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1
Okwumabua, Ogi Emeke. "Biochemical and molecular characterization of urease-positive campylobacters (campylobacter pylori and campylobacter mustelae." Thesis, Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/25297.
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Pratt, Alisa Annabelle. "Antibiotic Resistance Determinants of Australian Campylobacter Jejuni & Campylobacter Coli Isolates." Thesis, Griffith University, 2008. http://hdl.handle.net/10072/366198.
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Campylobacter species are the most common cause of foodborne disease in Australia and many countries throughout the World. Although campylobacteriosis is usually self-limiting, severe cases and those in the young, elderly and immunocompromised require antibiotic therapy. Antibiotic resistant Campylobacter isolates however may prolong illness and increase the risk of invasive disease. Antibiotic resistance in Campylobacter is thought to have arisen through the selective pressure of exposure to antimicrobial agents in veterinary medicine or animal husbandry, leading to the acquisition and dissemination of antibiotic resistance determinants, and genetic elements that harbour such genes, amongst isolates.
Little was known about tetracycline and trimethoprim resistance in Australian campylobacters, including the presence of resistance genes and associated genetic elements. Aims of this study were therefore to identify in Australian Campylobacter jejuni and Campylobacter coli isolates i). Tetracycline resistant determinants and associated genetic elements, ii). Trimethoprim resistant determinants and associated genetic elements, and iii). Integron like structures and associated genetic elements.
High-level tetracycline resistance was observed in 46 C. jejuni and C. coli isolates, with MICs ranging from 32 to >256mg/ml. All isolates examined harboured the tetO gene, confirming that tetracycline resistance in Australian campylobacters is also due to the previously reported TetO determinant. While several studies have described a significant role for plasmids in tetracycline resistance, this study demonstrated that in the majority of isolates (78%), including two thirds of strains that harboured plasmids, resistance was due to chromosomally encoded tetO. Six C. jejuni isolates were able to transfer a tetO harbouring plasmid to another C. jejuni strain. Plasmids were detected in approximately 74% of resistant strains, and ranged in size from small to larger plasmids (21 - 50kb). ClaI profiling of plasmids revealed genetic diversity and indicated that the tetO gene may be carried by a variety of plasmids.
High level trimethoprim resistance (MICs of 1000mg/ml and >1000mg/ml) was observed in all isolates (>100) examined from a second collection of C. jejuni, C. coli and non-C. jejuni/coli spp. Just over half of isolates harboured plasmids indicating that plasmids may not be involved in trimethoprim resistance in campylobacters. Isolates were also examined for the presence of the previously identified Campylobacter associated trimethoprim resistance genes dfr1 and dfr9. Although these genes play a significant role in this resistance, only approximately 16% of strains examined putatively harboured dfr1, and dfr9 was not detected.
Integrons, antibiotic resistance gene acquisition and expression systems, play an important role in trimethoprim resistance due to carriage of dfr genes as inserted gene cassettes. Trimethoprim resistant Campylobacter isolates were examined for the presence of the intI1 and intI2 genes, encoding the class 1 and class 2 integrons. Only 5.56% of strains examined for intI1 putatively carried this gene, and only 1.67% of isolates examined for intI2 putatively carried intI2. Both putative intI1 positive and negative isolates produced a variety of amplicons, ranging in size from »210bp to >1.5kb, when analysed for gene cassette sequences inserted into class 1 integrons.
This study has contributed to the knowledge of tetracycline and trimethoprim resistance, including the presence of resistance genes and associated genetic elements, in Australian isolates of C. jejuni and C. coli.Thesis (Masters)
Master of Philosophy (MPhil)
Griffith University. School of Medical Science.
Griffith Health
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Nguyen, Hai. "Acanthamoeba-Campylobacter Interactions." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20172.
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Campylobacter jejuni is an avian commensal bacterium and causes gastrointestinal diarrhea in humans called campylobacteriosis. Campylobacteriosis is acquired by consumption of undercooked poultry contamined with C. jejuni. Poultry can become colonized from contaminated drinking water. The chicken flock and drinking water of 4 poultry farms in Ontario were sampled and the prevalence of C. jejuni in these flocks was determined to be 16.7% over a 1 year sampling period. We determined that contamined- water was a significant risk factor for Campylobacter-positive flocks from flaA typing, PFGE analysis, and genomotyping several isolated strains. Free living amoebae, such as Acanthamoeba species, live in the drinking water of poultry farms. It is hypothesized that Acanthamoeba in the drinking water of poultry farms can take up and act as environmental reservoirs of C. jejuni. Acanthamoeba species were isolated from the drinking water. Acanthamoeba strains were found to act as a vehicle for protection, persistence and growth of C. jejuni isolated from the farm water. The transcriptome of both C. jejuni and A. castellanii during the initial stages of C. jejuni internalization were described by RNA-seq. C. jejuni oxidative defence genes (such as katA, sodB, fdxA) and some other unknown genes (Cj0170, Cj1325, Cj1725) were found to be essential in the interaction with A. castellanii. Our findings suggest that Acanthamoebae act as a C. jejuni reservoir and could be a contributing source of C. jejuni in the environment. Through transcriptomics studies, we have begun to uncover some genetic clues involved in this interaction.
4
Ghaffer, Nacheervan M. "Filamentation of Campylobacter." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/35597/.
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The bacterial pathogen Campylobacter jejuni is a leading cause of foodborne gastroenteritis worldwide. Consumption of contaminated poultry meat is considered a major source of infection. Changes in cell morphology were demonstrated to occur spontaneously on entry in to stationary phase, with development of filamentous cells amongst short spiral morphotypes. The aim of this study was to investigate differences between the morphotypes of C. jejuni and C. coli and gain insights into their development. Using a minimal culture medium filament formation was observed to be wide spread amongst C. jejuni strains tested but was not universal in C. coli strains. Filamentation did not appear to arise due to the release of diffusible molecules or the accumulation of either toxic metabolites or oxidative stressors in the medium. Separated filaments exhibited greater intracellular ATP contents compared to spiral cells, and were able to survive longer in water at 4 and 37 C. C. jejuni 12661 was identified as producing long filaments but genome sequence analysis provided no clear explanation for the enhanced filament formation. Using RNA-Seq, transcriptome differences were examined between cells growing in exponential phase and separated cell morphotypes recovered from stationary phase cultures of the C. jejuni strains 12661 and PT14. These studies identified profound transcriptional differences between the cell morphotypes present at stationary phase, and highlighted problems of interpreting such data without separation of these sub-populations. Stationary phase cells of either morphotype were impaired in motility, which likely resulted from down-regulation of rpoN encoding sigma factor 54, and several key motility associated genes. The spoT gene of C. jejuni mediates the synthesis of ppp(G)pp as part of the stringent response to stress. The spoT gene was differentially regulated in the stationary phase morphotypes recovered in this study, as were the genes encoding the phosphohydrolases PPX1/PPX2 and polyphosphate kinases PPK1/PPK2 that control cellular (p) pp(G)pp pools. Prominent heat-shock and oxidative stress responses were evident in stationary phase cells compared to cells in exponential growth phase but transcription of the ribosomal proteins was not down-shifted. The transcript levels of several cell division associated genes were down-regulated in stationary phase spiral and filamentous cells. The formation of long filamentous cell morphotypes by C. jejuni 12661 corresponds with reduced expression of maf (inhibitor of septum formation), mreB (actin-like rod-shape determining protein), mreC (rod-shape determining protein), parA, parB (chromosome partitioning proteins), ftsA (actin-like function in cytokinesis), ftsH (ATP-dependent zinc metallopeptidase), ftsW (lipid II-linked peptidoglycan transporter) and ftsZ (tubulin-like z-ring formation) that collectively function in septum formation between daughter cells.
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Gormley, Fraser James. "The epidemiology of Campylobacter jejuni and Campylobacter coli in north east Scotland." Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2008. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=25813.
