[Molecular characterization of diarrheagenic Escherichia coli from an outpatient pediatric population with diarrhea attended in two hospitals from Buenos Aires, Argentina]. / Caracterización molecular de Escherichia coli diarreogénica proveniente de población pediátrica ambulatoria con diarrea, atendida en dos hospitales de Buenos Aires, Argentina.

Diarrheagenic Escherichia coli comprises a heterogeneous group of pathotypes or pathogenic variants that share phenotypic characteristics with marked differences in virulence genes, colonization sites, pathogenesis, clinical presentation, and epidemiology of infection. The most studied pathotypes are Shiga toxin-producing E.coli (STEC), enterotoxigenic E.coli (ETEC), enteropathogenic E.coli (EPEC), enteroaggregative E.coli (EAEC), and enteroinvasive E.coli (EIEC). The objective of the study was to characterize the isolates of diarrheagenic E.coli from an outpatient pediatric population with diarrhea attended in two public hospitals from Buenos Aires, Argentina. Diarrheagenic E.coli pathotypes were investigated by amplifying characteristic virulence gene fragments: intimin (eae), heat-labile toxin (lt), heat-stable toxins (stp, sth), invasion plasmid antigen H (ipaH), transcriptional activator R (aggR) and Shiga toxins (stx1, stx2). Molecular subtyping of isolates was performed using PFGE (XbaI). Diarrheagenic E.coli was detected in 14% (84/601) of cases. The EAEC pathotype was prevalent, while ETEC, STEC, EPEC and EIEC were found in a lower proportion. EAEC isolates exhibited a high degree of genetic diversity. All pathotypes were found in children under 5years of age, while only EAEC, EIEC and ETEC were detected in the older population. Future studies that include the characterization of isolates from a greater number of genes and populations from other geographical areas will be necessary to determine the relevance of diarrheagenic E.coli in Argentina.

Primer reporte de Escherichia coli diarreogénica en población pediátrica ambulatoria con diarrea atendida en la ciudad de La Plata, Argentina / First report of diarrheagenic Escherichia coli in pediatric outpatient population with diarrhea in La Plata, Argentina

Resumen Escherichia coli diarreogénica comprende un grupo heterogéneo de cepas que presentan diversos factores de virulencia y causan diferentes síndromes diarreicos. Los patotipos más estudiados son Escherichia coli enteropatogénica (EPEC), Escherichia coli enterotoxigé-nica (ETEC), Escherichia coli enteroagregativa (EAEC), Escherichia coli enteroinvasiva (EIEC) y Escherichia coli productora de toxina Shiga (STEC). El objetivo de este estudio fue estimar la frecuencia de infección de los diversos patotipos de E. coli diarreogénica en una población pediátrica ambulatoria con diarrea, atendida en el Hospital Sor María Ludovica de La Plata, Argentina, durante el período mayo-octubre de 2017. Los patotipos fueron detectados mediante la amplificación molecular de ocho genes de virulencia característicos. Se estudiaron las heces de 211 ninos (76% menores de 5 años). Se detectó infección con E. coli diarreogénica en el 12,3% (n = 26/211) de los niños con diarrea. Los patotipos identificados fueron EAEC, ETEC (todos lt positivos), EPEC y STEC (stx2 y eae positivos). El patotipo EAEC fue prevalente en todos los grupos etarios, mientras que los patotipos ETEC, EPEC y STEC solamente se observaron en niñnos menores de 5 anños. Este estudio constituye el primer reporte de detección por técnicas de amplificación molecular de Escherichia coli diarreogénica en una población pediátrica ambulatoria con diarrea, de la zona de La Plata. Se necesitan estudios más amplios que incluyan la caracterización de los aislamientos abarcando un mayor número de genes, controles asintomáticos, distintas épocas del ano y población de diversas áreas geográficas para esclarecer la relevancia de la infección por E. coli diarreogénica en niños de Argentina.

