In vitro susceptibility to 19 agents other than β-lactams among third-generation cephalosporin-resistant Enterobacteriaceae recovered on hospital admission

Objectives

As part of the multicentre Antibiotic Therapy Optimisation Study, MIC values of 19 non-β-lactam agents were determined for third-generation cephalosporin-resistant Escherichia coli , Klebsiella species and Enterobacter species (3GCREB) isolates collected in German hospitals.

Methods

A total of 328 E. coli , 35 Klebsiella spp. (1 Klebsiella oxytoca and 34 Klebsiella pneumoniae ) and 16 Enterobacter spp. (1 Enterobacter aerogenes and 15 Enterobacter cloacae ) isolates were submitted to broth microdilution antimicrobial susceptibility testing with the MICRONAUT system. MICs of fluoroquinolones (levofloxacin and moxifloxacin), aminoglycosides (gentamicin, tobramycin, amikacin, streptomycin, neomycin and paromomycin), tetracyclines (tetracycline, minocycline and tigecycline), macrolides (erythromycin, clarithromycin and azithromycin) and miscellaneous agents [trimethoprim/sulfamethoxazole, chloramphenicol, nitrofurantoin, colistin and fosfomycin intravenous (iv)] were determined and reviewed against 2016 EUCAST breakpoints.

Results

The MIC of levofloxacin was >2 mg/L for 128 of 328 E. coli and 8 of 35 Klebsiella spp., but only 1 of 16 Enterobacter spp. Rates of resistance to trimethoprim/sulfamethoxazole were high (>70%), except for Enterobacter spp. Rates of resistance to colistin and fosfomycin iv were still low. About 20% of the tested isolates were resistant to chloramphenicol. Only 1 (of 328) E. coli isolate had an MIC of amikacin >16 mg/L and only 33 of 328 E. coli and 1 of 35 Klebsiella spp. had an MIC of tobramycin >4 mg/L, whereas average gentamicin MICs were in general more elevated. A tigecycline MIC >2 mg/L was only found for 1 of 16 Enterobacter spp., but in none of the E. coli or Klebsiella spp. isolates.

Conclusions

Our study gives insight into previously unreported non-β-lactam MIC distributions of 3GCREB isolates.

Drug-induced inhibition of phosphorylation of STAT5 overrides drug resistance in neoplastic mast cells

Systemic mastocytosis (SM) is a mast cell (MC) neoplasm with complex pathology and a variable clinical course. In aggressive SM (ASM) and MC leukemia (MCL) responses to conventional drugs are poor and the prognosis is dismal. R763 is a multi-kinase inhibitor that blocks the activity of Aurora-kinase-A/B, ABL1, AKT and FLT3. We examined the effects of R763 on proliferation and survival of neoplastic MC. R763 produced dose-dependent inhibition of proliferation in the human MC lines HMC-1.1 (IC₅₀ 5-50 nM), HMC-1.2 (IC₅₀ 1-10 nM), ROSA^{KIT WT} (IC₅₀ 1-10 nM), ROSA^{KIT D816V} (IC₅₀ 50-500 nM) and MCPV-1.1 (IC₅₀ 100-1000 nM). Moreover, R763 induced growth inhibition in primary neoplastic MC in patients with ASM and MCL. Growth-inhibitory effects of R763 were accompanied by signs of apoptosis and a G2/M cell cycle arrest. R763 also inhibited phosphorylation of KIT, BTK, AKT and STAT5 in neoplastic MC. The most sensitive target appeared to be STAT5. In fact, tyrosine phosphorylation of STAT5 was inhibited by R763 at 10 nM. At this low concentration, R763 produced synergistic growth-inhibitory effects on neoplastic MC when combined with midostaurin or dasatinib. Together, R763 is a novel promising multi-kinase inhibitor that blocks STAT5 activation and thereby overrides drug-resistance in neoplastic MC.