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Shaheen, Bashar Wajeeh. "In vitro survival of Campylobacter jejuni and Campylobacter coli at low Ph." Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Spring/master's/SHAHEEN_BASHAR_0.pdf.
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McTavish, Sharla. "Comparative analysis of New Zealand campylobacter isolates using MLST, PFGE and flaA PCR RFLP genotyping : a thesis submitted to the Victoria University of Wellington in partial fulfilment of the requirements for the degree of Master of Science in Molecular Microbiology /." ResearchArchive@Victoria e-Thesis, 2008. http://hdl.handle.net/10063/413.
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Murphy, Helen. "Host Responses to Campylobacter." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520636.
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John, Amy. "Campylobacter in farm animals." Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/13732/.
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Campylobaeter jejuni and C. coli are common causes of acute gastroenteritis in humans that are also associated with Guillain Barre and Miller Fisher syndrome. Poultry and other farm animals are the major sources of these pathogens. In this thesis it was demonstrated that hydrogen has the potential to act as an antioxidant to reduce oxidative stress caused during the growth of C. jejuni HPC5 when grown in a gas replacement jar. Growth in the absence of hydrogen in a modular atmosphere controlled system (MACS) was characterised by an intiallag that could be overcome by adding an antioxidant reagent FBP (10% ferrous sulphate, sodium pyruvate and sodium metabisulphite). Transcriptomic studies revealed that growth in the absence of hydrogen resulted in significant increases in the expression of superoxide dismutase, thiol peroxidase and ribosomal proteins. Transcriptomic studies were performed on the variants of C. jejuni HPC5 where bacteriophage predation had provoked intragenornic recombination to create second generation resistant types that are inefficient colonisers of chickens but revert to efficient colonisers and bacteriophage sensitivity when reintroduced into chickens to create third generation variants. The second generation variants were temperature sensitive, exhibited increased expression ofprophage Mu genes and low expression of motility associated genes. In contrast third generation variants showed an increase in the expression of the motility genes, an increase in the genes associated with the putative bacteriophage immunity factor CRISPR and reduced expression of Mu genes. Studies conducted on pigs demonstrated that a single pig can be colonised by campylobacters belonging to multiple genotypes and species. Comparative genomic hybridisation (CGH) of C. coli and C. jejuni isolated from the intestines of a single pig demonstrated these isolates shared plasmid and chromosomal encoded genes, and therefore may have undergone inter-species gene transfer due to cohabitation of a common intestinal niche. The aim of this thesis is to genotypically characterise Campylobaeter strains from chicken and pig in ideal atmospheric conditions. Our hypothesis is that Campylobacter can be grown in vitro both in gas replacement jar (ORJ) and in MACS and the molecular characterisation by transcriptomic analysis and CGH of the strains will be ideal in an atmospheric condition which is stress free.
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Garg, Nitanshu. "Copper, cytochromes and Campylobacter." Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/22930/.
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Runsick, Cara Denise. "Phenotypic and genotypic characterization of several unidentified new strains of campylobacter-like bacteria." Thesis, Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/25340.
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Horrocks, Shane Michael. "Effects of short-chain nitrocompounds against Campylobacter jejuni and Campylobacter coli in vitro." Texas A&M University, 2006. http://hdl.handle.net/1969.1/5022.
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Campylobacter is an important human pathogen that colonizes the gut of food
producing animals. In this study, the effects of 2-nitro-1-propanol, 2-nitroethanol,
nitroethane, and 2-nitro-methyl-propionate (0, 10, and 20 mM) on growth of
Campylobacter jejuni were tested during culture in Bolton Broth adjusted to pH 5.6, 7.0,
or 8.2. The effects of the nitrocompounds were also tested against C. coli in Bolton
Broth but adjusted to pH 8.2 only. Viable cell counts of samples taken at intervals during
incubation revealed main effects (P < 0.05) of nitroethane, 2-nitro-1-propanol, 2-
nitroethanol, and 2-nitro-methyl-propionate as evidence by reduced survivability of C.
jejuni. A marked effect of pH on the survivability of C. jejuni during incubation with all
compounds was observed, with greater activity observed at pH 8.2 than at pH 5.6 or 7.0
for nitroethane, 2-nitro-1-propanol, 2-nitroethanol, but not for 2-nitro-methyl-propionate.
In the case of 2-nitro-methyl-propionate, survivability of C. jejuni was reduced most at
pH 5.6. Except for 2-nitro-methyl-propionate, which was ineffective, all nitrocompounds
elicited similar effects on C. coli when cultured at pH 8.2. The effect of nitroethane and
2-nitro-1-propanol (10 mM) on naturally-occurring Campylobacter was further
investigated during incubation of a porcine fecal suspension. Campylobacter concentrations decreased more rapidly (P < 0.05) during incubation of porcine fecal
suspensions supplemented with 2-nitro-1-propanol than unsupplemented control
suspensions or suspensions supplemented with nitroethane thus reiterating the superior
inhibitory effect of 2-nitro-1-propanol.
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Deibel, Kurt Eugene. "A study of Campylobacter jejuni /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487260135358.
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Basardien, Laeeqa. "Molecular characterization of Campylobacter isolates from free range and commercial chicken in South Africa." University of the Western Cape, 2012. http://hdl.handle.net/11394/5068.
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>Magister Scientiae - MScCampylobacter species are the most common bacteria associated with acute diarrhoea and is responsible for 400 to 500 million reported cases globally. It is not uncommon for 35% to 85% of chicken flocks to be infected with campylobacters and it is because of this high prevalence that chicken is considered to be the primary source of Campylobacter contamination in the domestic setting. Therefore, a very high risk of acquiring campylobacteriosis is associated with the mishandling and consumption of contaminated chicken. The present study had isolated a total number of 156 Campylobacter isolates, of which 102 isolates were C. jejuni and 51 were C. coli. The speciation of 3 Campylobacter isolates could not be determined. It had shown that there is a high prevalence of Campylobacter in South African chicken. Retail chicken (n = 84) has a lower prevalence of 27% whereas chicken sampled directly from the abattoir (n = 182), but also intended for human consumption, had an average prevalence of 73%. It also showed that free range chicken (n = 118) has a higher prevalence (average of 79%) of Campylobacter than commercial chicken (n = 64) (average of 56%). It is for this reason that free range chicken is not always the safer option considering that the purchasing of free range chicken is becoming more popular for health reasons. There is no standardized universal isolation protocol for Campylobacter species and the current isolation techniques creates a bias for the optimal growth of C. jejuni and C. coli, the two thermotolerant species most commonly associated with human illnesses. Recently, the non-selective Cape Town Protocol was designed for efficient isolation of campylobacters from clinical samples and proved to be superior to the former techniques in the isolation of the thermotolerant campylobacters as well as emerging campylobacters. However, the protocol is not suited to the isolation of Campylobacter from food samples. This study successfully optimized the Cape Town protocol by incorporating the use of the selective Bolton broth for the recovery and enrichment of injured cells from raw chicken samples. The technique proved to be equal in isolation efficiency to the ISO 1272-1:2006 method but loses its ability to recover all campylobacters that may be present in the food sample. It is for this reason that a non selective enrichment broth should be sought but the technique boasts superiority over the ISO 10272-1:2006 method in that it reduces the time in obtaining the results at least by 48 h and is more cost effective.
National Research Foundation (NRF)
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Stiller, Christiane. "Zum Vorkommen von Campylobacter jejuni und Campylobacter coli in Rohmilch von Erzeugerbetrieben in Nordbayern mit Versuchen zur Überlebensfähigkeit von Campylobacter jejuni in Milch." [S.l. : s.n.], 1999. http://www.diss.fu-berlin.de/1998/88/index.html.
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Cox, Joanne Mary. "Molecular genetics of Campylobacter species." Thesis, University of Leicester, 1997. http://hdl.handle.net/2381/29782.
