Emergence of VIM-4 metallo-β-lactamase-producing Klebsiella pneumoniae ST15 clone in the Clinical Centre University of Pécs, Hungary

Since November 2009 carbapenemase-producing Klebsiella pneumoniae isolates have been detected in increasing numbers at the Clinical Centre University of Pécs. Molecular typing was performed for 102 clinical isolates originating from different time periods and various departments of the Clinical Centre. Pulsed-field gel electrophoresis revealed the predominance of a single clone (101/102), identified as sequence type ST15. PCR and sequencing showed the presence of blaCTX-M-15 and blaVIM-4 genes. The blaVIM-4 was located on a class 1 integron designated In238b. To our knowledge, this is the first description of a blaVIM-4 gene in the predominant CTX-M-15 extended spectrum β-lactamase-producing Hungarian Epidemic Clone/ST15.

Effect of particle size on the surface properties and morphology of ground flax

Flax fibers were ground with a ball-mill and four fractions with different size ranges were collected by sieving. These were tested for water sorption, degree of polymerization (DP), copper number, hydroxyl number and analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and inverse gas chromatography (IGC). Significant differences were found between the properties of the flax fiber and those of the ground versions, including fragmentation of fibers, increase of water sorption, copper number, hydroxyl number and surface O/C ratio, and decrease of DP, crystallite size and dispersive component of surface energy (γs(d)). Some parameters depended on the particle size: O/C ratio and hydroxyl number had local maxima at 315-630 μm, while γs(d) increased steadily with the decrease of particle size. These relationships were explained by fiber disintegration, destruction of waxy surface layer, exposure of cellulosic components, increase of surface area and crystalline imperfections.

Structure-activity relationships of vanilloid receptor agonists for arteriolar TRPV1

BACKGROUND AND PURPOSE

The transient receptor potential vanilloid 1 (TRPV1) plays a role in the activation of sensory neurons by various painful stimuli and is a therapeutic target. However, functional TRPV1 that affect microvascular diameter are also expressed in peripheral arteries and we attempted to characterize this receptor.

EXPERIMENTAL APPROACH

Sensory TRPV1 activation was measured in rats by use of an eye wiping assay. Arteriolar TRPV1-mediated smooth muscle specific responses (arteriolar diameter, changes in intracellular Ca(2+)) were determined in isolated, pressurized skeletal muscle arterioles obtained from the rat and wild-type or TRPV1(-/-) mice and in canine isolated smooth muscle cells. The vascular pharmacology of the TRPV1 agonists (potency, efficacy, kinetics of action and receptor desensitization) was determined in rat isolated skeletal muscle arteries.

KEY RESULTS

Capsaicin evoked a constrictor response in isolated arteries similar to that mediated by noradrenaline, this was absent in arteries from TRPV1 knockout mice and competitively inhibited by TRPV1 antagonist AMG9810. Capsaicin increased intracellular Ca(2+) in the arteriolar wall and in isolated smooth muscle cells. The TRPV1 agonists evoked similar vascular constrictions (MSK-195 and JYL-79) or were without effect (resiniferatoxin and JYL-273), although all increased the number of responses (sensory activation) in the eye wiping assay. Maximal doses of all agonists induced complete desensitization (tachyphylaxis) of arteriolar TRPV1 (with the exception of capsaicin). Responses to the partial agonist JYL-1511 suggested 10% TRPV1 activation is sufficient to evoke vascular tachyphylaxis without sensory activation.

CONCLUSIONS AND IMPLICATIONS

Arteriolar TRPV1 have different pharmacological properties from those located on sensory neurons in the rat.

Hot spots in density fingering of exothermic autocatalytic chemical fronts

Measurements of two-dimensional (2D) temperature fields are performed by an interferometric method during density fingering of the autocatalytic chlorite-tetrathionate reaction in a Hele-Shaw cell. These measures confirm that, because of heat losses through the glass walls of the reactor, the temperature profile across the front is a pulse rather than a front. Moreover, the full 2D temperature field shows the presence in the reactive zone of hot spots where the temperature exceeds the maximum temperature measured in a stable planar front. We investigate here experimentally the increase of temperature in the hot spots when the composition of the reactants is varied to increase the exothermicity of the reaction. We back up these experimental observations by nonlinear simulations of a reaction-diffusion-convection model which show that the maximum temperature reached in the system depends on the intensity of convection.

