Preparation and characterization of inactivated tick-borne encephalitis virus samples for single-particle imaging at the European XFEL

X-ray imaging of virus particles at the European XFEL could eventually allow their complete structures to be solved, potentially approaching the resolution of other structural virology methods. To achieve this ambitious goal with today's technologies, about 1 ml of purified virus suspension containing at least 1012 particles per millilitre is required. Such large amounts of concentrated suspension have never before been obtained for enveloped viruses. Tick-borne encephalitis virus (TBEV) represents an attractive model system for the development of enveloped virus purification and concentration protocols, given the availability of large amounts of inactivated virus material provided by vaccine-manufacturing facilities. Here, the development of a TBEV vaccine purification and concentration scheme is presented combined with a quality-control protocol that allows substantial amounts of highly concentrated non-aggregated suspension to be obtained. Preliminary single-particle imaging experiments were performed for this sample at the European XFEL, showing distinct diffraction patterns.

Evidence for effect of l-serine, a novel therapy for GRIN2B-related neurodevelopmental disorder

RATIONALE

To date, causal therapy is potentially available for GRIN2B-related neurodevelopmental disorder (NDD) due to loss-of-function (LoF) variants in GRIN2B, resulting in dysfunction of the GluN2B subunit-containing N-methyl-d-aspartate receptor (NMDAR). Recently, in vitro experiments showed that high doses of NMDAR co-agonist d-serine has the potential to boost the activity in GluN2B LoF variant-containing NMDARs. Initial reports of GRIN2B-NDD patients LoF variants, treated with l-serine using different regimens, showed varying effects on motor and cognitive performance, communication, behavior and EEG. Here, this novel treatment using a standardized protocol with an innovative developmental outcome measure is explored further in an open-label observational GRIN2B-NDD study.

METHODS

Initially, in vitro studies were conducted in order to functionally stratify two de novo GRIN2B variants present in two female patients (18 months and 4 years old). Functional studies showed that both variants are LoF, and thus the patients were treated experimentally according to an approved protocol with oral l-serine (500 mg/kg/day in 4 doses) for a period of 12 months. Both patients showed a heterogeneous clinical phenotype, however overlapping symptoms were present: intellectual developmental disability (IDD), behavioral abnormalities and hypotonia. Outcome measures included laboratory tests, quality of life, sleep, irritability, stool, and performance skills, measured by, among others, the Perceive-Recall-Plan-Perform System of Task Analysis (PRPP-Assessment).

RESULTS

Both patients tolerated l-serine without adverse effects. In one patient, improvement in psychomotor development and cognitive functioning was observed after 12 months (PRPP mastery score 10% at baseline, 78% at twelve months). In the most severe clinically affected patient no significant objective improvement in validated outcomes was observed. Caregivers of both patients reported subjective increase of alertness and improved communication skills.

CONCLUSION

Our observational study confirms that l-serine supplementation is safe in patients with GRIN2B-NDD associated with LoF variants, and may accelerate psychomotor development and ameliorate cognitive performance in some but not all patients. The PRPP-Assessment, a promising instrument to evaluate everyday activities and enhance personalized and value-based care, was not performed in the severely affected patient, meaning that possible positive results may have been missed. To generate stronger evidence for effect of l-serine in GRIN2B-NDD, we will perform placebo-controlled n-of-1 trials.

Development of DNA Aptamers for Visualization of Glial Brain Tumors and Detection of Circulating Tumor Cells

Here, we present DNA aptamers capable of specific binding to glial tumor cells in vitro, ex vivo, and in vivo for visualization diagnostics of central nervous system tumors. We selected the aptamers binding specifically to the postoperative human glial primary tumors and not to the healthy brain cells and meningioma, using a modified process of systematic evolution of ligands by exponential enrichment to cells; sequenced and analyzed ssDNA pools using bioinformatic tools and identified the best aptamers by their binding abilities; determined three-dimensional structures of lead aptamers (Gli-55 and Gli-233) with small-angle X-ray scattering and molecular modeling; isolated and identified molecular target proteins of the aptamers by mass spectrometry; the potential binding sites of Gli-233 to the target protein and the role of post-translational modifications were verified by molecular dynamics simulations. The anti-glioma aptamers Gli-233 and Gli-55 were used to detect circulating tumor cells in liquid biopsies. These aptamers were used for in situ, ex vivo tissue staining, histopathological analyses, and fluorescence-guided tumor and PET/CT tumor visualization in mice with xenotransplanted human astrocytoma. The aptamers did not show in vivo toxicity in the preclinical animal study. This study demonstrates the potential applications of aptamers for precise diagnostics and fluorescence-guided surgery of brain tumors.

