Dissertations / Theses: 'Campylobacter species'

1

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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2

Frost, Helen. "N-linked protein glycosylation in Campylobacter and Helicobacter species." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/nlinked-protein-glycosylation-in-campylobacter-and-helicobacter-species(ca49728c-1406-463f-bead-99d7cf336cb9).html.

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N-linked protein glycosylation is the enzymatic transfer of a carbohydrate glycan to an asparagine residue of a polypeptide, catalysed by an N-oligosaccharyl transferase(OTase). Bacterial N-glycosylation is best understood in the foodborne pathogen Campylobacter jejuni, in which a heptasaccharide glycan is built at cytoplasmic face of the inner membrane, flipped to the periplasm and transferred to a polypeptide enbloc. C. jejuni encodes each of the proteins required for the N-glycosylation pathway in a single genetic region, termed the pgl locus. Homologues of the gene encoding the C. jejuni OTase, PglB, are found in all Campylobacter species, three Helicobacter species, and more distantly related ε- and δ-Proteobacteria species such as Wolinella succinogenes, Desulfovibrio desulfuricans and Nitratiruptor tergarcus. A small numberof Campylobacter species and all three pglB-containing Helicobacter species have two distinct pglB genes, pglB1 and pglB2, along with homologues of other C. jejuni pgl genes. The work presented in this thesis investigated the N-glycosylation system of a bacterial species encoding two distinct PglBs, C. concisus. The roles of the two PglB enzymes in C. concisus were investigated using an in vitro OTase assay, and the structure of a C. concisus N-glycan elucidated by mass spectrometry. The work in this thesis also expands our knowledge of C. jejuni N-glycosylation by investigating the full scope of N-glycosylation using an in silico method to predict the total C. jejuni N-glycoproteome. This was followed by experimental validation of these predictions, in which three novel C. jejuni N-glycoproteins were identified, bringing the number of reported C. jejuni NCTC 11168 N-glycoproteins to 57. One of these novel N-glycoproteins, Cj0633, is the most extensively N-glycosylated bacterial glycoprotein reported to date, with the addition of up to eight N-glycans when expressed in the presence of the C. jejuni pgl machinery. In the final investigation presented in this thesis, a method to identify bacterial N-glycoproteins using anti-glycan antisera to immunoprecipitate N-glycoproteins was developed. These data expand our knowledge of C. concisus N-glycosylation and provide valuable insight into the full scope of N-glycosylation in C. jejuni.

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3

Williams, Lisa Kate. "Optimisation of detection methods for the foodborne pathogen Campylobacter species." Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.508068.

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4

Morris, Samantha J. S. "Characterisation of toxins produced by 'Campylobacter jejuni' and related species." Thesis, Nottingham Trent University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.442085.

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5

Hodge, Jeffrey Paul. "Development and use of a chemically defined medium for estimating the oxygen tolerance of campylobacter species." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-03032009-040333/.

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6

Daucher, James Andrew. "Occurrence of pyruvate:ferredoxin oxidoreductase in Campylobacter, Wolinella, Helicobacter and Arcobacter species." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-09052009-040436/.

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7

Aroori, Sree Vidya. "Effect of host factors on the virulence properties of Campylobacter species." Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.509760.

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8

Lawson, Andrew Jeffrey. "The prevalence of Campylobacter species in human gastroenteritis : a molecular approach." Thesis, Open University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342935.

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9

Mehat, Jai. "Characterisation of CapC, a novel strain-specific autotransporter in Campylobacter species." Thesis, University of Surrey, 2017. http://epubs.surrey.ac.uk/841594/.

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Campylobacter jejuni and Campylobacter coli are recognised as the principal causative agents of bacterial gastroenteritis in the developed world. However, despite the identification of factors integral to infection, characterisation of the virulence strategies employed by Campylobacter remains a significant challenge. Bacterial autotransporter proteins comprise the largest and most diverse class of secretory proteins in Gram-negative bacteria; notably almost all previously characterised autotransporter proteins contribute to bacterial virulence to some extent. The aim of this study was to characterise CapC, a newly identified, strain-specific gene predicted to encode an autotransporter protein, and to examine the contribution of this factor to the virulence of Campylobacter jejuni. The capC gene was initially confirmed as being encoded by approximately 60% of C. jejuni and C. coli human clinical and poultry associated isolates. Moreover, CapC was confirmed as a member of the autotransporter family through the use of bioinformatic prediction tools and the localisation site of this protein was determined as the outer membrane of C. jejuni. Targeted mutagenesis of the capC gene in C. jejuni 81116 and C. jejuni M1 and subsequent comparison of wild-type and isogenic mutant strains demonstrated that CapC contributes directly to virulence in the Galleria mellonella invertebrate model (p=0.00017; p=0.002323). Furthermore, tissue culture assays using non-polarised, partially differentiated Caco-2 and T84 intestinal epithelial cells indicate that deletion of CapC resulted in significantly decreased adhesion and invasion efficiency. Additional analyses indicated that CapC primarily contributes to adhesion to intestinal epithelial cells. Additional assays showed that deletion of the capC gene has no significant phenotypic effect on cytotoxicity in a Caco-2 cell model. A secondary aim of this study was to examine the distribution of capC amongst campylobacters and to establish any potential genetic associations of this virulence determinant. Using publically vi available genome sequences, capC was established to be highly prevalent in C. jejuni (67.9%) and C. coli (84%). Campylobacter autotransporter proteins were also shown to be present in truncated and full length forms. Interestingly, full length CapC was shown to be primarily associated with the ST-45, ST-283 and ST-573 clonal complexes in C. jejuni and the ST-828 clonal complex in C. coli. Furthermore, this study detailed the identification of a novel autotransporter in Campylobacter species, tentatively designated as CapD. This autotransporter was found to be genetically distinct from CapC and is the most prevalent autotransporter identified in Campylobacter species. The studies presented in this thesis indicate that CapC is a strain-specific virulence determinant in Campylobacter species that is associated with select lineages of C. jejuni and C. coli. CapC contributes to the integral infection process of adhesion however further studies are required to fully elucidate the exact nature of this interaction. Additionally, it can be concluded that possession of Campylobacter autotransporter proteins is dependent on genetic background.