IL-4 downregulates expression of the target receptor CD30 in neoplastic canine mast cells

CD30 is a novel therapeutic target in human mast cell (MC) neoplasms. In this 'comparative oncology' study, we examined CD30 expression and regulation in neoplastic canine MC using a panel of immunomodulatory cytokines [interleukin-2 (IL-2), IL-4, IL-5, IL-6, IL-13 and stem cell factor (SCF)] and the canine mastocytoma cell lines NI-1 and C2. Of all cytokines tested IL-4 was found to downregulate expression of CD30 in NI-1 and C2 cells. We also found that the CD30-targeting antibody-conjugate brentuximab vedotin induces growth inhibition and apoptosis in both MC lines. Next, we asked whether IL-4-induced downregulation of CD30 interferes with brentuximab vedotin-effects. Indeed, pre-incubation of NI-1 cells with IL-4 decreased responsiveness towards brentuximab vedotin. To overcome IL-4-mediated resistance, we applied drug combinations and found that brentuximab vedotin synergizes with the Kit-targeting drugs masitinib and PKC412 in inhibiting growth of NI-1 and C2 cells. In summary, CD30 is a new marker and IL-4-regulated target in neoplastic canine MC.

Colonization with third-generation cephalosporin-resistant Enterobacteriaceae on hospital admission: prevalence and risk factors

OBJECTIVES

The objectives of this study were to prospectively assess the rectal carriage rate of third-generation cephalosporin-resistant Enterobacteriaceae (3GCREB) in non-ICU patients on hospital admission and to investigate resistance mechanisms and risk factors for carriage.

METHODS

Adult patients were screened for 3GCREB carriage at six German tertiary care hospitals in 2014 using rectal swabs or stool samples. 3GCREB isolates were characterized by phenotypic and molecular methods. Each patient answered a questionnaire about potential risk factors for colonization with MDR organisms (MDROs). Univariable and multivariable risk factor analyses were performed to identify factors associated with 3GCREB carriage.

RESULTS

Of 4376 patients, 416 (9.5%) were 3GCREB carriers. Escherichia coli was the predominant species (79.1%). ESBLs of the CTX-M-1 group (67.3%) and the CTX-M-9 group (16.8%) were the most frequent β-lactamases. Five patients (0.11%) were colonized with carbapenemase-producing Enterobacteriaceae. The following risk factors were significantly associated with 3GCREB colonization in the multivariable analysis (P < 0.05): centre; previous MDRO colonization (OR = 2.12); antibiotic use within the previous 6 months (OR = 2.09); travel outside Europe (OR = 2.24); stay in a long-term care facility (OR = 1.33); and treatment of gastroesophageal reflux disease (GERD) (OR = 1.22).

CONCLUSIONS

To our knowledge, this is the largest admission prevalence study of 3GCREB in Europe. The observed prevalence of 9.5% 3GCREB carriage was higher than previously reported and differed significantly among centres. In addition to previously identified risk factors, the treatment of GERD proved to be an independent risk factor for 3GCREB colonization.

Intermittent Lagrangian velocities and accelerations in three-dimensional porous medium flow

Intermittency of Lagrangian velocity and acceleration is a key to understanding transport in complex systems ranging from fluid turbulence to flow in porous media. High-resolution optical particle tracking in a three-dimensional (3D) porous medium provides detailed 3D information on Lagrangian velocities and accelerations. We find sharp transitions close to pore throats, and low flow variability in the pore bodies, which gives rise to stretched exponential Lagrangian velocity and acceleration distributions characterized by a sharp peak at low velocity, superlinear evolution of particle dispersion, and double-peak behavior in the propagators. The velocity distribution is quantified in terms of pore geometry and flow connectivity, which forms the basis for a continuous-time random-walk model that sheds light on the observed Lagrangian flow and transport behaviors.

