Comparison of selective culture media for the isolation of Taxon K species belonging to the Burkholderia cepacia complex

Objetivo: Dentro del complejo Burkholderia cepacia (cBc), el Taxón K, integrado por B. contaminans y B. lata, es frecuentemente aislado de muestras clínicas e industriales. Los métodos para aislar bacterias del cBc están consensuados en el ámbito clínico pero no para muestras de origen industrial y tampoco hay información documentada sobre la capacidad de recuperación de los medios de cultivo frente a especies del Taxón K. Dada la importancia del uso correcto de medios selectivos para la recuperación de microorganismos, el objetivo de este trabajo fue comparar el agar Trypan Blue-Tetraciclina (TB-T), el agar selectivo para Burkholderia cepacia (BCSA) y el BCSA comercial modificado (BCSAm) en el aislamiento de cepas del Taxón K. Métodos: empleamos el método ecométrico utilizado en el control de calidad de medios de cultivo. Analizamos criterios de productividad, selectividad y especificidad frente a cepas de referencia del cBc, aislamientos clínicos e industriales del Taxón K y cepas de otras especies. Resultados: no se observaron diferencias de productividad y selectividad entre los medios BCSA. Con ambos se obtuvo adecuada productividad y selectividad parcial por permitir el crecimiento de especies taxonómicamente cercanas al cBc. El medio TB-T presentó menor productividad (especialmente con B. contaminans) y menor selectividad. Por otra parte, no se observaron diferencias atribuibles al origen clínico o industrial de los aislamientos. Conclusión: los resultados permiten sugerir al BCSA o BCSAm como los medios selectivos de elección para el aislamiento del Taxón K, tanto en muestras de origen clínico como industrial.Objective: Within the Burkholderia cepacia complex (Bcc), the so called Taxon K, integrated by B. contaminans and B. lata, is frequently isolated from clinical and industrial samples. There is consensus in the use of culture media for the isolation of Bcc from clinical origin but not for industrial samples. By the other side there is no documented information about the performance of culture media recovering Taxon K species. Regarding the importance of the proper use of selective media in the recovery of microorganisms from clinical and industrial samples, the objective of this work was to compare Trypan Blue-Tetracycline agar (TB-T), Burkholderia cepacia selective agar (BCSA) and commercial modified Burkholderia cepacia selective agar (BCSAm) in the isolation of Taxon K strains. Methods: we employed the ecometric method for culture media quality control. Productivity, selectivity and specificity criteria were analyzed by testing Bcc reference strains, clinical and industrial Taxon K isolates and non Bcc strains. Results: no differences in terms of productivity and selectivity were observed between BCSA and BCSAm. Both medium, displayed adequate productivity and partial selectivity since the growth of non Bcc isolates was observed. Productivity (especially with B. contaminans isolates) and selectivity in TB-T was lower than BCSA medium. No differences were observed related to the clinical or industrial origin of isolates. Conclusion: results allow us to suggest BCSA or BCSAm selective media for the isolation of Taxon K strains in clinical or industrial samples.Los fondos para la realización del presente trabajo fueron aportados por la cuenta “Métodos Microbianos” administrada bajo el ámbito de la Facultad de Farmacia y Bioquímica de la Universidad de Buenos Aires

Biodiversity of cultivable Burkholderia species in Argentinean soils under no-till agricultural practices

No-tillage crop production has revolutionized the agriculture worldwide. In our country more than 30 Mha are currently cultivated under no-till schemes, stressing the importance of this management system for crop production. It is widely recognized that soil microbiota is altered under different soil managements. In this regard the structure of Burkholderia populations is affected by soils management practices such as tillage, fertilization, or crop rotation. The stability of these structures, however, has not been evaluated under sustainable schemes where the impact of land practices could be less deleterious to physicochemical soils characteristics. In order to assess the structure of Burkholderia spp. populations in no-till schemes, culturable Burkholderia spp. strains were quantified and their biodiversity evaluated. Results showed that Burkholderia spp. biodiversity, but not their abundance, clearly displayed a dependence on agricultural managements. We also showed that biodiversity was mainly influenced by two soil factors: Total Organic Carbon and Total Nitrogen. Results showed that no-till schemes are not per se sufficient to maintain a richer Burkholderia spp. soil microbiota, and additional traits should be considered when sustainability of productive soils is a goal to fulfil productive agricultural schemes.Fil: Draghi, Walter Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Degrossi, Jose. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bialer, Magali Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Brelles Mariño, Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; ArgentinaFil: Abdian, Patricia Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Soler Bistue, Alfonso Jc. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Wall, Luis Gabriel. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zorreguieta, Ángeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentin

Whole Genome Sequence Analysis of Burkholderia contaminans FFH2055 Strain Reveals the Presence of Putative β-Lactamases

Burkholderia contaminans is a member of the Burkholderia cepacia complex (Bcc), a pathogen with increasing prevalence among cystic fibrosis (CF) patients and the cause of numerous outbreaks due to the use of contaminated commercial products. The antibiotic resistance determinants, particularly β-lactamases, have been poorly studied in this species. In this work, we explored the whole genome sequence (WGS) of a B. contaminans isolate (FFH 2055) and detected four putative β-lactamase-encoding genes. In general, these genes have more than 93% identity with β-lactamase genes found in other Bcc species. Two β-lactamases, a class A (Pen-like, suggested name PenO) and a class D (OXA-like), were further analyzed and characterized. Amino acid sequence comparison showed that Pen-like has 82% and 67% identity with B. multivorans PenA and B. pseudomallei PenI, respectively, while OXA-like displayed strong homology with class D enzymes within the Bcc, but only 22–44% identity with available structures from the OXA family. PCR reactions designed to study the presence of these two genes revealed a heterogeneous distribution among clinical and industrial B. contaminans isolates. Lastly, bla PenO gene was cloned and expressed into E. coli to investigate the antibiotic resistance profile and confers an extended-spectrum β-lactamase (ESBL) phenotype. These results provide insight into the presence of β-lactamases in B. contaminans, suggesting they play a role in antibiotic resistance of these bacteria.Fil: Degrossi, José J.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Merino, Cindy. University Fullerton; Estados UnidosFil: Isasmendi, Adela M.. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Ibarra, Lorena M.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Collins, Chelsea. University Fullerton; Estados UnidosFil: Bo, Nicolás E.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Papalia, Mariana Andrea. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Microbiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Fernandez, Jennifer S.. University Fullerton; Estados UnidosFil: Hernandez, Claudia M.. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Papp Wallace, Krisztina M.. Case Western Reserve University; Estados UnidosFil: Bonomo, Robert A.. Case Western Reserve University; Estados UnidosFil: Vazquez, Miryam S.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Power, Pablo. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Microbiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Ramirez, María S.. University Fullerton; Estados Unido

Microesferas de alginato con Bacillus subtilis

La microencapsulación de organismos ha sido considerada como una alternativa de inmovilización de células, a fin de que éstas puedan ejercer sus funciones en forma gradual. El objetivo del presente estudio fue elaborar microesferas de Bacillus subtilis ya sea en forma esporulada como vegetativa. Microesferas de Bacillus subtilis son preparadas utilizando alginato de sodio. Algunas propiedades típicas del sistema microencapsulado, tales como contenido de microorganismos, tamaño de partícula y tiempo de germinación han sido estudiados. Las microesferas se prepararon mediante el método de coaservación-separación de fases, utilizando una etapa intermedia de emulsión múltiple. Las condiciones de preparación han sido lo suficientemente benignas para no producir cambios en las propiedades biológicas generales del sistema, pero con la protección que le otorga la matriz del hidrogel, la cual evita la directa comunicación con el medio externo. La viabilidad demostrada por las microesferas con las formas esporuladas fue significativamente superior a las de las formas vegetativas.Bacillus subtilis microspheres were prepared by using sodium alginate. Some typical properties of microencapsulated systems such as content of microorganisms, particle size and germination time were studied. Microspheres are prepared by the coacervation phase separation method, mainly based on an intermediate stage of primary emulsion. The preparation conditions were very soft to avoid changes in general biological products of calcium alginate microspheres containing cells, but giving them protection with a hydrogel matrix, without preventing the communication with the surrounding medium. The encapsulation of microbial spores and viable cells of a model microorganism (Bacillus subtilis) can be achieved by using sodium alginate in a satisfactory manner. Spore microspheres showed higher viability comparated to vegetative microspheres.The authors wish to acknowledge the support of this work provided UBACyT (01/TB12)

