Evidencia molecular de la ocurrencia de bacterias celulolíticas del género Cohnella en especies neotropicales de Nasutitermitinae colectadas en el NEA / Molecular evidence that cellulolytic bacterial genus Cohnella is widespread among Neotropical Nasutitermitinae from NE Argentina

Cohnella is a highly cellulolytic bacterial genus, which can be found in a variety of habitats. The aim of this study was to assess its presence in the digestive tract of termite species collected in North-eastern Argentina: Nasutitermes aquilinus, N. corniger and Cortaritermes fulviceps. Gut homogenates were incubated with cellulosic substrate for bacterial growth. Bacterial 16S rDNA was partially amplified using new primers for Cohnella spp. and cloned. Sequences obtained showed highest similarity (97.2-99.9%) with those of Cohnella spp. previously reported from diverse environments. Phylogenetic analysis tended to group the clones according to their host species and sampling sites. These results indicate the association of Cohnella-related intestinal symbionts with three common Neotropical termites. Their potential industrial application encourages further research.

Cohnella es un género de bacterias celulolíticas que puede ser encontrado en una variedad de hábitats. El propósito de este estudio fue registrar su presencia en el tracto digestivo de termitas (Nasutitermes aquilinus, N. corniger y Cortaritermes fulviceps) colectadas en el noreste argentino (NEA). Se incubaron homogenados de intestinos en sustrato celulósico para multiplicar las bacterias. Utilizando nuevos cebadores para Cohnella spp., se amplificó una porción del ADN ribosomal 16S bacteriano, el cual fue posteriormente clonado. Las secuencias obtenidas mostraron su mayor porcentaje de similitud (97,2-99,9%) con Cohnella spp., previamente reportadas en diversos ambientes. El análisis filogenético tendió a agrupar a los clones de acuerdo a la especie hospedante y al sitio de muestreo. Estos resultados indican que especies de termitas frecuentes en el NEA albergan simbiontes intestinales relacionados con el género Cohnella. Las potenciales aplicaciones industriales de estos microorganismos animan a profundizar los estudios.

Evaluación económica de la implantación del autoanalizador Alfred 60/AST de detección de crecimiento bacteriano con sembrador automático / Economic evaluation of the Alfred 60/AST device implantation for bacterial growth detection with automatic sewing machine

Introducción: En los laboratorios de microbiología se impone cada vez más utilizar sistemas de cribado automatizados para descartar las orinas negativas. Nuestro objetivo fue estimar el umbral presupuestario a partir del cual el autoanalizador Alfred-60/AST sería rentable para nuestro hospital. Material y métodos: Estudio de minimización de costes mediante árboles de decisión, realizado en un Hospital General. Se comparó el coste del urocultivo tradicional con el procesamiento automático mediante Alfred-60/AST. El procesamiento tradicional supone el cultivo manual de todas las orinas recibidas en agar sangre y MacConkey e identificación de todos los microorganismos aislados con el sistema Vitek-2. El autoanalizador sembraría solo las orinas positivas en un medio cromogénico que identificaría directamente los aislamientos de Escherichia coli. Resultados: Las variables con mayor impacto económico en el modelo fueron la probabilidad de obtener un cultivo positivo, la prevalencia de E. coli en los urocultivos y el coste por muestra del sembrador. El análisis de sensibilidad multivariante mostró que el modelo es sólido. El análisis de sensibilidad bivariable mostró que el modelo es sensible a la modificación de los costes, principalmente del sembrador automático. A un valor umbral de 1,40 euros por determinación, el procesamiento automático reduciría los costes anuales en 2.879 euros. Conclusión: La introducción del autoanalizador Alfred-60/AST en nuestro laboratorio a un precio de 1,40 euros por determinación reduciría la carga de trabajo en el procesamiento de orinas, ahorrando tiempo y costes

