Clostridium perfringens type A isolates producing enterotoxin (CPE) are an important cause of food poisoning and non-food-borne human gastrointestinal (GI) diseases, including antibiotic-associated diarrhea (AAD), and spontaneous diarrhea (SD). In enterotoxigenic type A isolates, the cpe gene is found on the chromosome in food poisoning isolates, but is present on a large virulence plasmid in AAD and SD type A isolates. Food poisoning cases typically exhibit shorter duration of infection and less severe GI symptoms than AAD or SD. Since previous epidemiological evidence has linked the newly discovered beta2-toxin (CPB2) to gastroenteritis in pigs, horses, and chickens, we hypothesize that the CPB2 toxin may be an accessory toxin when cpe positive type A isolates cause human AAD or SD. In the current study, the presence and expression of CPE and CPB2 were assessed in 44 C. perfringens type A human fecal isolates associated with GI diseases in the United Kingdom. Polymerase chain reaction (PCR) and restriction fragment length polymorphisim (RFLP) confirmed the presence of the cpe (32%) and cpb2 (39%) genes. Furthermore, pulsed field gel electrophoresis (PFGE) and I-CeuI RFLP PFGE Southern blot analysis was used to show the localization of the cpe and cpb2 genes, as well as to determine that there was no clonal relationship between the isolates. All surveyed cpb2-positive isolates were determined to carry their cpb2 gene on a large plasmid that was estimated to be the similar size of the cpe large plasmid. Finally, CPE and CPB2 Western blotting demonstrated that all cpe-positive isolates expressed CPE and that all cpb2-positive isolates expressed CPB2. This study identified, for the first time, the C. perfringens non-food-borne human GI disease isolates carrying both the cpe and cpb2 genes (18%), and these isolates all actively expressed both CPE and CPB2. It was also shown that, although CPE expression occurs only under sporulation conditions, CPB2 expressed both in vegetative and sporulation conditions. The CPB2 made by two of these cpe /cpb2 - positive isolates was determined to be very (-99%) similar to the deduced amino acid sequence of the biologically-active CPB2 made by the original type C isolate CWC245. Finally, the expression of CPB2 by only type A isolates carrying the cpe gene on a plasmid and not the isolates carrying a chromosomal cpe gene, could possibly explain the increased GI symptoms and disease duration associated with these non-food-borne GI diseases. Collectively, the current results support a significant association between cpb2-positive C. perfringens isolates and non-food-borne GI disease in human. / Graduation date: 2004

This study was conducted to determine if alternative heating times and slower cooling times, other than those defined by FSIS, could be utilized and still comply with FSIS performance standards. Large (10.43 to 12.25 kg), cured bone-in hams (n = 190) and large (greater than or equal to 9.07 kg), uncured beef inside rounds (n = 180) were utilized in a two-phase study. Phase 1 of the study investigated the effect of alternative lethality parameters on toxin production of Staphylococcus aureus and log reduction of Salmonella Typhimurium and coliforms. Both the hams and roast beef were subjected to 1 of 10 treatments defined by varying final internal product temperatures (48.9 degrees C, 54.4 degrees C, 60.0 degrees C, 65.6 degrees C, or 71.1 degrees C) and smokehouse relative humidities (50% or 90%). Phase 2 investigated the effect of alternative stabilization parameters on log growth of Clostridium perfringens. Stabilization treatments extended the times taken to reduce internal product temperature from 54.4 degrees C to 26.7 degrees C and from 26.7 degrees C to 7.2 degrees C (ham) or 4.5 degrees C (beef), independently. Further, a control treatment following current FSIS, Appendix B guidelines was conducted for ham, and a "worst case" scenario was assessed for both products. The "worst case" treatment evaluated the effects of cooling products at room temperature (approximately 22.8 degrees C) in place of normal cooling procedures in a temperature controlled environment. Results of the study showed at least a 6.5-log10 reduction in S. Typhimurium across all lethality treatments for both products. Further, coliform counts also were reduced significantly, and S. aureus toxin kits returned negative results for toxin production for all treatments of ham and roast beef. Stabilization showed less than 1-log growth of C. perfringens for any treatment, with the exception of the "worst case" scenario for roast beef. As expected, > 1 log growth of C. perfringens was found for uncured roast beef maintained at room temperature for cooling. This study supports that there are multiple time and temperature combinations, other than those currently provided by FSIS, which may be utilized for cooking and cooling large roast beef and bone-in ham products while still meeting FSIS lethality and stabilization microbiological performance standards.