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Campylobacter species are becoming increasingly significant to the health of humans. Campylobacters are notably difficult to isolate, maintain and manipulate and the use of molecular biology techniques is very limited. As a result few genes have been identified from this bacterium and little is known of its association with humans or animal disease in comparison to other enteric pathogens. A specifically targeted strategy employing the polymerase chain reaction with degenerate oligonucleotide primers (PCRDOP) was used to successfully clone portions of the C. upsaliensis flagellin genes, fla1 and fla2. Sequence analysis showed that the C. upsaliensis flagellin gene fragments were highly similar to the flagellin genes of C. jejuni and C. coli, although it contained a region of DNA extra to that of the other species. An alternative strategy was attempted to identify genes encoding potentially exported proteins using the transposon, TnPhoA. This technique resulted in the cloning of portions of the gene homologues of the a subunit of ATP synthase (uncB), an ATP-dependent protease (sms), two cytochromes (clpA and clpB), a cytochrome oxidase bd (cydA) and polyphosphate kinase (ppK). This is the first report of the identification of cytochrome bd in a campylobacter species. Campylobacters were previously thought to possess cytochromes of the b and c types only, and not the a or d types. The cytochrome bd is often hidden in other species when using traditional methods for identification of bacterial cytochromes involving spectrophotometry. A defined mutant in the putative cydA gene was engineered using a novel strategy for the transformation of campylobacters. The phenotype was investigated and revealed severe growth restrictions at low oxygen tensions.
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Hill, Helena Anne. "Non cultural detection of Campylobacter." Thesis, Queen's University Belfast, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247366.
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Stones, Leanne. "Beta-lactam resistance in Campylobacter." Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/1679/.
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Resistance to β-lactam antibiotics in Campylobacter is often associated with the production of a β-lactamase; to date the genomically encoded bla\(_{OXA-61}\) and the closely related cj0299 are the only described β-lactamase genes of Campylobacter. Cj0299 of C. jejuni NCTC11168 was assigned a novel oxacillinase number OXA-193. Previously, a novel β-lactamase (CjBla2)was identified in two bla\(_{OXA-193}\) negative isolates,P843 and P854. Southern blotting with a probe for bla\(_{OXA-193}\) confirmed that Bla2 is not the product of a mutated bla\(_{OXA-193}\) gene. A further thirteen veterinary isolates of Campylobacter have been identified that have the same phenotype as P843 and P854. Whole genome sequencing of P854 revealed four putative beta-lactamase genes, one of which, P854_1490, encodes a completely novel oxacillinase (OXA-184). PCR screening and sequencing of the other putative CjBla2 producers revealed six to contain the novel oxacillinase. A further five encode a variant of this novel OXA in which a point mutation has led to an amino acid coding change from leucine to isoleucine (OXA-185). These isolates represent a selection of flaA types and were isolated from two separate locations at different times, therefore it is unlikely that they are a clonal population. Two conjugative plasmids, each approximately 45Kb in size, have been identified from two veterinary isolates of Campylobacter. These plasmids have been shown to horizontally transfer resistance to tetracycline and to the β-lactams penicillin, ampicillin and oxacillin, between Campylobacter, a process never previously described. The two β-lactam resistance encoding plasmids thought to contain a β-lactamase gene(s) have been named pBla1 and pBla2. The role of efflux in beta-lactam resistance has also been investigated; inactivation of the efflux pump gene cmeB in the reference strain NCTC11168 resulted in increased susceptibility to a range of beta-lactams including the cephalosporins which Campylobacter are reported to be innately resistant to and have been included in some Campylobacter selective media. The work completed as part of this PhD program has furthered the understanding of beta-lactam resistance in Campylobacter and has demonstrated that it is clearly a multi-faceted mechanism incorporating various chromosomally encoded beta-lactamases, putative transferable beta-lactamases and efflux.
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Everest, Paul Howard. "The pathogenesis of Campylobacter diarrhoea." Thesis, University of Leicester, 1992. http://hdl.handle.net/2381/34407.
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Campylobacter jejuni/coli are the most common cause of acute diarrhoeal disease in man. The disease is worldwide, affects all age groups, and is mostly sporadic although common source outbreaks are frequently reported. The organism characteristically causes infection of the small intestine with extension into the colon and rectum, the disease being an acute enterocolitis. Illness may be inflammatory, with mucosal oedema and polymorphonuclear infiltration and blood in the faeces, or non-inflammatory with watery diarrhoea. The pathogenesis of the disease is unknown. Bacterial invasion of intestinal mucosa has been proposed as a mechanism of mucosal inflammation causing tissue damage. Investigation of the enterocyte-like Caco-2 and other epithelial cell lines for the ability of clinically characterised strains to adhere and invade showed that strains from colitic illness exhibited a greater tendency to invade than strains from non-inflammatory illness. Colitis and some non-inflammatory strains were also shown to transcytose from the apical to the basolateral cell membrane. Phosphorylation of mammalian cell proteins (such as ion channels) is important in diarrhoeal illness, mediated by bacterial cells and their secreted toxins. C. jejuni bacterial cells and a secreted toxin in culture supernatants caused phosphorylation of Caco-2 cell proteins, effects that mimic protein kinase C phosphorylation of myosin light chain. Culture supernatants increased intracellular calcium, an effect known to mediate fluid secretion. These effects are independent of the cholera-like toxin that is found in small amounts in culture supernatants. Colitis strains tested in rabbit ileal loops induced similar histological effects to those seen in man, caused fluid secretion, and white cell infiltrate consisting of polymorphonuclear leucocytes and macrophages. Villi were shortened and tissue was oedematous with submucosal bleeding. Tissue damage may prevent effective absorption of fluid and contribute to diarrhoea but biochemical analysis suggests a true secretory component to the diarrhoea. By contrast a non-inflammatory strain showed no histological changes in loops and elicited no fluid secretion. Large amounts of the host derived secretagogue prostaglandin E2 were induced in infected ileal loops and correlated with the tissue white cell infiltrate (along with leukotriene B4). In the absence of a cholera-like toxin produced by the bacteria PGE2 seems to be responsible for the increase in infected tissue cyclic AMP. PGE2 acts by binding to a cellular receptor and activating cell adenylate cyclase resulting in a rise in cAMP. Thus a host inflammatory mediator may contribute to fluid secretion in C. jejuni enterocolitis.
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Lau, Sok Kiang. "Molecular interrogation of Campylobacter infection." Thesis, University of Exeter, 2014. http://hdl.handle.net/10871/15425.
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Campylobacteriosis is common in both developing and developed countries. Although there had been numerous studies performed to gain a better understanding of the disease, much still remains to be unravel. In this project, the interactions between the bacteria and host cells or organisms were interrogated. Raman based imaging was initially investigated using an established Salmonella typhimurium and cell infection model. The results obtained showed the potential for real-time imaging. However, due to the instability of the laser system of the microscope, reproducible results could not be obtained. Therefore, this technique was not applied to Campylobacter jejuni. Zebrafish embryo was established as a new infection model suitable for C. jejuni studies. C. jejuni strains and mutants were screened using this model to determine their virulence. This model was used to screen two type six secretion system mutants constructed in this study. The results obtained showed that one of the mutants, Cj1DtssM(syn)::kanR_cas, was attenuated in the ZFE model. Subsequent competitive index challenges performed in piglets with C. jejuni wild-type and the two T6SS mutants, also showed that Cj1DtssM(syn)::kanR_cas was attenuated. Both T6SS mutants had shown increased adherence to macrophages and Cj1DtssM(syn)::kanR_cas also showed increased cell invasion. Together, these findings suggested that the T6SS is involved in establishment of infection in ZFE and piglet and as well as in adhesion and invasion of macrophages.