Introduction: It is becoming increasingly necessary to automatize screening of urine samples to culture at Microbiology laboratories. Our objective was to estimate the budget threshold from which the Alfred 60/AST device would be profitable for our hospital. Material and methods: Cost minimization study by decision trees, carried out in a General Hospital. The cost of traditional urine culture and urine processing using Alfred-60/AST were compared. Traditional processing involves the culture of all urine specimens received onto blood and MacConkey agar, and identification of every microorganism isolated by Vitek-2 system. The autoanalyzer would only inoculate the positive urines onto a chromogenic media, directly identifying the Escherichia coli isolates. Results: The variables with the greatest economic impact in the model were the probability of obtaining a positive culture, the prevalence of E. coli in the urine cultures and the cost per sample using Alfred-60/AST. The multivariate sensitivity analysis showed that the model was solid. The bivariate sensitivity analysis showed that the model is suceptible to cost modification, mainly of the automatic device. At a threshold value of 1.40 euros/determination, the automatic processing would decrease the annual costs in 2,879 euros. Conclusion: The introduction of the Alfred-60/AST device in our laboratory at 1.40 euros/determination would reduce urine processing workload, saving time and costs

Antimicrobial peptide from Bacillus subtilis CSB138: characterization, killing kinetics, and synergistic potency

We studied the prospect of synergy between the antimicrobial peptide p138c and non-peptide antibiotics for increasing the potency and bacterial killing kinetics of these agents. The production of p138c was maximized in the late exponential growth phase of Bacillus subtilis CSB138. Purification of p138c resulted in a total of 4800 arbitrary units (AU) with 19.15-fold and 3.2% recovery. Peptide p138c was thermo-tolerant up to 50 °C and stable at pH 5.8 to 11. The biochemical nature of p138c was determined by a bioassay, similar to tricine-SDS-PAGE, indicating inhibition at 3 kDa. The amino acid sequence of p138c was Gly-Leu-Glu-Glu-Thr-Val-Tyr-Ile-Tyr-Gly-Ala-Asn-Met-X-Ser. Potency and killing kinetics against vancomycin-resistant Staphylococcus aureus improved considerably when p138c was synergized with oxacillin, ampicillin, and penicillin G. The minimal inhibitory concentration (MIC) of p138c showed a 4-, 8-, and 16-fold improvement when p138c was combined with oxacillin, ampicillin, and penicillin G, respectively. The fractional inhibitory concentration index for the combination of p138c and oxacillin, ampicillin, and penicillin G was 0.3125, 0.25, and 0.09, respectively. Synergy with non-peptide antibiotics resulted in enhanced killing kinetics of p138c. Hence, the synergy between antimicrobial peptide and non-peptide antibiotics may enhance the potency and bacterial killing kinetics, providing more potent and rapidly acting agents for therapeutic use (AU)

No disponible

Endophytic and rhizospheric bacterial communities isolated from the medicinal plants Echinacea purpurea and Echinacea angustifolia

In this work we analyzed the composition and structure of cultivable bacterial communities isolated from the stem/leaf and root compartments of two medicinal plants, Echinacea purpurea (L.) Moench and Echinacea angustifolia (DC.) Hell, grown in the same soil, as well as the bacterial community from their rhizospheric soils. Molecular PCR-based techniques were applied to cultivable bacteria isolated from the three compartments of the two plants. The results showed that the two plants and their respective compartments were characterized by different communities, indicating a low degree of strain sharing and a strong selective pressure within plant tissues. Pseudomonas was the most highly represented genus, together with Actinobacteria and Bacillus spp. The presence of distinct bacterial communities in different plant species and among compartments of the same plant species could account for the differences in the medicinal properties of the two plants (AU)

No disponible

Duodenosis linfocítica: estudio etiológico y formas de presentación clínica / Lymphocytic duodenosis: etiological study and clinical presentations