Cohort profile: the ESC EURObservational Research Programme Non-ST-segment elevation myocardial infraction (NSTEMI) Registry

AIMS

The European Society of Cardiology (ESC) EURObservational Research Programme (EORP) Non-ST-segment elevation myocardial infarction (NSTEMI) Registry aims to identify international patterns in NSTEMI management in clinical practice and outcomes against the 2015 ESC Guidelines for the management of acute coronary syndromes in patients presenting without ST-segment-elevation.

METHODS AND RESULTS

Consecutively hospitalised adult NSTEMI patients (n = 3620) were enrolled between 11 March 2019 and 6 March 2021, and individual patient data prospectively collected at 287 centres in 59 participating countries during a two-week enrolment period per centre. The registry collected data relating to baseline characteristics, major outcomes (in-hospital death, acute heart failure, cardiogenic shock, bleeding, stroke/transient ischaemic attack, and 30-day mortality) and guideline-recommended NSTEMI care interventions: electrocardiogram pre- or in-hospital, pre-hospitalization receipt of aspirin, echocardiography, coronary angiography, referral to cardiac rehabilitation, smoking cessation advice, dietary advice, and prescription on discharge of aspirin, P2Y12 inhibition, angiotensin converting enzyme inhibitor (ACEi)/angiotensin receptor blocker (ARB), beta-blocker, and statin.

CONCLUSION

The EORP NSTEMI Registry is an international, prospective registry of care and outcomes of patients treated for NSTEMI, which will provide unique insights into the contemporary management of hospitalised NSTEMI patients, compliance with ESC 2015 NSTEMI Guidelines, and identify potential barriers to optimal management of this common clinical presentation associated with significant morbidity and mortality.

Structure- and Interaction-Based Design of Anti-SARS-CoV-2 Aptamers

Aptamer selection against novel infections is a complicated and time-consuming approach. Synergy can be achieved by using computational methods together with experimental procedures. This study aims to develop a reliable methodology for a rational aptamer in silico et vitro design. The new approach combines multiple steps: (1) Molecular design, based on screening in a DNA aptamer library and directed mutagenesis to fit the protein tertiary structure; (2) 3D molecular modeling of the target; (3) Molecular docking of an aptamer with the protein; (4) Molecular dynamics (MD) simulations of the complexes; (5) Quantum-mechanical (QM) evaluation of the interactions between aptamer and target with further analysis; (6) Experimental verification at each cycle for structure and binding affinity by using small-angle X-ray scattering, cytometry, and fluorescence polarization. By using a new iterative design procedure, structure- and interaction-based drug design (SIBDD), a highly specific aptamer to the receptor-binding domain of the SARS-CoV-2 spike protein, was developed and validated. The SIBDD approach enhances speed of the high-affinity aptamers development from scratch, using a target protein structure. The method could be used to improve existing aptamers for stronger binding. This approach brings to an advanced level the development of novel affinity probes, functional nucleic acids. It offers a blueprint for the straightforward design of targeting molecules for new pathogen agents and emerging variants.

MINIMALLY INVASIVE TREATMENT OF ABDOMINAL LYMPHOCELE: A REVIEW OF CONTEMPORARY OPTIONS AND HOW TO APPROACH THEM

Lymphoceles are lymphatic fluid collections resulting from lymphatic vessel disruption after surgery or trauma. They are most often described following retroperitoneal surgeries such as cystectomies, prostatectomies, renal transplants, and gynecologic surgeries. Most lymphoceles are asymptomatic and resolve spontaneously without treatment. If persistent, they can become infected or exert mass effect on adjacent structures causing pain, urinary, or lower limb edema particularly for lymphoceles in the pelvis Symptomatic lymphoceles should be treated to relieve symptoms and prevent functional compromise of vital adjacent structures. Although surgery has been traditionally accepted as the gold standard treatment, advances in imaging and interventional technology allow for less invasive, percutaneous treatment. Available minimally invasive treatment options include percutaneous aspiration, catheter drainage, sclerotherapy, and lymphangiography with lymphatic embolization. A review of these treatment options and a suggested algorithm for managing lymphoceles is presented.