Abstract Diarrheagenic Escherichia coli is a heterogeneous group of strains that presents various virulence factors and causes different diarrheal syndromes. The most studied pat-hotypes are enteropathogenic Escherichia coli (EPEC), enterotoxigenic Escherichia coli (ETEC), enteroaggregative Escherichia coli (EAEC), enteroinvasive Escherichia coli (EIEC) and Shiga toxin-producing Escherichia coli (STEC). The objective was to estimate the frequency of infec-tion of diarrheagenic E. coli pathotypes in children with diarrhea, attended at the Sor María Ludovica Hospital in La Plata, Argentina, during the period May-October 2017. E. coli pathotypes were detected by molecular amplification of eight characteristic virulence genes. The feces of 211 children (76% under 5 years) were studied. Infection with diarrheagenic E. coli was detected in 12.3% of the samples. The pathotypes were EAEC (10.43%), ETEC (1.42%, all of them positive for thermolabile toxin), EPEC (0.95%) and STEC (0.47%, positive for Shiga toxin 2). The EAEC pathotype was prevalent in children of all age groups, while ETEC, EPEC and STEC were only observed in children under 5 years of age. This study constitutes the first report of diarrheagenic Escherichia coli detection in an outpatient pediatric population with diarrhea from La Plata, using molecular amplification techniques. Broader future studies, including the charac-terization of the isolates with the largest number of genes, asymptomatic controls, different times of the year and population from different geographic areas will be necessary to clarify the relevance of diarrheagenic E. coli infection in children from Argentina.

[First report of diarrheagenic Escherichia coli in pediatric outpatient population with diarrhea in La Plata, Argentina]. / Primer reporte de Escherichia coli diarreogénica en población pediátrica ambulatoria con diarrea atendida en la ciudad de La Plata, Argentina.

Diarrheagenic Escherichia coli is a heterogeneous group of strains that presents various virulence factors and causes different diarrheal syndromes. The most studied pathotypes are enteropathogenic Escherichia coli (EPEC), enterotoxigenic Escherichia coli (ETEC), enteroaggregative Escherichia coli (EAEC), enteroinvasive Escherichia coli (EIEC) and Shiga toxin-producing Escherichia coli (STEC). The objective was to estimate the frequency of infection of diarrheagenic E. coli pathotypes in children with diarrhea, attended at the Sor María Ludovica Hospital in La Plata, Argentina, during the period May-October 2017. E. coli pathotypes were detected by molecular amplification of eight characteristic virulence genes. The feces of 211 children (76% under 5 years) were studied. Infection with diarrheagenic E. coli was detected in 12.3% of the samples. The pathotypes were EAEC (10.43%), ETEC (1.42%, all of them positive for thermolabile toxin), EPEC (0.95%) and STEC (0.47%, positive for Shiga toxin 2). The EAEC pathotype was prevalent in children of all age groups, while ETEC, EPEC and STEC were only observed in children under 5 years of age. This study constitutes the first report of diarrheagenic Escherichia coli detection in an outpatient pediatric population with diarrhea from La Plata, using molecular amplification techniques. Broader future studies, including the characterization of the isolates with the largest number of genes, asymptomatic controls, different times of the year and population from different geographic areas will be necessary to clarify the relevance of diarrheagenic E. coli infection in children from Argentina.

Survival, physical and physiological changes of Taenia hydatigena eggs under different conditions of water stress.

Taenia hydatigena eggs were investigated for morphological and physiological changes under water stress conditions. Fresh eggs were exposed at 31%, 47% and 89% of relative humidity (RH), and survival, size and ultrastructural changes were accounted up to 365 days of exposition. The article shows how each RH environment affects the vitality of the eggs. Results of this study suggest that T. hydatigena eggs have mechanisms to withstand water stress, indicating that the eggs clustering improves protection against desiccation, and that endogenous metabolism using triacylglycerols play an important role in the maintenance of embryo vitality under low, medium and high relative humidity conditions. This contributes to understanding the water stress resistance mechanism in eggs belonging to Taeniidae family. The findings shown herein have provided a basis to better comprehend basic biology and epidemiology of the cysticercosis caused by T. hydatigena.

First study about the development of adult Echinococcus canadensis G6 genotype of goat origin in experimentally infected dogs.

