• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 12
  • 7
  • 6
  • 6
  • 2
  • 1
  • Tagged with
  • 43
  • 43
  • 8
  • 7
  • 7
  • 5
  • 5
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Recuento de Vibrio parahaemolyticus Kanagawa positivo en especies marinas de consumo en Lima Metropolitana y Callao

Dueñas Peña, Talia Greta Amalia January 2008 (has links)
El objetivo del presente trabajo fue hacer un recuento de Vibrio parahaemolyticus Kanagawa positivo a partir de 50 muestras de pescados, moluscos y crustáceos crudos procedentes de terminales pesqueros, muelles y supermercados de consumo en Lima Metropolitana y Callao entre noviembre de 1999 y abril de 2000. El análisis microbiológico se realizó de acuerdo a la metodología recomendada por el Manual Bacteriológico Analítico (BAM, 7 ed.). Se halló Vibrio parahaemolyticus Kanagawa positivo en 4 muestras aislándose 5 cepas con las características bioquímicas correspondientes de un total de 568 cepas sospechosas. Los valores hallados de Número Más Probable (NMP) fueron en pescados y crustáceos de 3/g cada uno y en moluscos un valor mínimo de 3/g y un máximo de 7,4/g. Las muestras que presentaron Vibrio parahaemolyticus Kanagawa positivo (n=4) representaron un 8% del total de especies marinas (n=50), siendo los porcentajes hallados en pescados 2% (n=1), moluscos 4% (n=2) y crustáceos 2% (n=1). Palabras Clave: Vibrio parahaemolyticus, pescados, crustáceos, moluscos, Kanagawa positivo, NMP, Lima Metropolitana y Callao. / The aim of this research was performing a count of Vibrio parahaemolyticus Kanagawa positive out of 50 samples including raw fish, mollusks and crustaceans collected from fishermen’s wharf, fisheries, and supermarkets of edible character in Metropolitan Lima and Callao between november 1999 and april 2000. The microbiological analysis was performed according to Bacteriological Analytical Manual (BAM, 7 ed.). Vibrio parahaemolyticus Kanagawa positive was found in 4 samples from 5 strains with biochemical features that met those of Vibrio parahaemolyticus out of a total of 568 analized strains. The Most Probable Number (NMP) values found are as follows: Fish and crustaceans 3/g each, while molluscs had a minimum value of 3/g and a maximum of 7,4/g. Vibrio parahaemolyticus Kanagawa positive samples (n=4) represented 8% out of the total marine samples (n=50), being the percentages found in fish 2% (n=1), mollusks 4% (n=2) and crustaceans 2% (n=1) out of the total number of samples as well. Key Words: Vibrio parahaemolyticus, fish, mollusks, crustaceans, Kanagawa positive, MPN, Metropolitan Lima and Callao.
12

Temperature-assisted pressure inactivation of Vibrio parahaemolyticus and Vibrio vulnificus in oysters

Kural, Ayse G. January 2007 (has links)
Thesis (M.S.)--University of Delaware, 2007. / Principal faculty advisor: Haiqiang Chen, Animal & Food Sciences. Includes bibliographical references.
13

Low-temperature post-harvest processing for reducing Vibrio parahaemolyticus and Vibrio vulnificus in raw oysters /

Chae, Minjung. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 78-97). Also available on the World Wide Web.
14

