Actividad antibacteriana del aceite esencial de la conobea scopariodes frente a cinco cepas bacterianas de interés clínico en Colombia

En Colombia el manejo de pacientes en los diferentes servicios hospitalarios han presentado inconvenientes en el combate de infecciones por bacterias y la resistencia de las mismas; el Staphylococcus aureus Escherichia coli y Pseudomonas aeruginosa, han demostrado evolución en la creación de generaciones resistentes y también han participado junto con la Salmonella y el B.cereus en brotes por ETAS como principales microorganismos causales. En el presente estudio se analizó el aceite esencial de la Conobea scoparioides para evaluar su actividad frente a cinco cepas bacterianas. Se obtuvo el AE y se prepararon las bacterias aplicándose pruebas de sensibilidad y no paramétricas para determinar el porcentaje de inhibición, la evaluación de la MIC y comparar la efectividad del aceite vs la estreptomicina. El aceite esencial presentó actividad principalmente contra el B. cereus con el mayor % de inhibición y una MIC de 3.2 ug/ml, caso diferente presentó P. aeruginosa con un % de crecimiento por encima del 50% presentando una MIC de 16.7 ug/ml. Finalmente podemos concluir que se presentó mayor actividad frente a bacterias gram positivas como el caso del B. cereus que en gram negativas con MIC bajas. Estos resultados permite comparar la actividad de la conobea con estudios recientes bajo la misma modalidad que permiten identificar nuevas plantas con actividad biológica y percibir que la conobea es efectiva en mayor proporción frente a bacterias gram positivas.

Mediastinitis post revascularización miocárdica: impacto del cambio de profilaxis antibiótica en la fundación Cardioinfantil 2012 - 2013

INTRODUCCIÓN. La mediastinitis posterior a cirugía de revascularización miocárdica es una infección infrecuente, pero potencialmente fatal. En la Fundación Cardioinfantil se ha observado una tendencia al incremento de la misma en los últimos años, obligando a un cambio en las medidas de profilaxis antimicrobiana, pasando de cefalosporinas a vancomicina – gentamicina, sin embargo no se conoce aún el impacto de estas medidas. OBJETIVO: Determinar si el cambio de la profilaxis antibiótica en pacientes sometidos a revascularización miocárdica influye en una disminución de la incidencia de mediastinitis durante los años 2012 – 2013. METODOLOGÍA: Estudio de cohortes retrospectivo, evaluando la incidencia de mediastinitis post revascularización miocárdica, en pacientes expuestos a 2 diferentes tipos de profilaxis antimicrobiana (cefalosporinas vs vancomicina-gentamicina). Se describieron los patrones de susceptibilidad y resistencia de los patógenos encontrados en mediastinitis y la mortalidad de esta patología. RESULTADOS: Los patógenos más frecuentemente aislados en la mediastinitis fueron Staphylococcus aureus y Klebsiella pneumoniae, en la mayoría monomicrobiano. Se encontraron patógenos con perfiles de resistencia como betalactamasas de espectro extendido en Gram negativos y resistencia a la meticilina en cocos Gram positivos. El RR de mediastinitis del grupo expuesto a vancomicina-gentamicina respecto al grupo de cefalosporinas fue de 0,9 con IC 95% 0,28 – 3,28. CONCLUSIÓN: la epidemiologia microbiana de la mediastinitis no difiere de la reportada en otras series. La profilaxis antimicrobiana con vancomicina - gentamicina en pacientes sometidos a revascularización miocárdica, no redujo la incidencia de mediastinitis. Se propone regresar a la terapia de profilaxis con cefalosporinas.

