Characterization of the enzymatic resistance to β-lactamics in enterobacteria

Detecting the resistance to CTG in severe infections-by enterobacteria guides to successful treatments. The main resistance mechanisms are the production of extended spectrum β-lactamases (BLEE), chromosomal inducible or derepressed β-lactamases Amp-C type or plasmidic Amp-C. The aim of this study was to investigate and characterize the mechanisms involved in the resistance to CTG in clinical isolations of enterobacteria, by phenotypic and genotypic methods. 64 isolations resistant to CTG were studied (K. pneumoniae, E. coli, Enterobacter spp and Proteus spp ). Antimicrobial agents sensibility and phenotypic detection of Amp-C and BLEE enzymes was performed by diffusion and dilution methods. In cefotaxime resistant E. coli and K. pneumoniae strains a possible enzymatic resistance mechanism was detected by Masuda Bioassay. The genes bla CTX-M-2 and bla PER-2 were detected by PCR. Of 64 isolations, 8 strains were presumptively producers of derepressed Amp-C and 56 were BLEE producers (with prevalence of CTX-M-2). Accompanying resistance was observed. Masuda Bioassay was negative and accompanying resistance suggests it is due an impermeability phenomenon. Our results confirm that the resistance to CTG in our strains is mainly caused by enzymes coded in plasmids so that it merit to establish epidemic control measures and to emphasize wise use of β-lactamic agents available.Fil: Castillo, Natalia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Jure, M. A.. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Allori, C.. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Castillo, M.. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaXXIII Jornadas Científicas de la Asociación de Biología de TucumánTucumánArgentinaAsociación de Biología de Tucumá

Caracterización de la resistencia enzimática a β -lactámicos en enterobacterias

La emergencia de enterobacterias resistentes a los antimicrobianos es una realidad en nuestro medio, el manejo de las infecciones severas por estos microorganismos se realiza con cefalosporinas de 3ra Generación (CTG). Detectar la resistencia a estos antimicrobianos precozmente en el laboratorio orienta el tratamiento según la especie aislada. La producción de β-lactamasas es el principal mecanismo de resistencia. Según su actividad hidrolítica estas enzimas se clasifican en: β-lactamasas plasmídicas de espectro extendido (BLEE), β-lactamasas cromosómica e inducible (Amp-C) y Amp-C plasmídicas. El objetivo de este trabajo fue investigar los mecanismos enzimáticos responsables de la resistencia a CTG en aislamientos clínicos de Enterobacterias, así como caracterizar las ß-lactamasas presentes por métodos fenotípicos y genotípicos. Se estudiaron 64 aislamientos de Enterobacterias (K. pneumoniae, E. coli, Enterobacter spp y Proteus spp) resistentes a CTG. Se ensayó la sensibilidad por difusión y dilución en agar según normas de la NCCLS (actualmente CLSI) frente a los siguientes antimicrobianos: ampicilina, cefalotina, cefoxitina, ceftazidima (CAZ), cefotaxima (CTX), aztreonam, imipenem (IMP), meropenem, ciprofloxacina (CIP), trimetoprima/sulfametoxazol (SXT), gentamicina (GEN), amikacina, cefepime (FEP), amoxicilina/ac.clavulánico y piperacilina/tazobactama (PTAZ). Como control de calidad se utilizaron las cepas ATCC: E. coli 25922 y 35218 y K. pneumoniae 700603. Por difusión con discos se realizó la detección fenotípica de ßlactamasas inducibles y derreprimida y de BLEEs. En las cepas de E. coli y K. pneumoniae resistentes a CXT se detectó la posible resistencia enzimática por el bioensayo de Masuda y se evaluó la resistencia acompañante con discos de tetraciclina (30ug) y cloranfenicol (30ug). Se detectaron los genes bla CTX-M-2 y bla PER-2 por PCR. De los 64 aislamientos de Enterobacterias; 8 cepas fueron presuntivamente productoras de AMPC derreprimida y 56 productoras de BLEE las que fueron resistentes a ampicilina, piperacilina, cefalotina, amoxicilina/clavulánico, el 39% fueron resistentes a P/TAZ y ninguna a Imipenem. Los valores de CIM para CTX fueron >16 ug/ml y para CAZ >32 ug/ml asociados a elevados valores de CIM para FEP >64. Se presentó resistencia acompañante a CIP (85%), GEN (79%) y TMS (64%). La detección de genes bla CTX-M-2 y bla PER-2 indicó un marcado predominio de cepas productoras de CTX-M2. El ensayo de inducción realizado en los aislamientos de Enterobacter sp indica la presencia de AMP-C induclble en 6 cepas también productoras de BLEE. En las cepas resistentes a cefoxitina el bioensayo dio negativo. Se encontró resistencia acompañante a tetraciclina en 1 aislamiento, a cloranfenicol en 2, y a ambos en 8, lo que sugiere que la resistencia a cefoxitina se debe posiblemente a un fenómeno de impermeabilidad. Nuestros resultados confirman que la resistencia a CTG en nuestras cepas está mediada principalmente por enzimas codificadas en plásmidos rápidamente transferibles lo que amerita instaurar medidas de control epidemiológico en las instituciones de salud y enfatizar el uso prudente de los agentes β-lactamicos disponibles.Fil: Castillo, Natalia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Jure, Maria Angela. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Allori, C.. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Castillo, M.. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaXXIII Jornadas Científicas de la Asociación de Biología de TucumánTafí del ValleArgentinaAsociacion de Biologia de Tucuma