Incorporation of full-fat flaxseed, and to a lesser extent, canola seed in diets to produce n-3-enriched products has attracted interest in the poultry industry. However, high amounts of nonstarch polysaccharides (NSP) in oilseeds compromise their nutritive value. The objectives of the current research were to develop enzyme supplements effective in cell wall depolymerization and viscosity reduction, particularly in flaxseed; to evaluate the effects of enzyme addition and feed processing on oil utilization and egg n-3 fatty acid deposition in broiler chickens and laying hens fed oilseed-containing diets; to characterize the NSP hydrolysis products and to investigate the effects of diet type and enzyme addition on growth performance and the incidence of necrotic enteritis (NE) in broiler chickens challenged with Clostridium perfringens. Results showed that diets containing high levels of flaxseed reduced egg production and shell quality in laying hens, and impaired final body weight and feed conversion ratio (FCR) in broiler chickens. Reducing flaxseed particle size via grinding did not improve the growth performance of broiler chickens, whereas diet pelleting showed more pronounced and beneficial effects in improving the nutritive value of flaxseed, particularly when intact seeds were used. Multicarbohydrase supplementation resulted in a significant depolymerization of cell wall polysaccharides in soybean, canola and flaxseed meals, which was followed by the production of water-soluble NSP hydrolysis products, and the reduction of flax mucilage viscosity in vitro was also evident. Enzyme addition to flaxseed-containing diets improved FCR of broiler chickens and egg production performance of laying hens, and facilitated egg n-3 fatty acid deposition. The C. perfringens challenge caused intestinal NE lesions and increased the mortality of broiler chickens with the highest NE mortality and intestinal C. perfringens counts observed in those fed flaxseed-containing diets. Enzyme supplementation to diets containing high levels of water-soluble NSP (wheat/barley- or wheat/barley/flaxseed-based) facilitated post-disease compensatory growth in pathogen challenged birds. This was accompanied by a numerical reduction of intestinal C. perfringens by 1.4 log10 cfu/g in birds fed the flaxseed-containing diets. Such findings indicated that enzyme addition may be used as a nutritional strategy to reduce the risk of NE development in broiler chickens.

Incorporation of full-fat flaxseed, and to a lesser extent, canola seed in diets to produce n-3-enriched products has attracted interest in the poultry industry. However, high amounts of nonstarch polysaccharides (NSP) in oilseeds compromise their nutritive value. The objectives of the current research were to develop enzyme supplements effective in cell wall depolymerization and viscosity reduction, particularly in flaxseed; to evaluate the effects of enzyme addition and feed processing on oil utilization and egg n-3 fatty acid deposition in broiler chickens and laying hens fed oilseed-containing diets; to characterize the NSP hydrolysis products and to investigate the effects of diet type and enzyme addition on growth performance and the incidence of necrotic enteritis (NE) in broiler chickens challenged with Clostridium perfringens. Results showed that diets containing high levels of flaxseed reduced egg production and shell quality in laying hens, and impaired final body weight and feed conversion ratio (FCR) in broiler chickens. Reducing flaxseed particle size via grinding did not improve the growth performance of broiler chickens, whereas diet pelleting showed more pronounced and beneficial effects in improving the nutritive value of flaxseed, particularly when intact seeds were used. Multicarbohydrase supplementation resulted in a significant depolymerization of cell wall polysaccharides in soybean, canola and flaxseed meals, which was followed by the production of water-soluble NSP hydrolysis products, and the reduction of flax mucilage viscosity in vitro was also evident. Enzyme addition to flaxseed-containing diets improved FCR of broiler chickens and egg production performance of laying hens, and facilitated egg n-3 fatty acid deposition. The C. perfringens challenge caused intestinal NE lesions and increased the mortality of broiler chickens with the highest NE mortality and intestinal C. perfringens counts observed in those fed flaxseed-containing diets. Enzyme supplementation to diets containing high levels of water-soluble NSP (wheat/barley- or wheat/barley/flaxseed-based) facilitated post-disease compensatory growth in pathogen challenged birds. This was accompanied by a numerical reduction of intestinal C. perfringens by 1.4 log10 cfu/g in birds fed the flaxseed-containing diets. Such findings indicated that enzyme addition may be used as a nutritional strategy to reduce the risk of NE development in broiler chickens.