Perfil microbiológico, prevalencia de resistencia antibiótica y patrones de susceptibilidad en infección urinaria en una población pediátrica

Introducción: El incremento de la resistencia antibiótica se considera un problema de salud pública con consecuencias clínicas y económicas, por lo tanto se determinará la prevalencia de resistencia antibiótica en Infección del Tracto Urinario (ITU, el perfil microbiológico y los patrones de susceptibilidad en una población pediátrica atendida en la Fundación Cardioinfantil. Materiales y métodos: Estudio observacional de corte transversal, retrospectivo, entre 1 mes a 18 años de edad, con diagnóstico de ITU comunitaria atendidos entre Enero de 2011 y Diciembre de 2013. Se excluyeron pacientes con dispositivos en la vía urinaria, instrumentación quirúrgica previa, trayectos fistulosos entre la vía urinaria y sistema digestivo, ITU luego de 48 horas de hospitalización y recaída clínica en tratamiento. Se estableció la prevalencia de ITU resistente y se realizó un análisis descriptivo de la información. Resultados: Se evaluaron 385 registros clínicos, con una mediana de 1.08 años (RIQ 0.8 – 4.08), el 73.5% eran niñas. La fiebre predominó (76.5%), seguido de emesis (32.0%), disuria (23.7%) y dolor abdominal (23.1%). El uropatógeno más frecuente fue E.coli (75%), seguido de Proteus mirabilis (8.5%) y Klebsiella spp. (8.3%). La Ampicilina, el Trimetropim sulfametoxazol, la Ampicilina sulbactam y el ácido nalidixico tuvieron mayor tasa de resistencia. La prevalencia de BLEE fue 5.2% y AmpC 3.9%. La prevalencia de resistencia antimicrobiana fue de 11.9%. Conclusiones: La E.coli es el uropatogeno más frecuentemente aislado en ITU, con resistencia a la ampicilina en 60.2%, cefalosporinas de primera generación en 15.5%, trimetropin sulfametoxazol en 43.9%, cefepime 4.8%. La prevalencia de resistencia antimicrobiana fue de 11.9%.

Perfil de resistencia microbiológico en ciudados intensivos adultos en la fundación Santa Fe de Bogotá año 2014

Se realizó un estudio descriptivo, retrospectivo; se usó la base de datos de los aislamientos microbiológicos documentados en las UCI de la Fundación Santa fe de Bogotá para el año 2014. La prevalencia de bacterias resistentes en los aislamientos de la FSFB no es baja, por lo que se requiere una terapia empírica acertada acorde con la flora local. Se requieren estudios analíticos para evaluar factores asociados al desarrollo de gérmenes multi resistentes y mortalidad por sepsis

Tipificación y perfiles de resistencia antibiótica en unidades neonatales de Bogotá durante los años 2008-2012

La sepsis neonatal ha sido un problema en las unidades de cuidado intensivo al rededor del mundo. Su incidencia aumenta diez veces cuando el recién nacido es de muy bajo peso. El aislamiento de gérmenes resistentes en los cultivos tomados a los recién nacidos ha permitido identificar el comportamiento de los antibióticos de uso común. El presente estudio analítico de corte transversal realizado durante los años 2008 al 2012 en diez unidades de cuidados intensivos neonatales de la ciudad de Bogotá analizó la base de datos de los laboratorios de microbiología, obteniendo un total de 22.153 muestras de las cuales 7.132 ( 32.9%) fueron elegibles. Utilizando el software Whonet 5.6 y tomando solo el primer aislamiento por año y por paciente se realizaron análisis descriptivos y de resistencia bacteriana. Los resultados obtenidos fueron similares a los reportados en la literatura donde los gérmenes gran positivos son los más comúnmente aislados con un 53.2%, seguidos en importancia por los gérmenes gran negativos. Klebsiella pneumoniae y Escherichia coli en conjunto aportan 27.22%, presentando un aumento en el porcentaje de BLEE (Betalactamasa de Espectro Extendido) y aparición de carbapenemasas durante los años de estudio. El Acinetobacter baumannii ha duplicado la resistencia a ampicilina sulbactam llegando al 66.7%. Las candidas fueron aisladas en un porcentaje muy bajo sin documentarse resistencias. El Estafilococo aureus no presenta resistencias que sugiera la aparición de nuevos clones.