Efectiveness of chlorogenic products destinated to drinking waters

Se propone una metodología para la evaluación de productos clorógenos destinados a la desinfección de aguas para consumo, utilizando materia orgánica para simular el consumo de cloro que tienen las aguas no tratadas. Se evaluó el comportamiento de suspensión de levadura de cerveza, peptona y extracto de levadura frente a dosis usuales (10 mg/L, como cloro total) de comprimidos de la sal disódica de la dicloro-S-triazina-triona. Como comparación se utilizó agua de río. Se determinó la concentración de cada sustancia orgánica que despues de 30 minutos dejó 0,1 mg/L de cloro libre en la solución de ensayo. Posteriormente se ensayó microbiologicamente la efectividad del clorógeno en presencia de dichas sustancias según metodología AFNOR.This work intends a methodology for the evaluation of chlorogenic products destinated to the disinfection of drinking waters . The use of organic matter as challenge sustances to emulate the consumption of chlorine showed by untreated waters is postulated. The behavior of suspensions of beer of yeast, peptone and yeast extract against usual dose (10mg / L, expressed as total chlorine) of Tablets of the disodic salt of the Dichloro - S - Triazine - Trione, was evaluated. River water was used as comparison. The concentration of each organic substance that left at least 0,1 mg/L of free chlorine in the test solution, after 30 min was assayed. Then the chlorogenic compound was microbiologically assayed in presence of the organic solutions, according to AFNOR methodology.Se agradece a la Universidad de Buenos Aires , por apoyar este trabajo a través del programa UBACYT TB21 (período 1998-2000)

A Systematic Literature Review of Geospatial Web Service Composition

Geospatial Web services (GWSs) can be viewed as modular Web applications that provide services or geospatial data, information or knowledge. Combining GWSs and generating composite web services out of atomic services can provide users with a higher level of functionality. Aim: The aim of this study is to obtain an overview of research on geospatial web services composition through a systematic literature review (SLR). Method: A SLR was performed by formulating four research questions to evaluate the selected works. In total, 121 papers were accepted into the final set. Results: The most widely used GWS composition model is the syntactic followed by semantic service composition. Considering that geospatial domain is dynamic, it is necessary to understand the challenges and limitations of the semantic model in depth. Conclusions: There are a significant number of research projects being conducted in this specific Web service composition area targeting the geospatial domain. Our findings identified the need to improve the robustness of the empirical evaluation of existing research

An Experimental Evaluation of a Crowdsourcing-Based Approach for Flood Risk Management

Volunteered geographic information (VGI) is a potential source of information to complement other sources in flood risk management. However, there is still not enough experimental evidence about the usefulness of VGI in different situations and scenarios. We conducted an experimental evaluation for verifying if VGI, obtained through a crowdsourcing platform, can be useful for the flood risk management context. The experiment occurred in two points of the watershed of Sao Carlos/ SP in Brazil with 15 participants. The results show that volunteered geographic information is, in average, comparable to sensor data. Thus, we can conclude that using crowdsourcing for producing VGI can be a useful source for flood risk management

Does Keyword Noise Change Over Space and Time? A Case Study of Social Media Messages

Social media is a valuable source of information for different domains, since users share their opinion and knowledge in (near) real-time. Moreover, users usually use different words to refer to a particular event (e.g., a rain event). These words may be later employed to filter social media messages regarding new occurrences of the event and, thus, to reduce the number of unrelated messages. These words, however, may have different meanings and, thus, may not reduce the number of messages. In this work, we conduct a case study to measure which rain- or flood-related keywords are less relevant to reduce the number of unrelated messages. The results show that the keywords change over space, due to local language/culture, and time, specially in different time scales