Echinococcus granulosus sensu lato (E. granulosus sl) must be considered as a species complex, comprising Echinococcus granulosus sensu stricto (E. granulosus ss, genotypes G1-G3), Echinococcus equinus (G4), Echinococcus ortleppi (G5) and Echinococcus canadensis (G6-G10) although the species status of E. canadensis is still controversial. These genotypes closely match the intermediate hosts associated strains described in earlier times among which E. canadensis G6 corresponds to the camel strain. As there are no studies concerning the development of adult stages of the G6 genotype from non-camel origin, the aims of the present study were: to characterize for the first time the development of E. canadensis G6 in dogs experimentally infected with protoscoleces derived from goats, to describe the resultant adult morphology, to evaluate the growth of their rostellar hooks from larval to adult stages and to determine the prepatent period of the strobilar stage of E. canadensis G6 derived from goats. The development of the strobilar stage of E. canadensis G6 genotype of goat origin was examined by studying the growth (variation of the total worm length) and segmentation in experimentally infected dogs at 14, 25, 35 and 56days post infection. A morphological characterization of 35-day-old worms as well as of larval and adult rostellar hooks was also carried out by conventional optical microscopic observations and/or by scanning electron microscopy. The prepatent period of the strobilar stage was assessed by microscopic examination of faeces from 2 infected dogs. Our results were compared with published data from the camel and other strains. The roles of the host, genotype and species in morphological and developmental features as well as the taxonomic position of E. canadensis G6 were discussed. The prepatent period of E. canadensis G6 genotype of goat origin was determined as at least, 41days. The obtained results contribute to increase the knowledge about the biology and genetics of E. granulosus sl complex and are also of practical usefulness for the design of disease control strategies.

Effects of Enterococcus faecalis CECT 7121 on Cryptosporidium parvum infection in mice.

Cryptosporidium is an opportunistic protozoan parasite of humans and animals worldwide and causes diarrheal disease that is typically self-limiting in immunocompetent hosts but often life threatening to immunocompromised individuals. However, there is a lack of completely efficient therapy available. Probiotics have attracted the attention as potential antiparasite compounds against protozoa involved in intestinal infections. This study investigated the effects of administration of probiotic Enterococcus faecalis CECT 7121 on Cryptosporidium parvum infection in immunosuppressed mice. Effects on C. parvum infection at the intestinal mucosa were studied and scored at each portion of the gut. It was demonstrated that Ef CECT 7121 interfered with C. parvum infection when both probiotic and parasite were present in the same intestinal location suggesting that Ef CECT 7121 supplementation can alleviate the negative effects of C. parvum infection.

Hongos queratinofílicos en suelos de parques de la ciudad de Corrientes, Argentina / Keratinophilic fungi in soils of parks of Corrientes city, Argentina

Antecedentes. El suelo es el reservorio natural de hongos queratinofílicos que constituyen un pequeño pero importante grupo de hongos filamentosos; algunos de ellos se desarrollan típicamente sobre tejidos queratinizados de animales vivos. Hay numerosas especies de geohongos saprobios con habilidades queratolíticas reconocidas y son varios los trabajos realizados con el fin de vincular su presencia a la posible enfermedad humana. Objetivos. Conocer la biota de geohongos en general y la de aquellos queratolíticos en particular en suelos de dos parques públicos. Métodos. Las muestras se tomaron de suelos de dos parques públicos de la ciudad de Corrientes, Argentina, durante dos estaciones del año. Para el aislamiento de los hongos se usaron las técnicas del anzuelo queratínico y la de las diluciones. Resultados. Mediante la técnica del anzuelo se aislaron 170 cepas que se clasificaron en 17 géneros y 21 especies, entre las que merece destacar la presencia de Microsporum canis. El índice de Shannon de hongos queratolíticos fue medio, siendo en otoño (2,27) más alto que en primavera (1,92). Con la técnica de diluciones seriadas se obtuvieron 278 cepas que se clasificaron en 33 géneros y 71 especies; el índice de Shannon fue más alto en otoño (3,9) que en primavera (3,5). Conclusiones. Los suelos estudiados presentan condiciones particularmente favorables para la supervivencia de geohongos patógenos y oportunistas para el hombre y los animales (AU)

Background. The soil is a natural reservoir of keratinophilic fungi, which are a small but important group of filamentous fungi, some of which typically develop on keratinized tissues of living animals. There are numerous species of saprophytic fungi with recognized keratinophilic abilities, and several studies have been undertaken in order to link their presence to possible human disease. Aims. To know the biota of geophilic fungi in general and of keratinophilic fungi particularly in soils from two public parks. Methods. Soil samples from two public parks of Corrientes city, Argentina, were studied during two seasons, using the hook technique and serial dilutions for fungal isolation. Results. Using the hook technique, 170 isolates were classified into 17 genera and 21 species, among which it is worth mentioning the presence of Microsporum canis. Shannon index for keratinophilic fungi in autumn was 2.27, and 1.92 in spring. By means of the serial dilutions technique, 278 fungi isolated were identified into 33 genera and 71 species. Shannon index in autumn was 3.9, and 3.5 in spring. Conclusions. The soils studied have particularly favorable conditions for the survival of pathogens and opportunistic geophilic fungi for humans and animals (AU)

[Keratinophilic fungi in soils of parks of Corrientes city, Argentina]. / Hongos queratinofílicos en suelos de parques de la ciudad de Corrientes, Argentina.

