved by managing molecular dynamics results with advanced techniques of data analysis. As a result, the time-dependent identification of all the interactions simultaneously occurring in the chiral selector-enantiomeric analyte binding process was obtained. Accordingly, it was found that only (R)-carnosine is able to engage a stabilizing charge-charge interaction through its ionized imidazole ring with the carboxylate counter-part on the chiral selector. Instead, (S)-carnosine establishes intramolecular contacts between its ionized functional groups, that limit its conformational freedom and impair the association with the chiral selector unit.

Boronate affinity glycosyl molecularly imprinted polymer microspheres for the determination of teicoplanin using ultra-high performance liquid chromatography coupled with tandem mass spectrometry.

Inspired by the fact that antibody recognizes antigen's epitope rather than its whole structure, we selected the glycosyl moiety of teicoplanin as the template, 4-vinylphenylboronic acid and methyl methacrylate as the functional monomers, and divinylbenzene as the cross-linker to synthesis molecularly imprinted polymer microspheres via precipitation co-polymerization. The glycosyl-imprinted microspheres can selectively capture the target glycopeptide antibiotic in aqueous solutions when the pH of surrounding environment is 9.0, and the captured antibiotic can be reversibly released when the pH falls below 4.0 again. This pH-controlled catch-and-release mechanism permits entrapping of glycopeptide antibiotics in slightly basic environments and keeping them entrapped under neutral conditions, and eluting in acidic media. Five teicoplanin components were selectively captured by using the prepared glycosyl-imprinted microspheres as solid-phase extraction adsorbents, and then detected using ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). Finally, the method was thoroughly validated for accuracy and reproducibility by determining teicoplanin in food and biological samples, and achieving quantification limits of 0.1 µg/kg, 0.5 µg/L and 1.0 µg/L for milk, urine and plasma samples, respectively.

Epithelial Lining Fluid and Plasma Concentrations of Dalbavancin in Healthy Adults after a Single 1,500-Milligram Infusion.

Dalbavancin is a lipoglycopeptide antibiotic with a prolonged half-life. A phase 1 study assessed dalbavancin levels in epithelial lining fluid (ELF) in 35 healthy adults using ELF bronchial microsampling up to 168 h after administration of 1,500 mg dalbavancin. The penetration of dalbavancin into ELF was 36%. ELF levels of dalbavancin exceeded the MIC90s of Streptococcus pneumoniae and Staphylococcus aureus for ≥7 days.

Application of an HPLC-MS/MS method for Teicoplanin drug substance and related impurities, part 2: Identity assignment of related impurities.

A liquid chromatographic MS-compatible method was applied to the structural elucidation of Teicoplanin for identification CRS components. The method, previously developed by our group, involves the use of LiChrospher 100 RP-18 column with a mobile phase composed of ammonium formate 25 mM at pH 6.00 and acetonitrile (ACN). All the peaks with a 0.10% UV area, largely above the disregard limit of 0.15% as fixed by EMA, were considered and submitted to MS/MS fragmentation experiments. The study of MS/MS spectrum collected for Teicoplanin complex major component (namely A2-2) allowed to elucidate the fragmentation pathway and enabled the successful identity assignment of all the 42 detected species. Elution order was also rationalized. An in house batch sample of Teicoplanin was analyzed and, while the 86% of the detected species were structurally identical to those in Teicoplanin for identification CRS, five new derivatives were revealed and structurally characterized. In both the Teicoplanin samples, all the considered species were found to have a Teicoplanin-like structure that allows their classification as closely related impurities, with a significant implication in their qualification threshold.

A new MS compatible HPLC-UV method for Teicoplanin drug substance and related impurities, part 1: Development and validation studies.

Teicoplanin is a glycopeptide antibiotic prepared by fermentation from cultures of Actinoplanes teichomyceticus, used as drug of last resort for the treatment of bacterial infections in humans. This study, which is the first in a series of two parts, describes the development of a LC method for the separation of Teicoplanin drug substance and its related impurities compatible with MS detection. The separation conditions for Teicoplanin were set on a LiChrospher 100 RP-18 column under gradient elution with a mobile phase composed of ammonium formate 25 mM at pH 6.00 and ACN. The new method was shown equivalent in terms of selectivity to the one reported in the European Pharmacopoeia Teicoplanin monograph, and was validated according to ICH Q2 R1 guidelines for the drug substance assay. The new method offers similar performance to the compendial one but has the advantage of being fully compatible with MS and it can be proposed as a useful tool also for controlling the quality of Teicoplanin fermentation batches and the occurrence of potential impurities.