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McGinley, Susan. "New Campylobacter Vaccine for Poultry." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2008. http://hdl.handle.net/10150/622083.
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CAYEZ, BOIDIN BENEDICTE. "Epidemiologie des diarrhees a campylobacter." Lille 2, 1997. http://www.theses.fr/1997LIL2P037.
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Guthrie-Irons, Colette. "Biofilm formation in `Campylobacter jejuni'." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.536794.
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Semchenko, Evgeny A. "Characterisation of Campylobacter jejuni Lipooligosaccharides." Thesis, Griffith University, 2012. http://hdl.handle.net/10072/366659.
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Campylobacter jejuni is a major bacterial cause of food-borne enteritis, and its lipooligosaccharide (LOS) plays an initiating role in the development of the autoimmune neuropathy, Guillain-Barré syndrome, by induction of anti-neural cross-reactive antibodies through ganglioside molecular mimicry. Herein we describe the existence and heterogeneity of multiple LOS forms in C. jejuni strains of human and chicken origin grown at 37°C and 42°C. The C. jejuni NCTC 11168 original isolate (11168-O) was compared to the genome-sequenced variant (11168-GS), and both were found to have a lower-Mr LOS form, which was different in size and structure to the previously characterized higher-Mr form bearing GM1 mimicry. The lower-Mr form production was found to be dependent on the growth temperature as the production of this form increased from ~5 %, observed at 37°C to ~35 % at 42°C. The structure of the lower-Mr form contained a Galβ1,3GalNAc disaccharide moiety which is consistent with the termini of the GM1, asialo-GM1, GD1, GT1 and GQ1 gangliosides, however, it did not display GM1 mimicry as assessed in blotting studies but was shown by NMR analysis to resemble asialo-GM1. The production of multiple LOS forms and lack of GM1 mimicry was not a result of phase variation in the genes tested for NCTC 11168 and was also observed in most of the human and chicken isolates of C. jejuni tested.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Institute for Glycomics
Science, Environment, Engineering and Technology
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Lewis, Sally O'Donovan Gerard A. "Development of a real-time PCR assay for the detection of Campylobacter jejuni and Campylobacter coli." [Denton, Tex.] : University of North Texas, 2009. http://digital.library.unt.edu/permalink/meta-dc-9840.
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Lewis, Sally. "Development of a Real-time Pcr Assay for the Detection of Campylobacter Jejuni and Campylobacter Coli." Thesis, University of North Texas, 2009. https://digital.library.unt.edu/ark:/67531/metadc9840/.
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Campylobacter organisms are the most commonly reported bacterial causes of foodborne infection in the world, with Campylobacter jejuni and Campylobacter coli responsible for over 99% of reported infections. Traditionally, Campylobacter species detection is an arduous process, requiring a special incubation environment as well as specific growth media for an extended growth period. The development of a rapid and reliable diagnostic tool for the detection of Campylobacter species would be a valuable aid to the medical diagnostic decision process, especially to rule out Campylobacter infection during the enteric pre-surgical time period. Improved patient outcomes would result if this rapid assay could reduce the number of enteric surgeries. Assays performed during this dissertation project have demonstrated that both SYBR® green and hydrolysis probe assays targeting an 84 nucleotide portion of cadF, a fibronectin-binding gene of Campylobacter jejuni and Campylobacter coli, were able to detect from 101 to 108 copies of organism from stool specimens, did not detect nonspecific targets, and exhibited a coefficient of variation (CV) of 1.1% or less. Analytical validation of sensitivity, specificity and precision, successfully performed in these studies, warrants additional clinical validation of these assays.
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Merchant-Patel, Shreema. "Development of rapid and highly resolving combinatorial genotyping schemes for Campylobacter jejuni and Campylobacter coli." Thesis, Queensland University of Technology, 2009. https://eprints.qut.edu.au/33194/1/Shreema_Merchant-Patel_Thesis.pdf.
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Campylobacter jejuni followed by Campylobacter coli contribute substantially to the economic and public health burden attributed to food-borne infections in Australia. Genotypic characterisation of isolates has provided new insights into the epidemiology and pathogenesis of C. jejuni and C. coli. However, currently available methods are not conducive to large scale epidemiological investigations that are necessary to elucidate the global epidemiology of these common food-borne pathogens. This research aims to develop high resolution C. jejuni and C. coli genotyping schemes that are convenient for high throughput applications.
Real-time PCR and High Resolution Melt (HRM) analysis are fundamental to the genotyping schemes developed in this study and enable rapid, cost effective, interrogation of a range of different polymorphic sites within the Campylobacter genome. While the sources and routes of transmission of campylobacters are unclear, handling and consumption of poultry meat is frequently associated with human campylobacteriosis in Australia. Therefore, chicken derived C. jejuni and C. coli isolates were used to develop and verify the methods described in this study.
The first aim of this study describes the application of MLST-SNP (Multi Locus Sequence Typing Single Nucleotide Polymorphisms) + binary typing to 87 chicken C. jejuni isolates using real-time PCR analysis. These typing schemes were developed previously by our research group using isolates from campylobacteriosis patients. This present study showed that SNP + binary typing alone or in combination are effective at detecting epidemiological linkage between chicken derived Campylobacter isolates and enable data comparisons with other MLST based investigations. SNP + binary types obtained from chicken isolates in this study were compared with a previously SNP + binary and MLST typed set of human isolates. Common genotypes between the two collections of isolates were identified and ST-524 represented a clone that could be worth monitoring in the chicken meat industry. In contrast, ST-48, mainly associated with bovine hosts, was abundant in the human isolates. This genotype was, however, absent in the chicken isolates, indicating the role of non-poultry sources in causing human Campylobacter infections. This demonstrates the potential application of SNP + binary typing for epidemiological investigations and source tracing.
While MLST SNPs and binary genes comprise the more stable backbone of the Campylobacter genome and are indicative of long term epidemiological linkage of the isolates, the development of a High Resolution Melt (HRM) based curve analysis method to interrogate the hypervariable Campylobacter flagellin encoding gene (flaA) is described in Aim 2 of this study. The flaA gene product appears to be an important pathogenicity determinant of campylobacters and is therefore a popular target for genotyping, especially for short term epidemiological studies such as outbreak investigations. HRM curve analysis based flaA interrogation is a single-step closed-tube method that provides portable data that can be easily shared and accessed. Critical to the development of flaA HRM was the use of flaA specific primers that did not amplify the flaB gene. HRM curve analysis flaA interrogation was successful at discriminating the 47 sequence variants identified within the 87 C. jejuni and 15 C. coli isolates and correlated to the epidemiological background of the isolates. In the combinatorial format, the resolving power of flaA was additive to that of SNP + binary typing and CRISPR (Clustered regularly spaced short Palindromic repeats) HRM and fits the PHRANA (Progressive hierarchical resolving assays using nucleic acids) approach for genotyping. The use of statistical methods to analyse the HRM data enhanced sophistication of the method. Therefore, flaA HRM is a rapid and cost effective alternative to gel- or sequence-based flaA typing schemes.
Aim 3 of this study describes the development of a novel bioinformatics driven method to interrogate Campylobacter MLST gene fragments using HRM, and is called ‘SNP Nucleated Minim MLST’ or ‘Minim typing’. The method involves HRM interrogation of MLST fragments that encompass highly informative “Nucleating SNPS” to ensure high resolution. Selection of fragments potentially suited to HRM analysis was conducted in silico using i) “Minimum SNPs” and ii) the new ’HRMtype’ software packages. Species specific sets of six “Nucleating SNPs” and six HRM fragments were identified for both C. jejuni and C. coli to ensure high typeability and resolution relevant to the MLST database. ‘Minim typing’ was tested empirically by typing 15 C. jejuni and five C. coli isolates. The association of clonal complexes (CC) to each isolate by ‘Minim typing’ and SNP + binary typing were used to compare the two MLST interrogation schemes. The CCs linked with each C. jejuni isolate were consistent for both methods. Thus, ‘Minim typing’ is an efficient and cost effective method to interrogate MLST genes. However, it is not expected to be independent, or meet the resolution of, sequence based MLST gene interrogation. ‘Minim typing’ in combination with flaA HRM is envisaged to comprise a highly resolving combinatorial typing scheme developed around the HRM platform and is amenable to automation and multiplexing.