Das MMS stellt eine lebensbedrohliche Erkrankung großwüchsiger Hunde dar. Die ansteigenden Inzidenzzahlen der letzten Jahre, die ungeklärte Ätiologie sowie die hohe Mortalitätsrate rechtfertigen weitere Untersuchungen zu diesem Krankheitskomplex. Daher wurden in der vorliegenden Arbeit Mageninhalte (30 Tiere mit MMS / 13 Kontrolltiere) und Blutproben (102 Tiere mit MMS / 116 Kontrolltiere) mikrobiologisch, biochemisch (kurz-kettige Fettsäuren, Amylase, Lipase, Laktat, pH) und immunologisch (BotNt, CRP, Gesamt-immunglobuline, IgA-, IgG- und IgM-Spiegel ausgewählter mikrobieller Antigene) untersucht. Die Untersuchung des Mageninhaltes der Tiere mit MMS erbrachte signifikant gesteigerte Nachweishäufigkeiten für Hefen, hier v.a. von Rhodotorula mucilaginosa. Des Weiteren konnten in der Gruppe der Tiere mit MMS signifikant gesteigerte pH-Werte sowie signifikant erhöhte Mengen an Acetat, Butyrat und Gesamtfettsäuren im Vergleich zu den Kontrolltieren festgestellt werden. Die gesteigerte bakterielle Fermentation, die ursächlich mit der Entstehung des MMS zusammenhängen dürfte, ist vermutlich auf ein gesteigertes Vorkommen gasbildender Kokken zurückzuführen. Ein Einfluss von Clostridium perfringens an der Entstehung des MMS lässt sich anhand der ermittelten bakteriologischen Ergebnisse nicht belegen. BotNt haben nach den in der vorliegenden Arbeit gewonnenen Daten keinen Einfluss auf die Entstehung des MMS. Serologisch konnten in der Gruppe der Tiere mit MMS signifikant erhöhte CRP-Spiegel gemessen werden. Das CRP ließ aber keine prognostische Aussage über die Überlebenschancen der Tiere zu. Der erhöhte Gesamtimmunglobulin A-Spiegel, bei signifikant erniedrigtem Gesamtimmunglobulin G-Titer weist auf eine vermehrte Auseinandersetzung mit Antigenen hin, die über die geschädigten Schleimhäute eindringen können. Während der Serumlaktatspiegel eine prognostische Aussage über das Outcome der Tiere erlaubt, erscheint eine Bestimmung der Amylase und Lipase beim MMS nicht sinnvoll. Über einen Fragebogen konnte ein gesteigertes Risiko mit zunehmendem Alter, steigender Futtermenge pro Mahlzeit und niedriger Fütterungsfrequenz ermittelt werden. Eine gesteigerte Freßgeschwindigkeit übt einen tendenziellen Einfluss auf die Ausbildung des MMS aus. Keinen Einfluss dahingegen haben das Geschlecht und der Charakter der Tiere, bestehende gastrointestinale Störungen sowie vorangegangene Antibiotikumgaben.