INTRODUCCIÓN: La duodenosis linfocítica (DL) es una lesión característica en las fases iniciales de la enfermedad celíaca (EC), pero puede asociarse a otras muchas entidades. El objetivo de este trabajo fue evaluar la prevalencia de las diferentes causas de DL y valorar posibles diferencias en la presentación clínica según la etiología responsable. Métodos Estudio retrospectivo que incluye 194 pacientes diagnosticados de una DL (más de 25 linfocitos intraepiteliales por 100 células epiteliales). Se siguió una estrategia de evaluación etiológica definida que incluyó serología celíaca (anticuerpos antitransglutaminasa), genotipos HLA-DQ2/DQ8, diagnóstico Helicobacter pylori (H. pylori) y sobrecrecimiento bacteriano intestinal (SBID). El diagnóstico de EC se estableció en función de la respuesta clínica e histológica a una DSG en pacientes con serología positiva o un estudio HLA-DQ2 (al menos uno de los alelos) o −DQ8 (ambos alelos) compatibles. Resultados La EC (39%) resultó la causa más frecuente de DL, seguida por SBID (22%), H. pylori (14%), EC y SBID (12%) y otras causas (13%). La mayoría (83%) de los pacientes presentaron un genotipo HLA-DQ2 o −DQ8 compatible. En estos pacientes el diagnóstico más frecuente fue la EC (46%), mientras que en ausencia de HLA-DQ2/DQ8 los diagnósticos más frecuentes fueron el SBID (44%) y H. pylori (22%). En los pacientes enviados por dispepsia, diarrea y anemia, la EC fue el diagnóstico más frecuente, mientras que H. pylori lo fue en los pacientes con dolor abdominal. Conclusiones La EC, seguida del SBID y la infección por H. pylori, constituyen las causas más frecuentes de DL en nuestro medio

INTRODUCTION: Lymphocytic duodenosis (LD) is a characteristic lesion in the initial phases of celiac disease (CD) but can be associated with many other entities. The aim of this study was to evaluate the prevalence of distinct causes of LD and possible differences in clinical presentation according to etiology. METHODS: A retrospective study was performed that included 194 patients diagnosed with LD(more than 25 intraepithelial lymphocytes per 100 epithelial cells). A preestablished strategy to evaluate the cause of the disease was followed that included celiac serology (antitransglutaminase antibodies), HLA-DQ2/DQ8 genotypes, diagnosis of Helicobacter pylori and small intestinal bacterial overgrowth (SIBO). Diagnosis of CD was established on the basis of clinical and histological response to a gluten-free diet in patients with positive serology or compatible findings on HLA-DQ2 (at least one of the alleles) or -DQ8 (both alleles) study. RESULTS: The most frequent cause of LD was CD (39%), followed by SBBO (22%), H.pylori (14%), CD and SIBO (12%), and other causes (13%). Most of the patients (83%) had a compatible HLA-DQ2 or -DQ8 genotype. In these patients, the most frequent diagnosis was CD (46%), while in the absence of HLA-DQ2/DQ8, the most frequent diagnoses were SIBO (44%) and H. pylori (22%). CD was the most frequent diagnosis in patients referred for dyspepsia, diarrhea and anemia, while H. pylori was the most frequent diagnosis in patients with abdominal pain. CONCLUSIONS: The most common causes of LD in our environment are CD, followed by SIBO and H. pylori infection

Tuberculosis drogorresistente: mecanismos moleculares y métodos diagnósticos / Drug resistant tuberculosis: molecular mechanisms and diagnostic methods

Pese a que la tuberculosis (TB) viene acompañando a la humanidad desde el neolítico, ésta se mantiene como un serio problema de salud pública, agravado en los últimos años por el fenómeno de la resistencia a los antibióticos. La OMS establece que el diagnóstico de la tuberculosis drogorresistente (TB-DR) es fundamental para su control y al mismo tiempo considera que los procedimientos diagnósticos tradicionales han llegado a un límite resolutivo. Ante este crítico escenario, el entendimiento de los mecanismos moleculares que explican el fenómeno de la TB-DR, combinado con novedosas técnicas moleculares, están permitiendo desarrollar de toda una nueva generación de procedimientos diagnósticos de TB-DR. Sin embargo, ¿cuáles son estos mecanismos genéticos generadores de TB-DR? y ¿cuáles son las características, ventajas y limitaciones de estas nuevas metodologías diagnósticas? son las preguntas que se pretenden responder con el presente trabajo (AU)