Emergence of Citrobacter freundii carrying IMP-8 metallo-β-lactamase in Germany

Metallo-β-lactamases (MBLs) in Enterobacteriaceae are an increasing problem worldwide. This report describes the isolation of Citrobacter freundii carrying IMP-8 MBL from three patients during the period from March 2012 until March 2013 in Germany. The bla_IMP-8 enzyme is predominantly found in Asia, where IMP-8 has spread to various enterobacterial species causing serious infections. To our best knowledge, this is the first report of bla_IMP-8 habouring Enterobacteriaceae in Europe.

Clinical efficacy and safety of a water-soluble micellar paclitaxel (Paccal Vet) in canine mastocytomas

OBJECTIVE

To determine the clinical efficacy and safety of a cremophor-free formulation of paclitaxel (Paccal Vet, Oasmia Pharmaceuticals) in dogs with mast cell tumours.

METHODS

Paccal Vet was administered at a median dose of 145 (range, 135 to 150) mg/m(2) intravenously once every 21 days for three cycles to 29 dogs with macroscopic grade 2 or 3 mast cell tumour. Efficacy was assessed by tumour response (Response Evaluation Criteria in Solid Tumours version 1.0) and performance status score. Progression-free survival, quality of life and safety/adverse events were also evaluated. Clinical safety was assessed by clinicopathological analyses and recording of adverse events.

RESULTS

Complete or partial response was observed in 59% of dogs. Performance status score remained constant or improved for 20 dogs and decreased by one grade for 9 dogs. Median time to progression was 247 (range, 42 to 268) days. Expected, transient frequently subclinical adverse events (primarily grade 3/4 neutropenia and grade 1/2 leukopenia) were observed in the majority of dogs. Nine dogs were euthanased and one dog died due to disease progression.

CLINICAL SIGNIFICANCE

Paccal Vet appears to be a clinically safe and effective treatment for canine mast cell tumours. Further controlled confirmatory investigation is warranted.

NI-1: a novel canine mastocytoma model for studying drug resistance and IgER-dependent mast cell activation

BACKGROUND

Advanced mast cell (MC) disorders are characterized by uncontrolled growth of neoplastic MC in various organs, mediator-related symptoms, and a poor prognosis. Kit mutations supposedly contribute to abnormal growth and drug resistance in these patients.

METHODS

We established a novel canine mastocytoma cell line, NI-1, from a patient suffering from MC leukemia.

RESULTS

NI-1 cells were found to form mastocytoma lesions in NOD/SCID IL-2Rgamma(null) mice and to harbor several homozygous Kit mutations, including missense mutations at nucleotides 107(C→T) and 1187(A→G), a 12-bp duplication (nucleotide 1263), and a 12-bp deletion (nucleotide 1550). NI-1 cells expressed several MC differentiation antigens, including tryptase, Kit, and a functional IgE receptor. Compared to the C2 mastocytoma cell line harboring a Kit exon 11 mutation, NI-1 cells were found to be less responsive against the Kit tyrosine kinase inhibitors (TKI) masitinib and imatinib, but were even more sensitive against proliferation-inhibitory effects of the mammalian target of rapamycin (mTOR) blocker RAD001 and PI3-kinase/mTOR blocker NVP-BEZ235. The Kit-targeting multikinase inhibitors PKC412 and dasatinib were also found to override TKI resistance in NI-1 cells, and produced growth inhibition with reasonable IC(50) values (<0.1 μM).

CONCLUSION

NI-1 may serve as a useful tool to investigate IgE-dependent reactions and mechanisms of abnormal growth and drug resistance in neoplastic MC in advanced mastocytosis.

Characterization of NVX-207, a novel betulinic acid-derived anti-cancer compound

BACKGROUND

Development of betulinic acid derivatives for clinical use has been hampered by adverse pharmacological and physico-chemical characteristics of this class of compounds. We here present a novel semi-synthetic betulinic acid-derived drug candidate well suited for further clinical development.