The genotyping techniques described in this thesis involve the combinatorial interrogation of differentially evolving genetic markers on the unified real-time PCR and HRM platform. They provide high resolution and are simple, cost effective and ideally suited to rapid and high throughput genotyping for these common food-borne pathogens.
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Rosenau-Ilias, Agnès. "Intéractions in vivo et in vitro entre Campylobacter Jejuni - Campylobacter coli et les cellules épithéliales humaines." Paris 11, 1988. http://www.theses.fr/1988PA114820.
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Pacheco, Sophia A. "Identification of Campylobacter jejuni secreted proteins." Pullman, Wash. : Washington State University, 2010. http://www.dissertations.wsu.edu/Thesis/Spring2010/s_pacheco_021610.pdf.
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Hani, Eric. "Hippurate hydrolase gene of Campylobacter jejuni." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0001/NQ27943.pdf.
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Al, Kandari Sharifa. "Characterization and comparison of Campylobacter bacteriophages." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/14529/.
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Members of the genus Campylobacter are a major cause of food-borne disease worldwide. They can colonize the intestinal mucosa of poultry, to high levels leading to contamination of meat, at slaughter. Their numbers can be reduced in different ways including chicken treatment with bacteriophages. For such treatments to be successful, in depth understanding of the bacteriophage that infects and kills campylobacters is vital. The work in this thesis describes: isolation and comprehensive characterisation of bacteriophage candidates for future therapy applications. In order to increase the available stocks of characterized candidate bacteriophage, a number of attempts were made to isolate bacteriophages from poultry excreta. The new isolates together with some uncharacterized phages from our laboratory stocks were characterized with respect to their host range and genomic size. Some bacteriophages preparations in previous studies showed genomes of different sizes and a number of attempts were done for their separation. This raised questions about the relationship between the two different sized genomes. Prior to this work, a co isolate pair had been successfully separated and the sequence of the larger genome, CP220, was determined. Part of the work here, was performed to extend this study by obtaining the sequence of the smaller co isolate, CPX and compare it to CP220. They did not appear to have any identifiable relationship at the genetic level, but the availability of the CPX sequence will further extend our knowledge of bacteriophage genetics and this phage has clear therapeutic potential. Attempts were also made to separate and characterize a second co-isolate pair but these were unsuccessful. The availability of the DNA sequence of CP220 allowed a much closer molecular characterisation and comparison of Campylobacter phage genomes, than had previously been possible. One area that was investigated in this study was the presence of repeat regions identified in the CP220 genome, which were amplified by PCR, but could not be cloned in E. coli. Furthermore, genes encoding potential lysins were identified in the CP220 genome and they were amplified, cloned and attempts were made to express the proteins, which may have potential therapeutic value. One gene product was successfully expressed and showed evidence of lytic activity on Campylobacter and other bacterial genera. In summary, this thesis describes a much closer examination of molecular biology of Campylobacter bacteriophage than had previously been possible, including the determination of the sequence CPX phage.
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Zilbauer, Matthias. "Innate immune defence to Campylobacter jejuni." Thesis, University College London (University of London), 2007. http://discovery.ucl.ac.uk/1445170/.
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Campylobacter jejuni is the most prevalent cause of bacterial diarrhoea worldwide and is frequently associated with severe post-infectious complications such as the Guillain-Barre syndrome. Despite the serious health burden caused by the bacterium disease pathogenesis remains ill defined. Human (3-defensins (hBDs)), a family of epithelial antimicrobial peptides, are a major component of host innate defence at mucosal surfaces. In the present study we investigated the effect of C. jejuni on intestinal epithelial innate responses. Up-regulation of IL-8, hBD-2 and hBD-3 gene and peptide expression was observed in Caco-2 and HT-29 cell-lines in response to C. jejuni strains 11168H and 81-176. Furthermore, recombinant hBDs were found to exhibit potent bactericidal activity against C. jejuni suggesting a major role for these peptides in disease pathogenesis. Secondly, we aimed to identify host receptor(s) involved in sensing of C. jejuni and initiating innate defence. Given the invasive nature of infection, we investigated the potential role of cytoplasmic nucleotide-binding oligomerisation domain (NOD) proteins. Using small interfering (si) RNA targeting NODI and transfection of NOD2 overexpression plasmids, we identified NODI as a major pattern recognition receptor involved in mediating innate host defence to C. jejuni while NOD2 was found to play a minor role. Additionally, reduced NODI expression resulted in an increased number of intracellular C. jejuni thus highlighting a critical role for NODI mediated antimicrobial defence in limiting infection. In the final part of the study an ex-vivo model of C. jejuni infection using human intestinal biopsies was developed. Additionally, a vertical diffusion chamber system was utilised to improve culture conditions in C. jejuni infection models. In conclusion, this study highlights the important role of intestinal innate host defence to C. jejuni. The development of new and improved models of infections has the potential to provide previously unavailable opportunities to study C. jejuni disease pathogenesis.
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Netzer, Simon Lukas [Verfasser], Oliver [Akademischer Betreuer] Einsle, and Philipp [Akademischer Betreuer] Kurz. "The alternative NrfA of Campylobacter rectus." Freiburg : Universität, 2017. http://d-nb.info/1151817643/34.
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McFarland, Elizabeth Adeline. "Studies of Campylobacter isolates from poultry." Thesis, Queen's University Belfast, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335563.
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Wainwright, Laura. "The truncated haemoglobin of Campylobacter jejuni." Thesis, University of Sheffield, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419585.
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Ainsworth, Paul. "Chemotaxis signal transduction in Campylobacter jejuni." Thesis, University of Leicester, 2014. http://hdl.handle.net/2381/28667.
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The bacterium Campylobacter jejuni is the most common cause of food borne disease in the UK, causing a 5-7 day enteritis including profuse watery diarrhoea, abdominal pain, fever, headache and occasionally vomiting. In rare cases leading to the paralysing autoimmune disease, Guillain-Barré syndrome. C. jejuni are highly motile cells, propelled through the environment by flagella, their motility is directed through a behaviour called chemotaxis. Cells are able to detect attractants or repellents and reposition the cell accordingly. Chemotaxis is central to C. jejuni colonisation as non-motile and non-chemotactic mutant strains poorly colonise their usual hosts. In Escherichia coli chemotaxis is regulated by the Che proteins which form a two component phospho relay system. In previous studies In silico comparison of E. coli Che proteins identified homologues in C. jejuni, which display altered chemotactic phenotypes in Δche mutant strains. Studies of interactions between the Che proteins using bacterial and yeast two hybrid systems, suggested ways in which the homologues may interact, but to further discern these mechanisms required in vitro study. For the purpose of this study the C. jejuni Che homologues were cloned, expressed and purified, for use in in vitro experiments. Radiolabelled Phosphotransfer assays confirmed CheA as a histidine kinase, and demonstrated Pi transfer to the response regulators of CheY, CheV and CheA, in that order of preference. Affinity tag pull-down assays found the predicted decrease in affinity between phosphorylated CheY and CheA, but also an increase in the affinity of phosphorylated CheV for the receptor, TLP[subscript 1]. The results of this study confirm the two component backbone of the C. jejuni Che model, and suggest how CheV may regulate methylation adaption in a system devoid of a CheB response regulator.
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Liang, Lu. "Variation in Campylobacter phage and prophage." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/41924/.