Vibrio sp. em ostras e águas de áreas de cutivo da Baía Sul de Santa Catarina

Ramos, Roberta Juliano January 2012 (has links)
Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias. Programa de Pós-graduação em Ciências dos Alimentos / Made available in DSpace on 2013-03-04T19:09:44Z (GMT). No. of bitstreams: 1 309352.pdf: 1330978 bytes, checksum: 53f32bc5f3243f33f297d2c1954775e2 (MD5) / Esta pesquisa teve por objetivo identificar e quantificar vibrios marinhos potencialmente patogênicos em ostras (Crassostrea gigas) e águas provenientes da Baía Sul de Santa Catarina, Brasil. Assim como avaliar a patogenicidade e susceptibilidade destas cepas frente a diferentes antibióticos e verificar a eficácia da depuração de ostras (Crassostrea gigas) contaminadas com Vibrio parahaemolyticus ou Vibrio vulnificus usando luz ultravioleta (UV) isoladamente e efeito sinérgico com cloro. Das 60 amostras de ostras 48,3% estavam contaminadas por uma ou mais espécies de vibrio. As espécies mais frequentes foram V. parahaemolyticus e V. vulnificus. As contagens de V. parahaemolyticus e V. vulnificus nas amostras variaram entre < 0,5 log10 NMP g-1 a 2,3 log10 NMP g-1 de ostra, e < 0,5 log10 NMP g-1 a 2,1 log10 NMP g-1 de ostra, respectivamente. Das 60 amostras de água 73,3% estavam contaminadas por uma ou mais espécies de vibrios. As contagens de V. parahaemolyticus e V. vulnificus nas amostras variaram entre < 0,3 log10 NMP 100 mL-1 a 1,7 log10 NMP 100 mL-1 de água marinha, e < 0,3 log10 NMP 100 mL-1 a 2,0 log10 NMP 100 mL-1 de água marinha, respectivamente. Das 120 cepas enviadas para tipificação, foram avaliadas as características de 106 cepas reativadas. Destas 83 (78,3%) foram previamente identificadas como V. parahaemolyticus, 20 (18,9%) como V. vulnificus, três (2,8%) como V. cholerae. Foram caracterizados 20 diferentes sorotipos de V. parahaemolyticus, e identificados genes de patogenicidade tanto de V. parahaemolyticus quanto de V. cholerae. A resistência à gentamicina e cefuroxima foi observada em 84,3% das cepas testadas para ambos antibióticos, e a resistência a ampicilina foi observada em 80,0% das cepas de Vibrio spp. O cloranfenicol foi o antibiótico ao qual as cepas de Vibrio spp. foram mais sensíveis, seguido da tetraciclina, diferente do observado para V. cholerae que apresentou maior sensibilidade a Amoxicilina + clavulanato. Para o experimento de depuração as ostras foram contaminadas com um coquetel de cinco cepas de V. parahaemolyticus ou V. vulnificus ao nível de 104 a 105 UFC mL-1. A depuração foi realizada num sistema fechado de recirculação. As contagens de V. parahaemolyticus ou V. vulnificus foram realizadas no tempo zero, 6, 18, 24 e 48 h. Três tratamentos foram realizados: T1 (controle), T2 (luz UV) e T3 (luz UV mais cloro). Após 48 h de depuração de V. parahaemolyticus, T3 reduziu 3,1 log NMP g-1 e T2 reduziu 2,4 log NMP g-1, enquanto T1 reduziu apenas 2,0 log NMP g-1. Após 48 h de depuração de V. vulnificus, tanto T2, como T3 foram eficientes na redução das contagens, reduzindo a população em 2,5 e 2,4 log NMP g-1, respectivamente, enquanto que T1 reduziu apenas 1,4 log NMP g-1. O tratamento utilizando Luz UV mais cloro foi mais eficiente para controlar V. parahaemolyticus em ostras. Tanto o tratamento utilizando luz