BACKGROUND: The soil is a natural reservoir of keratinophilic fungi, which are a small but important group of filamentous fungi, some of which typically develop on keratinized tissues of living animals. There are numerous species of saprophytic fungi with recognized keratinophilic abilities, and several studies have been undertaken in order to link their presence to possible human disease. AIMS: To know the biota of geophilic fungi in general and of keratinophilic fungi particularly in soils from two public parks. METHODS: Soil samples from two public parks of Corrientes city, Argentina, were studied during two seasons, using the hook technique and serial dilutions for fungal isolation. RESULTS: Using the hook technique, 170 isolates were classified into 17 genera and 21 species, among which it is worth mentioning the presence of Microsporum canis. Shannon index for keratinophilic fungi in autumn was 2.27, and 1.92 in spring. By means of the serial dilutions technique, 278 fungi isolated were identified into 33 genera and 71 species. Shannon index in autumn was 3.9, and 3.5 in spring. CONCLUSIONS: The soils studied have particularly favorable conditions for the survival of pathogens and opportunistic geophilic fungi for humans and animals.

Análisis bibliométrico de la literatura científica sobre epidemiología de Giardia en Argentina (1995-2014) / Bibliometric analysis of scientific literature on epidemiology of Giardia in Argentina (1995-2014) / A análise bibliométrica da produção científica sobre epidemiologia da Giardia em Argentina (1995-2014)

Las publicaciones sobre la epidemiología de Giardia en humanos de Argentina se hallan dispersas en numerosas fuentes de información, lo que dificulta su acceso y visibilidad para la comunidad científica. El objetivo de este trabajo fue realizar un análisis bibliométrico cuantitativo de la producción científica sobre Giardia en humanos de Argentina durante el período 1995-2014. El volumen de publicaciones científicas hallado fue igual a 112 (36 artículos, 73 comunicaciones y 3 tesis). La distribución idiomática mostró un predominio del español. Los artículos fueron publicados en 25 revistas de América, Europa y Asia. Este estudio bibliométrico demostró un incremento del volumen de publicaciones sobre Giardia en Argentina durante los últimos 20 años. Los artículos mostraron un índice de colaboración entre investigadores similar a la bibliografía. El índice de institucionalidad fue elevado para instituciones nacionales, e inexistente para la colaboración internacional. La utilización de indicadores bibliométricos permite contar con una herramienta sólida para el diagnóstico y prospección de las actividades de investigación sobre epidemiología de Giardia y contribuye a la difusión y visibilidad de la información relativa a la producción científica desarrollada en Argentina.

The scientific literature on Giardia epidemiology in humans from Argentina is scattered in numerous sources, making it difficult to access them and provide visibility to the scientific community. The aim of this study was to perform a quantitative bibliometric analysis of the scientific production on Giardia in humans from Argentina during the 1995-2014 period. The volume of scientific literature was 112 (36 articles, 73 communications, and 3 theses). The language distribution showed a predominance of Spanish. The articles were published in 25 journals from America, Europe and Asia. This bibliometric study showed an increased volume of publications on Giardia in Argentina during the last 20 years. The articles showed a Collaboration Index between researchers similar to the literature. The institutional Index was elevated for national institutions and non-existent for international collaboration. The use of bibliometric indicators can provide a solid tool for the diagnosis and survey of the research on epidemiology of Giardia, and it contributes to the dissemination and visibility of information on the scientific production developed in Argentina.