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Campylobacter is a bacterial pathogen commonly responsible for foodborne gastroenteritis worldwide. Due to the rapid development of resistance to antibiotics, many alternative interventions have been studied and bacteriophage therapy is one of them. To maximise the impact of the intervention and to ensure it remains sustainable it important to study the ecology and coevolution of Campylobacter and the bacteriophage that infect the pathogen. Coevolution interactions between Campylobacter and bacteriophage drive rapid molecular change and contribute to a higher mutation rates for both parties. In this study genetic modifications were examined in the bacterial host and phage arising either in vivo or in vitro. We observed the impact of C. jejuni containing Mu-like pro-phage on campylobacters populating the caeca of commercial broiler flocks. The Mu-containing campylobacters initially colonised and became the dominant strain, only to be out-competed before depopulation of the broiler house. The presence of the transposable Mu-like prophage ultimately proved to be a limitation in the fitness of the host. Campylobacter-specific phage CP30 is a T4-like phage of the Eucampyvirinae that was isolated from a farm with several other phage showing differences in host range of contemporary farm isolates. After serial passage the phage population acquired sequence variants. One newly characterised sequence type, CP30C, was defective in a tail fibre protein and revealed reduced adsorption ability and sensitivity against C. jejuni host strains. Whole genome sequencing identified host mutation in C. jejuni carrier state strains that maintain viability despite the continual production of virulent phage. A point mutation in the flhF gene (flhF(T368A)) was hypothesised to contribute to the non-motile phenotype of carrier state strains. Expression of flhF(T368A) in a flhF knockout background provedto have impaired motility, exhibit structural defects in flagella synthesis, were less susceptible to phage infection and show down regulation of σ28 dependent and σ54 dependent flagellar associated genes. Recombinant protein expression of FlhF demonstrated the protein to have GTPase activity and the FlhF(T368A) to have reduced enzyme activity, greater thermal sensitivity and to be impaired in protein folding compared to wild type FlhF.
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Morley, L. "Niche-adaptive evolution in Campylobacter jejuni." Thesis, Nottingham Trent University, 2014. http://irep.ntu.ac.uk/id/eprint/27913/.
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Campylobacter jejuni is the leading causative agent of human bacterial gastroenteritis. Human C. jejuni infection (campylobacteriosis) is frequently associated with poultry; through consumption of undercooked products, cross contamination from raw meats, or through direct contact with birds or their faecal matter, however it is established that poultry is not the sole cause of C. jejuni infection in humans. This research reveals new information on the MLST ST403 Clonal Complex, a previously identified C. jejuni lineage associated with the porcine host. ST403CC C. jejuni have also been linked with other mammalian hosts to a lesser degree, and have been implicated in human campylobacteriosis, however to date this clonal complex has not been linked to poultry. The original hypothesis of this research predicted that due to sharing a host niche commonly associated with C. coli, the porcine ST403CC may show evidence of increased recombination with C. coli, however this was not observed. Six ST403CC isolates of porcine origin were subjected to phenotype testing and whole genome sequencing; these isolates were capable of invasion in vitro, and were revealed both to have acquired seemingly lineage specific content, in the form of Restriction-Modification (R-M) system associated genes, and to have undergone degredation of certain loci. The ST403CC isolates also exhibited a distinct pattern of reduced genomic recombination compared to non-ST403CC C. jejuni, with evidence of lineage specific recombination events. Both generalist & specialist lineages have previously been revealed in C. jejuni. The research presented here identifies a new specialist lineage which is associated with mammalian hosts, and not found in poultry.
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Speegle, Leslie Nicole Oyarzabal Omar A. "Use of cellulose filters to isolate naturally occurring Campylobacter spp. from contaminated retail broiler meat and survival of Campylobacter jejuni and Campylobacter coli in retail broiler meat." Auburn, Ala., 2009. http://hdl.handle.net/10415/1984.
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Penfold, Sonya. "A molecular biological study on Campylobacter pylori." Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/25731.
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C. pylori have been shown to be associated with gastritis and peptic ulceration, but the mechanism of their pathogenicity is unknown. Since a number of virulence factors are known to be plasmid mediated, it was decided to study the plasmids of C. pylori. A variety of techniques were used to establish the best method of plasmid extraction from C. pylori. The method of alkaline lysis as described by Birnboim and Doly was shown to give the most consistent results and the greatest plasmid yield. Plasmid DNA was found in 54% (26 out of 48) of the isolates examined and the plasmids varied in size from 3,4kb to greater than 137kb. The majority (21 out of 26) of isolates had unique plasmid profiles, but 5 isolates showed common ones. Three of these 5 isolates were studied in more detail. The evidence presented here suggests that all 3 plasmid bands visible in these three isolates were different conformations of the same plasmid which has a molecular weight of 6, 2 kilo bases. The plasmids appeared labile and covalently closed circular DNA was rarely isolated. Restriction enzyme digestion was done with a variety of enzymes, but only 3 of the enzymes used digested the DNA. EcoRI and HindIII partially digested the DNA, while Sau3A digested the plasmids completely, generating 2 fragments of 2,2kb and 2,4kb, and a number of smaller fragments. The DNA was shown to be methylated and the fragments generated by Sau3A digestion suggest that the plasmids may contain a repetitive element. Chromosomal DNA was also isolated and digested with a variety of enzymes. The chromosomal DNA restriction pattern was shown to be affected by methylation, which may be important when using restriction enzyme patterns to differentiate between strains. Plasmid restriction fragments were end-labelled to detect bands which were poorly visible by ethidium bromide staining. This technique was shown to be more sensitive than ethidium bromide staining of DNA, but the inability to obtain complete digestion of C. pylori DNA made it impossible to construct a restriction enzyme map of the plasmids. Hybridization experiments showed the plasmids of C. pylori to be related and was also used to detect bands which were not easily visible after ethidium bromide staining. Attempts were made to clone C. pylori DNA into pUC18 and pUC19, but no recombinant plasmids containing C. pylori DNA were obtained.
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Kim, Joo-Sung. "NATURAL TRANSFORMATION-MEDIATED TRANSFER OF ERYTHROMYCIN RESISTANCE IN Campylobacter coli AND Campylobacter jejuni." NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-10272005-170447/unrestricted/etd.pdf.
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Schnider, Andrea. "Prevalence of "Campylobacter jejuni" and "Campylobacter coli" on Swiss broiler carcasses determined by comparative real-time PCR /." [S.l.] : [s.n.], 2009. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Flynn, Orla Mary Josephine. "Surface protein antigens of Campylobacter jejuni and their application in the differentiation of wild type Campylobacter isolates." Thesis, University of Ulster, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241476.
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Kervella, Michèle. "Identification de protéines externes impliquées dans la fixation de "Campylobacter jejuni", "Campylobacter coli" aux cellules épithéliales humaines." Paris 11, 1990. http://www.theses.fr/1990PA114855.
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Kiess, Aaron S. "Prevalence of Campylobacter in a turkey production facility." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=2224.
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Thesis (M.S.)--West Virginia University, 2001.Title from document title page. Document formatted into pages; contains viii, 90 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 59-66).
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Quetz, Josiane da Silva. "Estudo sobre Campylobacter jejuni e Campylobacter coli em crianças da área urbana de Fortaleza, Ceará/Brasil : Identificação genética, inflamação intestinal e impacto no estado nutricional." reponame:Repositório Institucional da UFC, 2009. http://www.repositorio.ufc.br/handle/riufc/2445.