Bohmian Mechanics and Quantum Information

Many recent results suggest that quantum theory is about information, and that quantum theory is best understood as arising from principles concerning information and information processing. At the same time, by far the simplest version of quantum mechanics, Bohmian mechanics, is concerned, not with information but with the behavior of an objective microscopic reality given by particles and their positions. What I would like to do here is to examine whether, and to what extent, the importance of information, observation, and the like in quantum theory can be understood from a Bohmian perspective. I would like to explore the hypothesis that the idea that information plays a special role in physics naturally emerges in a Bohmian universe.Comment: 25 pages, 2 figure

A Novel Flow-Perfusion Bioreactor Supports 3D Dynamic Cell Culture

Background. Bone engineering requires thicker three-dimensional constructs than the maximum thickness supported by standard cell-culture techniques (2 mm). A flow-perfusion bioreactor was developed to provide chemotransportation to thick (6 mm) scaffolds. Methods. Polyurethane scaffolds, seeded with murine preosteoblasts, were loaded into a novel bioreactor. Control scaffolds remained in static culture. Samples were harvested at days 2, 4, 6, and 8 and analyzed for cellular distribution, viability, metabolic activity, and density at the periphery and core. Results. By day 8, static scaffolds had a periphery cell density of 67% ± 5.0%, while in the core it was 0.3% ± 0.3%. Flow-perfused scaffolds demonstrated peripheral cell density of 94% ± 8.3% and core density of 76% ± 3.1% at day 8. Conclusions. Flow perfusion provides chemotransportation to thick scaffolds. This system may permit high throughput study of 3D tissues in vitro and enable prefabrication of biological constructs large enough to solve clinical problems

Realism about the Wave Function

A century after the discovery of quantum mechanics, the meaning of quantum mechanics still remains elusive. This is largely due to the puzzling nature of the wave function, the central object in quantum mechanics. If we are realists about quantum mechanics, how should we understand the wave function? What does it represent? What is its physical meaning? Answering these questions would improve our understanding of what it means to be a realist about quantum mechanics. In this survey article, I review and compare several realist interpretations of the wave function. They fall into three categories: ontological interpretations, nomological interpretations, and the \emph{sui generis} interpretation. For simplicity, I will focus on non-relativistic quantum mechanics.Comment: Penultimate version for Philosophy Compas

Comprehensive study of the reactions induced by 12C on 103Rh up to 33 MeV/nucleon