Cardiac calmodulin kinase: a potential target for drug design

Therapeutic strategy for cardiac arrhythmias has undergone a remarkable change during the last decades. Currently implantable cardioverter defibrillator therapy is considered to be the most effective therapeutic method to treat malignant arrhythmias. Some even argue that there is no room for antiarrhythmic drug therapy in the age of implantable cardioverter defibrillators. However, in clinical practice, antiarrhythmic drug therapies are frequently needed, because implantable cardioverter defibrillators are not effective in certain types of arrhythmias (i.e. premature ventricular beats or atrial fibrillation). Furthermore, given the staggering cost of device therapy, it is economically imperative to develop alternative effective treatments. Cardiac ion channels are the target of a number of current treatment strategies, but therapies based on ion channel blockers only resulted in moderate success. Furthermore, these drugs are associated with an increased risk of proarrhythmia, systemic toxicity, and increased defibrillation threshold. In many cases, certain ion channel blockers were found to increase mortality. Other drug classes such as ßblockers, angiotensin-converting enzyme inhibitors, aldosterone antagonists, and statins appear to have proven efficacy for reducing cardiac mortality. These facts forced researchers to shift the focus of their research to molecular targets that act upstream of ion channels. One of these potential targets is calcium/calmodulin-dependent kinase II (CaMKII). Several lines of evidence converge to suggest that CaMKII inhibition may provide an effective treatment strategy for heart diseases. (1) Recent studies have elucidated that CaMKII plays a key role in modulating cardiac function and regulating hypertrophy development. (2) CaMKII activity has been found elevated in the failing hearts from human patients and animal models. (3) Inhibition of CaMKII activity has been shown to mitigate hypertrophy, prevent functional remodeling and reduce arrhythmogenic activity. In this review, we will discuss the structural and functional properties of CaMKII, the modes of its activation and the functional consequences of CaMKII activity on ion channels.

Role of Ca²+-sensitive K+ currents in controlling ventricular repolarization: possible implications for future antiarrhytmic drug therapy

Normal heart function and repolarization of the cardiac action potential (AP) is to a high extent subjective to synchronized activity of sarcolemmal K(+) channels, expressed in both ventricular and atrial myocardium, largely contributing to regulation of the resting potential, the pacemaker activity, and the shape and duration of the AP. Clinical observations and experimental studies in cardiomyocytes and multicellular preparations provided firm evidence for the sensitivity of some major outward K+ currents and the corresponding ion channels to shifts in intracellular Ca(2+) concentration ([Ca(2+)](i)). Direct regulation via interaction between [Ca(2+ )](i) and the channel protein or indirect modulation via Ca(2+ ) signaling pathways of these currents have strong implications to mechanical and electrical performance of the heart, and its physiological adaptation to altered load. It may also lead to severe cardiac dysfunction, if [Ca(2+ )](i) handling is disturbed in a variety of pathological conditions. In this review we attempt to summarize the present state of the topic on two ubiquitous repolarizing K(+) currents (I(to1) and I(K1)) with documented Ca(2+)-sensitivity and critical significance in cellular antiarrhythmic defense, to highlight fields where clue data are missing, and discuss the apparently unsolved "mystery" of the cardiac small conductance Ca(2+ )-activated K(+ ) (SK) channels. We have collected the available information on the known novel, although usually still not enough selective inhibitors and activators of these currents justifying the need for more selective ones. Finally, we emphasize a few related therapeutical perspectives to be considered for future experimental research and particularly in pharmaceutical development.

Dissemination of ST274 Klebsiella pneumoniae epidemic clone in newborn and adult hospital settings harbouring SHV-2A or CTX-M-15 type extended spectrum β-lactamases-producing known plasmids