MATERIALS AND METHODS

In vitro activity and mode of action of NVX-207 were determined using normal as well as cancer cell lines. Gene expression profiling was performed with Affymetrix U133 microarrays. NVX-207 binding partners were identified using a heterobifunctional chemical crosslinker system. Potential binding proteins were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) analysis. Clinical studies were conducted in canine cancer patients suffering from spontaneously arising pre-treated tumours.

RESULTS

NVX-207 showed anti-tumour activity (mean IC(50) = 3.5 microM) against various human and canine cell lines. NVX-207-induced apoptosis was associated with activation of the intrinsic apoptotic pathway via cleavage of caspases -9, -3, -7 and of poly (ADP-ribose) polymerase (PARP). Global gene expression profiling demonstrated regulation of genes associated with lipid metabolism, most notably an upregulation of genes coding for insulin-induced gene 1 (Insig-1), low-density lipoprotein receptor (LDL-R) and of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA). NVX-207 bound to apolipoprotein A-I, a major regulator of lipid metabolism and cholesterol transport. A phase I/II study in dogs suffering from naturally occurring cancer receiving local treatment of NVX-207 (10 mg mL(-1)) showed excellent clinical responses including a complete remission in so far 5/5 treated animals.

CONCLUSIONS

NVX-207 is well tolerated and has significant anti-cancer activity in vitro and in vivo in dogs with treatment-resistant malignancies.

Pax5 immunostaining in paraffin-embedded sections of canine non-Hodgkin lymphoma: a novel canine pan pre-B- and B-cell marker

The Pax5 gene encodes the B-cell specific activator protein (BSAP), a member of the highly conserved paired box (PAX)-domain family of transcription factors and a key regulator in the development and differentiation of B-cells. Pax5 serves as a valuable B-cell marker in the classification of human lymphoma patients as it is restricted to lymphomas of B-cell lineage. In dogs, detection of Pax5 protein in lymphoma tissue has not been reported. Therefore, we have investigated the expression and detection of BSAP using a monoclonal anti-Pax5 antibody (anti-BSAP, clone 24) in canine lymphoma tissue samples to evaluate its diagnostic relevance as a B-cell marker. A series of 25 lymph nodes from 23 canine non-Hodgkin lymphoma patients, a reactive canine lymph node, and a normal non-reactive canine lymph node, were evaluated. All B-cell non-Hodgkin lymphomas (15) were found to express Pax5 protein. In addition, there was a strong correlation between Pax5 and CD79a expression. Three CD3 positive and five CD3 and CD79a positive lymphomas were immunophenotypically negative for anti-Pax5, indicating a T-cell lineage. In conclusion, anti-Pax5 antibody may offer an excellent B-cell marker in canine lymphomas.

Expression of Vascular Endothelial Growth Factor and its Receptors in Canine Lymphoma

Vascular endothelial growth factor (VEGF) stimulates endothelial cell proliferation and has a pivotal role in tumour angiogenesis. The expression of VEGF and its receptors VEGFR-1 and VEGFR-2 was examined immunohistochemically in 43 specimens of canine lymphoma and in six normal lymph nodes. Western blotting and reverse transcriptase polymerase chain reaction (RT-PCR) were performed to detect VEGF protein and mRNA, respectively. VEGF protein was expressed by 60% of the tumours with diffuse cytoplasmic labelling of the neoplastic cells. Endothelial cells, macrophages and plasma cells were also immunolabelled. VEGFR-1 was expressed by variable numbers of neoplastic cells in 54% of lymphoma specimens. VEGFR-1 was also expressed by macrophages, plasma cells, reticulum cells, and vascular endothelial cells. Macrophages and lymphocytes in germinal centres of normal lymph nodes were also immunoreactive with anti-VEGF and VEGFR-1. Most tumours did not express VEGFR-2 but in 7% of sections there was focal labelling of neoplastic and endothelial cells, with a cytoplasmic and perinuclear pattern. The observed variability in expression of VEGF and its receptors probably relates to the fact that lymphoma is a heterogeneous lymphoproliferative tumour. Individual differences in VEGF and VEGFR expression must be taken into account when VEGF and VEGFR-targeted approaches for anti-angiogenic therapy are considered in dogs.

