Inoculum effect on the efficacies of amoxicillin-clavulanate, piperacillin-tazobactam, and imipenem against extended-spectrum ß-lactamase (ESBL)-producing and non-ESBL-producing Escherichia coli in an experimental murine sepsis model.

Escherichia coli is commonly involved in infections with a heavy bacterial burden. Piperacillin-tazobactam and carbapenems are among the recommended empirical treatments for health care-associated complicated intra-abdominal infections. In contrast to amoxicillin-clavulanate, both have reduced in vitro activity in the presence of high concentrations of extended-spectrum ß-lactamase (ESBL)-producing and non-ESBL-producing E. coli bacteria. Our goal was to compare the efficacy of these antimicrobials against different concentrations of two clinical E. coli strains, one an ESBL-producer and the other a non-ESBL-producer, in a murine sepsis model. An experimental sepsis model {~5.5 log10 CFU/g [low inoculum concentration (LI)] or ~7.5 log(10) CFU/g [high inoculum concentration (HI)]} using E. coli strains ATCC 25922 (non-ESBL producer) and Ec1062 (CTX-M-14 producer), which are susceptible to the three antimicrobials, was used. Amoxicillin-clavulanate (50/12.5 mg/kg given intramuscularly [i.m.]), piperacillin-tazobactam (25/3.125 mg/kg given intraperitoneally [i.p.]), and imipenem (30 mg/kg i.m.) were used. Piperacillin-tazobactam and imipenem reduced spleen ATCC 25922 strain concentrations (-2.53 and -2.14 log10 CFU/g [P < 0.05, respectively]) in the HI versus LI groups, while amoxicillin-clavulanate maintained its efficacy (-1.01 log10 CFU/g [no statistically significant difference]). Regarding the Ec1062 strain, the antimicrobials showed lower efficacy in the HI than in the LI groups: -0.73, -1.89, and -1.62 log10 CFU/g (P < 0.05, for piperacillin-tazobactam, imipenem, and amoxicillin-clavulanate, respectively, although imipenem and amoxicillin-clavulanate were more efficacious than piperacillin-tazobactam). An adapted imipenem treatment (based on the time for which the serum drug concentration remained above the MIC obtained with a HI of the ATCC 25922 strain) improved its efficacy to -1.67 log10 CFU/g (P < 0.05). These results suggest that amoxicillin-clavulanate could be an alternative to imipenem treatment of infections caused by ESBL- and non-ESBL-producing E. coli strains in patients with therapeutic failure with piperacillin-tazobactam.

Assessment of the presence of extended-spectrum beta-lactamase-producing Escherichia coli in eggshells and ready-to-eat products.

The principal objective of this study was to assess whether chicken eggshells may be contaminated by ESBL-producing E. coli (ESBLC). Additional analyses were carried out to determine if ESBLEC could be detected in other foodstuffs such as cooked poultry or fresh vegetables. Seventy-two eggshells from different supermarkets and stores as well as 32 salads, 30 samples of cooked poultry and six samples of chicken-based pet food samples were analysed. Characterization of ESBL was performed by PCR and sequencing. Antimicrobial resistance was determined by disk diffusion method. Phylogenetic group was assigned by multiplex-PCR. No ESBLEC was isolated from chicken eggshells, cooked chicken and pet food. One SHV-12-producing E. coli was isolated from a salad sample. This is the first study to analyse chicken eggs in an area where there is a high prevalence of ESBLEC in retail chicken meat.

Effects of ligand binding on the association properties and conformation in solution of retinoic acid receptors RXR and RAR.