Molecular epidemiology and genetic features of an extended-spectrum β-lactamase (ESBL) producing Klebsiella pneumoniae epidemic clone (KP-EC) with elevated ciprofloxacin MIC (minimum inhibitory concentration) values from multiple nosocomial outbreaks and sporadic cases between 2006 and 2008 in Hungary were investigated. As a result of continuous monitoring of ESBL-producing KP-ECs, 27 isolates collected from five healthcare facilities were selected for macrorestriction profile analysis by PFGE (pulsed field gel electrophoresis). Of these, 12 strains were isolated from adult inpatients, while 15 strains were from newborns. The MIC values for several antibiotics were determined by agar dilution technique. Molecular typing was further performed by PCR (polymerase chain reaction) and sequencing of several antibiotic resistance genes, plasmid profile analysis, transfer of resistance determinants and multilocus sequence typing (MLST). All isolates showed moderate resistance to ciprofloxacin (MICs ranged from 0.5 to 8 mg L(-1)). PFGE revealed the existence of only one genetic cluster defined as EC IV. PstI digestion of plasmid DNA revealed two highly diverse restriction patterns in "adult" and "newborn" isolates corresponding to plasmids from the Hungarian Epidemic Clone and plasmids isolated from a neonatal nosocomial outbreak in 1998, respectively. Sequence analysis of β-lactamase genes from plasmids of 14 selected isolates detected bla SHV-2a in strains isolated exclusively from newborns and bla CTX-M-15 in strains isolated exclusively from adult inpatients. MLST established that strains of the PFGE cluster belonged to a novel sequence type ST274. ESBL-producing K. pneumoniae isolates belonging to the novel sequence type ST274 appeared in the newborn and adult hospital settings in Hungary and acquired SHV-2a or CTX-M-15 type enzymes, respectively. Thus, a new antimicrobial resistance strategy for successful conformation to distinct hospital settings was found.

Insertion/deletion polymorphism of the angiotensin-converting enzyme predicts left ventricular hypertrophy after renal transplantation

BACKGROUND

Kidney transplant recipients show a higher risk for cardiovascular complications, such as left ventricular hypertrophy and heart failure, leading to the premature death in many cases.

METHODS

We investigated the contribution of angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism to the development of left ventricular hypertrophy (LVH), an indicator of heart disease progression among kidney transplant recipients.

RESULTS

We observed a significant correlation between graft function and left ventricular mass index. The occurrence of LVH or severe LVH was significantly greater among patients with at least one D-allele (ID or DD).

CONCLUSION

The use of ACE inhibitors or angiotensin receptor blockers seemed to be advantageous for patients with the ID and especially, the DD genotype.

Insertion/Deletion polymorphism of Angiotensin-converting enzyme as a risk factor for chronic allograft nephropathy

Angiotensin-converting enzyme (ACE) inhibitor therapy is widely used to treat chronic allograft nephropathy (CAN), which suggests a possible role of the renin-angiotensin system in the pathologic mechanism of the disease. The objective of this study was to investigate the possible link between CAN and ACE. The ACE insertion/deletion polymorphism and the amount and activity of ACE were determined in cadaver kidney recipients with CAN (n = 38) or normal renal function (n = 34). The DD genotype was observed significantly more frequently in the CAN group compared with the group with normal renal function. Moreover, the DD genotype was associated with a higher serum ACE concentration and greater serum ACE activity, compared with II genotype homozygotes. The insertion/deletion polymorphism of ACE affects ACE expression and activity in serum, and, therefore, may have an important role in the pathogenesis of CAN. These findings suggest that determination of the ACE genotype may be useful in identifying patients at high risk. In particular, the DD genotype may be considered an indication for ACE inhibitor therapy.

The role of cardiovascular magnetic resonance imaging in cardiac resynchronisation therapy

Cardiac electromechanical resynchronisation therapy (CRT) is an effective non-pharmacological treatment of patients suffering from drug refractory heart failure. However, approximately 20–30% of patients are non-responder. Cardiac magnetic resonance imaging (CMR) may play significant role in clarifying many questions in this patient population. Forty-five patients, suffering from severe drug refractory heart failure, underwent CMR before applying CRT. Left ventricular end-diastolic, end-systolic volumes, ejection fraction, myocardial mass, wall motion disturbances, localisation of non-viable myocardium were determined. Left ventricular dyssynchrony was determined by illustrating wall-time thickening in short-axis slices of left ventricle from basis to apex. CMR-proved underlying heart disease were postinfarction heart failure, dilated cardiomyopathy and non-compaction cardiomyopathy in 62, 27 and in 11%, respectively. Mean left ventricular ejection fraction was 24.5±10%, intraventricular dyssynchrony was 200±78 ms. In four patients, requiring surgical revascularisation after unsuccessful coronary sinus electrode implantation, optimal position for epicardial screw-in electrode was selected. According to the results of CMR, biventricular device was not implanted in 7 patients. During the follow-up of the 38 patients, 5 patients (13.16%) were non-responders, despite the approximately 22% non-responder ratio in our whole patient population treated by CRT but without performing previous CMR examination. In this patient population CMR may have a significant role in the selection of responder patient population.