L´onconasa com a model per l´estudi de les bases moleculars de la citotoxicitat de les ribonucleases pancreàtiques. Aplicacions a la construcció de ribonucleases amb activitat antimicrobiana

La primera part d'aquest treball s´ha centrat en la caracterització i optimització del procés d'activació de l´onconasa recombinant per tal d'obtenir l´enzim igual a la forma nativa. Per això, les reaccions d'eliminació de la Met-1 i la ciclació de la Glu1, necessàries per generar el piroglutamic han estat seguides per MALDI-TOF MS. La segona part d´aquest treball s´ha centrat en l´estudi de la contribució del pont disulfur 30-75 de l´onconasa a les seves propietats biològiques. Els resultats suggereixen que el potencial redox del citosol cel·lular podria reduir el pont disulfur 30-75 de l´onconasa salvatge afectant la unió onconasa -inhibidor proteic de ribonucleases. La tercera part ha consistit en la construcció de variants de l´HP-RNasa i onconasa amb activitat bactericida. Per això, s´ha introduït el determinant bactericida (YRWR) descrit per la proteïna catiònica d'eosinòfils en els dos enzims. Els resultats obtinguts han evidenciat que les dues ribonucleases amb el determinant bactericida presenten activitat citotòxica contra bacteris gram-negatius preferentment.

Síntesi de base sòlida de pèptids biarílics contenint 5-arilhistidines

Els aminoàcids biarílics es troben en una àmplia varietat de pèptids naturals amb important activitat biològica. Concretament, les arilhistidines formen part de les aciculitines, pèptids amb activitat citotòxica i antifúngica, La reacció de Suzuki-Miyaura és el mètode més versàtil per obtenir biarils assimètrics, encara que, fins el moment, no s'havia aplicat per a l'arilació de l'imidazole de la histidina. L'objectiu general d'aquesta tesi fou demostrar que es podia arilar l'imidazole de la histidina en fase sòlida mitjançant una reacció de Suzuki-Miyaura. En primer lloc, es sintetitzaren 4(5)-metil-5(4)-fenilimidazole i 4(5)-metil-5(4)-(2-metoxifenil)imidazole a través de l'acoblament creuat entre un N-benzilbromoimidazole i el corresponent àcid arilborònic. Posteriorment, s'arilaren 5-bromohistidines utilitzant diversos àcids arilborònics mitjançant una reacció de Suzuki-Miyaura assistida per irradiació micrones, tant en dissolució com en fase sòlida. I finalment, mitjançant aquesta metodología, es sintetitzaren pèptids antimicrobians contenint 5-arilhistidines actius contra bacteris gram-negatius responsables d'importants malalties en plantes com el foc bacterià.

Pesquisa das actividades antioxidante e antimicrobiana em extractos de plantas do género Plectranthus

O uso de plantas medicinais é uma tendência generalizada na medicina popular. O género Plectranthus pertence à família das Lamiaceae tal como a salva (Salvia), o manjericão (Ocimum) e a hortelã (Mentha), que apresentam uma grande diversidade de usos etnobotânicos. No presente trabalho, foram avaliadas as atividades antimicrobiana e antioxidante de extractos de cinco espécies do género Plectranthus: P. hadiensis (vd), P. madagascarensis, P. neochilus, P. verticillatus e P. barbatus. Os extractos foram obtidos por diversos métodos: infusão, decocção, ultra-sons, micro-ondas e maceração (10% m/v de planta seca) com dois solventes diferentes (água e acetona). O método de infusão permitiu obter a maior quantidade de extrato seco a partir da planta Plectranthus barbatus (22 ± 1,0 – 33 ± 3,0 mg/mL). A actividade antimicrobiana dos extratos obtidos foi determinada usando o método da difusão em poço e foi testada contra três bactérias Gram-positivas e duas bactérias Gram-negativas. Só os extratos acetónicos de P. madagascarensis, P. verticillatus e P. hadiensis (vd) demonstraram ser ativos e exclusivamente em bactérias Gram-positivas. O extrato de P. madagascarensis demonstrou a maior actividade antibacteriana com halos de inibição entre 23 e 36 mm. A atividade antioxidante dos extratos foi determinada qualitativamente usando o método do radical 2,2-difenil-1-picril-hidrazina (DPPH) em ccd obtiveram-se resultados positivos na maioria dos extractos estudados.