A literatura sobre a epidemiologia da Giárdia em seres humanos da Argentina estão espalhados em inúmeras fontes de informação, tornando difícil seu acesso e visibilidade para a comunidade científica. O objetivo deste estudo foi realizar uma análise bibliométrica quantitativa da produção científica sobre Giárdia em seres humanos da Argentina durante o período 1995-2014. O volume de publicações científicas encontrado foi igual a 112 (36 artigos, 73 comunicações e 3 teses). A distribuição idiomática mostrou uma predominância do espanhol. Os artigos foram publicados em 25 revistas da América, Europa e Ásia. Este estudo bibliométrico mostrou um aumento do volume de publicações sobre Giárdia na Argentina durante os últimos 20 anos. Os artigos apresentaram um índice de colaboração entre pesquisadores semelhante à bibliografia. O índice de institucionalidade foi elevado para instituições nacionais, e inexistente para a colaboração internacional. A utilização de indicadores bibliométricos permite contar com uma ferramenta sólida para o diagnóstico e levantamento das atividades de pesquisa sobre epidemiologia da Giárdia e contribui para a divulgação e visibilidade das informações sobre a produção científica desenvolvida na Argentina.

Huevos de Toxocara canis como anzuelo para hongos geófilos en una ciudad subtropical / Toxocara canis eggs as bait for soil fungus in a subtropical city

Antecedentes. Las diferentes técnicas de aislamiento permiten recuperar hongos en función de su capacidad para utilizar o no un determinado sustrato. La técnica de espolvoreado es un método para la recuperación de hongos nematófagos del suelo. Estos hongos son predadores naturales de los nematodos y están ampliamente distribuidos en la naturaleza. Objetivos. Detectar hongos con posible capacidad nematófaga en suelos de parques de la ciudad de Corrientes (Argentina). Métodos. Las muestras de tierra fueron tomadas eligiendo al azar una zona del suelo entre dos árboles, desechando la hojarasca y a no más de 2 cm de profundidad. El aislamiento se realizó según la técnica de espolvoreado utilizando huevos de Toxocara canis como anzuelo. Resultados. Se recogieron 18 muestras de suelo, de las que se aislaron 6 géneros y 8 especies de hongos. El método del espolvoreado, simple y eficiente, tiene la ventaja de utilizar una pequeña cantidad de suelo sin tratamiento y permite aislar hongos que pueden crecer sobre huevos de geohelmintos. Este estudio permitió recuperar hongos de los géneros Bipolaris, Fusarium, Purpureocillium, Curvularia, Phoma y Scytalidium. Conclusiones. No se ha encontrado bibliografía de los géneros Curvularia, Phoma y Scytalidium que describa la interacción de estos hongos con huevos de nematodos y queda, por tanto, el desafío de investigar cuál es su verdadera acción sobre estos huevos (AU)

Background. The use of different isolation techniques allows the recovery of fungi based on their ability to use selective substrates. The sprinkle method is a technique for the recovery of nematophagous fungi in the soil. These fungi are natural predators of nematodes and are widely distributed in nature. Aims. To detect possible fungi with nematophagous ability in the soil of city parks in Corrientes (Argentina). Methods. The soil samples were taken from an area of ground between two trees and to no more than 2 cm deep. The isolation was performed according to the sprinkle method with Toxocara canis eggs as bait. Results. Eighteen soil samples were collected, and 6 genera and 8 species of fungi were isolated. The sprinkle method, simple and efficient, has the advantage of using a small amount of untreated soil for the isolation of fungi that can grow on the eggs of geohelminths. The genera Bipolaris, Fusarium, Purpureocillium, Curvularia, Phoma and Scytalidium were isolated in this study. Conclusions. No other studies describing the interaction between the genera Curvularia, Phoma and Scytalidium with nematode eggs have been found in the literature, thus more studies are required to determine what is their real action on these eggs (AU)

[Toxocara canis eggs as bait for soil fungus in a subtropical city]. / Huevos de Toxocara canis como anzuelo para hongos geófilos en una ciudad subtropical.

BACKGROUND: The use of different isolation techniques allows the recovery of fungi based on their ability to use selective substrates. The sprinkle method is a technique for the recovery of nematophagous fungi in the soil. These fungi are natural predators of nematodes and are widely distributed in nature. AIMS: To detect possible fungi with nematophagous ability in the soil of city parks in Corrientes (Argentina). METHODS: The soil samples were taken from an area of ground between two trees and to no more than 2cm deep. The isolation was performed according to the sprinkle method with Toxocara canis eggs as bait. RESULTS: Eighteen soil samples were collected, and 6 genera and 8 species of fungi were isolated. The sprinkle method, simple and efficient, has the advantage of using a small amount of untreated soil for the isolation of fungi that can grow on the eggs of geohelminths. The genera Bipolaris, Fusarium, Purpureocillium, Curvularia, Phoma and Scytalidium were isolated in this study. CONCLUSIONS: No other studies describing the interaction between the genera Curvularia, Phoma and Scytalidium with nematode eggs have been found in the literature, thus more studies are required to determine what is their real action on these eggs.

