Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias. Programa de Pós-Graduação em Ciência dos Alimentos / Made available in DSpace on 2012-10-21T12:28:23Z (GMT). No. of bitstreams: 1 202289.pdf: 1012107 bytes, checksum: 6b0f4b9adf2f01bc2c09b66ab41b351b (MD5) / Campylobacter termofílicos foram analisados em diversos pontos da cadeia produtiva de frangos de corte, desde o aviário até a obtenção do frango pronto para expedição, congelado. Em "Ocorrência de Campylobacter termofílicos antes do abate de aves" (1), foram analisadas amostras de cama de aviário (swab de arrasto), penas de frango, cloaca de frango, com objetivo de determinar qual amostra melhor representa lotes de frango Campylobacter positivos que chegam ao abatedouro, bem como, gaiolas de transporte de aves, água de lavagem de gaiolas e parapeito após a pendura das aves, antes da sangria, com intuito de identificar pontos de contaminação cruzada antes do abate. Em "Processamento de frango de corte: ocorrência de Campylobacter termofílicos" (2), as amostras analisadas compreenderam o frango logo após o processo de depenagem, após o processo de evisceração, após o processo de resfriamento em água, a água de resfriamento, o frango congelado e superfície do setor de embalagem primária, objetivando determinar a ocorrência de Campylobacter durante o processamento, após cada etapa. Em (1), foram analisadas 144 amostras, das quais 50 % foram positivas para Campylobacter. A ocorrência de positividade foi de 79,16% na amostra de penas, 75% na amostra de "swab de cloaca" e apenas 37,5% na amostra "swab de arraste" efetuado na cama de aviário. A evidência de possibilidade de contaminação cruzada também foi constatada nas amostras de gaiola de transporte (50%), água de lavagem de gaiola (25%) e parapeito após pendura do frango na nórea (33,33%). Em (2), foram analisadas 335 amostras, das quais 71,34% foram positivas para Campylobacter. As ocorrências de positividade nas amostras de frango foram de 68,05 % após o processo de depenagem, 69,44 % após o processo de evisceração, 84,72 % após resfriamento em chiller, 63,33 % após congelamento; A água de resfriamento apresentou 91,30 % de positividade e a superfície no setor de embalagem 50%.

Made available in DSpace on 2014-06-11T19:32:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-05-04Bitstream added on 2014-06-13T19:43:39Z : No. of bitstreams: 1 cortez_all_dr_jabo.pdf: 430590 bytes, checksum: 666a520b7c02417cfef371371e073100 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Os objetivos do presente trabalho foram verificar a ocorrência de Campylobacter jejuní, Campylobacter calí, Salmonella spp., Salmonella Enteritidis e Salmonella Typhimurium em abatedouros de aves e avaliar a resistência das amostras de Salmonella spp. isoladas frente a antimicrobianos de uso comum. Foram colhidas amostras de fezes; penas; água de escaldamento, evisceração e resfriamento; e amostras de carcaça não eviscerada, eviscerada e resfriada em seis abatedouros de aves. Campylobacter jejuni foi detectada em 14 amostras (5%), a maior porcentagem foi em amostras de fezes oito amostras (22%), e C. calí em foi isolada em uma amostra de pena (0,35%). Salmonella spp. foi detectada em 18% (52/288) dos isolados, enquanto os sorotipos S. Enteritidis em 5,6% (16/288) e S. Typhimurium em 2,4% (7/288). Os testes de resistência aos antimicrobianos apontaram 25 amostras resistentes ao aztreonam e à ampicilina (86,2%), 21 à tetraciclina (72,4%) e 16 à amoxicilina/ácido clavulânico e sulfazotrim (55,2%). Nenhum dos isolados testados apresentou 100% de resistência ou sensibilidade aos antimicrobianos utilizados. Os resultados indicam que há uma necessidade de melhorar a qualidade higiênico-sanitária em linhas de abate de aves e o cuidado com o uso indiscriminado de antibióticos na avicultura, oferecendo aos consumidores produtos livres de agentes zoonóticos. / The present study was carried out to report the occurrence of Campylobacter jejuní, Campylobacter calí, Salmonella spp., Salmonella Enteritidis e Salmonella Typhimurium in chicken abattoirs and to evaluate the resistance of Salmonella spp. isolated to antibiotics of common use. Samples of feces; feathers; scald, evisceration, and chiller water; and non-eviscerated, eviscerated, and chilted carcasses were coUeded from six chicken abattoirs. Campylobacter jejuni was isolated in 14 samples (5%), isolation was greater in feces, eight samples (22%), one feather sample was positive for the species C. calí (0.35%). Salmonella spp. was detected in 18% (52/288) of the isolates, whereas serotypes S. Enteritidis were identified in 5.6% (16/288) and S. Typhimurium and 2.4% (7/288). Antibiotic tests indicate 25 resistant samples to aztreonam and to ampicilin (86.2%), 21 to tetracycline (72.4%) and 16 to amoxicilin/clavulanic acid and to sulfazotrim (55.2%). None sample tested were 100% resistant or sensitive to ali the antibiotics tested. The results exhibit the need to improve hygiene and sanitary standards in poultry sfaughter fines, and care with the indiscriminate use of antibiotics in avicultura, offering to the consumers products free of zoonotic agents.