Abstract Fifty-three excitation functions for the production of radioactive residues in the interaction of 12C with 103Rh have been measured from the Coulomb barrier up to 400 MeV by means of the activation technique. These excitation functions have been analyzed considering complete fusion, incomplete fusion of 8Be and α-particle fragments and, above about 200 MeV, the transfer of either one proton or one neutron from 12C to 103Rh. The emission of pre-equilibrium particles during the thermalization of the excited composite nuclei formed in all these processes and, in the case of 8Be and α incomplete fusion, also the re-emission of α-particles after a mean-field interaction or a few interactions with the target nucleons have been taken into account

The Development, Deployment, and Evaluation of the CLEFT-Q Computerized Adaptive Test:A Multimethods Approach Contributing to Personalized, Person-Centered Health Assessments in Plastic Surgery

BackgroundRoutine use of patient-reported outcome measures (PROMs) and computerized adaptive tests (CATs) may improve care in a range of surgical conditions. However, most available CATs are neither condition-specific nor coproduced with patients and lack clinically relevant score interpretation. Recently, a PROM called the CLEFT-Q has been developed for use in the treatment of cleft lip or palate (CL/P), but the assessment burden may be limiting its uptake into clinical practice. ObjectiveWe aimed to develop a CAT for the CLEFT-Q, which could facilitate the uptake of the CLEFT-Q PROM internationally. We aimed to conduct this work with a novel patient-centered approach and make source code available as an open-source framework for CAT development in other surgical conditions. MethodsCATs were developed with the Rasch measurement theory, using full-length CLEFT-Q responses collected during the CLEFT-Q field test (this included 2434 patients across 12 countries). These algorithms were validated in Monte Carlo simulations involving full-length CLEFT-Q responses collected from 536 patients. In these simulations, the CAT algorithms approximated full-length CLEFT-Q scores iteratively, using progressively fewer items from the full-length PROM. Agreement between full-length CLEFT-Q score and CAT score at different assessment lengths was measured using the Pearson correlation coefficient, root-mean-square error (RMSE), and 95% limits of agreement. CAT settings, including the number of items to be included in the final assessments, were determined in a multistakeholder workshop that included patients and health care professionals. A user interface was developed for the platform, and it was prospectively piloted in the United Kingdom and the Netherlands. Interviews were conducted with 6 patients and 4 clinicians to explore end-user experience. ResultsThe length of all 8 CLEFT-Q scales in the International Consortium for Health Outcomes Measurement (ICHOM) Standard Set combined was reduced from 76 to 59 items, and at this length, CAT assessments reproduced full-length CLEFT-Q scores accurately (with correlations between full-length CLEFT-Q score and CAT score exceeding 0.97, and the RMSE ranging from 2 to 5 out of 100). Workshop stakeholders considered this the optimal balance between accuracy and assessment burden. The platform was perceived to improve clinical communication and facilitate shared decision-making. ConclusionsOur platform is likely to facilitate routine CLEFT-Q uptake, and this may have a positive impact on clinical care. Our free source code enables other researchers to rapidly and economically reproduce this work for other PROMs

On the Meaning of the String-Inspired Noncommutativity and its Implications

We propose an alternative interpretation for the meaning of noncommutativity of the string-inspired field theories and quantum mechanics. Arguments are presented to show that the noncommutativity generated in the stringy context should be assumed to be only between the particle coordinate observables, and not of the spacetime coordinates. Some implications of this fact for noncomutative field theories and quantum mechanics are discussed. In particular, a consistent interpretation is given for the wavefunction in quantum mechanics. An analysis of the noncommutative theories in the Schr\"odinger formulation is performed employing a generalized quantum Hamilton-Jacobi formalism. A formal structure for noncommutative quantum mechanics, richer than the one of noncommutative quantum field theory, comes out. Conditions for the classical and commutative limits of these theories have also been determined and applied in some examples.Comment: References, comments, and footnotes are included; some changes in section