Assessment of the presence of Toxocara eggs in soils of an arid area in central-western Argentina.

With the aim of studying the contamination of soils with eggs of Toxocara spp. in an arid area in the central-western region of Argentina, 76 soil samples were collected from 18 towns belonging to six provinces of central-western Argentina. They were processed by the centrifugal flotation method. No eggs of Toxocara spp. were found. It can be concluded that the negative results are directly related to the characteristics of the environment and climate present in the studied area. The finding of eggs in soils depends on several factors: the presence of canine or feline feces, the hygienic behavior of pet owners, the presence of stray animals without veterinary supervision, the weather and environmental conditions, and laboratory techniques used; and all these circumstances must be considered when comparing the results found in different geographical regions. In order to accurately define the importance of public spaces in the transmission of infection to humans, it is important to consider the role of backyards or green spaces around housing in small towns, where the population is not used to walking pets in public spaces, and in such cases a significant fraction of the population may acquire the infection within households.

Assessment of the presence of toxocara eggs in soils of an arid area in central-western Argentina / Evaluación de la presencia de huevos de Toxocara en suelos de una zona árida en la región centro-oeste Argentina

With the aim of studying the contamination of soils with eggs of Toxocara spp. in an arid area in the central-western region of Argentina, 76 soil samples were collected from 18 towns belonging to six provinces of central-western Argentina. They were processed by the centrifugal flotation method. No eggs of Toxocara spp. were found. It can be concluded that the negative results are directly related to the characteristics of the environment and climate present in the studied area. The finding of eggs in soils depends on several factors: the presence of canine or feline feces, the hygienic behavior of pet owners, the presence of stray animals without veterinary supervision, the weather and environmental conditions, and laboratory techniques used; and all these circumstances must be considered when comparing the results found in different geographical regions. In order to accurately define the importance of public spaces in the transmission of infection to humans, it is important to consider the role of backyards or green spaces around housing in small towns, where the population is not used to walking pets in public spaces, and in such cases a significant fraction of the population may acquire the infection within households.

Con el objetivo de estudiar la contaminación de los suelos con huevos de Toxocara spp, se obtuvieron 76 muestras de suelo de 18 pueblos pertenecientes a 6 provincias del centro-oeste de Argentina. Las muestras fueron procesadas por el método de centrifugación-flotación. No se encontraron huevos de Toxocara spp. en ninguna de las muestras de suelo. Llegamos a la conclusión de que los resultados negativos podrían estar en relación directa con las características ambientales y climáticas presentes en el área estudiada. El hallazgo o no de huevos en el suelo depende de varios factores: la presencia de heces de caninos o felinos, el comportamiento de los dueños de mascotas, la presencia de animales abandonados y sin control veterinario, las condiciones climáticas y ambientales y las técnicas de laboratorio utilizadas. Todas estas circunstancias deben ser consideradas cuando se comparan los resultados encontrados en diferentes regiones geográficas. Con el fin de definir la importancia que tienen los espacios públicos en la transmisión de la infección a los humanos, se debería considerar el papel que tienen los patios y veredas de las viviendas en las ciudades pequeñas, donde la población no acostumbra a pasear mascotas en parques y plazas, y en esos casos, la población puede adquirir la infección dentro de los hogares.

Immunomodulatory properties of cell wall extract from Enterococcus faecalis CECT7121.

The aim of this study was to investigate the immunomodulatory properties of cell wall extract from Enterococcus faecalis CECT7121, measuring the induction of cytokines TNF-α, IL-6, IL-10 and IL-12 from human peripheral blood mononuclear cells (PBMCs). Cell wall extract was prepared from their growth in brain heart infusion broth (18h, 35°C). Subsequently, toxicity of the obtained cell wall extract was tested in Balb-C mice. PBMCs were isolated from buffy coats at the Blood Transfusion Service of Hospital Ramón Santamarina (Tandil, Argentina). PBMCs were purified using standard Ficoll-Paque gradient centrifugation. Aliquots of purified leukocytes were incubated at 37°C for 24h with heat-killed E. faecalis CECT7121 and cell wall extract. Concentrations of IL-6, TNFα, IL-10 and IL-12 (p70) were measured by solid phase sandwich ELISA. Changes in appearance and behavior of mice were evidenced only in the group with the maximal concentration of wall cell extract used (10,000µg). Cell wall extract and heat-killed E. faecalis CECT7121 induced the production of significantly higher amounts of Il-12, IL-6, TNF-α and IL-10 cytokines compared to the nonstimulated PBMCs. These findings provide helpful information on immunomodulation activity by cell wall extract in sight of the application of this compound in controlling certain infectious diseases.