Memoria para optar al Título Profesional de Médico Veterinario / El objetivo de este estudio fue comparar el método alternativo Merck Singlepath® Direct Campy Poultry kit contra el método de referencia (cultivo en placa) descrito por la OIE para la detección de Campylobacter spp. en muestras cecales de pollo, con el fin de evaluar el grado de concordancia que existe entre ambos métodos. Para ello, se obtuvieron 130 intestinos de pollo desde una planta faenadora de la Región Metropolitana. En una primera etapa, se evaluó la capacidad de detección del método alternativo respecto de Campylobacter spp., para lo cual, 10 muestras cecales de pollo fueron contaminadas con la cepa Campylobacter jejuni ATCC 33560 a una concentración de 9 x 108 UFC por gramo de contenido cecal (control positivo), mientras que 10 muestras de agua peptonada fueron contaminadas con la cepa Escherichia coli ATCC 25922 a una concentración de 9 x 108 UFC por mL de agua peptonada (control negativo). En una segunda etapa, se analizaron las restantes 120 muestras cecales de pollo a través del método de referencia y por medio del método alternativo, en donde posteriormente se analizaron los resultados de la segunda etapa por medio de los métodos estadísticos McNemar y Kappa (κ). Los resultados de la primera etapa arrojaron que el kit efectivamente detecta Campylobacter jejuni (control positivo) y no otra bacteria como Escherichia coli (control negativo) a partir de una determinada concentración. Por otra parte, los resultados de la segunda etapa mostraron que no hubo diferencias significativas entre las mediciones realizadas por ambos métodos respecto de una misma muestra (p > 0,05), mientras que a través del método estadístico Kappa, se pudo determinar que los resultados entregados por el método alternativo son equivalentes a los que entregaría el método de referencia para muestras de heces de pollo, por lo que el método alternativo desarrollado por Merck puede efectivamente ser utilizado previo al sacrificio de pollos para identificar lotes de aves que estén altamente infectados con Campylobacter spp. a una concentración igual o mayor a 3 x 107 UFC por gramo de heces. / The aim of this study was to compare the Merck Singlepath® Direct Campy Poultry kit alternative method against the reference method (plate culture) described by the OIE for the detection of Campylobacter spp. in chicken cecal samples in order to assess the degree of concordance between both methods. For this, 130 intestines were obtained from a chicken slaughterhouse located in the Metropolitan Region. In a first step, the detection capability of the alternative method for Campylobacter spp. was assessed, for which 10 chicken cecal samples were contaminated with Campylobacter jejuni ATCC 33560 strain at a concentration of 9 x 108 CFU per gram of cecal content (positive control), while 10 samples of peptone water were contaminated with Escherichia coli ATCC 25922 strain at a concentration of 9 x 108 CFU per ml of peptone water (negative control). In a second step, the remaining 120 chicken cecal samples were analyzed by the reference method and by the alternative method. Subsequently the results of the second stage were analyzed by statistical methods McNemar and Kappa (κ). The results showed that in the first stage the 10 samples used as positive control were all positive by the alternative method, while in the 10 samples used as negative control, there was no Escherichia coli bacteria detected. Moreover, the results of the second stage showed that there were no significant differences between the measurements made by both methods within a single sample (p > 0.05), while using the statistical method Kappa determined that the results provided by the alternative method are equivalent to those that would provide the reference method for chicken fecal samples. Then, the alternative method developed by Merck can effectively be used prior to slaughter chickens to identify lots of batches that are highly infected with Campylobacter spp. at a concentration equal or greater than 3 x 107 CFU per gram of feces. / Financiamiento: Proyecto Fondecyt 11110200.

No description available.

Magister Scientiae - MSc / South Africa

The full text of this thesis/dissertation is not available online. Please <a href="mailto:upetd@up.ac.za">contact us</a> if you need access. Read the abstract in the section 00front of this document. / Dissertation (MSc (Microbiology))--University of Pretoria, 2006. / Microbiology and Plant Pathology / unrestricted

Campylobacter species are the primary cause of bacterial food-borne diarrhoea worldwide. Comparative genomic analyses of Campylobacter strains reveal genome plasticity providing insight into the evolution of virulence traits. The goal of this study was to identify genes important for infectivity and for naturally occurring variability in phenotypic traits in C. jejuni and C. coli strains. Transcriptome and phenotype analyses were conducted to determine if genetic and phenotypic characteristics could be attributed to the source of the strains. Isolates from water sources had higher biofilm formation than animal strains. Clinical strains had decreased sensitivity to hydrogen peroxide as well as increased adherence and invasion when compared to animal strains. A number of genetic differences were observed; however, without further analysis it is difficult to determine which of these impact virulence in Campylobacter. Ultimately, this project will lead to the identification of markers associated with strains of Campylobacter causing illness.