Cellulose-Based Hydrogels and Aerogels Embedded with Silver Nanoparticles: Preparation and Characterization

The paper presents the preparation and characterization of novel composite materials based on microcrystalline cellulose (MCC) with silver nanoparticles (Ag NPs) in powder and gel forms. We use a promising synthetic conception to form the novel composite biomaterials. At first MCC was modified with colloidal solution of Ag NPs in isopropyl alcohol prepared via metal vapor synthesis. Then Ag-containing MCC powder was used as precursor for further preparation of the gels. The hydrogels were prepared by dissolving pristine MCC and MCC-based composite at low temperatures in aqueous alkali solution and gelation at elevated temperature. To prepare aerogels the drying in supercritical carbon dioxide was implemented. The as-prepared cellulose composites were characterized in terms of morphology, structure, and phase composition. Since many functional properties, including biological activity, in metal-composites are determined by the nature of the metal-to-polymer matrix interaction, the electronic state of the metal was carefully studied. The studied cellulose-based materials containing biologically active Ag NPs may be of interest for use as wound healing or water-purification materials.

Minimally invasive treatment of abdominal lymphocele: A review of contemporary options and how to approach them

Lymphoceles are lymphatic fluid collections resulting from lymphatic vessel disruption after surgery or trauma. They are most often described following retroperitoneal surgeries such as cystectomies, prostatectomies, renal transplants, and gynecologic surgeries. Most lymphoceles are asymptomatic and resolve spontaneously without treatment. If persistent, they can become infected or exert mass effect on adjacent structures causing pain, urinary, or lower limb edema particularly for lymphoceles in the pelvis Symptomatic lymphoceles should be treated to relieve symptoms and prevent functional compromise of vital adjacent structures. Although surgery has been traditionally accepted as the gold standard treatment, advances in imaging and interventional technology allow for less invasive, percutaneous treatment. Available minimally invasive treatment options include percutaneous aspiration, catheter drainage, sclerotherapy, and lymphangiography with lymphatic embolization. A review of these treatment options and a suggested algorithm for managing lymphoceles is presented.

Life cycle assessment of sludge management with phosphorus utilisation and improved hygienisation in Sweden

To provide input to sewage sludge management strategies that address expected new regulations in terms of hygienisation and phosphorus recovery in Sweden, an environmental life cycle assessment (LCA) was made. The LCA identified environmental hot spots for methods that may permit sludge or phosphorus from sludge to be applied on agricultural land. In particular, thermophilic digestion, pasteurisation, thermal hydrolysis, urea treatment and mono-incineration with phosphorus recovery were compared. In addition, a sludge management system involving drying of sludge before use in forestry was investigated. The results showed that some major impacts are related to large uncertainties, such as those related to emissions from sludge storage. It also showed that large gains can be achieved when products from the systems replace other products, in particular when biogas is used to replace natural gas in vehicles, but also when sludge is used in agriculture and forestry. In general, there are small differences between the sludge management methods. Retaining the sludge matrix to allow for its utilisation in agriculture may conflict with keeping emissions to air and water from the sludge matrix low. It is recommended that any sludge management option minimises emissions from sludge to air and water and that resources are recovered and used, in line with the principles of a circular economy.

A Genetic Method To Evaluate the Prevalence of Unique DNA Profiles between Sequential Ground Beef Batches

The delineation of ground beef batches has implications for the management of product disposition policies in the event of Shiga toxin-producing Escherichia coli contamination. Analysis of individual contributor animal-specific DNA profiles can provide valuable empirical data for understanding the dynamics of ground meat production processes and can act as a surrogate for cross-contamination. A genetic method was developed for characterizing the source raw material flow and carryover between discrete batches of ground beef in a large-scale commercial beef grinding operation. The application developed involves the introduction of a genetically distinct source raw material batch into the grinding system and comprehensive sampling of that index batch and subsequent batches followed by single nucleotide polymorphism genotyping of random subsamples. Capture-mark-recapture statistical techniques were used to estimate (i) the number of carcass contributors and (ii) the associated level of carryover between batches. Carryover, expressed as a percentage of the total weight of the batch material (in pounds), was observed between the genetically distinct index batch and the next sequential batch at approximately 1%. The nondetection of additional carryover to subsequent batches, with a detection level of approximately 0.2%, supports a serial dilution model of same source raw material carryover, consistent with the recorded weight of beef trimmings used in each batch. For ground beef manufacturers, this method is a simple approach for validating the independence of finished batches of beef in their grind systems in support of product disposition policies.

Thermally induced conformational changes and protein–protein interactions of bovine serum albumin in aqueous solution under different pH and ionic strengths as revealed by SAXS measurements

Temperature-induced oligomerization of albumin before and after protein melting was studied using SAXS and interpreted in terms of interaction potential.