About the equivalence between different batches of a glycopeptide drug.

CONTEXT: Teicoplanin is a glycopeptide antibiotic consisting of a combination of different active components. Clinical equivalence between different batches of this drug is not guaranteed by the present pharmacopeial specification of chemical composition based on an HPLC chromatogram. OBJECTIVE: To test a modification of this specification and to evaluate independent compositions recently published in the literature. MATERIALS AND METHODS: The expectable area under the plasma curve of each batch has been estimated based on its chemical composition as described in a former paper. Batch-comparisons are based on ratios between the area of the test batch and the area of a reference. RESULTS AND DISCUSSION: The modification of this specification recently proposed by the European Medicines Agency (EMA) has been tested confirming its goodness. A new acceptance range of AUC variation, rounding -10% to +15%, has been obtained. It is narrower than the current interval of the pharmacopeial specification. Concerning the generic batches that have been studied, the majority of differences with the reference is lower than ±10%. Variations in the compositions of the reference product have been observed to influence the results and a control criteria are proposed. CONCLUSION: The variability of the pharmacokinetic performance of teicoplanin can be better controlled with this new proposal of composition specification given by EMA.

Teicoplanin bonded sub-2 µm superficially porous particles for enantioseparation of native amino acids.

Superficially porous particles (SPPs) demonstrate superior efficiency than totally porous particles in chiral separations. In order to obtain high efficiency and fast separation, sub-2 µm SPPs with high surface area are synthesized, and with teicoplanin bonded, such materials are successfully applied into the rapid enantioseparation of native amino acids. In brief, 1.27 ± 0.06 µm nonporous silica particles are prepared by a modified seeded growth method, followed by mesoporous shell fabrication via one-pot templated dissolution and redeposition strategy, and pore size expansion via acid-refluxing. The diameter of the formed SPPs is 1.49 ± 0.04 µm, with the shell thickness as 206 nm. Nitrogen physisorption experiments show that the Brunauer-Emmett-Teller (BET) specific surface area is 213.6 m(2)/g and pore size is 9 nm. After teicoplanin derivatization with bonding capacity as 83.3 µmol/g, the prepared chiral stationary phase is packed into a stainless steel tube with the geometry of 50 mm × 2.1 mm i.d.. In less than 6.4 min, six native amino acids (norleucine, alanine, valine, methionine, leucine, norvaline) are enantioseparated with resolution factors ranging from 1.9 to 5.0. Besides, the resolution for chiral separation is improved with ethanol-water instead of methanol-water as the mobile phase. Moreover, the low temperature gives higher resolution, but longer retention time and higher backpressure. Finally, the effect of flow rate on enantiomeric separation is studied and fast chiral separation within 1 min is obtained with flow rate of 0.4 mL/min. All these results show that the synthesized teicoplanin bonded sub-2 µm SPPs have great potential to achieve the enantioseparation of native amino acids with high resolution and rapid speed.

Development of a Fourier transform infrared spectroscopy coupled to UV-Visible analysis technique for aminosides and glycopeptides quantitation in antibiotic locks.

Antibiotic Lock technique maintains catheters' sterility in high-risk patients with long-term parenteral nutrition. In our institution, vancomycin, teicoplanin, amikacin and gentamicin locks are prepared in the pharmaceutical department. In order to insure patient safety and to comply to regulatory requirements, antibiotic locks are submitted to qualitative and quantitative assays prior to their release. The aim of this study was to develop an alternative quantitation technique for each of these 4 antibiotics, using a Fourier transform infrared (FTIR) coupled to UV-Visible spectroscopy and to compare results to HPLC or Immunochemistry assays. Prevalidation studies permitted to assess spectroscopic conditions used for antibiotic locks quantitation: FTIR/UV combinations were used for amikacin (1091-1115cm(-1) and 208-224nm), vancomycin (1222-1240cm(-1) and 276-280nm), and teicoplanin (1226-1230cm(-1) and 278-282nm). Gentamicin was quantified with FTIR only (1045-1169cm(-1) and 2715-2850cm(-1)) due to interferences in UV domain of parabens, preservatives present in the commercial brand used to prepare locks. For all AL, the method was linear (R(2)=0.996 to 0.999), accurate, repeatable (intraday RSD%: from 2.9 to 7.1% and inter-days RSD%: 2.9 to 5.1%) and precise. Compared to the reference methods, the FTIR/UV method appeared tightly correlated (Pearson factor: 97.4 to 99.9%) and did not show significant difference in recovery determinations. We developed a new simple reliable analysis technique for antibiotics quantitation in locks using an original association of FTIR and UV analysis, allowing a short time analysis to identify and quantify the studied antibiotics.