UV, como o tratamento utilizando luz UV mais cloro foram eficientes para reduzir as contagens de V. vulnificus. Os resultados desta pesquisa servem de subsídio para analise de risco de vibrios potencialmente patogênicos em ostras. / The purpose of this study was to assess the incidence and level of contamination for Vibrio spp. in seawater and oysters (Crassostrea gigas) harvested in Southern Brazil, as to evaluate the pathogenicity of strains and test the susceptibility of these strains to different antibiotics, and to evaluate efficacy of depuration using UV light and UV light plus chlorinated seawater for decontaminating Vibrio parahaemolyticus and Vibrio vulnificus in oysters. Of the 60 oysters# samples analyzed, 29 (48.3%) contained one or more vibrio species. The most frequently isolated species were Vibrio parahaemolyticus and Vibrio vulnificus. The counts of Vibrio parahaemolyticus and Vibrio vulnificus in the samples ranged between < 0.5 log10 MPN g-1 to 2.3 log10 MPN g-1 of oyster, and < 0.5 log10 MPN g-1 to 2.1 log10 MPN g-1of oyster, respectively. Of the 60 seawater samples analyzed, 44 (73.3%) contained one or more species vibrios. The counts of Vibrio parahaemolyticus and Vibrio vulnificus in the samples ranged between < 0.3 log10 MPN 100 mL-1 to 1.7 log10 MPN 100 mL-1 of seawater, and < 0.3 log10 MPN 100 mL-1 to 2.0 log10 MPN 100 mL-1 of seawater, respectively. Of the 120 strains sent for typing were evaluated the characteristics of the strains 106 reactivated, 83 (78.3%) were previously identified as V parahaemolyticus, 20 (18.9%) as V vulnificus, three (2.8%) and V. cholerae. Were characterized 20 different serotypes of V. parahaemolyticus, and isolated genes of patogenicity for V. parahaemolyticus and V. cholerae. The gentamycin and cefuroxime resistance was observed in 84.3% of the strains to both antibiotics, and the ampicillin resistance was observed in 80.0% of the strains of Vibrio spp. Chloramphenicol is the antibiotic to which the strains of Vibrio spp. were more susceptible. The tetracycline antibiotic was the second to which the strains of V. parahaemolyticus and V. vulnificus were more susceptible than the observed for V. cholerae that showed greater susceptibility to amoxicillin + clavulanate. For depuration the oysters were contaminated with five-strain cocktail of V. parahaemolyticus or V. vulnificus to level of 104 to 105 CFU mL-1. The depuration was conducted in a recirulated closed system. Counts of V. parahaemolyticus or V. vulnificus were determined at zero, 6, 18, 24 and 48 h. Three treatments were conducted: T1 (control treatment); T2 (UV treatment); and T3 (UV plus chlorine treatment). After 48 h of depuration of Vibrio parahaemolyticus, T3 reduced 3.1 log MPN g-1 and T2 reduced 2.4 log MPN g-1, while T1 reduced only 2.0 log MPN g-1. After 48 h of depuration of Vibrio vulnificus, T2 as well as T3 were efficient reducing counts in 2.5 and 2.4 log MPN g-1, respectively; while T1 reduced only 1.4 log MPN g-1. UV light plus chlorine treatment was more efficient for controlling V. parahaemolyticus in oysters. Both UV light and UV light plus chlorine were efficient for V. vulnificus. These results serve as input for risk analysis studies of potentially pathogenic vibrios in oysters in southern Brazil.
15