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QUETZ, Josiane da Silva. Estudo sobre Campylobacter jejuni e Campylobacter coli em crianças da área urbana de Fortaleza, Ceará/Brasil : identificação genética, inflamação intestinal e impacto no estado nutricional. 2009. 142 f. Dissertação (Mestrado em Farmacologia) - Universidade Federal do Ceará. Faculdade de Medicina, Fortaleza, 2009.Submitted by denise santos (denise.santos@ufc.br) on 2012-04-12T12:44:16Z No. of bitstreams: 1 2009_dis_jsquetz.pdf: 1671276 bytes, checksum: 7b86044a2d433a11e1abdc0273d371d4 (MD5)
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Campylobacter jejuni and Campylobacter coli are important etiologic agents of worldwide diarrheal disease. Campylobacter sp. infection is usually identified by a 72 hour microbiological culture that identifies the genus of the responsible organism. Our main goal was to investigate the prevalence of C. jejuni and C. coli in children, aged 2-36 months, from urban Fortaleza, CE, Brazil, in an observational epidemiological case-control study using, as a tool of detection, the polymerase chain reaction (PCR). Our other goals were to investigate the nutritional impact of infection (cases) or colonization (controls) for Campylobacter sp., to determine the presence of three virulence genes of C. jejuni cytolethal distending toxin (CDT), and to evaluate the occurrence of inflammation in intestinal infections caused by Campylobacter sp. The study population consisted of 83 cases and 83 controls, where the cases consisted of children with a history of diarrhea in the 14 days prior to selection for the study. We assessed socioeconomic parameters through an epidemiological questionnaire. Anthropometric measurements were collected to determine z-score parameters for assessing the nutritional status of the children. Detection of Campylobacter from frozen samples was performed by enzyme-linked immunosorbent assay (ELISA) and PCR. Also, using PCR technology, we investigated the presence of C. jejuni genes cdtA, cdtB and cdtC. Intestinal inflammation was assessed by semi-quantitative ELISA detection of fecal lactoferrin (LFF). PCR technology detected C. jejuni in 9.6% of the cases (8/83) and 7.2% of the controls (6/83), while C. coli was detected in 6.0% of the cases (5/83) and 1.2% of the controls (1/83). CDT genes were found in 50% of hipO+ samples (7/14). There was a significant difference (p <0.05) in the weight for age z-scores (WAZ) and the weight for height z-scores (WHZ) between case and control carriers of C. jejuni, where case carriers showed lower average WAZ and WHZ than control carriers. Moreover, in the case group, carriers of C. jejuni showed a lower WHZ average than that of non-carrier cases of C. jejuni. More than 80.0% of the children studied had intestinal inflammation characterized by high levels of LFF regardless of the presence of diarrhea and Campylobacter sp. In conclusion, our findings corroborate data in the scientific literature related to the prevalence of C. jejuni and C. coli in pediatric populations, the existence of asymptomatic carriers and an association between the detection of the microorganism and malnutrition. In addition, our data suggest a genetic variability among the strains of C. jejuni detected in the study population, related to presence o absence of CDT genes.
Campylobacter jejuni e Campylobacter coli são importantes agentes etiológicos de doença diarréica na população mundial. A infecção por Campylobacter sp. é usualmente identificada por cultivo microbiológico que leva aproximadamente 72 horas para identificação do gênero. Nosso objetivo principal foi pesquisar a prevalência de C. jejuni e C. coli em população infantil, com idade entre 2-36 meses, da área urbana de Fortaleza/CE, Brasil, em estudo do tipo epidemiológico observacional caso-controle, utilizando, como ferramenta de detecção, a reação em cadeia da polimerase (PCR). Outros objetivos consistiram em: investigar o impacto nutricional da infecção (casos) ou da colonização (controles) por Campylobacter sp.; determinar a presença de três genes de virulência para a toxina citoletal distensora (CDT) de C. jejuni e avaliar a ocorrência de inflamação intestinal nas infecções causadas por Campylobacter sp. A população estudada consistiu de 83 casos e 83 controles, sendo os casos, crianças com histórico de diarréia nos 14 dias pregressos à seleção para o estudo. Foram avaliados parâmetros sócio-econômicos através de questionário epidemiológico. Medidas antropométricas foram coletadas para determinação de escores-z no intuito de avaliar o perfil nutricional das crianças. A detecção de Campylobacter nas amostras congeladas foi realizada por ensaio imuno-enzimático (ELISA) e PCR. Pela PCR também investigamos a presença dos genes cdtA, cdtB e cdtC da CDT de C. jejuni. A avaliação da inflamação intestinal foi realizada pela pesquisa de lactoferrina fecal (LFF), através de ELISA semiquantitativa. Foi detectado, por PCR, C. jejuni em 9,6% dos casos (8/83) e 7,2% dos controles (6/83). C. coli foi detectado em 6,0% dos casos (5/83) e 1,2% dos controles (1/83). Os genes cdtA, cdtB e cdtC foram encontrados em 50% das amostras hipO+ (7/14). Houve diferença significativa (p<0,05) dos escores WAZ e WHZ entre casos e controles portadores de C. jejuni, sendo que casos portadores apresentaram média inferior de WAZ e WHZ, quando comparados com os controles portadores. No grupo Casos, os portadores de C. jejuni apresentavam valor médio de WHZ inferior ao valor médio apresentado pelos casos não-portadores. Mais de 80,0% das crianças estudadas apresentaram inflamação intestinal caracterizada por elevados níveis de LFF, independente da presença de diarréia e Campylobacter sp. Em conclusão, nossos achados corroboram dados da literatura científica relacionados à prevalência de C. jejuni e C. coli na população infantil, existência de portadores assintomáticos e associação entre a detecção do microorganismo e desnutrição. Além disso, nossos dados apontam para ocorrência de variabilidade genética dentre as cepas de C. jejuni detectadas na população estudada em relação à presença ou ausência dos genes de CDT.
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Chandan, Vandana Carleton University Dissertation Biology. "Development of simple and economical methods for culturing campylobacter and for producing anti-campylobacter antibodies for enzyme immunoassay." Ottawa, 1991.
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Bento, Kérley Braga Pereira. "Padronização de PCR tradicional e em tempo real para detecção de Campylobacter jejuni e Campylobacter coli em alimentos." Universidade Estadual de Londrina, 2010. http://www.bibliotecadigital.uel.br/document/?code=vtls000157832.