Enantioseparations by high-performance liquid chromatography using macrocyclic glycopeptide-based chiral stationary phases: an overview.

Since their introduction by Armstrong in 1994, macrocyclic antibiotic-based chiral stationary phases have proven their applicability for the chiral resolution of various types of racemates. The unique structure of macrocyclic glycopeptides and their large variety of interactive sites (e.g., hydrophobic pockets, hydroxyl, amino and carboxyl groups, halogen atoms, aromatic moieties, etc.) are the reason for their wide-ranging selectivity. The commercially available Chirobiotic™ phases, which display complementary characteristics, are capable of separating a broad variety of enantiomeric compounds with good efficiency, good column loadability, high reproducibility, and long-term stability. These are the major reasons for the use of macrocyclic antibiotic-based stationary phases in HPLC enantioseparations. This overview chapter provides a brief summary of general aspects of macrocyclic antibiotic-based chiral stationary phases including their preparation and their application to direct enantioseparations of various racemates focusing on the literature published since 2004.

Actividad de vancomicina, teicoplanina y linezolid en Staphylococcus coagulasanegativos resistentes a meticilina en aislados de hemocultivos pediátricos / Activity of vancomycin, teicoplanin and linezolid in methicillin resistant coagulase-negative Staphylococci isolates from paediatric blood cultures

Introducción. Los Staphylococcus coagulasa negativos (ECN) son la principal causa de bacteriemia y sepsis en los recién nacidos. La resistencia meticilina y la pérdida de sensibilidad a glucopéptidos dificultan considerablemente el tratamiento antimicrobiano en infecciones por cocos grampositivos. Objetivos. Estudiar la CMI para vancomicina, teicoplanina y linezolid en diferentes especies de ECN meticilín resistentes aislados en hemocultivos procedentes de pacientes pediátricos. Métodos. Analizar los ECN resistentes a meticilina y clínicamente significativos, procedentes de hemocultivos de pacientes ingresados en diferentes Áreas del Servicio de Pediatría. Los aislamientos se identificaron mediante pruebas bioquímicas contenidas en los paneles Combo 31 de MicroScan (Dade Behring Siemens). La resistencia a oxacilina y la susceptibilidad frente a vancomicina, teicoplanina y linezolid se realizó mediante microdilución en placa contenida en los mismos paneles. Además se realizó Etest para teicoplanina y linezolid. Resultados. Se aislaron 50 cepas resistentes a meticilina: 37 (74%) S. epidermidis, 7 (14%) S. hominis, 4 (8%) S. haemolyticus y 2 (4%) Staphylococcus spp. Se observaron 26 cepas con sensibilidad disminuida para vancomicina, CMI de 2 mg/L, (22 S. epidermidis, 2 S. haemolyticus y 2 Staphylococcus spp.) y 21 cepas con disminución de sensibilidad a teicoplanina, CMI de 4-16 mg/L (20 S. epidermidis y 1 S. haemolyticus). Ningún ECN fue resistente a linezolid. Conclusiones. Existe una relación entre el aumento de CMI de vancomicina y el aumento de CMI de teicoplanina. Se observa una elevación estadísticamente significativa (p<0,001) en la CMI de teicoplanina en el grupo de vancomicina de 2 mg/L con respecto al grupo de vancomicina de ≤1 mg/L. Se observaron niveles muy bajos de CMI para linezolid en todas las cepas(AU)