Navigating complex labyrinths: optimal paths from chemical waves

The properties of excitable media are exploited to find minimum-length paths in complex labyrinths. Optimal pathways are experimentally determined by the collection of time-lapse position information on chemical waves propagating through mazes prepared with the Belousov-Zhabotinsky reaction. The corresponding velocity fields provide maps of optimal paths from every point in an image grid to a particular target point. Collisions of waves that were temporarily separated by obstacles mark boundary lines between Significantly different paths with the same absolute distance. The pathfinding algorithm is tested in very complex mazes with a simple reaction-diffusion model.

Successful surgical restoration of a giant immature left ventricular aneurysm with computer assisted ventricle engineering

Background: Although circular ventricle resection techniques are the gold standard of left ventricle restoration, these techniques can lead to suboptimal results. Postoperative systolic resection line can be inadequate, as it must be planned on a heart stopped in diastole. The impaired geometry and contractility may lead to increased short- and long-term mortality. Moreover, postoperative low cardiac output due to insufficient left ventricular volume results in a potentially unstable condition, and cannot be corrected. Our aim was to find a preoperative method to minimize risk and maximize outcome with left ventricle restoration. Methods: We have created a novel method combining surgery with modern imaging techniques to construct a preoperative 3D systolic heart model. The model was utilized to determine resection could be intraoperatively used to create the new left ventricle. Results: The computer assisted ventricle engineering technique is described step by step through a successful aneurysmectomy of a 61-year-old female patient with a complicated giant left ventricle aneurysm. Conclusions: Using this model we are able to find the optimal resection line providing excellent postoperative result, thus minimizing the risk of low cardiac output syndrome. This is the first report of our new combined approach to left ventricle restoration.

Investigation of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae outbreaks in Hungary between 2005 and 2008

Fourteen outbreaks in Hungary between 2005 and 2008 caused by extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-KP) were epidemiologically investigated and the isolated pathogens were characterized by molecular techniques. Ten of the fourteen outbreaks occurred in adult wards and four in neonatal units affecting a total number of 73 patients. The 54% [40] of the patients developed bloodstream infections and 21.9%-21.9% [16] pneumonia and surgical site infections, respectively. The overall rate of mortality proved high: 36.9% [27]. Outbreaks in adults affected more patients, had higher attack rates, were more prolonged in duration and had a 6.9-fold higher mortality rate than outbreaks observed in neonates. The outbreaks in neonates were caused by SHV-type ESBL-producing klebsiellae, while in the "adult outbreaks" exclusively CTX-M-type ESBL-KP strains were involved. While the outbreak strains isolated from neonatal units could be assigned to a variety of pulsotypes, the previously described K. pneumoniae epidemic clones, ST15 and ST147, could be identified among the pathogens causing outbreaks in adult units.

Precipitation pattern formation in the copper(II) oxalate system with gravity flow and axial symmetry

Chemical systems that are far from thermodynamic equilibrium may form complex temporal and spatiotemporal structures. In our paper, we present unusual precipitation patterns that have been observed in the system of Cu(II)-oxalate. Starting with a pellet of copper sulfate immersed in or by pumping copper sulfate solution into a horizontal layer of sodium oxalate solution, we have observed the formation of a precipitate ring and an array of radially oriented thin fingers. The development of these patterns is related to the internal structure of the different crystals, the gravity flow, and the circular symmetry of the experimental arrangement.

Risk factors and outcomes for bloodstream infections with extended-spectrum beta -lactamase-producing Klebsiella pneumoniae ; Findings of the nosocomial surveillance system in Hungary

Risk factors for and outcomes of bloodstream infections (BSIs) caused by ESBL-producing and by ESBL-non-producing Klebsiella pneumoniae were compared in a four-year multicenter study in Hungary. One hundred ESBL-positive and one hundred ESBL-negative patients were included as cases and controls. Investigated risk factors were related to demographics, comorbid conditions, treatments, invasive procedures, surgery prior bacteremia, presence of additional nosocomial infections and preceding hospital admission within a year. Measured outcomes were crude mortality, mortality related to infection and delay in introducing appropriate therapy (DAT). Though some risk factors for infection (admission to intensive care units, having central venous and/or urinary catheter, mechanical ventilation) were shared by both groups, in other respects cases and controls were found to differ substantially. The 36 percent of patients with BSIs with ESBL-producing Klebsiella died versus 23 percent of controls (odds ratio [OR]: 2.5; 95% confidence interval [CI]: 1.0-5.4; p = 0.02). The 18 percent of deaths in cases versus 9% in controls could be attributed to infection (OR: 5.0; 95% CI: 1.5-16.2; p = 0.006). Cases more often received previous antibiotic therapy than controls (OR: 2.7; 95% CI: 1.1-6.7; p = 0.02) and delay in the introduction of appropriate antibiotic treatment was observed in 44% of cases versus 19% of controls (OR: 3.4; 95% CI: 1.6-7.3; p = 0.001). The results demonstrate that BSIs caused by ESBL-producing K. pneumoniae are related to previous antibiotic therapy and are associated with a high rate of mortality that is often linked to delay in the introduction of appropriate antibiotic therapy. This confirms that besides infection control measures the early identification and antibiotic resistance profiling of the infecting pathogen is salient in the control of BSIs caused by ESBL-producing K. pneumoniae .