Post-invasion events after infection with Staphylococcus aureus are strongly dependent on both the host cell type and the infecting S. aureus strain

Host cell invasion is a major feature of Staphylococcus aureus and contributes to infection development. The intracellular metabolically active bacteria can induce host cell activation and death but they can also persist for long time periods. In this study a comparative analysis was performed of different well-characterized S. aureus strains in their interaction with a variety of host cell types. Staphylococcus aureus (strains 6850, USA300, LS1, SH1000, Cowan1) invasion was compared in different human cell types (epithelial and endothelial cells, keratinocytes, fibroblasts, osteoblasts). The number of intracellular bacteria was determined, cell inflammation was investigated, as well as cell death and phagosomal escape of bacteria. To explain strain-dependent differences in the secretome, a proteomic approach was used. Barrier cells took up high amounts of bacteria and were killed by aggressive strains. These strains expressed high levels of toxins, and possessed the ability to escape from phagolysosomes. Osteoblasts and keratinocytes ingested less bacteria, and were not killed, even though the primary osteoblasts were strongly activated by S. aureus. In all cell types S. aureus was able to persist. Strong differences in uptake, cytotoxicity, and inflammatory response were observed between primary cells and their corresponding cell lines, demonstrating that cell lines reflect only partially the functions and physiology of primary cells. This study provides a contribution for a better understanding of the pathomechanisms of S. aureus infections. The proteomic data provide important basic knowledge on strains commonly used in the analysis of S. aureus-host cell interaction.

Unveiling the molecular basis of antimicrobial resistance in Staphylococcus aureus from the Democratic Republic of the Congo using whole genome sequencing

Staphylococcus aureus from sub-Saharan Africa is frequently resistant to antimicrobial agents that are commonly used to treat invasive infections in resource-limited settings. The underlying mechanisms of resistance are largely unknown. We therefore performed whole genome sequencing (WGS) on S. aureus from the Democratic Republic of the Congo (DRC) to analyse the genetic determinants of antimicrobial resistance. One hundred S. aureus samples were collected from community-associated asymptomatic nasal carriers in the metropolitan area of Kinshasa, DRC, between 2013 and 2014. Phenotypic resistance against 15 antimicrobial agents was compared to the genotypic results that were extracted from WGS data using Mykrobe predictor and the SeqSphere(+) software that screened for 106 target genes associated with resistance. Isolates were phenotypically resistant against penicillin (97%, n=97), trimethoprim (72%, n=72) and tetracycline (54%, n=45). Thirty-three isolates (33%) were methicillin-resistant S. aureus (MRSA). Of these, nine isolates (27.3%) were oxacillin-susceptible MRSA (OS-MRSA) and belonged to ST8 (t1476). The Y195F mutation of FemA was associated with OS-MRSA (p 0.015). The majority of trimethoprim resistant isolates carried dfrG. Tetracycline resistance was associated with tet(K). The concordance between phenotypic susceptibility testing and both WGS analysis tools was similar and ranged between 96% and 100%. In conclusion, a high proportion of OS-MRSA in the DRC was linked to mutations of FemA. Genotypic and phenotypical antimicrobial susceptibility testing showed high concordance. This encourages the future use of WGS in routine antimicrobial susceptibility testing.

In the centre of an epidemic: Fifteen years of LA-MRSA CC398 at the University Hospital Münster

Ten years after initial publications on livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in 2005, we report on the course of the LA-MRSA CC398 epidemic among patients of the University Hospital Münster. This tertiary care facility is located in the Dutch-German border region (EUREGIO), which is characterized by a high density of livestock production and is hence a hotspot for the occurrence of LA-MRSA CC398. Taking advantage of the unique opportunity to track the emergence and spread of MRSA CC398 among humans from the very beginning of the epidemic until today, a total of 6555 non-duplicate MRSA isolates from all screenings and clinical specimens cultivated within the period from 2000 to 2014 were included in the analysis. Retrospectively, the first MRSA CC398 isolate (spa type t034) was obtained from a screening specimen of a patient in 2000, which represents one of the first human-associated LA-MRSA CC398 isolates reported in Europe. After sporadic detections between 2000 and 2004, this clonal lineage accounted for 9.6% of all local MRSA in 2005; a proportion which increased to 35% in 2013 and became stable since then. Considering the period from 2000 to 2014, the group of MRSA CC398 isolates comprised a total of 45 different spa types among which t011 (48.3%), t034 (39.3%) and t108 (3.5%) were predominant and so far unreported types were found. Overall, LA-MRSA CC398 emerged rapidly during the past decade, developed enormous sublineage diversity and contributed substantially to the total burden of MRSA colonization and infection at the hospital.

