A importância da espécie suína na transmissão de Campylobacter spp. assemelha-se aos demais grupos de animais que se destinam à produção de carne, incluindo aves, bovinos e ovinos. Os objetivos deste estudo foram isolar Campylobacter spp. a partir de fezes e carcaças de suínos abatidos no Estado de São Paulo; identificar as espécies de Campylobacter spp. presentes nos animais abatidos; caracterizar os isolados obtidos através do Polimorfismo do Comprimento de Fragmentos Amplificados (AFLP). Para tal, foram utilizadas 120 amostras de fezes e 120 suabes de carcaças de suínos, colhidas de quatro diferentes abatedouros do Estado de São Paulo. Das 120 amostras de fezes analisadas, 30 foram positivas para o isolamento de Campylobacter coli (25%) e duas foram positivas para isolamento de Campylobacter jejuni (1,6%). Todas as amostras analisadas de suabes de carcaça foram negativas para Campylobacter spp. As estirpes isoladas que apresentaram características bioquímicas sugestivas de Campylobacter spp. foram submetidas ao teste de susceptibilidade ao ácido nalidixico e cefalotina, destas 19,16% (23/120) apresentaram resistência ao ácido nalidixico apesar de todas as características bioquímicas indicarem se tratar de Campylobacter coli. Foram selecionadas para a análise genotípica 38 amostras isoladas, sendo 36 de C. coli e dois de C. jejuni. A análise dos isolados através do AFLP revelou a presença de 28 perfis que foram designados P1 a P28. A técnica discriminou as cepas de acordo com a espécie, porém, uma cepa previamente caracterizada como C. coli foi agrupada com isolados de C. jejuni. Não foi possível estabelecer a correlação entre os isolados e o abatedouro de origem, no entanto observa-se uma forte tendência dos isolados resistentes ao ácido nalidixico em formar grupamentos de maior similaridade. / The importance of swine species in the transmission of Campylobacter spp. resembles to the other groups of animals that are destined to the meat production, including bovine and ovine animals. The objectives of this study were to isolate Campylobacter spp. from swine feces and carcasses slaughtered in São Paulo State; to identify the Campylobacter spp. species presents in the slaughtered animals; to characterize the isolated samples by amplified fragment length polymorphism (AFLP), for this, 120 swine feces samples and the same number of carcasses swabs were collected of four different slaughterhouses in São Paulo State. From 120 feces samples, 30 (25%) were positive for Campylobacter coli isolation and two (1,6%) were positive for Campylobacter jejuni. All the analyzed carcass swabs samples were negatives for Campylobacter spp. The isolated samples that presented suggestive biochemical characteristics of Campylobacter spp. were submitted to the susceptibility test to the nalidixic acid and cefalotine, from that 19.16% (23/120) presented resistance to the nalidixic acid in spite of all the biochemical characteristics indicate that they were Campylobacter coli. They were selected for the genotypic analysis 38 isolated samples, being 36 of C. coli and two of C. jejuni. The analysis of the 38 tested samples by AFLP showed the presence of 28 profiles that had been assigned P1 to P28. The technique discriminated the samples in agreement with the species, however, one sample previously characterized as C. coli was clustered as C. jejuni. It was not possible to establish the correlation between the isolated samples and the origin slaughterhouse, however a strong tendency of the isolated samples acid nalidixic resistant to create clusters with more similarity.