Despite the fact that Tuberculosis (TB) has been found in humans since the Neolithic Age, it still remains serious public health problem, increased in the last few years due to the phenomenon of drug resistance (DR). The World Health Organization (WHO) established that the diagnosis of tuberculosis drug resistance (DR) is essential for its control, and at the same time considers that the traditional diagnostic procedures have reached their limit. In view of this critical scenario, the understanding of the molecular mechanisms that explain the phenomenon of the TB-DR, in combination with novel techniques in molecular biology, are allowing a new generation of diagnostic procedures to be developed for TB-DR. However, this work sets out to answer the questions of what these molecular mechanisms TB-DR are,as well as their characteristics, advantages and limitations of these new diagnostic methodologies (AU)

Trombo e vegetação em átrio direito em paciente renal crônico e bacteremia frequente / Right atrium thrombosis and vegetation in chronic renal patient with frequent bacteremia

A utilização temporária de catéter central, em pacientes com insuficiência renal crônica, pode estar associada a trombo em átrio direito. Na ocorrência de bacteremia, a hipótese de trombo infectado, apesar de raro, deve ser lembrada, devido à gravidade do quadro clínico e à necessidade de intervenção cirúrgica.

Predicción del crecimiento de la Lactococcus lactis subsp. lactis en leche descramada estéril en función a la temperatura / Growth prediction of Lactococcus lactis subsp. lactis in sterile skimed milk as a function of temperature

Diversos modelos matemáticos han sido desarrollados con el objeto de predecir el comportamiento de las poblaciones bacterianas en fase de crecimiento en condiciones controladas a nivel de laboratorio, muchos de estos han sido validados en condiciones de producción, transporte y almacenamiento de alimentos. El objetivo del presente trabajo fué adaptar un modelo matemático utilizando ecuaciones obtenidas como resultado del análisis con modelos secundarios de los coeficientes de regresión de la ecuación de Gompertz, a efectos de lograr predecir las poblaciones en crecimiento de Lactococcus lactis subsp. lactis en leche en polvo reconstituida y esterilizada, controlando la temperatura en el rango desde 9 a 39°C. Con este fin, los coeficientes “A” y “B” se analizaron con el modelo de la raíz cuadrada, obteniéndose valores de R2 = 0,819 y 0,991, respectivamente, mientras que el modelo hiperbólico se utilizó para modelar los coeficientes “D” (R2= 0,812) y “M” (R2= 0,995). Finalmente se obtuvo una expresión reparametrizada del modelo original de Gompertz, sustituyendo cada coeficiente de regresión por la ecuación que lo describe, en función a las diferentes temperaturas estudiadas, siendo este modelo utilizado para predecir directamente las poblaciones del microorganismo en estudio a cualquier temperatura dentro del rango estudiado. Se obtuvieron diferencias muy pequeñas entre la población observada experimentalmente y la ajustada según la aplicación del modelo desarrollado, observándose una distribución bastante equilibrada de los valores residuales. Se recomienda utilizar este tipo de modelo para describir el crecimiento de poblaciones combinadas en productos como leche pasteurizada comercial.

Several mathematic models have been developed to predict the behavior of bacteria populations in growing phase and controlled conditions at the laboratory. Many of these models have been validated under food production, transportation and storage conditions. The objective of this study was to adapt a mathematical model using equations obtained as a result of the analysis with secondary models of regression coefficients from the Gompertz equation, to predict population of Lactococcus lactis subsp. lactis in the growing phase in reconstituted and sterilized powder milk, controlling temperature in a range of 9 to 39°C. Prediction was done by the analysis of “A” and “B” coefficients, using the square root model, obtaining R2 values = 0.819 and 0.991, respectively. Furthermore, a hyperbolic model was used for modeling “D” (R2= 0.812) and “M” (R2= 0.995) coefficients. Finally, a reparametrized expression of the original Gompertz model was obtained replacing each regression coefficient by the described equation, in relation to the different studied temperatures. Thus, this model was used to directly predict the population of microorganism under study at any temperature in the studied range. Small differences were obtained between both, the experimental and the adjusted populations, according to the application of the developed model. A well balanced distribution of the residual values was observed. The use of this type of models is recommended to describe growth of combined microorganism populations in products such as commercial pasteurized milk.