Inativação microbiana em ostras (Crassostrea gigas) empregando dióxido de carbono supercrítico

Matos, Katherine Helena Oliveira de January 2013 (has links)
Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia de Alimentos, Florianópolis, 2013. / Made available in DSpace on 2013-12-05T22:55:59Z (GMT). No. of bitstreams: 1 320887.pdf: 646974 bytes, checksum: 26010f70ebe59bf7c847f9b58283013b (MD5) Previous issue date: 2013
16

Pesquisa de Vibrio parahaemolyticus em atum (Thunnus spp) comercializado na zona sul do município de São Paulo ? SP / Study of Vibrio parahaemolyticus in tuna (Thunnus spp) traded in the south region of the city of São Paulo ? SP.

Juliana Chen 01 October 2004 (has links)
Com o objetivo de avaliar a presença de Vibrio parahaemolyticus em atum, foram coletadas 112 amostras, sendo 56 durante o inverno de 2003 (junho a julho) e 56, durante o verão de 2003-2004 (dezembro a janeiro), vendidos em diversos pontos comerciais da zona sul da cidade de São Paulo. Foi determinado o Número Mais Provável (NMP) de Vibrio parahaemolyticus, comparando a contaminação observada durante os dois períodos. As cepas foram estudadas quanto à produção de urease, ao fenômeno de Kanagawa e à sensibilidade a antibióticos. Apenas 2,68% das amostras foram positivas (3/112). Dessas, duas amostras foram coletadas no verão e uma, no inverno. A amostra positiva obtida no inverno apresentou 3 NMP/g, as outras duas, coletadas durante o verão, apresentaram respectivamente, 3 e 4 NMP/g. Todas as cepas isoladas de Vibrio parahaemolyticus foram negativas ao teste de Kanagawa e não produtoras de Urease, não apresentando nenhuma característica patogênica. Todas as cepas foram resistentes a ampicilina, eritromicina, estreptomicina penicilina G, polimixina B e vancomicina. Apresentaram susceptibilidade intermediária a ciprofloxacina, kanamicina e gentamicina, e sensibilidade a ácido nalixídico, cloranfenicol e tetraciclina. Conclui-se que, nas condições desse estudo, o sashimi de atum revelou-se um alimento de baixo risco ao consumidor, no que se refere a infecção (toxigênica) por Vibrio parahaemolyticus / In order to evaluate the presence of Vibrio parahaemolyticus in tuna traded in retail stores in the south region of the city of São Paulo, 112 samples were collected, 56 during the winter of 2003 (June and July) and 56, during the summer of 2003-2004 (December to January). Most probable number (MPN) of Vibrio parahaemolyticus was determined, comparing the contamination level observed in the two periods. Strains were analyzed in relation to urease production, Kanagawa phenomenon and sensitivity to antibiotics. Only 2.68% of the samples were positive (3/112), two of them collected in the summer, and one of them, in the winter. The positive sample obtained in the winter presented 3 NMP/g, and the other two samples, collected in the summer, presented 3 and 4 NMP/g, respectively. All Vibrio parahaemolyticus samples isolated were Kanagawa, urease negative. Therefore, they did not present any pathogenic characteristic. All strains were resistant to ampicillin, erythromycin, streptomycin, penicillin G, polymyxin B and vancomycin. They presented intermediate susceptibility to ciprofloxacin, kanamycin and gentamicin, and sensitivity to nalidixic acid, chloramphenicol and tetracycline. It may be concluded that, in the conditions of this study, tuna sashimi is considered low risk food in relation to toxigenic infection by Vibrio parahaemolyticus
17

Variabilidad bacteriana en los efluentes y afluentes de los cuerpos de agua, por influencia de la producción larvaria del camarón, en la zona de Mar Bravo – Ecuador

Mendoza Lombana, Sonnya Patricia January 2017 (has links)
Estudia la variabilidad bacteriana de los cuerpos de agua de la zona de Mar Bravo en Ecuador, producido por la producción larvaria del camarón blanco Litopenaeus vannamei, basados en la cuantificación de bacterias viables y bacterias no viables. Encuentra que las concentraciones de bacterias fueron más altas en la estación seca, así como en las tomas realizadas en sicigia, presentando valores 4.5E+05 UFC/ml y para cuadratura 2.0E+05 UFC/ml. Los parámetros químicos como clorofila, carbono, DBO y DQO fueron influenciados con las estaciones ambientales guardando similitud entre los comportamientos de carbono y clorofila. Los datos de producción como sobrevivencia y densidades, no presentaron diferencias significativas cuando fueron analizados por épocas del año. Las correlaciones bacterianas comparando ufc/ml y sitios de muestreos, así como las correlaciones de las bandas moleculares con los sitios fueron más positivas cuando se trabajó con bacterias no viables demostrando que este método fue más exitoso que el método tradicional. No se detectaron genes de toxinas para los genes TDH, TRH y TOX en las bacterias analizadas y el análisis de resistencia a antibióticos fue mayor al 65 % para algunas cepas, teniendo relación también con la época del año. / Tesis
18

Desarrollo de métodos moleculares para la detección y caracterización de bacterias patógenas emergentes del género Vibrio en aguas y alimentos