In higher eukaryotes, vitamin A derived metabolites such as 9-cis and all-trans retinoic acid (RA), are involved in the regulation of several essential physiological processes. Their pleiotropic physiological effects are mediated through direct binding to cognate nuclear receptors RXRs and RARs that act as regulated transcription factors belonging to the superfamily of nuclear hormone receptors. Hormone binding to the structurally conserved ligand-binding domain (LBD) of these receptors triggers a conformational change that principally affects the conserved C-terminal transactivation helix H12 involved in transcriptional activation. We report an extensive biophysical solution study of RAR alpha, RXR alpha LBDs and their corresponding RXR alpha/RAR alpha LBD heterodimers combining analytical ultracentrifugation (AUC), small-angle X-ray and neutron scattering (SAXS and SANS) and ab initio three-dimensional shape reconstruction at low resolution. We show that the crystal structures of RXRs and RARs LBDs correlate well with the average conformations observed in solution. Furthermore we demonstrate the effects of 9-cisRA and all-transRA binding on the association properties and conformations of RXR alpha and RAR alpha LBDs in solution. The present study shows that in solution RAR alpha LBD behaves as a monomer in both unliganded and liganded forms. It confirms the existence in solution of a ligand-induced conformational change towards a more compact form of the LBD. It also confirms the stability of the predicted RXR alpha/RAR alpha LBD heterodimers in solution. SAS measurements performed on three different types of RXR alpha/RAR alpha LBD heterodimers (apo/apo, apo/holo and holo/holo) with respect to their ligand-binding site occupancy show the existence of three conformational states depending on the progressive binding of RA stereoisomers on RAR alpha and RXR alpha LBD subunits in the heterodimeric context. These results suggest that the subunits are structurally independent within the heterodimers. Our study also underlines the particular behaviour of RXR alpha LBD. In solution unliganded RXR alpha LBD is observed as two species that are unambiguously identified as homotetramers and homodimers. Molecular modelling combined with SAS data analysis allows us to propose a structural model for this autorepressed apo-tetramer. In contrast to the monomeric state observed in the crystal structure, our data show that in solution active holo-RXR alpha LBD bound to 9-cisRA is a homodimer regardless of the protein concentration. This study demonstrates the crucial role of ligands in the regulation of homodimeric versus heterodimeric association state of RXR in the NR signalling pathways.

Ligand-protein interactions in nuclear receptors of hormones.

Nuclear hormone receptors are transcription factors regulated by lipophilic ligands. These hormones bind to their nuclear receptor targets using an induced fit mechanism that triggers a large conformational change and generates the proper surface for the binding of protein coactivators. The molecular details of the various steps of this activation process or its inhibition by antagonists are now understood for several nuclear receptors.

Extended-spectrum and CMY-type beta-lactamase-producing Escherichia coli in clinical samples and retail meat from Pittsburgh, USA and Seville, Spain.

Infections due to Escherichia coli producing extended-spectrum beta-lactamase (ESBL) or CMY-type beta-lactamase (CMY) are increasingly observed in non-hospitalized patients. The origin of these organisms is uncertain, but retail meat contaminated with E. coli may be a source. In the present study, clinical information and strains collected from patients infected or colonized with ESBL-producing and CMY-producing E. coli at hospitals in Pittsburgh, USA and Seville, Spain were investigated. Retail meat purchased in these cities was also studied for the presence of these organisms. Twenty-five and 79 clinical cases with ESBL-producing E. coli and 22 cases and one case with CMY-producing E. coli were identified in Pittsburgh and Seville, respectively. Among them all, community-acquired and healthcare-associated cases together constituted 60% of the cases in Pittsburgh and 73% in Seville. Community-acquired cases were more common in Seville than in Pittsburgh (49% vs. 13%; p <0.001). ESBL-producing and CMY-producing E. coli isolates were commonly recovered from the local retail meat. In particular, 67% (8/12) of retail chickens in Seville and 85% (17/20) of those in Pittsburgh contained ESBL-producing and CMY-producing E. coli isolates, respectively. Among the ESBL-producing isolates, CTX-M and SHV were the most common ESBL types in both clinical and meat isolates. Approximately half of the ESBL-producing and CMY-producing E. coli isolates from meat belonged to phylogenetic groups associated with virulent extra-intestinal infections in humans. Community and healthcare environments are now significant reservoirs of ESBL-producing and CMY-producing E. coli. Retail meat is a potential source of these organisms.

Crystal structure of the human RXRalpha ligand-binding domain bound to its natural ligand: 9-cis retinoic acid.