Introduction. Coagulase-negative-Staphylococci (CNS) are the major cause of bacteraemia and sepsis in newborns. CNS methicillin resistance and its loss of sensitivity to glycopeptide antibiotics, make treatment significantly more difficult in positive cocci infections. Objective. To study MIC vancomycin, teicoplanin and linezolid in different species of CNS methicillin resistant isolates from blood cultures from paediatric patients. Methods. Clinically relevant CNS methicillin resistant isolates from paediatric blood cultures from different hospitalization wards were tested. The isolates were identified by biochemical tests by means in the Combo panels 31 of MicroScan (Dade Behring, Siemens). Resistance to oxacillin and susceptibility to vancomycin, teicoplanin and linezolid were tested by microdilution panels as cited above. We also tested teicoplanin and linezolid sensitivity using Etest. Results. 50 methicillin resistant strains were isolated: 37 (74%) S. epidermidis, 7 (14%) S. hominis, 4 (8%) S. haemolyticus and 2 (4%) Staphylococcus spp. 26 strains were observed with reduced susceptibility to vancomycin MIC = 2 mg/L, (22 S. epidermidis, 2 S. haemolyticus and 2 Staphylococcus spp.) and 21 strains with loss of susceptibility to teicoplanin, MIC = 4-16 mg/L (20 S. epidermidis and 1 S. haemolyticus). No CNS linezolid resistant was found. Conclusions. There is a linear correlation between increased vancomycin MIC and teicoplanin MIC. There is a statistically significant difference (p <0.001) in the MIC of teicoplanin in the vancomycin group = 2 mg/L with respect to the vancomycin group ≤ 1 mg/L. We also observed very low levels of linezolid MIC for all strains(AU)

Comparison of teicoplanin disk diffusion and broth microdilution methods against clinical isolates of Staphylococcus aureus and S. epidermidis

The CLSI M100-S19 document has recommended the disuse of vancomycin disks for staphylococci and informed that studies on the action of teicoplanin in disk-diffusion testing should be performed. We describe the comparison of two methods, disk diffusion and broth microdilution, for determining teicoplanin susceptibility in clinical isolates of staphylococci. Overall results showed an aggregation rate of 96.8 percent; Staphylococcus aureus showed total agreement while S. epidermidis showed 93.8 percent of agreement. According to these local results, disk diffusion can still be employed to teicoplanin susceptibility determination for staphylococci in our institution.

A microfluidic chip platform with electrochemical carbon nanotube electrodes for pre-clinical evaluation of antibiotics nanocapsules.

This paper presents a microfluidic chip platform with electrochemical carbon nanotube electrodes for preclinical evaluation of antibiotics nanocapsules. Currently, there has been an increasing interest in the development of nanocapsules for drug delivery applications for localized treatments of diseases. So far, the methods to detect antibiotics are liquid chromatography (LC), high performance liquid chromatography (HPLC), mass spectroscopy (MS). These conventional instruments are bulky, expensive, not ease of access, and talented operator required. In order to help the development of nanocapsules and understand drug release profile before planning the clinical experiments, it is important to set up a biosensing platform which could monitor and evaluate the real-time drug release profile of nanocapsules with high sensitivity and long-term measurement ability. In this work, a microfluidic chip platform with electrochemical carbon nanotube electrodes has been developed and characterized for rapid detection of antibiotics teicoplanin nanocapsules. Multi-walled carbon nanotubes are used to modify the gold electrode surfaces to enhance the performance of the electrochemical biosensors. Experimental results show that the limit of detection of the developed platform using carbon nanotubes electrodes is 0.1 µg/ml with a linear range from 1 µg/ml to 10 µg/ml. The sensitivity of the developed system is 0.023 mA ml/µg at 37°C. The drug release profile of teicoplanin nanocapsules in PBS shows that the antibiotics nanocapsules significantly increased the release of drug on the 4th day, measuring 0.4858 µg/(ml hr). The release of drug from the antibiotics nanocapsules reached 34.98 µg/ml on the 7th day. The results showed a similar trend compared with the measurement result using the HPLC instrument. Compared with the traditional HPLC measurements, the electrochemical sensing platform we developed measures results with increased flexibility in controlling experimental factors for long-term preclinical measurement of nanocapsules in real time and at low cost.

Analyses of teicoplanin concentrations from 1994 to 2006 from a UK assay service.