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10

Peyrot, Belinda Margaret. "A microbiological and molecular study of campylobacter and related species isolated from ostriches (Struthio camelus)." Thesis, University of the Western Cape, 2014. http://hdl.handle.net/11394/4155.

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>Magister Scientiae - MSc
Campylobacter and related Epsilonproteobacteria (Arcobacter and Helicobacter) are currently viewed as emerging pathogens and are able to cause gastroenteritis, bacteraemia, the Guillain-Barré syndrome, reactive arthritis and other diseases in humans. While poultry, cattle and sheep are known reservoirs for campylobacter, very little is known about ostriches as a vector for these organisms. What is known, however, is that these birds can and sometimes do get infected. Studies by various researchers have provided evidence that various species of animals shed Epsilonproteobacteria in their faeces. In this study, qualitative microbiological assays were performed on liver, caecum and colon samples predominantly from healthy ostriches presented for slaughter, to detect any Epsilonproteobacteria present. Samples were collected at an abattoir in the Western Cape between February and December 2010. Qualitative microbiological assays were also performed on 50 faecal samples collected on a farm. Epsilonproteobacteria were isolated from the tissue samples and characterized following the phenotypic and biochemical scheme presented in the Cape Town protocol. This protocol uses membrane filtration onto antibiotic-free Tryptose blood agar plates, and incubation at 37 ºC in a hydrogen-enhanced microaerobic atmosphere (Lastovica, 2006). The isolates were identified as C. jejuni subsp. jejuni. The multiplex PCR of Neubauer and Hess (2006) was applied to some of these isolates. A panel of isolates consisting of C. jejuni subsp. jejuni, C. fetus and E. coli was used to verify the DNA extraction procedure. The C. fetus and E. coli isolates were used as negative controls, and although DNA was successfully extracted from them, no bands were observed in the respective lanes of electrophoresed gels after application of the PCR.

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11

Holmes, Kathryn. "Isolation and molecular characterisation of toxins from Campylobacter jejuni and related species." Thesis, Nottingham Trent University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393525.

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12

Sanad, Yasser M. "Molecular Epidemiological and Pathogenesis Studies on Campylobacter Species in Cattle and Sheep." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1322032603.

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13

Mander, Carolyn Vivienne. "The application of subtractive hybridisation to detect intra-species variation in Campylobacter jejuni." Thesis, University of Canterbury. Department of Plant and Microbial Sciences, 2001. http://hdl.handle.net/10092/4250.

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Significant intra-species variation is evident in many pathogenic bacteria. Possession of a specific gene or cluster of genes can lead to the greater pathogenicity of that strain. Campylobacter jejuni is seemingly ubiquitous in the environment and is frequently isolated from many species of birds, cattle, sheep and other animals, as well as water. Molecular typing studies suggest C. jejuni populations are heterogenous, with the emergence of some stable clones. Strains of C. jejuni are naturally competent with a propensity for intraspecies DNA uptake. Virulence determinants and disease mechanisms are poorly understood and research with regards to the pathogenic potential of this organism is contradictory. The primary objective of this study was to determine whether all strains of C. jejuni are equally pathogenic to humans. A PCR-based subtractive hybridisation method was applied to detect differences between two strains of C. jejuni, NCTCll168 (tester) and F38011 (driver). Using this method, a total of eleven DNA fragments were isolated and sequenced. Blast searches revealed all fragments corresponded to the tester strain NCTCl1168. The fragments showed significant amino acid identities with the flagella hook protein (FlgE), an AJG-specific adenine glycosylase and a L-serine dehydratase. Nucleotide sequences corresponding to flgE were further analysed and one base pair substitution was observed between the tester and the driver (F38011). This study demonstrates that the PCR-based subtractive hybridisation method was reproducible and has the potential to identify fragments corresponding to genes with relevance to virulence. However, this method requires optimisation for the efficient isolation of strain differences in C. jejuni. The feasibility of the application of mRNA approaches and RAPD-PCR to detect intra-species variation in C. jejuni were also investigated. Difficulties encountered with mRNA detection excluded further investigation of mRNA-based techniques. RAPD-PCR was not sufficiently reproducible to continue analysis of the significance of differences in RAPD profiles in relation to the pathogenic potential of C. jejuni.