Direct blood culturing on solid medium outperforms an automated continuously monitored broth-based blood culture system in terms of time to identification and susceptibility testing

Pathogen identification and antimicrobial susceptibility testing (AST) should be available as soon as possible for patients with bloodstream infections. We investigated whether a lysis-centrifugation (LC) blood culture (BC) method, combined with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) identification and Vitek 2 AST, provides a time advantage in comparison with the currently used automated broth-based BC system. Seven bacterial reference strains were added each to 10 mL human blood in final concentrations of 100, 10 and 1 CFU/mL. Inoculated blood was added to the Isolator 10 tube and centrifuged at 3000 g for 30 min, then 1.5 mL sediment was distributed onto five 150-mm agar plates. Growth was observed hourly and microcolonies were subjected to MALDI-TOF MS and Vitek 2 as soon as possible. For comparison, seeded blood was introduced into an aerobic BC bottle and incubated in the BACTEC 9240 automated BC system. For all species/concentration combinations except one, successful identification and Vitek 2 inoculation were achieved even before growth detection by BACTEC. The fastest identification and inoculation for AST were achieved with Escherichia coli in concentrations of 100 CFU/mL and 10 CFU/mL (after 7 h each, while BACTEC flagged respective samples positive after 9.5 h and 10 h). Use of the LC-BC method allows skipping of incubation in automated BC systems and, used in combination with rapid diagnostics from microcolonies, provides a considerable advantage in time to result. This suggests that the usefulness of direct BC on solid medium should be re-evaluated in the era of rapid microbiology.

Staphylococcus aureus develops increased resistance to antibiotics by forming dynamic small colony variants during chronic osteomyelitis

OBJECTIVES

Staphylococcus aureus osteomyelitis often develops to chronicity despite antimicrobial treatments that have been found to be susceptible in in vitro tests. The complex infection strategies of S. aureus, including host cell invasion and intracellular persistence via the formation of dynamic small colony variant (SCV) phenotypes, could be responsible for therapy-refractory infection courses.

METHODS

To analyse the efficacy of antibiotics in the acute and chronic stage of bone infections, we established long-term in vitro and in vivo osteomyelitis models. Antibiotics that were tested include β-lactams, fluoroquinolones, vancomycin, linezolid, daptomycin, fosfomycin, gentamicin, rifampicin and clindamycin.

RESULTS

Cell culture infection experiments revealed that all tested antibiotics reduced bacterial numbers within infected osteoblasts when treatment was started immediately, whereas some antibiotics lost their activity against intracellular persisting bacteria. Only rifampicin almost cleared infected osteoblasts in the acute and chronic stages. Furthermore, we detected that low concentrations of gentamicin, moxifloxacin and clindamycin enhanced the formation of SCVs, and these could promote chronic infections. Next, we treated a murine osteomyelitis model in the acute and chronic stages. Only rifampicin significantly reduced the bacterial load of bones in the acute phase, whereas cefuroxime and gentamicin were less effective and gentamicin strongly induced SCV formation. During chronicity none of the antimicrobial compounds tested showed a beneficial effect on bone deformation or reduced the numbers of persisting bacteria.

CONCLUSIONS

In all infection models rifampicin was most effective at reducing bacterial loads. In the chronic stage, particularly in the in vivo model, many tested compounds lost activity against persisting bacteria and some antibiotics even induced SCV formation.

Systematic literature analysis and review of targeted preventive measures to limit healthcare-associated infections by meticillin-resistant Staphylococcus aureus

Meticillin-resistant Staphylococcus aureus (MRSA) is a major cause of healthcare-associated infections in Europe. Many examples have demonstrated that the spread of MRSA within healthcare settings can be reduced by targeted infection control measures. The aim of this systematic literature analysis and review was to summarise the evidence for the use of bacterial cultures for active surveillance the benefit of rapid screening tests, as well as the use of decolonisation therapies and different types of isolation measures. We included 83 studies published between 2000 and 2012. Although the studies reported good evidence supporting the role of active surveillance followed by decolonisation therapy, the effectiveness of single-room isolation was mostly shown in non-controlled studies, which should inspire further research regarding this issue. Overall, this review highlighted that when planning the implementation of preventive interventions, there is a need to consider the prevalence of MRSA, the incidence of infections, the competing effect of standard control measures (e.g. hand hygiene) and the likelihood of transmission in the respective settings of implementation.