Campylobacter spp. infections are an increasing global concern responsible for a significant burden of disease every year. Wildlife and domestic animals are considered important reservoirs, but little is known about host-factors driving pathogen infection dynamics in wild mammal populations. In countries like Botswana, there is significant spatial overlap between humans and wildlife with a large proportion of the population vulnerable to Campylobacter infection, making Botswana an ideal location to study these interactions. This thesis reviews mammalian wildlife species that have been identified as carriers of Campylobacter spp., identifies life-history traits (urban association, trophic level, and sociality) that may be driving Campylobacter infection, and utilizes banded mongoose (Mungos mungo) (n=201) as a study species to illuminate potential Campylobacter spp. transmission at the human-wildlife interface in northern Botswana. Results of the latter study suggest that human-landscapes are critical to C. jejuni infection in banded mongooses, as mongooses utilizing man-made structures as dens had significantly higher levels of C. jejuni than mongooses using natural dens (p=0.019). A similar association was found across all wild mammals with significantly greater number of urban dwelling species positive for C. jejuni than urban avoiders (p = 0.04). Omnivorous and social mammals were significantly associated with C. coli presence (p=0.04 and p<0.00 respectively), but not with C. jejuni indicating there may be important differences in transmission dynamics between Campylobacter species. These results suggest that landscape features and life-history traits can have important influences on Campylobacter species exposure and transmission dynamics in wildlife. / Master of Science / Campylobacter infections are increasing worldwide but we still know little about the true burden of disease in the developing world, and even less about the role of wildlife and environmental reservoirs in human exposure and disease. I reviewed life-history traits (urban association, animal rank on the food chain, and sociality) that might be driving Campylobacter spp. infection in wildlife and investigated interactions between an urbanizing wildlife species, banded mongoose (Mungos mungo), humans, and the environment. Banded mongooses live in close association with humans and infections with C. jejuni were greater among mongooses utilizing man-made structures compared to those using natural dens. Across all wild mammal species tested for Campylobacter spp., mammals associated with urban living were significantly more likely to be positive for C. jejuni than mammals that avoid urban areas. Lowerranking mammals on the food chain and social mammals were associated with presence of C. coli, suggesting life-history rates are playing a role in wild mammal exposures to the pathogen and that these exposures are different for C. coli than C. jejuni. These data suggest that wildlife life-history traits and utilization of human landscapes are important for pathogen presence. In turn, pathogen circulation and transmission in urbanizing wildlife reservoirs may increase human vulnerability to disease, particularly in impoverished populations, where greater environmental exposures are expected. Improvement of waste management and hygiene practices may help reduce transmission between wildlife and humans.

Le Campylobacter est le plus important agent d'entérites bactériennes dans les pays industrialisés et en voie de développement. Des études récentes suggèrent que l'eau non-traitée est une source sous-estimée d'infections sporadiques chez l'humain. Dans le cadre du volet environnemental du projet CampyloGIS, mon projet principal consistait en l'étude de la prévalence et de la quantité du Campylobacter retrouvé dans les eaux environnementales de l'Estrie. Trente-deux sites d'échantillonnage d'eau ont été sélectionnés dans les 7 MRC de l'Estrie pour être échantillonnés hebdomadairement du 17 juillet 2005 au 08 juillet 2007. Globalement, 1071/2481 (43%), 1481/2471 (60%) et 1463/2471 (59%) échantillons d'eau étaient respectivement positifs pour Campylobacter spp., les coliformes thermotolérants et E. coli . Il y avait une faible corrélation entre la prévalence hebdomadaire du Campylobacter spp. et des coliformes thermotolérants (rho de Spearman = 0,27; P = 0,008) et entre la quantité de ces deux microorganismes (tau-b de Kendall = 0,233; P < 0,0001). Également, plus de 150 échantillons d'eau de puits privés situés en Estrie ont été gracieusement analysés au cours de ce projet. Cinq échantillons d'eau de puits de surface sur 53 étaient positifs pour C. jejuni et seulement deux d'entre eux étaient aussi positifs pour les coliformes thermotolérants. Ces résultats suggèrent que les indicateurs de pollution fécale, comme les coliformes thermotolérants, ne sont pas suffisants pour correctement évaluer la présence et/ou la quantité du Campylobacter dans l'eau environnementale. Mon deuxième projet consistait en le développement d'une approche moléculaire d'identification à l'espèce de C. jejuni, C. coli, C. lari, C. upsaliensis et C. fetus basée sur la PCR hippurate, la PCR 16S et la PCR-RFLP. Présentement, l'approche moléculaire permettrait d'éviter la mauvaise identification de 526/1950 isolats (27%) préalablement mal identifiés par les tests biochimiques seuls. Jusqu'à présent, l'approche moléculaire ne permettrait toutefois pas d'identifier correctement à l'espèce 35/1950 isolats (1,8%) de Campylobacter. Cette approche moléculaire a permis de confirmer la nécessité d'utiliser plus d'une technique afin de s'assurer de l'identification à l'espèce adéquate du Campylobacter. Finalement, la présence soutenue et la forte concentration occasionnelle du Campylobacter détecté dans les eaux environnementales de l'Estrie, ont porté à se questionner sur l'utilité de développer une méthode efficace de détection et de quantification du Campylobacter dans l'eau. De cette réflexion et des difficultés d'exécution qu'entraîne l'utilisation de la méthode MPN comme outil quantitatif, est né mon troisième projet, soit un protocole de RT-PCR semi-quantitative précédée d'un enrichissement pour la quantification de C. jejuni, C. coli et C. lari dans l'eau. Ce projet a permis de constater qu'un enrichissement de 16 h permettait d'augmenter, par un facteur relativement constant, le nombre de C. jejuni contenu dans un échantillon d'eau naturellement contaminé et ce, peut importe la condition cellulaire initiale occasionnée par un séjour dans l'eau. De plus, les résultats obtenus via le protocole de RT-PCR semi-quantitative sont comparables à la quantification obtenue via la méthode MPN (rho de Spearman = 0,84; P < 0,001), ce qui permet de croire que ce protocole simple pourrait éventuellement être un choix envisageable pour la détection et la quantification du Campylobacter dans l'eau.