The function of RNAi in plant development

The morphological phenotype of mutations in genes required for posttranscriptional gene silencing (PTGS) or RNA interference (RNAi) in Arabidopsis demonstrates that this process is critical for normal development. One way in which RNAi contributes to gene regulation is through its involvement in the biogenesis of trans-acting small interfering RNAs (siRNAs). These endogenous siRNAs are derived from noncoding transcripts that are cleaved by a microRNA (miRNA) and mediate the silencing of protein-coding transcripts. Some protein-coding genes are also subject to miRNA-initiated transitive silencing. Several developmentally important transcription factors regulated by these silencing mechanisms have been identified.

Travel time and trajectory moments of conservative solutes in two-dimensional convergent flows

We address advective transport of a solute traveling toward a single pumping well in a two-dimensional randomly heterogeneous aquifer. The two random variables of interest are the trajectory followed by an individual particle from the injection point to the well location and the particle travel time under steady-state conditions. Our main objective is to derive the predictors of trajectory and travel time and the associated uncertainty, in terms of their first two statistical moments (mean and variance). We consider a solute that undergoes mass transfer between a mobile and an immobile zone. Based on Lawrence et al. [Lawrence, A.E., Sánchez-Vila, X., Rubin, Y., 2002. Conditional moments of the breakthrough curves of kinetically sorbing solute in heterogeneous porous media using multirate mass transfer models for sorption and desorption. Water Resour. Res. 38 (11), 1248, doi:10.1029/2001WR001006.], travel time moments can be written in terms of those of a conservative solute times a deterministic quantity. Moreover, the moments of solute particles trajectory do not depend on mass transfer processes. The resulting mean and variance of travel time and trajectory for a conservative species can be written as functions of the first, second moments and cross-moments of trajectory and velocity components. The equations are developed from a consistent second order expansion in sigmaY (standard deviation of the natural logarithm of hydraulic conductivity). Our solution can be completely integrated with the moment equations of groundwater flow of Guadagnini and Neuman [Guadagnini, A., Neuman, S.P., 1999a. Nonlocal and localized analyses of conditional mean steady state flow in bounded, randomly non uniform domains 1. Theory and computational approach. Water Resour. Res. 35(10), 2999-3018.,Guadagnini, A., Neuman, S.P., 1999b. Nonlocal and localized analyses of conditional mean steady state flow in bounded, randomly non uniform domains 2. Computational examples. Water Resour. Res. 35(10), 3019-3039.], it is free of distributional assumptions regarding the log conductivity field, and formally includes conditioning. We present analytical expressions for the unconditional case by making use of the results of Riva et al. [Riva, M., Guadagnini, A., Neuman, S.P., Franzetti, S., 2001. Radial flow in a bounded randomly heterogeneous aquifer. Transport in Porous Media 45, 139-193.]. The quality of the solution is supported by numerical Monte Carlo simulations. Potential uses of this work include the determination of aquifer reclamation time by means of a single pumping well, and the demarcation of the region potentially affected by the presence of a contaminant in the proximity of a well, whenever the aquifer is very thin and Dupuit-Forchheimer assumption holds.

[Renal amyloidosis caused by Ehrlichia canis]

An 8 year old, intact female, Old English Sheepdog was presented with lethargy and chronic weight loss of one year duration. The dog suffered from recurrent fever and a mild peripheral lymphadenopathy. Mild thrombocytopenia, monoclonal hyperglobulinemia and positive Ehrlichia canis antibody titer were indicative of Ehrlichiosis. The patient developed proteinuria and renal failure, which suggested the presence of glomerulopathy. Immunohistochemical staining of renal biopsy specimen demonstrated AA amyloidosis. Chronic ehrlichiosis was suspected to be the cause of the dog's renal amyloidosis.