The pleiotropic effects of active retinoids are transduced by their cognate nuclear receptors, retinoid X receptors (RXRs) and retinoic acid receptors (RARs), which act as transcriptional regulators activated by two stereoisomers of retinoic acid (RA): 9-cis RA (9-cRA) and all-trans RA (a-tRA). Among nuclear receptors, RXR occupies a central position and plays a crucial role in many intracellular signalling pathways as a ubiquitous heterodimerization partner with numerous other members of this superfamily. Whereas RARs bind both isomers, RXRs exclusively bind 9-cRA. The crystal structure of the ligand-binding domain (LBD) of human RXRalpha bound to 9-cRA reveals the molecular basis of this ligand selectivity and allows a comparison of both apo and holo forms of the same nuclear receptor. In the crystal, the receptor is monomeric and exhibits a canonical agonist conformation without direct contacts between the ligand and the transactivation helix H12. Comparison with the unliganded RXRalpha LBD structure reveals the molecular mechanisms of ligand-induced conformational changes and allows us to describe at the atomic level how these changes generate the proper protein interface involved in nuclear receptor-coactivator interaction.

Functional and structural characterization of the insertion region in the ligand binding domain of the vitamin D nuclear receptor.

Vitamin D nuclear receptor mediates the genomic actions of the active form of vitamin D, 1,25(OH)2D3. This hormone is involved in calcium and phosphate metabolism and cell differentiation. Compared to other nuclear receptors, VDR presents a large insertion region at the N-terminal part of the ligand binding domain between helices H1 and H3, encoded by an additional exon. This region is poorly conserved in VDR in different species and is not well ordered as observed by secondary structure prediction. We engineered a VDR ligand binding domain mutant by removing this insertion region. Here we report its biochemical and biophysical characterization. The mutant protein exhibits the same ligand binding, dimerization with retinoid X receptor and transactivation properties as the wild-type VDR, suggesting that the insertion region does not affect these main functions. Solution studies by small angle X-ray scattering shows that the conformation in solution of the VDR mutant is similar to that observed in the crystal and that the insertion region in the VDR wild-type is not well ordered.

Aproximación a un servicio de atención domiciliaria (SAD) municipal / Approach to a local home care service

Introducción: El envejecimiento progresivo de la población española y la importancia demográfica de las personas mayores se concreta en que 17 de cada 100 españoles tiene 65 años o más. El descenso de la tasa de mortalidad y aumento de la esperanza de vida hace que exista un crecimiento considerable de la dependencia, fragilidad y necesidad de cuidados de larga duración de este grupo de población. La familia es el principal proveedor de cuidados en un 80% de los casos, pudiéndose considerar como un elemento socio- sanitario de primer orden por su faceta de proveedores de atención y cuidados. La literatura revisada destaca la importancia de la complementariedad en la distribución de prestación de cuidados y asistencia entre las redes informales y formales. El Servicio de Atención Domiciliaria (SAD) del Ayuntamiento de L’Hospitalet de Llobregat cubre diferentes servicios como higiene personal, limpieza de casa y ropa, comida y compra, teleasistencia, acompañamiento en diversas gestiones. Objetivos del estudio: Describir el perfil socio-demográfico y situaciones de dependencia de los usuarios del Servicio de Atención Domiciliaria de L’Hospitalet del Llobregat. Conocer el perfil y la situación de salud del cuidador principal de los usuarios del SAD. Material y métodos: La población de estudio estaba formada por 320 usuarios, la mayor parte del total (358) de los usuarios del SAD. Los factores de inclusión fueron ser usuario del SAD durante la realización del estudio y aceptar voluntariamente la participación en el estudio. Para la valoración de los usuarios se utilizaron los siguientes cuestionarios validados: Barber, Barthel, Pfeiffer y Lawton. Se utilizaron también otros cuestionarios de elaboración propia para conocer otras características: problemas de salud, gestión de la medicación, relación con atención primaria de salud. La información se recogió mediante visitas domiciliarias que realizaron alumnos de Enfermería. El análisis estadístico consiste en el análisis descriptivo de las variables y se ha realizado con el programa estadístico SPSS 11.0. Resultados: La media de edad de los usuarios analizados es de 82 años y en su mayoría mujeres (77,3%). En cuanto al estado civil, más de la mitad de la población son viudos/as (58,6%), casados 24,9% y solteros el 10,7% y separados o divorciados el 5,9%. La distribución del nivel de autonomía de los usuarios del SAD analizados, según el Índice de Barthel era respectivamente de dependencia moderada (50,1%), dependencia severa (24%), dependencia total (12,5%), autonomía (7,6%) y dependencia ligera (5,9%). Respecto a la capacidad para realizar actividades instrumentales según el cuestionario de Lawton y Brody, un 51,6% necesitaba de cierta ayuda, un 46,6% requiere mucha ayuda y sólo un 1,8% de los usuarios es independiente. Las actividades más solicitadas han sido: la higiene personal (28%), limpieza del hogar y compra (16,9%), de los otros 18 servicios que se valoraron su utilización está por debajo del 10%. Entre algunas de las situaciones detectadas por los alumnos destaca la soledad, tristeza, pobreza y un posible cansancio del rol de cuidador. Conclusiones: El perfil de los usuarios del SAD analizados son mujeres, con sobreenvejecimiento, alto nivel de dependencia, que presenta pluripatología, soledad y escasez de recursos económicos. Entre algunas de las situaciones detectadas por los estudiantes durante la visita domiciliaria destaca el riesgo de cansancio del rol de cuidador