La toxina-ε, produïda per la soca D de Clostridium perfringens, és la principal responsable de l’enterotoxèmia en animals de granja. Produeix un edema generalitzat, uns efectes citotòxics molt greus al ronyó (mort de les cèl•lules epitelials dels túbuls distals) i també efectes neurològics (mort neuronal provocada per excitotoxicitat). Tots aquests efectes porten finalment a la mort de l’animal. Actualment existeixen tractaments preventius de la toxina mitjançant la vacunació, però encara es desconeix el mecanisme d’acció letal, el seu receptor i els primers passos que porten a la citotoxicitat. Amb la finalitat d’estudiar el comportament d’aquesta toxina, al nostre laboratori vàrem produir una proteïna de fusió formada per la toxina-ε i la proteïna verda fluorescent GFP (toxina-ε-GFP). Aquesta eina va ser de gran utilitat, ja que es comportava igual que la toxina-ε nativa i podia localitzar-se de manera directa utilitzant microscòpia de fluorescència. De fet, injeccions i.v de toxina-ε-GFP a ratolí, varen revelar un edema generalitzat i una mort de les cèl•lules epitelials dels túbuls distals del ronyó de manera idèntica a la toxina nativa. A més, també mostrava citotoxicitat en cultius de la línia cel•lular MDCK, on heptameritzava a la membrana cel•lular, formava porus i provocava la mort cel•lular (Soler-Jover et al., 2004). L’objectiu d’aquesta tesi va ser aprofundir en el coneixement de les primeres etapes de la intoxicació per la toxina-ε, caracteritzant la seva unió i distribució en els diferents òrgans i sistemes, en especial el renal i nerviós. Per dur a terme aquest objectiu general, vàrem realitzar dues aproximacions experimentals: 1. Vàrem incubar la toxina-ε-GFP sobre seccions de teixits, on vàrem observar la seva unió a la mielina tant del SNC com del SNP. També vàrem veure que en el sistema renal, la toxina-ε-GFP reconeixia cèl•lules epitelials dels túbuls distals i col•lectors del ronyó, així com cèl•lules de l’uroteli. Els estudis realitzats en aquest treball (tractaments amb pronasa E, detergents, Nglicosidasa F i beta-eliminació) apunten que el receptor podria tractar-se d’una Oglicoproteïna tant en el sistema nerviós com en el renal, i que un ambient lipídic (o la integritat de la membrana) seria necessari per permetre la unió de la toxina-ε al seu receptor. A més, els estudis realitzats amb cross-linkers en les cèl•lules MDCK han permès identificar una proteïna d’uns 36 kDa (Annexina A2) que podria actuar com a correceptor o intervenir en l’oligomerització i formació de porus a la membrana plasmàtica. Mitjançant un assaig d’ELISA en cèl•lules MDCK, vàrem observar que només hi ha un sol lloc d’unió per a la toxina-ε, i aquest és saturable i d’alta afinitat. 2. Vàrem reproduir a ratolí els efectes de la toxina injectant i.v dosi letals de toxina-ε- GFP, i vàrem estudiar la seva distribució en el sistema nerviós. Vàrem veure que la toxina-ε-GFP a banda d’unir-se a les cèl•lules endotelials també era capaç de travessar la barrera hematoencefàlica (BHE) i arribar així al parènquima del cervell, on provocaria la mort neuronal ja fos d’una manera directa o indirecta (Soler-Jover et al., 2007). Donat l’interés en trobar nous vehicles capaços de travessar la BHE, vàrem analitzar aquesta propietat en diferents mutants de toxina-ε, tot i que encara no hem identificat cap mutant que hagi perdut la capacitat tòxica però no seva capacitat invasiva. La futura identificació del receptor de la toxina-ε, la formació dels heptàmers i la seva inserció a la membrana són, sens dubte, els grans reptes que ajudaran a caracteritzar el mecanisme d’acció de la toxina-ε de Clostridium perfringens. / ε-Toxin, produced by Clostridium perfringens type D, is the main agent responsible for enterotoxaemia in livestock. ε-Toxin accumulates specifically in the renal and nervous system were it produces the death of the epithelial cells from the distal tubules and neurons, respectively. Vaccines are very useful in the prevention of the ε-toxin intoxication, but nothing is known about the receptor and the first intoxication steps. We produced a recombinant ε-toxin protein with the green fluoresence