First report of Enterocytozoon bieneusi from dairy cattle in Argentina.

Fecal specimens were obtained from a total of 70 dairy calves less than two months old on 11 municipalities in Buenos Aires, Argentina. After removal of fecal debris by sieving and sucrose flotation, specimens were subjected to PCR to detect the presence of Enterocytozoon bieneusi. PCR revealed a 14.3% of prevalence for E. bieneusi with 10 positive calves from 7 municipalities. Gene sequence analysis conducted in all samples positives by PCR revealed the presence of six genotypes; four previously reported in cattle as well as humans (D, I, J, and BEB4), one never reported in cattle before but previously reported in humans (EbpC), and one novel genotype (BEB10). These results constitute the first molecular characterization of E. bieneusi in Argentina, and suggest a potential risk of zoonotic transmission in this area.

Enterococcus spp. aislados de queso de oveja: resistencia a los antimicrobianos de utilización clínica / Enterococcus spp. isolated from goat cheese: resistance to clinically used antimicrobials

En Enterococcus spp. aislados de quesos de oveja se investigó la resistencia in vitro a antimicrobianos de utilización clínica. Se determinó la concentración inhibitoria mínima (CIM) para gentamicina, estreptomicina, vancomicina, teicoplanina, ampicilina, imipenem, linezolid y tigeciclina. Se detectó la producción de β-lactamasa y se realizaron experimentos de conjugación para transferir resistencia a gentamicina. En un aislamiento de E. faecalis y en 10 de E. faecium se observó resistencia a ampicilina; se demostró la producción de β-lactamasa en un E. faecalis. En E. faecium, 15 aislamientos fueron resistentes a imipenem; 4 a linezolid y 5 a glucopéptidos. En 4 aislamientos de E. faecalis se demostró alto nivel de resistencia plasmídica a gentamicina. No se observaron aislamientos resistentes a tigeciclina. El queso de oveja es un reservorio de enterococos resistentes con potencial diseminación al hombre a través de la cadena alimentaria.

In vitro resistance to clinically used antimicrobials was investigated in Enterococcus spp. isolated from goat cheese. The gentamycin, streptomycin, vancomycin, teicoplanin, ampicillin, imipenem, linezolid and tigecyclin minimum inhibitory concentration (MIC) was determined. Β-lactamase production was detected and conjugation experiments were carried out for transferring gentamycin resistance. In one E. faecalis and in 10 E. faecium isolates there was ampicillin resistance and β-lactamase production was demonstrated in one E. faecalis. Fifteen E. faecalis were imipenenem resistant; 4 linezolid resistant and 5 glucopeptide resistant. There was a high level of plasmidic resistance to tigecyclin in 4 E. faecalis isolates. There were no tigecyclin resistant isolates. Goat cheese is a reservoir of resistant enterococci with potencial human dissemination through the food chain.

Influencing factors in the occurrence of injured coliforms in the drinking water distribution system in the city of La Plata, Argentina.

The objective of this study was to evaluate the influencing factors in the occurrence of coliforms in the drinking water in La Plata (Argentina) from June 1999 to June 2001. A total of 180 samples were collected from Rio de La Plata (102 samples) and Puelche Aquifer (78 samples); 45 samples were collected for each of the four seasons. The membrane filter procedure was used for isolating bacteria, and each sample was tested for chlorine and pH. The highest percentage of samples positive for coliforms in the two tested media was obtained in summer while the highest percentage of negative samples was obtained in winter. No Escherichia coli was isolated. The percentage of injured coliforms fluctuated between 70 and 100%. The most frequently isolated bacteria was Enterobacter cloacae in summer, Enterobacter agglomerans in autumn and Klebsiella oxytoca in winter and spring. Significant correlations were observed between coliforms and the distance from the initial treatment point, and with the level of free chlorine. We conclude that drinking water contamination in La Plata occurs in the distribution system due to increased temperatures and reduced disinfectant levels, which result in bacterial regrowth.

A wide diversity of zoonotic intestinal parasites infects urban and rural dogs in Neuquén, Patagonia, Argentina.