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Campylobacter jejuni e Campylobacter coli são freqüentemente associadas à campilobacteriose humana, com mais de 80% das infecções causadas por C. jejuni. A infecção é esporádica e os surtos são raros. Além de gastrenterite, C. jejuni também tem sido associada a doenças auto-imunes pós-infecção, incluindo artrite, síndrome de Guillain-Barré (SGB), síndrome de Miller-Fisher e síndrome de Reiter. Aves e produtos avícolas têm sido implicados como os principais veículos para a infecção por Campylobacter. Métodos convencionais de isolamento e de identificação de Campylobacter em alimentos geralmente utilizam meios de enriquecimento seletivo com posterior subcultivo em meios sólidos seletivos. Estes métodos são muito demorados e após o isolamento, a identificação fenotípica requer testes bioquímicos e sorológicos adicionais. Os métodos moleculares, como reação em cadeia da polimerase (PCR) têm sido padronizados para detecção, identificação e quantificação de Campylobacter spp. em alimentos por serem rápidos, sensíveis e específicos. Os objetivos deste estudo foram desenvolver um ensaio PCR multiplex para detecção e diferenciação entre C. jejuni e C. coli em carcaças de frango, além disso, quantificar C. jejuni em culturas puras e detectar C. jejuni em carcaças de frango artificialmente e naturalmente contaminadas, por PCR em tempo real. A PCR multiplex foi desenvolvida utilizando iniciadores mapA específico para a detecção de C. jejuni e iniciadores ceuE específicos para detecção de C. coli. A PCR multiplex desenvolvida foi testada em 11 diferentes isolados de Campylobacter e 22 espécies não-Campylobacter e a especificidade do ensaio padronizado foi de 100%. A PCR multiplex padronizada foi também testada em carcaças de frango contaminadas artificialmente e naturalmente. Campylobacter foi detectada a partir da pele de frango artificialmente contaminada com cerca de 50 unidades formadora de colônia (UFC) de Campylobacter por 10 g de pele após 48 h de enriquecimento seletivo. Fragmentos específicos de PCR confirmaram a presença de C. jejuni (202 pb) e/ou C. coli (889 pb) em treze (46,4%) das 28 carcaças de frango adquiridas de supermercados locais de Londrina. Para os ensaios de PCR em tempo real foram utilizados iniciadores mapA específico para a detecção de C. jejuni. Os testes de especificidade da PCR em tempo real empregando os iniciadores mapA para os isolados de Campylobacter e isolados de outras espécies bacterianas indicaram que apenas os isolados de C. jejuni produziram os produtos de PCR com pico de dissociação de 76,3°C. O limite de detecção da qPCR foi estimado em cerca de uma cópia de DNA por PCR para as culturas puras de C. jejuni. O ensaio PCR em tempo real foi testado em carcaças de frango contaminadas artificialmente e naturalmente. C. jejuni foi detectada a partir de peles de frango artificialmente contaminadas com aproximadamente 1, 10 ou 50 unidades formadoras de colônia (UFC) de C. jejuni por 10 g de pele após 48 h de enriquecimento seletivo. Os produtos de PCR específicos foram observados em todas as amostras analisadas pela PCR em tempo real, após 48 h de enriquecimento seletivo quando o DNA foi extraído por fervura usando Triton X-100. A PCR multiplex e a PCR em tempo real padronizadas mostraram serem métodos rápidos, sensíveis e específicos na detecção de Campylobacter em carcaças de frango quando comparado aos métodos convencionais, que exige 5 dias para um resultado negativo e 6-7 dias para confirmar um resultado positivo.Campylobacter jejuni and Campylobacter coli are frequently associated with human campylobacteriosis, with more than 80% of infections caused by C. jejuni. The infection is sporadic and outbreaks are rare. In addition to gastroenteritis, C. jejuni has also been associated to autoimmune diseases post-infection including arthritis, Guillain-Barré syndrome (GBS), Miller-Fisher syndrome and Reiter syndrome. Poultry and poultry products have been implicated as the major vehicles for Campylobacter infection. Conventional methods for the isolation and identification of Campylobacter from food products usually require enrichment culture and subculture on selective agar. These methods are time-consuming and after the isolation, phenotypic identification requires additional biochemical and serological tests. Molecular methods such as polymerase chain reaction (PCR) have been standardized for detection, identification and quantification of Campylobacter spp. in foods because they are rapid, sensitive and specific. The objectives of this study were to develop a multiplex PCR for detection and differentiation between C. jejuni and C. coli in chicken carcasses; moreover, quantify C. jejuni in pure cultures and detect C. jejuni with spiked and naturally contaminated chicken carcasses by real time PCR. The multiplex PCR was developed using mapA primers specific for detection of C. jejuni and ceuE primers specific for detection of C. coli. The multiplex PCR developed was tested on 11 different isolates of Campylobacter and on 22 non-Campylobacter species and specificity of the assay standardized was 100%. The PCR assay was tested with spiked and naturally contaminated chicken carcasses. Campylobacter was detected from chicken skin spiked contaminated with approximately 50 colony forming unit (CFU) of Campylobacter per 10-g after 48 h of selective enrichment. Specific DNA fragments of the PCR confirmed the presence of C. jejuni (202-bp) and or C. coli (889-pb) from thirteen (46.4%) out of 28 analyzed chicken carcasses purchased from local retail market, in Londrina. For real-time PCR assays were used mapA primers specific for detection of C. jejuni. Tests for specificity of real-time PCR using the gene mapA for isolates of Campylobacter and other bacterial genera showed that only isolates of C. jejuni produced PCR products with a peak separation of 76.3 ° C. The limit detection of qPCR was estimated at about one copy of DNA by PCR for pure cultures of C. jejuni. The real-time PCR assay was tested with spiked and naturally contaminated chicken carcasses. C. jejuni was detected from chicken skin spiked with approximately 1, 10 or 50 colony forming unit (CFU) of C. jejuni per 10-g of skin after 48 h of selective enrichment. Specific PCR products were observed in all samples analyzed by the real-time PCR after 48 h of selective enrichment when DNA was extracted by boiling using Triton X-100. The PCR multiplex and real-time PCR methods have shown to be rapid, sensitive and specific on the detection of Campylobacter in chicken carcasses, when compared with conventional methods that requires 5 days for a negative result and 6-7 days to confirm a positive result.
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Silva, Lidiane Azevedo. "Pesquisa de Campylobacter jejuni e Campylobacter coli em espécimes fecais de crianças com diarreia aguda e sem diarreia." Universidade Federal de Minas Gerais, 2012. http://hdl.handle.net/1843/BUOS-95DQ5B.
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Acute infectious diarrhea is still taken as a worldwide health problem associated with high morbidity and mortality rates among children living in developing countries. Campylobacter mainly Campylobacter jejuni and Campylobacter coli are considered major diarrheagenic agents. Besides this data regarding prevalence of the organism specially in our country is scarce. We addressed the detection of C. jejuni and C. coli in order to evaluate the contribution of the organism to the genesis of diarrhea and we also investigated the association between infection by the bacteria and clinical and demographic parameters. A total of 764 (363 with acute diarrhea and 401 without diarrhea) children aged up to 69 months of low socioeconomic stratum were included in the study. Fecal specimens were collected from 2004 to 2007 and submitted to DNA extraction. C. jejuni and C. coli were identified by two previously proposed PCR protocols. Infection by C. jejuni and C. coli was detected in 2.2% and 1.1% of children with diarrhea most of them (66.7%) C. jejuni. Any of the organisms was detected in the control group. Infection by Campylobacter was not associated with gender and age of the patient and do not showed temporal or seasonal variation. In regard to clinical parameters Campylobacter was associated with higher frequency of evacuation and bloody feces considered to be indicative of inflammatory diarrhea. Our data demonstrate lower rates of Campylobacter associated diarrhea in our population.A doença diarreica aguda é considerada um problema de saúde pública associado a taxas elevadas de morbimortalidade, que acomete, especialmente, a população pediátrica de nível socioeconômico baixo. Entre os agentes bacterianos diarreiogênicos, merece menção Campylobacter, com destaque para as espécies Campylobacter jejuni e Campylobacter coli. Embora a relevância do organismo seja reconhecida, estudos nacionais referentes à sua prevalência são bastante escassos. O objetivo desta investigação foi avaliar a participação de C. jejuni e C. coli na etiologia da enterite aguda e a existência de associação entre infecção por Campylobacter e parâmetros demográficos e clínicos. Foram incluídas no estudo espécimes fecais de 764 crianças, 363 com diarreia aguda e 401 sem diarreia, de nível socioeconômico baixo, com até 69 meses de idade, atendidas no Hospital Infantil João Paulo II, entre 2004 e 2007. A pesquisa de C. jejuni e C. coli foi realizada por PCR, empregando-se DNA extraído diretamente das fezes, sendo selecionados dois protocolos previamente propostos. Infecção por C. jejuni e C. coli foi observada em 2,2% e 1,1% do grupo caso, com predomínio (66,7%) de C. jejuni. Nenhuma criança sem diarreia apresentou-se colonizada pelo organismo. Infecção por Campylobacter não estava associada a sexo e faixa etária da criança nem apresentou variação temporal ou sazonal. No que se refere aos parâmetros clínicos, presença de Campylobacter estava associada a maior frequência de evacuações e presença de sangue nas fezes, características clínicas do quadro de diarreia inflamatória. Os dados indicaram redução da taxa de diarreia associada a Campylobacter no nosso meio.
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Adler, Linda [Verfasser]. "Autoinducer 2 in Campylobacter jejuni / Linda Adler." Berlin : Freie Universität Berlin, 2016. http://d-nb.info/1096221179/34.
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