Introduction: The progressive aging of the Spanish population and the demographical relevancy of the eldest is shown in percentage statistics, which state that 17 of each 100 of the Spanish population are 65 years old or over. Furthermore, the decrease of the mortality rate and the increase of the morbidity rate, result in an important relevancy of dependency, fragility and need of long term care in such population group. Families are the main care providers in 80% of the situations, being considered as the main social-health element because their large provision of care to the eldest. The documental background reviewed highlights the relevance of the complementation between the professional and the informal care services networks. The Home Care Service (SAD) of L’Hospitalet de Llobregat City Council provides different services such as personal clean, clean up of clothes and home, home shopping, tele-assistance, assistance in several personal affaires. Goals of the research: Describe the socio-demographical profile and the dependency situations of L’Hospitalet de Llobregat Home Care Service’s users. Take knowledge of the profile and the health situation of the main caregiver of SADs users. Materials and methods: The population studied was formed by 320 users, an important part of the total number of users (358) of SADs services. The requirements to be included in the study were being a SADs services user during the study (from February 2004 to May 2004) and accepting voluntarily to participate in the study. For the user’s evaluation there were used two different validated questionnaires: Barber, Barthel, Pfeiffer and Lawton. They were also used two own made questionnaires to know other characteristics: health problems, management of the mediation, and the relationship of the SAD with the health first cares centre. The information was collected in the visits undertaken by Nursery students at the user’s home. The statistic analysis consists in the descriptive analysis of the aforementioned issues variables and has been undertaken with the statistical software SPSS 11.0. Results: The user’s analyzed average age is 82 years old, being the most of them women (77.3%). Regarding the civil status, more than a half are widow/er (58.6%), married 24.9%, single 10.7% and divorced a 5.9%. The distribution of the independency level of SADs users included in the study, in accordance with Barthel Model were respectively of moderate dependency (50,1%), severe dependency (24%), full dependency (12.5%), independent (7.6%) and little dependency (5.9%). With regards to the ability to carry out instrumental activities according to Lawton and Brody questionnaires, 51.6% needed some assistance, a 46.6% needed much assistance, and only a 1.8% of the users are independent. The most requested assistance is focused in the following activities: personal clean (28%), home clean up and home shopping (16.9%), the other 18 services evaluated its necessity rate is under the 10%. Some of the issues detected along the study by the student were the following: solitude, sadness, poorness, and a possible weariness of the caregiver role. Discussions and conclusions: The profiles of most of SADs users analyzed are women, over aged, with a high level of dependency, who present several pathologies, solitude and a lack of economical resources. One of the issues detected by the students in the home visits undertaken is the risk of the weariness of the caregiver role

Importancia de la formación continuada de los profesionales en la prevención de caídas en pacientes geriátricos institucionalizados / Importance of the continuing education of professionals in the prevention of falls among institutionalized geriatric patients