Campylobacter jejuni is an enteric bacterium that causes human gastroenteritis worldwide. Some C. jejuni strains exhibiting human ganglioside-like lipooligosaccharide (LOS) structures, such as GM1 ganglioside, can induce an autoimmune neuropathy of the peripheral nervous system known as the Guillain-Barré syndrome (GBS). This GBS-inducible determinant is encoded by a gene cluster, which shows a high degree of variation among C. jejuni strains. The experiments presented in this thesis were conducted to give a better insight into the LOS synthesis genes in relation to the pathophysiology of C. jejuni. Firstly, a C. jejuni strain without GM1-like molecules was shown to be able to take up large DNA fragments, including LOS synthesis genes, from a strain expressing GM1-like molecules and consequently be transformed into a number of potential GBS-inducible transformants, which exhibited a high degree of genetic and phenotypic diversity. The ability of C. jejuni to take up and integrate foreign DNA explains the genome plasticity observed in this pathogen. Secondly, while attempting to analyse transcription of the LOS gene cluster, neither published methods nor any commercially available kits for RNA isolation could produce DNA-free RNA from C. jejuni. Combinations of these methods were trialled and only the combination of RNAzolB, TURBO DNase treatment, and acid phenol extraction was able to produce DNA-free RNA. The RNA isolated from most C. jejuni strains showed different RNA patterns to that of other bacteria. In addition the RNA from C. jejuni seemed closely associated with DNA compaired to RNA from other organisms. This might be caused by species-specific DNA conformation or chromatin structure. Thirdly, bidirectional transcription was observed in the LOS gene cluster. Both DNA strands were transcribed but transcription of the non-coding strands was at a lower rate, and both sense and antisense transcripts of each LOS gene tested were responsive to acid stress. This unusual transcription might have a potential effect on the expression of the GBS-inducing determinant. Finally, one of the LOS genes, the htrB gene, was further analysed. It was shown that expression of the htrB gene affects morphology, viability, growth ability, and sensitivity to stress environments. These results showed that the LOS molecule of C. jejuni is involved in many processes and is an important molecule for survival.

The purpose of this work was to examine the effectiveness of several replacements for antibiotics in broiler chickens using bacterial challenge models. For this work, pathogen challenge models were developed using three model pathogens; two human pathogens (<i>Salmonella enteritidis</i> and <i>Campylobacter jejuni</i>), and one poultry pathogen (<i>Clostridium perfringens</i>). The first set of experiments involved the selection and use of 2 model probiotics; <i>Bifidobacterium animalis</i> and <i>Lactobacillus fermentum</i>. Oral administration of either probiotic did not significantly reduce (P < 0.05) the level of intestinal colonization by either <i>S. enteritidis</i> or <i>C. jejuni</i> in experimentally infected broiler chickens. The next set of experiments examined the effectiveness of orally administered, pathogen-specific antibodies obtained from hyperimmunizing laying hens in controlling bacterial infections with <i>S. enteritidis</i>, <i>C. jejuni</i> or <i>Clostridium perfringens</i> in broiler chickens. Regardless of the concentration, or mode of administration, anti-<i>S. enteritidis</i> hen-egg antibodies or anti-<i>C. jejuni</i> hen-egg antibodies were unable to significantly reduce (P < 0.05) the intestinal colonization by either pathogen in experimentally infected broiler chickens. Likewise, administration of anti-<i>C. perfringens</i> hen-egg antibodies did not reduce intestinal colonization by <i>C. perfringens</i>, and actually exacerbated the clinical outcome of this important poultry pathogen by significantly increasing (P < 0.05) intestinal lesions scores compared to negative control birds. Lastly, the effect of dietary protein source on intestinal <i>C. perfringens</i> populations was investigated. In broiler chickens experimentally infected with <i>C. perfringens</i> and fed diets which varied in the source of dietary protein, it was shown that birds fed fish meal, meat/bone meal, feather meal and potato protein concentrate had significantly higher intestinal <i>C. perfringens</i> counts than the birds fed corn gluten meal, soy or pea protein concentrates or the control diet (P < 0.05). Further, it was shown that the glycine content of the diets and ileal contents was significantly, positively correlated with <i>C. perfringens</i> numbers in ileum and cecum. It is concluded that although the intervention strategies employed in these studies show promise, diet composition clearly had the largest effect on intestinal bacterial populations. Further studies are required to examine both the impact that diet and these intervention strategies have on the factors which control intestinal colonization by pathogens on a case by case basis.