Cañigral Cárcel, Irene 30 September 2011 (has links)
Vibrio parahaemolyticus y Vibrio vulnificus son microorganismos patógenos pertenecientes a la familia Vibrionaceae y al género Vibrio. Son microorganismos con morfología ligeramente curvada, gram negativos y oxidasa positivos. En cuanto a sus aspectos ecológicos son halófilos, por tanto suelen estar presentes en aguas marinas costeras y en el interior de moluscos, crustáceos y peces, y tienden a encontrarse en aguas cálidas. La patología que producen está asociada al consumo de mariscos, moluscos y pescado crudo o poco cocinado y a la exposición a aguas contaminadas. Ambas especies son consideradas patógenos emergentes debido al aumento en su incidencia y a la mayor distribución geográfica de los casos de intoxicación alimentaria, sobre todo en países asiáticos. La detección e identificación de ambas especies en alimentos de origen marino y agua, presenta gran dificultad, ya que los procedimientos convencionales son largos y tediosos, y pueden proporcionar falsos negativos. Los métodos de detección molecular pueden suponer una alternativa más rápida, sensible y fiable. Objetivos: Debido a esto, en este trabajo se han desarrollado métodos de detección y cuantificación de Vibrio spp., Vibrio parahaemolyticus y Vibrio vulnificus mediante PCR tradicional, PCR a tiempo real e hibridación in situ con sondas fluorescentes (FISH) para su aplicación en matrices alimentarias y en agua. En este estudio se han aplicado los distintos métodos a matrices ambientales (agua de playa y agua residual) y a alimentos de origen marino. Resultados: Los resultados muestran que la PCR a tiempo real es el método más rápido y sensible para la detección de las diferentes especies estudiadas, además de permitir la cuantificación del microorganismo en las muestras de forma fiable. En este trabajo hemos demostrado la presencia de bacterias del género Vibrio en ambos tipos de matrices y el potencial de aguas y alimentos de origen marino para actuar como vehículos de transmisión de V. parahaemolyticus y V. vulnificus / Cañigral Cárcel, I. (2011). Desarrollo de métodos moleculares para la detección y caracterización de bacterias patógenas emergentes del género Vibrio en aguas y alimentos [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/11799 / Palancia
19

Evaluation of Urea Hydrolysis as a Biomarker for Detecting Pathogenic Vibrio Parahaemolyticus in Clinical Isolates and Raw Oysters

Mohammadi-Aragh, Maryam Kate 09 December 2016 (has links)
Vibrio parahaemolyticus (Vp) infection is commonly caused by the consumption of raw or undercooked shellfish. Raw oysters are associated with most Vp outbreaks. Pathogenic Vp express thermostable-direct hemolysin (tdh) and to some extent thermostable-related hemolysin (trh). Additionally, some pathogenic Vp express urease (uh). The objectives of this work were to discern any relationships between urease (uh) expression, tdh/trh expression, and hemolytic activity in pathogenic and non-pathogenic clinical strains, and to compare urease, motility, tdh/trh expression, and hemolytic activity in raw oyster isolates. This information would determine if urease could be used as a biomarker to detect pathogenic Vp. About 80% of pathogenic strains were uh+ and all non-pathogenic strains were uh-. Two oyster samples were uh+ and no tdh or trh was detected in raw oyster strains.
20

Virulence Gene Expression of Vibrio parahaemolyticus in the Viable but Nonculturable State

Tse, Tiffany Pui-Yun 01 June 2015 (has links) (PDF)
Vibrio parahaemolyticus is a food-borne pathogen commonly associated with the consumption of raw or undercooked seafood resulting in primary infections of the human gastrointestinal tract. It is estimated to cause about 4500 illnesses each year in the United States. However, infection from this food-borne pathogen can be avoided if this organism is detected in the implicated food, prior to consumption. Current standard methods of detecting this organism are dependent on the culturability of the bacteria. Detection based on an organism’s culturability may be problematic as V. parahaemolyticus has been known to exist in a viable but nonculturable (VBNC) state. Bacteria in the VBNC state are characterized by low levels of metabolic activity and the inability to be cultured by standard laboratory practices. When bacteria enter the VBNC state, their gene expression profile may be different than the culturable counterpart. We were interested in comparing the expression of two virulence-associated genes between VBNC and culturable cells of V. parahaemolyticus. V. parahaemolyticus RIMD2210633 was incubated at 4°C in modified Morita mineral salt solution supplemented with 0.5% NaCl (MMS) or trypticase soy broth supplemented with 2% NaCl (TSBS), which represented nutrient poor and rich conditions, respectively. The number of VBNC and culturable cells were determined by standard plate count and fluorescence microscopy. The expression levels of virulence-associated genes tdh2 and escU, were measured relative to the housekeeping gene, pvsA, by qRT-PCR. Nutrient availability and temperatures exerted variable effects on the virulence gene expression. It is possible that VBNC V. parahaemolyticus cells may retain their pathogenicity potential.

Page generated in 0.058 seconds