Introducción: La caída es el tipo de accidente más frecuente y según la evidencia científica entre un 50 y 60% de los ancianos institucionalizados en residencias caen una vez al año. Las complicaciones son la principal causa de muerte por accidente y la sexta causa de muerte en personas mayores de 65 años. Prevenir este tipo de accidentes es uno de los objetivos prioritarios en todos los ámbitos de atención a los ancianos y muy especialmente en los centros residenciales y unidades de larga estancia. Los profesionales que se encuentran en la atención directa tienen la necesidad de determinar las causas del problema y valorar la eficacia de las múltiples acciones de prevención que llevan a cabo de forma interdisciplinaria. Fruto de esta colaboración se realizan diferentes trabajos donde se dan a conocer los resultados obtenidos. Objetivo: A fin de demostrar el interés en el tema entre los profesionales, y analizar las acciones de prevención que resultan más eficaces, nos planteamos realizar una revisión sistemática de los estudios científicos publicados durante los últimos 15 años, en el ámbito mundial y sin límites de idioma, acerca de las diferentes intervenciones de prevención de caídas en pacientes geriátricos institucionalizados en residencias y unidades de larga estancia. Material y Método: La población de estudio está compuesta por ensayos clínicos controlados y asignados aleatoriamente acerca de intervenciones de prevención primaria de caídas, en pacientes geriátricos institucionalizados en residencias y unidades de larga estancia, publicados en últimos 15 años en el ámbito mundial y sin límite de idioma. Para la búsqueda bibliográfica se combinaron 24 bases de datos científicos, consulta de catálogos de bibliotecas, utilización de buscadores especializados en Internet y consulta con expertos. El equipo investigador revisó un total de 2.382 estudios de los cuales se analizaron 156; finalmente se seleccionaron 7 estudios de forma enmascarada, previo examen de su calidad metodológica mediante el Checklist of Consort Statement (2002). Se ha realizado un análisis descriptivo para obtener información de tema y posteriormente un metaanálisis para determinar la eficacia de las intervenciones de prevención de caídas. Resultados: Las intervenciones de prevención de caídas en pacientes geriátricos en residencias geriátricas y unidades de larga estancia reducen de forma global la posibilidad de caerse en OR: 0,63, IC 95%: 0,53-0,74. Becker realizó una intervención de prevención de caídas en donde disminuía la posibilidad de caída en OR: 0,53, IC 95%: 0,41-0,69. Conclusiones: La realización de intervenciones de prevención de caídas en residencias geriátricas y unidades de larga estancia disminuye 1,58 veces la posibilidad de caerse. La formación del equipo aparece como un aspecto clave en la prevención de caídas en los estudios analizados. La prevención de caídas en el anciano institucionalizado requiere un enfoque multifactorial, interdisciplinario e individualizado

Introduction: Falls are the most common type of accidents among elder people and, as scientifical evidences show, between 50 and 60% of the elderly who are resident on nursing health care institutions fall once a year. Complications regarding this matter are the main cause of accidental death and the sixth cause of death of adults older than 65. Preventing such kind of accidents is a prior objective in all fields concerning nursing cares to older adults and specially in nursing care institutions or in long care institutions. Professionals who work in direct care need to determine the problem causes y to value the efficiency and effectiveness of multiple prevention actions that are actually engaged interdisciplinary. As a result of this collaboration some investigation works are being developed and their results are to be published. Objectives: To demonstrate the interest of such question for all professionals who work on this field, and to analyze the most effective prevention actions actually running, we propose to review systematically all scientific studies published during the last 15 years, worldwide and without language limitation, about different fall prevention actions on older adults who are living in nursing care or long care institutions. Methods: The study population is formed by randomized clinical trials about primary prevention interventions of falls, on old adults patients residents in nursing care or long care institutions, published during the last 15 years worldwide and without language limitation. For the research, 24 scientific databases have been checked. Besides, some bibliographic catalogues, expert consultations and Internet searching engines, have been used. The researching team reviewed an amount of 2,382 studies, from which 156 have been analyzed. Finally, 7 of the analyzed studies have been selected (this seven have been blanked), after examining their methodological quality through the Checklist of Consort Statement (2002). A descriptive analysis has been made, to obtain some information regarding the matter, and afterwards a goal analysis was made too. This analysis was made to establish the effectiveness of the interventions related to falls prevention. Results: Interventions of falls prevention on older adults residents in nursing care or long care institutions, reduce globally falling possibilities in OR: 0.63, IC 95%: 0.53-0.74. Becker set an intervention on falls prevention where falling possibilities decreased in OR: 0,53; IC 95%: 0.41-0.69. Conclusions: The setting of a plan or guidelines for the intervention regarding falls prevention in nursing care and long care institutions reduces 1.58 times the possibilities for older adults to fall. Team training appears to be a main aspect in falls prevention in the analyzed works and papers. Falling prevention on care institutions requires a multifactor, interdisciplinary and individualized approach