Darstellung und Charakterisierung von Tetrabutylammonium-Tetraiodooxotechnetat(V), (TBA) [TcOI4] / Preparation and Characterization of Tetrabutylammonium Tetraiodooxotechnetate(V), (TBA)[TcOI4]

Pure (TBA)[TcOI4] is prepared from (TBA)[TcOCl4] by ligand exchange reaction with Nal in acetone. The vibrational spectra indicate C4v symmetry for the complex ion. On excitation with the 514.5 nm line of an Ar-laser a resonance Raman spectrum is obtained showing v(TcO) = 996 cm-1 and four of its overtones, symmetrically surrounded by groups of bands arising as well from the sums as from the differences of frequencies with the other fundamentals. In contrast to the ligand exchange reaction the reduction of Tc04- with conc. HI yields products always contaminated with polyiodides. The extremely strong Raman scatterer (TBA)l3 is detected by a characteristic doublet at 111 and 116 cm-1 and even small amounts of it cover the Raman spectrum of (TBA)[TcOI4].

195Pt- und 19F-NMR-Spektren der Fluoro-Chloro-Platinate(IV), [PtFnCl6-n]2-, n = 0-6 / 195Pt and 19F NMR Spectra of the Fluoro-Chloro-Platinates(IV), [PtFnCl6-n]2-, n = 0-6

The 10 complex ions of the system [PtFnCl6-n]2-, n = 0—6, including the three pairs of stereoisomers for n = 2, 3, 4 have been characterized by 195Pt and 19F NMR spectroscopy in CD2Cl2 solution. A wide range from 4731 ([PtCl6]2-) to 11816 ppm ([PtF6]2-) is covered by the clearly separated 195Pt resonances. The chemical shift δ(195Pt) depends nearly linearly on the sum of the electronegativities of the ligands. In accordance with increasing deshielding of the 195Pt nucleus by increasing coordination with F ligands an averaged major downfield shift of 1181 ppm per substitution of Cl by F is observed, while a minor averaged value of 354 ppm downfield is found for the trans/mer isomers in comparison to the related cis/fac isomers. Coupling with 19F results in characteristic 195Pt multiplets, with 1J(PtF) coupling constants for symmetric F—Pt—F axes of averaged 1890 Hz about 31% larger than 1J(PtF•) for asymmetric F•—Pt—Cl′ axes with averaged 1296 Hz. The data reflect the trans influence of the ligands. Highly resolved and expanded 195Pt spectra reveal clearly separated isotopomer signals with intensities according to the expected statistical ratios given by the natural abundance of 35Cl and 37Cl. For [Pt35Cln 37Cl6-n]2- five distinct signals related to n = 6-2 with 0,18 ppm highfield shift per 37Cl atom have been reliably assigned. Resolved isotopomer peaks have also been observed for mer-[PtF3 35Cl3]2-/mer-[PtF3 35Cl2 37Cl]2- with 0,21 ppm and for [PtF5 35Cl]2/[PtF5 37Cl]2- with 0,32 ppm highfield shift per 37Cl atom, respectively. The 19F resonances of symmetric axes appear at higher field, in the range from —357 to —382 ppm, than those of asymmetric axes, from —266 to —287 ppm. Under high resolution compounds with inequivalent F nuclei show multiplets originating from homonuclear 2J(FF•) couplings of about 40 Hz.

Preparation of Octabromoditechnetate(III,II), [Tc2Br8]3- and the Vibronic Structure of the δ → δ* Transition

The dinstinct vibronic structure of the δ → δ* transition of Cs3[Tc2Br8] with its mixed valence is well resolved at 6 K. The electronic origin at about 5970 cm-1 is split into four components, each giving rise to progressions entirely assignable in terms of nν1 and nν1 + ν2 up to n = 9, utilizing the totally symmetric stretching modes ν1(TcTc) and ν2(TcBr) exclusively.

Darstellung und Charakterisierung der Tetrabutylammoniumsalze von [Tc2Cl8]2-, [Tc2Cl8]3- und [Tc2Br8]2- Preparation and Characterization of the Tetrabutylammonium Salts of [Tc2Cl8]2-, [Tc2Cl8]3- und [Tc2Br8]2-