The purpose of this work was to examine the effectiveness of several replacements for antibiotics in broiler chickens using bacterial challenge models. For this work, pathogen challenge models were developed using three model pathogens; two human pathogens (<i>Salmonella enteritidis</i> and <i>Campylobacter jejuni</i>), and one poultry pathogen (<i>Clostridium perfringens</i>). The first set of experiments involved the selection and use of 2 model probiotics; <i>Bifidobacterium animalis</i> and <i>Lactobacillus fermentum</i>. Oral administration of either probiotic did not significantly reduce (P < 0.05) the level of intestinal colonization by either <i>S. enteritidis</i> or <i>C. jejuni</i> in experimentally infected broiler chickens. The next set of experiments examined the effectiveness of orally administered, pathogen-specific antibodies obtained from hyperimmunizing laying hens in controlling bacterial infections with <i>S. enteritidis</i>, <i>C. jejuni</i> or <i>Clostridium perfringens</i> in broiler chickens. Regardless of the concentration, or mode of administration, anti-<i>S. enteritidis</i> hen-egg antibodies or anti-<i>C. jejuni</i> hen-egg antibodies were unable to significantly reduce (P < 0.05) the intestinal colonization by either pathogen in experimentally infected broiler chickens. Likewise, administration of anti-<i>C. perfringens</i> hen-egg antibodies did not reduce intestinal colonization by <i>C. perfringens</i>, and actually exacerbated the clinical outcome of this important poultry pathogen by significantly increasing (P < 0.05) intestinal lesions scores compared to negative control birds. Lastly, the effect of dietary protein source on intestinal <i>C. perfringens</i> populations was investigated. In broiler chickens experimentally infected with <i>C. perfringens</i> and fed diets which varied in the source of dietary protein, it was shown that birds fed fish meal, meat/bone meal, feather meal and potato protein concentrate had significantly higher intestinal <i>C. perfringens</i> counts than the birds fed corn gluten meal, soy or pea protein concentrates or the control diet (P < 0.05). Further, it was shown that the glycine content of the diets and ileal contents was significantly, positively correlated with <i>C. perfringens</i> numbers in ileum and cecum. It is concluded that although the intervention strategies employed in these studies show promise, diet composition clearly had the largest effect on intestinal bacterial populations. Further studies are required to examine both the impact that diet and these intervention strategies have on the factors which control intestinal colonization by pathogens on a case by case basis.

Thesis (M. Med. Sc.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 26-32).

Campylobacter jejuni (C. jejuni) is a food-borne bacterial pathogen that is the leading cause of Traveller’s Diaharea and Guillian-Barré Syndrome. Previous research determined that bacterial surface carbohydrates are virulence factors. Specifically, the study of the capsular polysaccharide (CPS) structures has widespread applications to understanding serotype cross-reactivity and biosynthetic pathways, the function of bacterial surface carbohydrates, and glycoconjugate vaccine development. This thesis characterized the CPS of C. jejuni HS:10 and subsequently used the CPS for developing a glycoconjugate vaccine. This was accomplished through extraction and purification of sugar from the bacteria, followed by characterization using chemical degradation, GC-MS, NMR and conjugation techniques. These analyses determined that the CPS was composed of a 3-linked GalNAc backbone and 6d-Galhepf attached at the 4th position with non-stoichiometrically attached O-methyl phosphoramidate attached to the 3 position of the heptose. Using this structure, a successful glycoconjugate vaccine was prepared using periodate oxidation and reductive amination.

No description available.

Thesis (Ph. D.)--Michigan State University. Dept. of Microbiology and Molecular Genetics, 2007. / Title from PDF t.p. (viewed on Apr. 16, 2009) Includes bibliographical references. Also issued in print.