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Abstract: In order to assess in vitro antimicrobial susceptibility for nosocomial enterobacteria ESBL producers for patients in the Autonomous University Hospital Service ‘Antonio Patricio de Alcalá,’ 27 bacterial strains were collected in the ICU, neonatology, medicine and pediatric facilities during September-November 2005. Antimicrobial susceptibility was determined by the disk diffusion method. The highest number of nosocomial infections was found in ICU and neonatology with 10 (37.03%) and 7 (25.93%) cases, respectively; 44.44% of the positive cultures were isolated from secretions. K. pneumoniae was the most frequently isolated species (51.85%), followed by Enterobacter aerogenes with 18.52%. The greatest antimicrobial resistance in the betalactam group was obtained for ceftazidime (77.77%), cefotaxime (70.37%) and cefepime (40.74%); in the aminoglycosides group, for tobramycin and gentamycin, (44.44% and 40.74%, respectively); also, chloramphenicol (70.37%), tetracycline (51.85%) and trimethoprim-sulfamethoxazole (44.44%). These results could be useful to the medical community when taking into account guidelines for treatment and risk behavior modification, which facilitate the induction of resistance, such as abuse in prescribing antibiotics and unnecessary hospitalizations. Resumen: Para evaluar la susceptibilidad antimicrobiana in vitro de enterobacterias nosocomiales productoras de BLEE en pacientes recluidos en el Servicio Autónomo Hospital Universitario “Antonio Patricio de Alcalá”, se recolectaron 27 cepas bacterianas procedentes de las salas de UCI, retén, medicina y pediatría, en el periodo septiembre-noviembre de 2005. La susceptibilidad antimicrobiana se determinó por el método de difusión del disco. El mayor número de infecciones nosocomiales se presentó en UCI y retén con 10 (37,03%) y 7 (25,93%) casos; 44,44% de cultivos positivos fueron aislados en secreciones. K. pneumoniae resultó la especie mayormente aislada (51,85%), seguida de Enterobacter aerogenes con 18,52%. La mayor resistencia antimicrobiana en el grupo de los -lactámicos, se obtuvo para ceftazidima (77,77%), cefotaxima (70,37%) y cefepima (40,74%); en el grupo de los aminoglucósidos, a tobramicina y gentamicina (44,44% y 40,74%); asimismo, cloranfenicol (70,37%), tetraciclinas (51,85%) y trimetoprim-sulfametoxazol (44,44%). Estos resultados pudieran ser útiles a la comunidad médica, al tomar en cuenta las pautas de tratamiento y modificar las conductas de riesgo, las cuales facilitan la inducción de resistencia, como el abuso al prescribir antimicrobianos y las hospitalizaciones innecesarias.

Abstract: The modified fluorescence staining differential was evaluated using Pseudomonas spp. isolated from cultivated agricultural soils in the State of Sucre, in order to observe microscopic events related to the cellular cycle. Each species of biochemically identified Pseudomonas was inoculated into a broth and incubated at room temperature, aerobiosis, for 15, 20, 30 and 45 minutes and 1, 24, 48 and 72 hours; then, slides were made and stained. For the 24 identified strains of Pseudomonas, P. mendocina (41.67%), P. aeruginosa (37.50%) and P. putida (20.83%), staining variations such as green, yellow and orange, fluorescent and low fluorescence were observed for the different incubation times. The stain uses acridine orange that interacts with DNA by intercalation, causing green fluorescence; it interacts with RNA by electrostatic attraction causing orange fluorescence; the alcohol-acetone decolorant removes the acridine orange not united with the genetic material and sodium fluorescein produces a yellow color in bacteria that retain a sufficient amount of acridine orange. Cytoplasmatic staining variations in Pseudomonas spp., are associated with the amount of RNA and DNA present in the cells according to the phase of their cellular cycle. Resumen: Se evaluó la coloración diferencial de fluorescencia modificada en Pseudomonas spp. aisladas de suelos de cultivos agrícolas del estado Sucre, a fin de observar eventos microscópicos relacionados con el ciclo celular. Cada especie de Pseudomonas identificada bioquímicamente se sembró en caldos incubados a temperatura ambiente, aerobiosis, durante 15, 20, 30 y 45 minutos, y 1, 24, 48 y 72 horas; luego, se elaboraron y colorearon los extendidos. En las 24 cepas de Pseudomonas identificadas, P. mendocina (41,67%), P. aeruginosa (37,50%) y P. putida (20,83%), se observaron variaciones de tinción en los diferentes tiempos de incubación como verde, amarilla y anaranjada, fluorescentes y de baja fluorescencia. La coloración emplea naranja de acridina que se intercala al ADN, provocando fluorescencia verde, e interactúa con el ARN provocando fluorescencia anaranjada; el decolorante remueve el naranja de acridina no unido al material genético y la fluoresceína de sodio produce color amarillo en bacterias que retienen suficiente cantidad de naranja de acridina. Las variaciones de tinción citoplasmática en Pseudomonas spp., están asociadas a la cantidad de ARN y ADN presente en la célula de acuerdo a la fase de su ciclo celular.

Non-destructive, reliable, and accurate measurements of low doping levels and carrier lifetimes in small direct-bandgap semiconductors such as indium arsenide (InAs) at room temperature are challenging due to intrinsic limitations of conventional experimental techniques. In this article, we introduce a contactless optical-terahertz (THz) pump–probe technique in a continuous-wave regime measuring low doping levels in the 10 15 − 10 16 cm − 3 range and lifetimes down to 8 ns at room temperature in InAs. We show that a single-parameter material model can be used to retrieve the free carrier density from THz transmission measurements of InAs layers. Additionally, we show that lifetime of photogenerated excess carriers can be measured by modulating this carrier density using an amplitude-modulated optical pump. [ABSTRACT FROM AUTHOR]