The reduction of [TcCl6]2- with Zn in conc. HCl after evaporation and extraction of ZnCl2 by diethylether yields a red-brown product from which after dissolving in dilute HCl by a solution of (TBA)Cl in CH2Cl2 (TBA)2[Tc2Cl8] and (TBA)3[Tc2Cl8] can be extracted. The separation is achieved by the much better solubility of the green (TBA)2[Tc2Cl8] in acetone compared with that of the grey-blue (TBA)3[Tc2Cl8]. On treatment of (TBA)2[Tc2Cl8] dissolved in acetone with bromine-free conc. HBr carmine red (TBA)2[Tc2Br8] is obtained for the first time. The vibrational spectra are similar and can be assigned according to the assumed D4h-symmetry. In the Raman spectra of both octachloroditechnetates the intensive Tc-Tc-vibration (A1g) is observed at 307 cm-1, for (TBA)2[Tc2Br8] it is found at 323 cm-1 . The electronic spectrum of (TBA)2[Tc2Cl8] agrees to a high extent with that of the corresponding Re compound

Geometrische Isomerie bei bindungsisomeren Hexakis(thiocyanatoisothiocyanato)osmaten(III) / Geometrie Isomerism of Bond Isomerie Hexakis(thiocyanatoisothiocyanato)osmates (III)

From the system of isomeric complex ions [Os(NCS)n(SCN)6-n]3-, 9 of 10 possible species, n = 1-6, are isolated, including for n = 2, 3, 4 the first representatives of pure geometric bond isomers. By reaction of K2[OsCl6] with aqueous KSCN solution at reflux temperature, trans(mer)-complexes, and on treatment at 60 °C exclusively cis(fac)- complexes are formed. By ion exchange chromatography on diethylaminoethyl-cellulose columns, from mixtures of pairs of geometric isomers the pure trans(mer)-compounds are enriched in front, the cis(fac)-species at the end of the zones. Characterization and assignment of the configuration of the geometric isomers is based upon the reproducible differences in the IR and Raman spectra.

Darstellung und Charakterisierung der Tetrabutylammoniumsalze der Tetrahalogenooxotechnetate(V), [TcOCl4]- und [TcOBr4]- / Preparation and Characterization of the Tetrabutylammonium Salts of the Tetrahalooxotechnetates(V), [TcOCl4]- and [TcOBr4]-

The treatment of (TBA)TcO4 with conc. HCl or HBr at room temperature yields (TBA)[TcOCl4] or (TBA)[TcOBr4], which are nearly insoluble in acidic aqueous solutions, but well soluble in organic solvents. The vibrational spectra indicate C4v symmetry for the complex ions. (TBA)[TcOBr4] shows an unusual resonance Raman effect, as the progression of overtones runs with the B1 TcCL4 stretching vibration instead of the symmetric A1 mode. The coupling of B1 with the first overtone of νTcO gives more intense difference than combination bands.

103Rh-NMR-Untersuchungen an Chloro-Bromo-Rhodaten(III) und Bestimmung der Stabilitätskonstanten im System [RhClnBr6-n]3-, n = 0-6 / 103Rh NMR Studies of Chloro-Bromo-Rhodates(III) and Determination of the Stability Constants in the System [RhCl„Br6-n]3-, n = 0-6

By 103Rh NMR spectroscopy the ten compounds of the system [RhCl„Br6_„]3-, n = 0-6 are identified by separate signals. A downfield shift of approximately 160 ppm is observed per substitution of Cl by Br, and the stereoisomers for n = 2, 3, 4 are separated by at least 4 ppm. From the relative intensities of the 103Rh signals in equilibrated solutions, whose total contents of Rh. Cl and Br are known, six individual stability constants are calculated. Their product gives the overall stability constant, indicating [RhBr6]3- to be 36,300 times more stable than [RhCl6]3-. On treatment of [RhBr6]3- with HCl cis/fac isomers are formed stereospecifically, whereas the reaction of [RhCl6]3- with HBr gives trans isomers, n = 2 and 4, containing 20—30% of the cis compounds; only mer-[RhCl3Br3] 3- is obtained pure. The high resolution spectra of [RhCl6]3- and [RhBr6]3- are exhibit five signals each, reflecting the intensity patterns of the most abundant isotopomers within [Rh35Cln 37Cl6-n]3-, n = 2-6, and [Rh79Br„81Br6_„]3-, n = 1-5, respectively.

Bindungsisomere Hexakis(thiocyanato-isothiocyanato)osmate(III) /Bond-Isomeric Hexakis(thiocyanato-isothiocyanato)osmates(III)

On treatment of K2[OsX6], X = Cl, Br, I with KSCN in aqueous solution mixtures of bond-isomeric hexakis(thiocyanato-isothiocyanato)complexes, [Os(NCS)n(SCN)6-n] 3-, n = 1-6, are formed. At low temperatures and short reaction times species with more S-bonded, after longer boiling species with more N-bonded ligands are preferred, indicating the increase of thermodynamic stability with growing n-values. The isolation of the pure bond isomers n = 1-6, is achieved by ion exchange chromatography on diethylaminoethyl-cellulose. The assignment of the individual species is based upon the intensity ratios of characteristic group frequencies in the IR and Raman spectra. The UV-VIS spectra also show significant shifts within the series.