The presence of parasites was investigated by the examination of 1944 dog faecal samples collected from urban (n=646) and rural (n=1298) areas of the province of Neuquén, Patagonia, Argentina. Parasitic agents (PA) were found in 37.86% of samples. A total of 15 different PA were detected, including Toxocara canis (16.35%), Taenia spp./Echinococcus spp. (12.65%), Trichurisvulpis (6.06%), Giardia spp. (1.29%), Toxascaris leonina (0.56%), Ancylostomacaninum (0.41%), Dipylidium caninum (0.31%), Diphyllobothrium spp. (0.10%), among others. Several of these PA are recognized as zoonotic agents. Therefore, the results of this investigation revealed that local population is exposed to a broad spectrum of zoonotic parasites by means of environmental contamination with dog faeces. Prevalence of PA was slightly higher in rural (40.06%) than in urban (33.44%) locations. Distribution of groups of PA (cestodes, nematodes, and protozoa) showed statistical differences between both habitats. Prevalence of cestodes (18.18%) and protozoa (11.86%) was significantly higher in the rural environment than in urban areas and nematodes (29.10%) were more frequent in urban locations. Infection of dogs with Linguatula serrata and Cryptosporidium sp. was demonstrated for the first time in Neuquén. Rural dogs of the study area are under hydatic disease control program, which includes treatment with praziquantel every 6 weeks; thus, the finding of high level of cestode infection in these areas is of great relevance. The epidemiology of zoonotic parasitic infections in urban and rural dogs showed different patterns and, in consequence, different control measurements should be applied in each location.

Células RK13: influencia de la concentración de suero fetal bovino en el tiempo de duplicación / RK13 cells: influence of fetal bovine serum concentration on doubling time

El objetivo de este trabajo fue analizar el Tiempo de Duplicación (TD) y la Fase de Latencia (Lag) de una línea celular con 2 concentraciones de Suero Fetal Bovino (SFB) y 2 inóculos celulares iniciales. Se realizaron 4 curvas de crecimiento de células adherentes RK13 (rabbit kidney) en Minimal Essential Medium (MEM) suplementado con glutamina, penicilina, estreptomicina y SFB no inactivado al 5 por ciento y 7 por ciento. Los inóculos iniciales fueron de 3 x 10 y 6,8 x 10 células viables/mL. El TD fue de 24 h para el cultivo con 7 por ciento de SFB con ambos inóculos y de 16,36 h para el cultivo con 5 por ciento de SFB con el mayor inóculo. El cultivo con 5 por ciento de SFB y 3 x 10 viables/mL presentó escaso desarrollo. Se observaron diferencias significativas en el TD (p=0,0055) cuando se utilizó el inóculo de 6,8 x 10 viables/mL y se varió el SFB (5 por ciento y 7 por ciento). La diferencia no fue significativa al utilizar los inóculos de 3 x 10 y 6,8 x 10 viables/mL manteniendo constante la concentración de suero fetal (7 por ciento)

Células RK13: influencia de la concentración de suero fetal bovino en el tiempo de duplicación / RK13 cells: influence of fetal bovine serum concentration on doubling time

El objetivo de este trabajo fue analizar el Tiempo de Duplicación (TD) y la Fase de Latencia (Lag) de una línea celular con 2 concentraciones de Suero Fetal Bovino (SFB) y 2 inóculos celulares iniciales. Se realizaron 4 curvas de crecimiento de células adherentes RK13 (rabbit kidney) en Minimal Essential Medium (MEM) suplementado con glutamina, penicilina, estreptomicina y SFB no inactivado al 5 por ciento y 7 por ciento. Los inóculos iniciales fueron de 3 x 10 y 6,8 x 10 células viables/mL. El TD fue de 24 h para el cultivo con 7 por ciento de SFB con ambos inóculos y de 16,36 h para el cultivo con 5 por ciento de SFB con el mayor inóculo. El cultivo con 5 por ciento de SFB y 3 x 10 viables/mL presentó escaso desarrollo. Se observaron diferencias significativas en el TD (p=0,0055) cuando se utilizó el inóculo de 6,8 x 10 viables/mL y se varió el SFB (5 por ciento y 7 por ciento). La diferencia no fue significativa al utilizar los inóculos de 3 x 10 y 6,8 x 10 viables/mL manteniendo constante la concentración de suero fetal (7 por ciento) (AU)