Epidemiology of Verocytotoxigenic<i>Escherichia coli</i>(VTEC) in Ruminants

Blanco, Jorge; Blanco, Miguel; Blanco, Jesús E.; Mora, Azucena; Alonso, Marı́a Pilar; González, Enrique A.; Bernárdez, María Isabel

doi:10.1002/9780470385098.ch6

Cited by 62 publications

(117 citation statements)

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“…Of these, 165 were isolated from cattle (151 from calves and cows and 14 from beef meat) belonging to separate herds and three were isolated from sheep. Isolation and characterization of the strains as STEC were performed as indicated in previous studies (Blanco et al, 2003). Of the 168 strains, 98 were E. coli O157 : H7, obtained from the Public Health Agency in Barcelona (Agència de Salut Pú blica de Barcelona), where several pathogenic strains from different origins are routinely analysed.…”

Section: Methodsmentioning

confidence: 99%

“…The most common virulent serotype is E. coli O157 : H7, although others have been described (Karmali, 2004). E. coli O157 : H7 and over 100 other STEC serotypes can be found on virtually all farms in countries throughout the world (Beutin et al, 1997;Heuvelink et al, 1998;Blanco et al, 2001;Hancock et al, 2001). Transmission of STEC from cattle to humans occurs via food-and waterborne routes.…”

Section: Introductionmentioning

confidence: 99%

“…Ruminant animals such as cattle, sheep and goats are naturally colonized with STEC and release these organisms into the environment with their faeces (Blanco et al, 2001(Blanco et al, , 2003Licence et al, 2001;Widiasih et al, 2004). STEC can cause haemorrhagic colitis and haemolytic uraemic syndrome (HUS) in humans (Ritchie et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

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Diversity of stx 2 converting bacteriophages induced from Shiga-toxin-producing Escherichia coli strains isolated from cattle

et al. 2004

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The presence of bacteriophages encoding Shiga toxin 2 (stx 2 phages) was analysed in 168 strains of Shiga-toxin-producing Escherichia coli (STEC) isolated from cattle. Following mitomycin C induction, strains carrying stx 2 phages were screened by plaque blot and hybridization with an stx 2 A-probe. In the stx 2 -phage-carrying strains, the amounts of phage production, phage DNA extracted and Stx 2 produced after induction were assessed. The induced stx 2 phages were characterized morphologically and genetically. Assays to obtain lysogens from different strains were also carried out and phages induced from the lysogens were compared with those induced from the STEC isolates. Results indicated that 18 % of the strains carried an inducible stx 2 phage. Most of them showed a direct relationship between phage induction and toxin production. Each strain carried only one inducible stx 2 phage, although a few strains had two copies of the stx 2 in the chromosome. The stx 2 phages showed diverse morphology and a wide variability in their genome. Assays to obtain lysogens showed that not all the phages were transduced with the same frequency and only six lysogens were obtained. Phages in the lysogens were the same as those induced from their respective initial STEC host strains, although the induction and relative toxin production of the lysogens varied. Most phages carried the stx 2 gene, while a few carried stx 2 variants. Infectivity of the phages depended on the different hosts, although O157 : H7 was preferentially infected by phages induced from O157 strains. The results show that inducible stx 2 phages are common among STEC of animal origin and that they may enhance the spread of stx 2 .

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Diversity of stx 2 converting bacteriophages induced from Shiga-toxin-producing Escherichia coli strains isolated from cattle

et al. 2004

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“…Infection with VTEC by human is acquired by the consumption of improperly cooked ground beef, raw milk, meat and dairy products, vegetables, unpasteurized fruit juices and water contaminated with faeces of animals [11]- [13]. VTEC strains are associated with Haemorrhagic colitis (HC) and Haemolyticuraemic syndrome (HUS) in human and also in oedema disease of pigs [12].…”

Section: Introductionmentioning

confidence: 99%

Detection of Verocytotoxigenic <i>Escherichia coli</i> O157 Serotype in Dairy Products in Abuja, Nigeria

Enem¹,

Oboegbulem²,

Nafarnda³

et al. 2015

OJVM

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Ruminants are recognized as healthy carriers of Verocytotoxigenic Escherichia Coli (VTEC) organisms and as such most dairy products may provide these bacteria with favourable conditions for their growth. A cross sectional study was conducted to detect the occurrence of VTEC O157 in dairy products in the Federal Capital Territory, Abuja, Nigeria. Raw milk, Nunu and yoghurt were analyzed using standard cultural and biochemical procedures to isolate typical E. coli. Isolated E. coli samples were sub-cultured into plates of sorbitol MacConkey and Cefixime Tellurite-Sorbitol MacConkey agar. Isolates that are sorbitol negative were further characterized using commercially procured latex agglutination test kits. A total of 367 samples were analyzed out of which 3 tested positive for VTEC O157 (108 of raw milk -1 (0.93%); 127 of Nunu -2 (1.57%) and 132 of yoghurt -none). There was no significant association (p > 0.05) between season and infection with VTEC O157 in dairy products. Dairy products remained a potential vehicle for VTEC O157 infection.