Influence of thermal effects on buoyancy-driven convection around autocatalytic chemical fronts propagating horizontally

The spatiotemporal dynamics of vertical autocatalytic fronts traveling horizontally in thin solution layers closed to the air can be influenced by buoyancy-driven convection induced by density gradients across the front. We perform here a combined experimental and theoretical study of the competition between solutal and thermal effects on such convection. Experimentally, we focus on the antagonistic chlorite-tetrathionate reaction for which solutal and thermal contributions to the density jump across the front have opposite signs. We show that in isothermal conditions the heavier products sink below the lighter reactants, providing an asymptotic constant finger shape deformation of the front by convection. When thermal effects are present, the hotter products, on the contrary, climb above the reactants for strongly exothermic conditions. These various observations as well as the influence of the relative weight of the solutal and thermal effects and of the thickness of the solution layer on the dynamics are discussed in terms of a two-dimensional reaction-diffusion-convection model parametrized by a solutal R(C) and a thermal R(T) Rayleigh number.

Replacement of methicillin-resistant Staphylococcus aureus clones in Hungary over time: a 10-year surveillance study

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in Hungary has been increasing and is now close to 20% among invasive isolates of S. aureus. In order to understand the evolution of MRSA in Hungary, two collections of isolates were studied: 22 representatives of a collection of 238 MRSA isolates recovered between 1994 and 1998, and a collection of 299 MRSA isolates recovered between 2001 and 2004. The isolates were first characterised by pulsed-field gel electrophoresis (PFGE) and were distributed into 19 different PFGE patterns. Representatives of each pattern were further characterised by spa typing, multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec (SCCmec) typing. The Hungarian clone that was predominant in 1994-1998 (PFGE E, ST239-III) had almost disappeared in 2003-2004, being replaced by the Southern German clone (PFGE B, ST228-I) and the New York/Japan epidemic clone (PFGE A, ST5-II), which represented c. 85% of the 2001-2004 isolates. Thus, this study describes, for the first time, the co-dominance and extensive spread of the New York/Japan clone in a European country.

Emergence of SHV-2a producing enterobacter cloacae in hungary

We report an investigation on a collection of multidrug-resistant Enterobacter cloacae isolates from a Hungarian neonatal intensive care unit. All the isolates (n=142) were examined by antimicrobial susceptibility testing and ERIC-PCR. The seven ESBL positive isolates (derived from six patients) made up a separated group with regard to their patterns by antimicrobial susceptibility testing and ERIC-PCR and were further tested by class-1-integron PCR and plasmid electrophoresis. The ESBL isolates were found indistinguishable in each of these laboratory tests, one genetic clone were revealed in the background of ESBL cases by PFGE. The ESBL positive isolates were proven to harbour a approximately 62 Md plasmid and two class-1 integrons (0.9 kb, 1.875 kb). With respect to their clinical relatedness and our laboratory findings there was a small outbreak caused by the ESBL clone. PCR-sequencing were performed on the outbreak strain and has revealed a blaSHV gene that encodes for an SHV-2a type ESBL enzyme. This is the first description of SHV-2a positive E. cloacae strains isolated in Hungary.

Periodic heterogeneity-driven resonance amplification in density fingering

Periodic heterogeneity is introduced in experiments with thin solution layers where downward propagating planar autocatalytic fronts are hydrodynamically unstable and cellular patterns develop. The evolution of fingers is greatly affected by the spatial heterogeneity when the wave number associated with it falls in the vicinity of the most unstable mode of the reference system with uniform thickness. The imposed heterogeneity will drive the instability by amplifying the modes with the matching wave numbers as indicated by the experimentally constructed dispersion curves.