103Rh- und 15N-NMR-Untersuchungen an bindungsisomeren Hexakis(thiocyanato(N)-thiocyanato(S))-rhodaten(III) / 103Rh and 15N NMR Investigations on Bond Isomeric Hexakis(thiocyanato(N)-thiocyanato(S))rhodates(III)

By 103Rh and 15N NMR spectroscopy eight bond isomers of the preparatively feasible system [Rh(NCS)n(SCN)6-n]3-, n = 0-4, including the three pairs of stereoisomers for n = 2,3,4 are identified and assigned unequivocally by their clearly resolved signals. A downfield shift of approximately 540 ppm per isomerization step from S bonding to N bonding is observed in the 103Rh spectra. The non-separable stereoisomers exhibit a high field shift of 4-30 ppm of the trans/mer as compared to the cis/fac isomers. The spectra of the 99% isotopically 15N enriched bond isomers reveal splittings of the 103Rh signals into the expected multiplets with 1J(RhN) couplings of about 23 Hz, which are confirmed and determined more precisely to 21,0 Hz for SRhN axes and 24,1 Hz for NRhN axes from the 15N spectra. The 15N resonances are observed in three characteristic regions depending on the bond type of the ambident ligands and their geometrical arrangement. For S bonding the signals appear at lowest field between — 134 and —141 ppm, for N bonding in asymmetric axes NRhS between —269 and —271 ppm, and in symmetric axes NRhN at highest field between —292 and —297 ppm. Some signals in the S bonding region are split by a very small 3J(RhN) coupling of about 0,7 Hz.

Kristallstruktur und Schwingungsspektren von [(n — C4H9)4N]2[Re2F8]·2(C2H5)2O / Crystal Structure and Vibration Spectra of [(n—C4H9)4N]2[Re2F8] · 2(C2H5)2O

The dark blue title compound has been prepared by reaction of [Re,Cl8]2- and F-, both dissolved as ion pairs with [(n–C4H9)4N]+ in anhydrous CH2Cl2, and recrystallization from acetone/diethylether. Structure determination by single crystal X-ray diffractometry at 150 K reveals crystallization in the cubic system, space group Pn3̄n with a = 19.783(3)Å, V = 7742.4Å3, Z = 6. The {[Re2F8]·O(C,H5)2}2- entity consists of an axially elongated F8-cubane frame around the Re, unit, which is coordinated at one side by an ether molecule (Re–O distance 2.64(4)Å) and displaced from the center towards the ether. The Re– Re quadruple bond (2.188(3)A) is the shortest of the four octahalogenodirhenates(III). In contrast to its Cl, Br and I homologues no disorder of the Re, units is observed. The Re– F distances of 1.92(3) and 1.96(3)A are equal within the standard error, and the Re–Re–F angles are 99.9(4)⚪ and 102.6(4) , respectively. The UV-Vis spectrum of [(n–C4H9)4N]2[Re2F8] shows only the δ-δ* transition at 558 nm (ε = 771 cm2/mmol). At 10 K this band exhibits a weak vibrational fine structure with an averaged progression of 209 cm-1. The Raman spectrum is dominated by v(Re–Re) at 317.5 cm-1 with up to five overtones, the IR spectrum by v(Re–F) at 560 cm-1. Additional bands for the solvated compound at 525 and 306 cm-1 are assigned to v(Re–O) and v(Re–Re), respectively. The 19F NMR spectrum in aceton-d6 shows a singlet at –135.06 ppm; in the presence of ether an additional weak signal arises at –134.15 ppm versus external CFC13.

Trends in antimicrobial non-susceptibility in methicillin-resistant Staphylococcus aureus from Germany (2004-2011)

We analysed trends in antimicrobial non-susceptibility in methicillin-resistant Staphylococcus aureus (MSRA) from Germany to assess the impact of the changing population structure of MRSA on antimicrobial resistance rates. During two large nationwide multicentre studies in 2004-2005 and 2010-2011, we collected consecutively spa-genotyped MRSA isolates. The increase in non-susceptibility rates for tetracycline and trimethoprim-sulphamethoxazole was associated with the spread of livestock-associated MRSA. A decrease in non-susceptibility rates for aminoglycosides and quinolones affected all major lineages (spa-clonal complexes 003, 008, and 032). All isolated remained susceptible to glycopeptides and linezolid.