Objectives An analysis of the trough serum concentrations sent to the UK Antimicrobial Reference Laboratory for teicoplanin therapeutic drug monitoring (TDM). Methods All trough concentrations over a 13 year period were analysed and the percentages were calculated for the following: <10 mg/L (a sub-optimal concentration for all); ≥10-<20 mg/L (the target used for ordinary Gram-positive infections); ≥20-<60 mg/L (the target for all severe staphylococcal infections including endocarditis); and ≥60 mg/L (the concentration associated with toxicity). Results The percentage of patients with concentrations of <10 mg/L decreased each year to 13% in 2006. Almost 40% of the samples each year were in the ≥10-<20 mg/L range. In 1996, the percentage of samples in the ≥20-<60 mg/L range reached a study high of ∼70%. That percentage then fell to 30% and increased slowly to 50% at the end of the study. Fewer than 5% of the samples were ≥60 mg/L. Conclusions Our study shows that there is a need to increase the initial dose or extend the number of days that the loading dose is used in a significant number of patients. With such a wide optimal range and a low potential for toxicity, it is unclear why optimal therapy is not achieved in a higher percentage of patients.

Direct fluorescence polarization assay for the detection of glycopeptide antibiotics.

Glycopeptide antibiotics are widely used in the treatment of infections caused by Gram-positive bacteria. They inhibit the biosynthesis of the bacterial cell wall through binding to the D-alanyl-D-alanine (D-Ala-D-Ala) terminal peptide of the peptidoglycan precursor. Taking advantage of this highly specific interaction, we developed a direct fluorescence polarization based method for the detection of glycopeptide antibiotics. Briefly, we labeled the acetylated tripeptide Ac-L-Lys-D-Ala-D-Ala-OH with a fluorophore to create a peptide probe. Using three glycopeptide antibiotics, vancomycin, teicoplanin, and telavancin, as model compounds, we demonstrated that the fluorescence polarization of the peptide probe increased upon binding to antibiotics in a concentration dependent manner. The dissociation constants (K(d)) between the peptide probes and the antibiotics were consistent with those reported between free d-Ala-d-Ala and the antibiotics in the literature. The assay is highly reproducible and selective toward glycopeptide antibiotics. Its detection limit and work concentration range are 0.5 microM and 0.5-4 microM for vancomycin, 0.25 microM and 0.25-2 microM for teicoplanin, and 1 microM and 1-8 microM for telavancin. Furthermore, we compared our assay in parallel with a commercial fluorescence polarization immunoassay (FPIA) kit in detecting teicoplanin spiked in human blood samples. The accuracy and precision of the two methods are comparable. We expect our assay to be useful in both research and clinical laboratories.

Absence of intestinal colonization by vancomycin-resistant enterococci in nonhuman primate / Ausência de enterococos resistentes à vancomicina na microbiota intestinal de primatas não-humanos

The animal reservoirs of vancomycin-resistant enterococci (VRE) have important role in the epidemiology of the bacteria and resistant genes. The present work searched fecal samples taken off nonhuman primates for the presence of VRE. Resistance profiles, virulence traits, and genetic variability among enterococci isolates were also analyzed. The samples included Capuchin monkeys (Cebus apella, n=28) and Common marmoset (Callithrix penicillata, n=37) housed in the Primate Center of the University of Brasília, Brazil. Most individuals were captive monkeys from the Central-West and South-East regions of Brazil (n=48). We collected rectal swabs and carried out selective isolation followed by multiplex Polymerase Chain Reaction (PCR) to identify species and resistance genes. No vanA or vanB-containing enterococci were found. The carriage rates ranged from 1.5 percent for the VanC-type E. casseliflavus and E. gallinarum until 12.3 percent (n=8) for Enterococcus faecalis. All E. faecalis isolates showed susceptibility to vancomycin, teicoplanin, ampicillin, gentamicin, and streptomycin. The virulence genes ace and esp were prevalent (100.0 percent, 87.5 percent). Multilocus variable number of tandem repeats (MLVA) revealed diversity in the number of repeats among E. faecalis isolates and targets, which was higher for espC, efa5, and efa6. We identified six different MLVA genotypes that were divergent from those described in human beings. Also, they were clustered into two genogroups that showed host-specificity for the species Cebus apella or Callithrix penicillata. In conclusion, no vanA- or vanB-containing enterococci were found colonizing those primate individuals. This finding suggested that the primate individuals investigated in our study are not directly involved in the epidemiological chain of high-level vancomycin-resistant genes vanA or vanB in Brazil. Our study also showed that E. faecalis isolated from nonhuman primates carry virulence...