Campylobacter jejuni infection is one of the leading causes of gastroenteritis in humans worldwide. During colonization of the gastrointestinal tract, C. jejuni will be unavoidably exposed to reactive oxygen species (ROS) produced by the host immune system and other intestinal microbiota. Identification of defenses against ROS is therefore important for understanding how Campylobacter survives this environmental stress during infection. Construction of isogenic deletion mutants into genes encoding potential oxidative stress defense systems followed by phenotypic screening revealed genes important for oxidant defense within C. jejuni. Surprisingly, genes involved in motility were found to play an indirect role in resistance to oxidative stress. Deletion of the flagellar motor apparatus genes, motAB, resulted in increased sensitivity towards superoxide which could be restored by fumarate supplementation or tandem deletion of motAB with ccoQ (cytochrome c oxidase). This finding suggested that disruption of the proton gradient across the inner membrane resulted in increased superoxide production in non-motile flagellar mutants. Phenotypic screening of the mutant library also identified a novel gene (cj1386) specifically involved in hydrogen peroxide defense within the cell. Hydrogen peroxide detoxification within living organisms is predominantly carried out by catalase enzymes. Interestingly, cj1386 is located directly downstream from katA (catalase) in the C. jejuni genome and it was found that a ∆cj1386 mutant had reduced catalase activity relative to wild-type C. jejuni. Immunoprecipitation of KatA from ∆cj1386 revealed a significant reduction in hemin content associated with KatA suggesting a role for cj1386 in hemin trafficking to KatA. Hemin binding experiments with purified Cj1386 demonstrated the ability of Cj1386 to bind hemin with a 1:1 hemin-to-protein binding ratio. Furthermore, co-immunoprecipitation experiments revealed an interaction between KatA and Cj1386. Mutagenesis of conserved amino acids in Cj1386 demonstrated that tyrosine 57 plays an important role in hemin affinity and is required for proper hemin content of KatA within the cell. Overall, this work provides a global characterization of key oxidant defenses within C. jejuni and provides one of the first studies investigating hemin trafficking to KatA.

Memoria para optar al Título Profesional de Médico Veterinario / El desarrollo de la resistencia a los antibióticos por parte de patógenos bacterianos es un significativo problema de salud pública a nivel mundial. Al respecto, para agentes zoonóticos como Campylobacter spp., este es un problema emergente de importante magnitud, existiendo en las últimas décadas un incremento en la resistencia a antibióticos de la familia de las fluoroquinolonas y macrólidos, fármacos utilizados para el tratamiento de campylobacteriosis en humanos. El uso indiscriminado de antibióticos en producción animal, se describe como una de las principales causas de este fenómeno. En Chile, existen muy pocos estudios sobre la susceptibilidad antimicrobiana en cepas de Campylobacter spp. aisladas de distintos orígenes. El objetivo de este trabajo fue evaluar la susceptibilidad a los antibióticos en 40 cepas provenientes de pacientes humanos, 40 cepas aisladas de carnes de pollos Broiler y 40 cepas aisladas de deyecciones de aves. Los antibióticos analizados fueron ciprofloxacino, tetraciclina, eritromicina y gentamicina. Se utilizaron dos métodos, un screening con la técnica de Etest y todas aquellas cepas que resultaron resistentes, fueron sometidas a dilución en agar mediante la técnica de concentración mínima inhibitoria. Del total de cepas estudiadas (120) se encontraron 59 cepas resistentes a ciprofloxacino, 35 a tetraciclina, 20 a eritromicina y 4 a gentamicina; mientras que 41 cepas fueron multiresistentes. De acuerdo a estudios realizados anteriormente en nuestro país, los niveles de resistencia de Campylobacter spp. a los antimicrobianos analizados han aumentado, lo que demuestra la importancia de establecer un sistema de vigilancia en Chile, el cual posea un enfoque integrado entre Medicina Veterinaria, alimentos y Medicina Humana, con el fin de resguardar la salud de la población / Financiamiento: Proyecto Fondecyt 11110200

Mononuclear molybdenum enzymes catalyze a variety of reactions that are essential in the cycling of nitrogen, carbon, arsenic, and sulfur. For decades, the structure and function of these crucial enzymes have been investigated to develop a fundamental knowledge for this vast family of enzymes and the chemistries they catalyze. The dimethyl sulfoxide reductase (DMSOR) family is the most diverse family of molybdoenzymes and, the members of this family catalyze a myriad of reactions that are important in microbial life processes. Periplasmic nitrate reductase (Nap) is an important member of the DMSO reductase family that catalyzes the reduction of nitrate to nitrite, and yet the physiological role of Nap is not completely clear. Enzymes in this family can transform multiple substrates; however, quantitative information about the substrate preference is sparse and more importantly, the reasons for the substrate selectivity are not clear. Substrate specificity is proposed to be tuned by the ligands coordinating the molybdenum atom in the active site. As such, periplasmic nitrate reductase is utilized as a vehicle to understand the substrate preference and delineate the mechanistic underpinning of these differences. To this end, NapA from <i>Campylobacter jejuni </i>has been heterologously overexpressed, and a series of variants, where the molybdenum-coordinating cysteine has been replaced with another amino acid, has been produced. The kinetic and biochemical properties of these variants will be discussed and compared with those of the native enzyme, providing quantitative information to understand the function.