protein GFP (ε- toxin-GFP) which is a useful tool because it behaves as the native ε-toxin and it can be detected by fluorescence (Soler-Jover et al., 2004). The aim of this thesis is to go into detail in the knowledge of the first steps in the intoxication pathway, characterizing the binding and distribution of the ε-toxin in different organs and tissues, especially in the renal and nervous system. To achieve this aim we performed two experimental approaches. On one hand, we incubated the ε-toxin-GFP on tissue sections, were its binding to myelin from CNS and PNS was observed. We also observed binding of ε-toxin to the urothelium and epithelial cells from distal and collecting tubules in the kidney. Our work revealed that the receptor in the nervous and renal system could be an Oglycoprotein, and that a lipidic environment (or the membrane integrity) would be required for the binding of ε-toxin to its receptor. In addition, an ELISA-based binding assay revealed a single high-affinity binding site for ε-toxin in MDCK cells. Moreover, cross-linking experiments identified a 36 kDa protein (Annexin A2) which could be involved in the membrane pore formation step. On the other hand, we reproduced in mice the in vivo effects by injecting i.v ε-toxin- GFP. The toxin crossed the BBB and penetrated the brain parenchyma producing neuronal death (Soler-Jover et al., 2007). We are interested in the finding of new vehicles to cross the BBB. In fact, some ε-toxin mutants have been studied but no one is able to cross the BBB without producing cell damage and animal death.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2004. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 4 uppsatser.

Universiẗat, Diss., 2004--Bonn.

Made available in DSpace on 2014-06-11T19:32:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-11-30Bitstream added on 2014-06-13T20:04:34Z : No. of bitstreams: 1 ragazani_avf_dr_jabo.pdf: 399859 bytes, checksum: f93ad8981a9e4aaa051ed6bff03ccacc (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Entre as espécies de Clostridium de importância em patologia animal, destaca-se o Clostridium perfringens, o Clostridium botulinum, o Clostridium chauvoei. O objetivo desta pesquisa foi verificar a presença de bactérias anaeróbias esporuladas (Clostridium sp), assim como, identificar as espécies de Clostridium patogênicos para a saúde animal, principalmente de bovinos, no solo de pastagem da micro-região de Jaboticabal, SP. Foram coletadas 250 amostras de solo e realizadas contagens de bactérias esporuladas do gênero Clostridium e identificação das espécies patogênicas presentes. Os resultados permitiram demonstrar a contagem de UFC de Closrtidium sp com média em log 10 igual a 2,79, sendo que os valores mínimo e máximo obtido foram 2,15 e 3,68 respectivamente. Para caracterização e identificação, os resultados permitiram identificar a presença de bactérias anaeróbias esporuladas em 233 amostras (93,2%), entre estas 180 eram do gênero Clostridium... / The species of Clostridium of major importance to animal pathology are Clostridium perfringens, Clostridium botulinum, and C. chauvoei. Considering this, the objective of this research was to verify the presence of anareobic sporulate bacteria (Clostridium sp), and also identify the species of pathogenic Clostridium for the animal health, mostly to bovine, in pasture soil of Jaboticabal-SP. A total of 250 samples were collected and used to determine the number of sporulated bacteria from Clostridium genderand identify the pathogenic species present. The results demonstrated that the average number of CFU in log 10 of Closrtidium sp was 2,79, and the minimum and maximum values obtained were 2,15 and 3,68 respectively. After characterization and isolation and identification, the results showed the presence of 233 samples (93,2%) of sporulated bacteria, of these 180 were of Clostridium gender. The biochemical tests were identified in 42 samples, being 23 samples (9,2%) of Clostridium perfringens, 13 samples (5,2%) of Clostridium botulinum and 6 samples (2,4%) of C. chauvoei ...(Complete abstract, click electronic access below)