Os reservatórios animais de Enterococos Resistentes à Vancomicina (VRE) têm um importante papel na epidemiologia destas bactérias e dos respectivos genes de resistência. O presente estudo examinou a presença de VRE em amostras fecais obtidas de primatas não-humanos. Foram analisados os perfis de resistência, as características de virulência e a variabilidade genética dos isolados. A amostragem incluiu macacos Prego (Cebus apella, n=28) e Sagüis do cerrado (Callithrix penicillata, n=37) alojados no Centro de Primatologia da Universidade de Brasília, Brasil. A maioria dos indivíduos amostrados foram macacos apreendidos na região Centro-Oeste e Sudeste do Brasil (n=48). Assim, foram coletados swabs retais e realizado o isolamento seletivo, seguido da Reação de Polimerização em Cadeia (PCR) multiplex para identificar espécies e genes de resistência. Não foram isolados enterococos contendo os genes vanA ou vanB. A porcentagem de enterococos variou de 1,5 por cento para E. casseliflavus e E. gallinarum VanC até 12,3 por cento (n=8) para Enterococcus faecalis. A totalidade dos isolados da espécie E. faecalis demonstrou sensibilidade aos antimicrobianos vancomicina, teicoplanina, ampicilina, gentamicina e estreptomicina. Os genes de virulência ace e esp foram prevalentes (100 por cento, 87.5 por cento). A análise em multilocus de repetições em tandem de número variável (MLVA) revelou diversidade no número de repetições entre os isolados de E. faecalis, que foi mais alta para espC, efa5 e efa6. Foram identificados seis diferentes genotipos de MVLA, divergindo daqueles já descritos em humanos. Os genotipos foram ainda agrupados em dois genogrupos, demonstrando especificidade de hospedeiro para as espécies Cebus apella ou Callithrix penicillata. Concluindo, não foram isoladas linhagens de enterococos contendo os genes vanA ou vanB colonizando as espécies de primatas analisadas. O presente estudo demonstrou que os isolados de E. faecalis obtidos...

Enantioanalysis of (-)butaclamol using vancomycin and teicoplanin as chiral selectors.

Butaclamol is an antipsychotic drug used in the treatment of schizophrenia. The macrocyclic antibiotics, vancomycin and teicoplanin, are proposed as chiral selectors for the design of the enantioselective, potentiometric membrane electrodes (EPMEs) for the assay of (-)butaclamol. The slopes of the electrodes are near-Nernstian for the assay of (-) butaclamol with linear concentration ranges between 10(-10) and 10(-7) mol/L and between 10(-9) and 10(-7) mol/L for vancomycin and teicoplanin based EPMEs. Limits of detections varied. The electrodes were used reliably for the enantioanalysis of (-) butaclamol in serum samples.

Microchip frontal affinity chromatography to study the binding of a ligand to teicoplanin-derivatized microbeads.

Microchip frontal affinity chromatography was demonstrated to estimate the binding of 5-carboxyfluorescin-(D-Ala)(3) (1) to magnetic microbeads derivatized with teicoplanin (Teic) from Actinoplanes teicomyceticus. In this technique, a cross-chip was used whereby the two side channels contained an identical length (1.5 mm) of derivatized Teic microbeads (affinity column) and underivatized beads (control column), respectively. Cylindrical NdFeB magnets were fabricated into the PDMS chips to retain the magnetic beads. Upon application of a voltage, a sample of 1 was continuously introduced into the affinity column followed by a buffer wash and the same sample from the control channel. The extent of interaction between 1 and the two types of beads in either microchannel resulted in differences in migration time of the ligand as detected by fluorescence. This difference was used to obtain a value for the binding constant between 1 and Teic-beads of 5.4 x 10(4) M(-1). This technique reduces the amount of sample needed for the binding assay as compared with conventional frontal affinity chromatography techniques.