Shifts in rhizosphere microbial communities and enzyme activity of Poa alpina across an alpine chronosequence

This study quantifies the influence of Poa alpina on the soil microbial community in primary succession of alpine ecosystems, and whether these effects are controlled by the successional stage. Four successional sites representative of four stages of grassland development (initial, 4 years (non-vegetated); pioneer, 20 years; transition, 75 years; mature, 9500 years old) on the Rotmoos glacier foreland, Austria, were sampled. The size, composition and activity of the microbial community in the rhizosphere and bulk soil were characterized using the chloroform-fumigation extraction procedure, phospholipid fatty acid (PLFA) analysis and measurements of the enzymes beta-glucosidase, beta-xylosidase, N-acetyl-beta-glucosaminidase, leucine aminopeptidase, acid phosphatase and sulfatase. The interplay between the host plant and the successional stage was quantified using principal component (PCA) and multidimensional scaling analyses. Correlation analyses were applied to evaluate the relationship between soil factors (C-org, N-t, C/N ratio, pH, ammonium, phosphorus, potassium) and microbial properties in the bulk soil. In the pioneer stage microbial colonization of the rhizosphere of P. alpina was dependent on the reservoir of microbial species in the bulk soil. As a consequence, the rhizosphere and bulk soil were similar in microbial biomass (ninhydrin-reactive nitrogen (NHR-N)), community composition (PLFA), and enzyme activity. In the transition and mature grassland stage, more benign soil conditions stimulated microbial growth (NHR-N, total amount of PLFA, bacterial PLFA, Gram-positive bacteria, Gram-negative bacteria), and microbial diversity (Shannon index H) in the rhizosphere either directly or indirectly through enhanced carbon allocation. In the same period, the rhizosphere microflora shifted from a G(-) to a more G(+), and from a fungal to a more bacteria-dominated community. Rhizosphere beta-xylosidase, N-acetyl-beta-glucosaminidase, and sulfatase activity peaked in the mature grassland soil, whereas rhizosphere leucine aminopeptidase, beta-glucosidase, and phosphatase activity were highest in the transition stage, probably because of enhanced carbon and nutrient allocation into the rhizosphere due to better growth conditions. Soil organic matter appeared to be the most important driver of microbial colonization in the bulk soil. The decrease in soil pH and soil C/N ratio mediated the shifts in the soil microbial community composition (bacPLFA, bacPLFA/fungPLFA, G(-), G(+)/G(-)). The activities of beta-glucosidase, beta-xylosidase and phosphatase were related to soil ammonium and phosphorus, indicating that higher decomposition rates enhanced the nutrient availability in the bulk soil. We conclude that the major determinants of the microllora vary along the successional gradient: in the pioneer stage the rhizosphere microflora was primarily determined by the harsh soil environment; under more favourable environmental conditions, however, the host plant selected for a specific microbial community that was related to the dynamic interplay between soil properties and carbon supply. (C) 2004 Elsevier Ltd. All rights reserved.

Shifts in rhizosphere microbial communities and enzyme activity of Poa alpina across an alpine chronosequence