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“…(Escalante Gómez, 2008), lo cual conlleva abordar con rigor las bases teóricas que sustentan las técnicas de análisis estadístico. En este punto aparecerán obstáculos diversos, donde destacaría la escasa formación en Estadística de los alumnos que acceden a la universidad; no siendo menos importantes los problemas relacionados delámbito emocional, puesto que los déficits motivacionales y actitudinales constatados, así como la importancia concedida a la dimensión actitudinal en el desempeño competente, incluso han alentado el desarrollo de unárea de investigación que aborda el dominio afectivo-actitudinal en los procesos de enseñanza-aprendizaje de la Estadística (Blanco, 2008).…”

Section: La Estadística En La Enseñanza Superiorunclassified

Un Recorrido de Estudio e Investigación para el aprendizaje del concepto devariable aleatoria discreta mediante métodos de Monte Carlo

Fuster

Planes

Meló

2017

Model. Sci. Educ. Learn.

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El concepto de variable aleatoria es un constructo matemático que presenta cierta complejidad teórica. No obstante, el aprendizaje de dicho concepto puede facilitarse si se plantea como el final de un proceso secuencial de modelización de un suceso real. Más concretamente, para aprender el concepto de variable aleatoria discreta, la simulación de Monte Carlo puede ofrecer una herramienta sumamenteútil puesto que en el proceso de modelización/simulación podremos abordar el concepto teórico de variable aleatoria, al tiempo que se observa a la variable aleatoria "en acción". Este trabajo expone un Recorrido de Estudio e Investigación (REI) basado en una serie de actividades relacionadas con variables aleatorias como entrenamiento e introducción de elementos de simulación, presentándose después la construcción de un modelo, que es la parte substancial de la actividad, generando una variable aleatoria y su función de probabilidad. Partiendo de una situación sencilla, relacionada con la reproducción y supervivencia de la camada de un roedor, con componentes aleatorios, se construye, paso a paso, el modelo que representa la situación planteada mediante una variable aleatoria "original". En las etapas intermedias de la construcción del modelo tienen un papel fundamental las distribuciones uniforme discreta y binomial. El recorrido de tales etapas permite reforzar el concepto de variable aleatoria al tiempo que se exploran las posibilidades que ofrecen los métodos de Monte Carlo para simular casos reales y se comprueba la sencillez que supone implementar dichos métodos mediante el lenguaje de programación de Matlab c .The concept of random variable is a mathematical construct that presents some theoretical complexity. However, learning this concept can be facilitated if it is presented as the end of a sequential process of modeling of a real event. More specifically, to learn the concept of discrete random variable, the Monte Carlo simulation can provide an extremely useful tool because in the process of modeling / simulation one can approach the theoretical concept of random variable, while the random variable is observed "in action". This paper presents a Research and Study Course (RSC) based on series of activities related to random variables such as training and introduction of simulation elements, then the construction of the model is presented, which is the substantial part of the activity, generating a random variable and its probability function. Starting from a simple situation related to reproduction and survival of the litter of a rodent, with random components, step by step, the model that represents the real raised situation is built obtaining an "original" random variable. In the intermediate stages of the construction of the model have a fundamental role the uniform discrete and binomial distributions. The trajectory of these stages allows reinforcing the concept of random variable while exploring the possibilities offered by Monte Carlo methods to simulate real cases and the simplicity of implemen...

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Epidemiology of VerocytotoxigenicEscherichia coli(VTEC) in Ruminants

Cited by 62 publications

References 65 publications

Diversity of stx 2 converting bacteriophages induced from Shiga-toxin-producing Escherichia coli strains isolated from cattle

Diversity of stx 2 converting bacteriophages induced from Shiga-toxin-producing Escherichia coli strains isolated from cattle

Detection of Verocytotoxigenic <i>Escherichia coli</i> O157 Serotype in Dairy Products in Abuja, Nigeria

Un Recorrido de Estudio e Investigación para el aprendizaje del concepto devariable aleatoria discreta mediante métodos de Monte Carlo

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Epidemiology of VerocytotoxigenicEscherichia coli(VTEC) in Ruminants

Cited by 62 publications

References 65 publications

Diversity of stx 2 converting bacteriophages induced from Shiga-toxin-producing Escherichia coli strains isolated from cattle

Diversity of stx 2 converting bacteriophages induced from Shiga-toxin-producing Escherichia coli strains isolated from cattle

Detection of Verocytotoxigenic &lt;i&gt;Escherichia coli&lt;/i&gt; O157 Serotype in Dairy Products in Abuja, Nigeria

Un Recorrido de Estudio e Investigación para el aprendizaje del concepto devariable aleatoria discreta mediante métodos de Monte Carlo

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Detection of Verocytotoxigenic <i>Escherichia coli</i> O157 Serotype in Dairy Products in Abuja, Nigeria