In vitro and in vivo evaluation of new radiolabeled neurotensin(8-13) analogues with high affinity for NT1 receptors

The potential utility of neurotensin (NT) in cancer diagnosis and therapy is limited by its rapid degradation. New stabilized analogues were synthesized, labeled with [99mTc] and screened in vitro and in vivo. High affinity and rapid internalization were obtained in binding assays. Despite their longer human plasma half-lives, a rapid degradation was observed with low concentrations as used in biodistribution tests. The tumor uptake rates were rather low but tumor/blood ratios increased according to the stability raise.

Synthesis, radiolabelling and biological characterization of (D)-7-iodo-N-(1-phosphonoethyl)-5-aminomethylquinoxaline-2,3-dione, a glycine-binding site antagonist of NMDA receptors

(D)-7-Iodo-N-(1-phosphonoethyl)-5-aminomethylquinoxaline-2,3 -dione (I-PAMQX), is a potent, in vivo active antagonist acting at the glycine binding site of the NMDA receptor complex. Radioiodinated [131I]I-PAMQX was prepared with good yields and high specific activity from its 7-bromo analogue. Biodistribution studies of [131I]I-PAMQX in mice showed a relatively slow clearance from the blood. The uptake of radioactivity was highest in the kidneys, moderate in the heart, lung, liver and bones, and low in the brain.

Catabolism of neurotensins. Implications for the design of radiolabeling strategies of peptides

A major impact in diagnosis and treatment of cancer with peptide based radiopharmaceuticals is expected. Among others neurotensin is considered to be a promising candidate. However, most neurotensin analogues, which bind to the neurotensin receptor have a too short biological half live due to catabolism. Therefore, stabilized fragments have been prepared and labeled with the newly developed [Tc(CO)3](+)-moiety. A single histidine or a (N alpha-His)-Ac group coupled to the N-terminus of the neurotensin fragments were used as a bidentate or a tridentate ligand respectively, which coordinate the metal carbonyl efficiently. Affinity and binding studies of the 99mTc(I) radiolabeled neurotensin fragments revealed a behavior influenced by catabolism and properties of the metal complex.

Measurement of the pregnant cervix by transvaginal sonography: an interobserver study and new standards to improve the interobserver variability

Transvaginal sonography has become an important tool for assessing the gravid cervix uteri, especially in patients at risk for cervical incompetence and preterm delivery. The purpose of our prospective study was to evaluate interobserver variability in measurements of the cervical length and, as a second step, improve the reproducibility and interobserver discrepancy by the introduction of quality control standards when producing and measuring the image of the cervix. Before the introduction of these standards we obtained 46 measurements and observed a mean cervical length (internal to external os) of 33.7 mm (range 26-52 mm) and an interobserver average discrepancy of 3.04 mm (range 0-6 mm). Later, measurements were obtained only when the following conditions were assured and visualized on the screen: (1) the internal os is either flat or is an isosceles triangle; (2) the whole length of the cervical canal can be observed; (3) a symmetric image of the external os can be obtained; and (4) the distance from the surface of the posterior lip to the cervical canal is equal to the distance from the anterior lip to the cervical canal. After the implementation of these quality control standards, 70 measurements were performed obtaining a mean length of 35.3 mm (range 27-51) and an average interobserver discrepancy of 1.24 mm (range 0-4). Thus the measurement error was significantly lower following introduction of quality control standards. Furthermore, the coefficient of variation dropped from 7.1% to 3.3% after the introduction of the guidelines. We believe that these guidelines could be helpful by making the measurements of the cervical length more accurate, reducing the interobserver variability, improving the reproducibility and promoting the role of transvaginal sonography in monitoring the incompetent cervix.