This study quantifies the influence of Poa alpina on the soil microbial community in primary succession of alpine ecosystems, and whether these effects are controlled by the successional stage. Four successional sites representative of four stages of grassland development (initial, 4 years (non-vegetated); pioneer, 20 years; transition, 75 years; mature, 9500 years old) on the Rotmoos glacier foreland, Austria, were sampled. The size, composition and activity of the microbial community in the rhizosphere and bulk soil were characterized using the chloroform-fumigation extraction procedure, phospholipid fatty acid (PLFA) analysis and measurements of the enzymes beta-glucosidase, beta-xylosidase, N-acetyl-beta-glucosaminidase, leucine aminopeptidase, acid phosphatase and sulfatase. The interplay between the host plant and the successional stage was quantified using principal component (PCA) and multidimensional scaling analyses. Correlation analyses were applied to evaluate the relationship between soil factors (C-org, N-t, C/N ratio, pH, ammonium, phosphorus, potassium) and microbial properties in the bulk soil. In the pioneer stage microbial colonization of the rhizosphere of P. alpina was dependent on the reservoir of microbial species in the bulk soil. As a consequence, the rhizosphere and bulk soil were similar in microbial biomass (ninhydrin-reactive nitrogen (NHR-N)), community composition (PLFA), and enzyme activity. In the transition and mature grassland stage, more benign soil conditions stimulated microbial growth (NHR-N, total amount of PLFA, bacterial PLFA, Gram-positive bacteria, Gram-negative bacteria), and microbial diversity (Shannon index H) in the rhizosphere either directly or indirectly through enhanced carbon allocation. In the same period, the rhizosphere microflora shifted from a G(-) to a more G(+), and from a fungal to a more bacteria-dominated community. Rhizosphere beta-xylosidase, N-acetyl-beta-glucosaminidase, and sulfatase activity peaked in the mature grassland soil, whereas rhizosphere leucine aminopeptidase, beta-glucosidase, and phosphatase activity were highest in the transition stage, probably because of enhanced carbon and nutrient allocation into the rhizosphere due to better growth conditions. Soil organic matter appeared to be the most important driver of microbial colonization in the bulk soil. The decrease in soil pH and soil C/N ratio mediated the shifts in the soil microbial community composition (bacPLFA, bacPLFA/fungPLFA, G(-), G(+)/G(-)). The activities of beta-glucosidase, beta-xylosidase and phosphatase were related to soil ammonium and phosphorus, indicating that higher decomposition rates enhanced the nutrient availability in the bulk soil. We conclude that the major determinants of the microllora vary along the successional gradient: in the pioneer stage the rhizosphere microflora was primarily determined by the harsh soil environment; under more favourable environmental conditions, however, the host plant selected for a specific microbial community that was related to the dynamic interplay between soil properties and carbon supply. (C) 2004 Elsevier Ltd. All rights reserved.

The effect of selective decontamination of the digestive tract on mortality in multiple trauma patients: a multicenter randomized controlled trial

Objective: Evaluation of selective decontamination of the digestive tract (SDD) on late mortality in ventilated trauma patients in an intensive care unit (ICU). Methods: A multicenter, randomized controlled trial was undertaken in 401 trauma patients with Hospital Trauma Index-Injury Severity Score of 16 or higher. Patients were randomized to control (n = 200) or SDD (n = 201), using polymyxin E, tobramycin, and amphotericin B in throat and gut throughout ICU treatment combined with cefotaxime for 4 days. Primary endpoint was late mortality excluding early death from hemorrhage or craniocerebral injury. Secondary endpoints were infection and organ dysfunction. Results: Mortality was 20.9% with SDD and 22.0% in controls. Overall late mortality was 15.3% (57/372) as 29 patients died from cerebral injury, 16 SDD and 13 control. The odds ratio (95% confidence intervals) of late mortality for SDD relative to control was 0.75 (0.40-1.37), corresponding to estimates of 13.4% SDD and 17.2% control. The overall infection rate was reduced in the test group (48.8% vs. 61.0%). SDD reduced lower airway infections (30.9% vs. 50.0%) and bloodstream infections due to aerobic Gram-negative bacilli (2.5% vs. 7.5%). No difference in organ dysfunction was found. Concluson: This study demonstrates that SDD significantly reduces infection in multiple trauma, although this RCT in 401 patients was underpowered to detect a mortality benefit.

Caf1A usher possesses a Caf1 subunit-like domain that is crucial for Caf1 fibre secretion

The chaperone/usher pathway controls assembly of fibres of adhesive organelles of Gram-negative bacteria. The final steps of fibre assembly and fibre translocation to the cell surface are co-ordinated by the outer membrane proteins, ushers. Ushers consist of several soluble periplasmic domains and a single transmembrane beta-barrel. Here we report isolation and structural/functional characterization of a novel middle domain of the Caf1A usher from Yersinia pestis. The isolated UMD (usher middle domain) is a highly soluble monomeric protein capable of autonomous folding. A 2.8 angstrom (1 angstrom = 0.1 nm) resolution crystal structure of UMD revealed that this domain has an immunoglobulin-like fold similar to that of donor-strand-complemented Caf1 fibre subunit. Moreover, these proteins displayed significant structural similarity. Although UMD is in the middle of the predicted amphipathic beta-barrel of Caf1A, the usher still assembled in the membrane in the absence of this domain. UMD did not bind Caf1M-Caf1 complexes, but its presence was shown to be essential for Caf1 fibre secretion. The study suggests that UMD may play the role of a subunit-substituting protein (dummy subunit), plugging or priming secretion through the channel in the Caf1A usher. Comparison of isolated UMD with the recent strcture of the corresponding domain of PapC usher revealed high similarity of the core structures, suggesting a universal structural adaptation of FGL (F(1)G(1) long) and FGS (F(1)G(1) short) chaperone/usher pathways for the secretion of different types of fibres. The functional role of two topologically different states of this plug domain suggested by structural and biochemical results is discussed.