O efeito do laser de baixa energia no crescimento bacteriano "in vitro" / Low level laser effect in \"in vitro\" bacterial growth

OBJETIVO: Avaliar, por meio de estudo bacteriológico in vitro, o efeito de dois tipos de laser de baixa energia (LBE) sobre diferentes populações bacterianas habitualmente presentes em feridas pós-traumáticas. MÉTODOS: Foram colhidos swabs diretamente do sítio de infecção de pacientes internados com osteomielite pós-traumática crônica. As bactérias isoladas foram Acinetobacter baumanii complex, Escherichia coli, Haemophilus influenzae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonela sp, Serratia sp e Staphylococcus aureus. O material coletado foi semeado em meio ágar-sangue, através de alça estéril, utilizando-se 30 placas de Petri para cada germe. Foram utilizados dois aparelhos de LBE: Ibramed Laser Pulse #01189, com 15W/904nm por 200 segundos, e Phisiolux dual Bioset #9909001, com 20W/904nm por 230 segundos. Nos grupos I (n = 10) e II (n = 10), as bactérias sofreram irradiação pelo laser. O grupo III (n = 10) serviu de controle, não sendo irradiado. As bactérias dos grupos I e II foram irradiadas em câmara de fluxo laminar, previamente esterilizada por raio ultravioleta. O laser foi administrado de forma direta, central e perpendicularmente à superfície de cultivo das bactérias, com distância-padrão de 1cm, através de orifício confeccionado na tampa das placas. O crescimento bacteriano foi analisado após 12 e 24 horas da irradiação. Os resultados foram processados estatisticamente, utilizando-se o teste não-paramétrico de Kruskall-Wallis, com nível de significância p < 5 por cento. RESULTADOS: Observou-se comportamento similar entre as populações bacterianas nos três grupos experimentais após 12 e 24 horas da irradiação com os dois tipos de LBE, não havendo diferença estatisticamente significante no crescimento bacteriano entre os grupos I e II e entre estes e o grupo III (controle). CONCLUSÃO: O efeito do LBE, nas condições estudadas, mostrou-se inócuo quanto ao aumento do número de unidades formadoras de colônias bacterianas,...

OBJECTIVE: To perform an in vitro bacteriologic study to evaluate the effect of two types of low level laser (LLL) on different bacterial populations usually present in post-traumatic wounds. METHODS: Swabs were prepared directly at the infection site of patients hospitalized with chronic post-traumatic osteomyelitis. Isolated bacteria were Acinetobacter baumanii complex, Escherichia coli, Haemophilus influenzae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonela sp, Serratia sp, and Staphylococcus aureus. The material collected was seeded in agar-blood medium with a sterile loop, using 30 Petri dishes for each germ. Two LLL devices were used: Ibramed Laser Pulse #01189, with 15W/904nm for 200 seconds, and Phisiolux dual Bioset #9909001, with 20W/904nm for 230 seconds. In groups I (n = 10) and II (n = 10), bacteria were irradiated with laser. Group III (n = 10) was the control group and was not irradiated. Bacteria in groups I and II were submitted to radiation in a laminar flow chamber that was previously sterilized with UV rays, and the laser was directly, centrally, and perpendicularly applied to the bacteria cultivation surface, from a standard distance of one centimeter, through an orifice made in the lid of the dishes. Bacterial growth was analyzed 12 and 24 hours after the irradiation. Results were statistically processed using the non-parametric test of Kruskall-Wallis, with a significance level p < 5 percent. RESULTS: A similar behavior was seen in the bacterial population of the three groups studied after 12 and 24 hours of irradiation with the two types of LLL, and there was no statistically significant difference in the bacterial growth between groups I and II and between these two groups and group III (control). CONCLUSION: In the conditions of this study, the effect of LLL showed to be innocuous for the increase in the number of units forming bacterial colonies, in the doses used in this study, as an adjuvant for...