Burkholderia Hep_Hag autotransporter (BuHA) proteins elicit a strong antibody response during experimental glanders but not human melioidosis

BACKGROUND: The bacterial biothreat agents Burkholderia mallei and Burkholderia pseudomallei are the cause of glanders and melioidosis, respectively. Genomic and epidemiological studies have shown that B. mallei is a recently emerged, host restricted clone of B. pseudomallei. RESULTS: Using bacteriophage-mediated immunoscreening we identified genes expressed in vivo during experimental equine glanders infection. A family of immunodominant antigens were identified that share protein domain architectures with hemagglutinins and invasins. These have been designated Burkholderia Hep_Hag autotransporter (BuHA) proteins. A total of 110/207 positive clones (53%) of a B. mallei expression library screened with sera from two infected horses belonged to this family. This contrasted with 6/189 positive clones (3%) of a B. pseudomallei expression library screened with serum from 21 patients with culture-proven melioidosis. CONCLUSION: Members of the BuHA proteins are found in other Gram-negative bacteria and have been shown to have important roles related to virulence. Compared with other bacterial species, the genomes of both B. mallei and B. pseudomallei contain a relative abundance of this family of proteins. The domain structures of these proteins suggest that they function as multimeric surface proteins that modulate interactions of the cell with the host and environment. Their effect on the cellular immune response to B. mallei and their potential as diagnostics for glanders requires further study.

The use of bioluminescence for monitoring in planta growth dynamics of a Pseudomonas syringae plant pathogen

The use of bioluminescence was evaluated as a tool to study Pseudomonas syringae population dynamics in susceptible and resistant plant environments. Plasmid pGLITE, containing the luxCDABE genes from Photorhabdus luminescens, was introduced into Pseudomonas syringae pv. phaseolicola race 7 strain 1449B, a Gram-negative pathogen of bean (Phaseolus vulgaris). Bacteria recovered from plant tissue over a five-day period were enumerated by counting numbers of colony forming units and by measurement of bioluminescence. Direct measurement of bioluminescence from leaf disc homogenates consistently reflected bacterial growth as determined by viable counting, but also detected subtle effects of the plant resistance response on bacterial viability. This bioluminescence procedure enables real time measurement of bacterial metabolism and population dynamics in planta, obviates the need to carry out labour intensive and time consuming traditional enumeration techniques and provides a sensitive assay for studying plant effects on bacterial cells.

Psychrobacter pulmonis sp nov., isolated from the lungs of lambs

Unusual Gram-negative, catalase- and oxidase-positive, coccus-shaped bacteria isolated from the lungs of two lambs were characterized by phenotypic and molecular-genetic methods. Comparative 16S rRNA gene sequencing studies demonstrated that the unknown isolates were genealogically highly related to each other (99.8% sequence similarity) and represent a novel subline within the genus Psychrobacter. The unknown bacterium was phylogenetically closely related to, but distinct from, Psychrobacter phenylpyruvicus, Psychrobacter immobilis, Psychrobacter glacincola and Psychrobacter urativorans. The novel Psychrobacter isolates were readily distinguished from all other Psychrobacter species and other Gram-negative, oxidase-positive bacteria usually responsible for lung infections in sheep by physiological and biochemical tests. Based on molecular-genetic and phenotypic evidence, it is proposed that the unknown Psychrobacter isolates from lambs be classified as Psychrobacterpulmonis sp. nov. The type strain is strain S-606(T) (= CECT 5989(T) = CCUG 46240(T)).