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14

Pegg, Elaine. "Eimeria species as novel antimicrobial vaccine delivery vectors." Thesis, Royal Veterinary College (University of London), 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.701658.

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15

Jonker, Annelize. "Antimicrobial susceptibility in thermophilic Campylobacter species isolated from pigs and chickens in South Africa." Diss., University of Pretoria, 2010. http://hdl.handle.net/2263/27117.

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The thermophilic Campylobacters, Campylobacter jejuni and Campylobacter coli are found as commensals in the intestinal tract of healthy mammals and birds. Campylobacter jejuni is one of the leading causes of sporadic food-borne bacterial disease in humans which is predominantly contracted from poultry products. Although the vast majority of these infections are mild, life-threatening complications should be treated with antimicrobials. Patients are usually treated with either macrolides of fluoroquinolones. However, globally there is an increased trend in the development of resistance to these antibiotics. This trend has also been observed in infection of poultry and pigs. The aim of this investigation was to determine antimicrobial sensitivity of thermophilic Campylobacters isolated from pigs and poultry by broth microdilution minimum inhibitory concentration testing. A total of 482 samples of the small intestinal content from poultry and pigs from the Western Cape and Gauteng Provinces were collected and analysed. Thirty-eight Campylobacter isolates were obtained. Statistical analyses included percentage resistance, minimum inhibitory concentrations (MIC50 and MIC90) as well as the distribution percentages of the MICs. The non-parametric Mann-Whitney U test was used to establish any significant differences at an interspecies, interhost and interprovincial level. Analyses of the data obtained revealed indications of decreasing susceptibility to several antibiotic groups including the tetracyclines, macrolides, erythromycin and tylosin, as well as the lincoasamides, and fluoroquinolones. It was found that isolates from the Western Cape were more likely to be resistant to the fluoroquinolones (p = 0.0392), macrolides (p = 0.0262), and lincoasmides (p = 0.0001) and, as well as to a certain extent the pleuromutulins (p = 0.0985), whereas isolates from Gauteng were more resistant to the tetracycyclines (p = <.0001). Poultry Campylobacter spp. were more prone to be resistant to enrofloxacin (p = 0.0021). Campylobacter jejuni, mainly isolated from poultry, was more liable to be resistant to the tetracyclines (chlrotetracycline p= 0.0307), whereas C. coli, predominatly isolated from pigs was more likely to be resistant to the macrolides (tylosin p= 0.063). Four of the bacteria isolated from the Western Cape were resistant to three or more antibiotic classes, namely; tetracyclines, macrolides, lincosamides, pleuromutulins and fluoroquinolones. No multi-resistant Campylobacter spp. were isolated from the flocks in Gauteng. With the exception of tiamulin, the bacterial populations could clearly be divided into resistant and susceptible populations. As consequence of the increased resistance to the antimicrobial classes used for human therapy and the geographical differences in antimicrobial susceptibility, it is recommended that an antimicrobial resistance monitoring system for the thermophilic Campylobacter spp. be initiated in the South Africa National Veterinary Surveillance and Monitoring Programme for Resistance to Antimicorbial Drugs (SANVAD) Copyright
Dissertation (MSc)--University of Pretoria, 2009.
Veterinary Tropical Diseases
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16

Rasmussen, David Dean. "The Effectiveness of Potassium Lactate and Lactic Acid Against Campylobacter Species and Psychrotrophic Bacteria." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/35318.

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This study examined the efficacy of potassium lactate and lactic acid to control Campylobacter sp. and psychrotrophic bacteria on chicken. The objectives of the two studies conducted were to determine the optimal combination of potassium lactate and lactic acid to inhibit Campylobacter sp. in a challenge study and to inhibit naturally occurring Campylobacter sp. and psychrotrophic bacteria in a shelf life study.

Boneless, skinless chicken breasts were injected with three levels of potassium lactate (0,1.5,2%), in conjunction with four levels of lactic acid. Lactic acid was injected (0, 0.1, 0.2, 0.3%) as well as applied directly to the surface (0.1% of weight of chicken breast). The chicken breasts were surface inoculated with a mixture of Campylobacter sp. and sampled over a period of 28 days at 11oC. The greatest inhibition was found using 2% potassium lactate in conjunction with any level of lactic acid (injected) or 0.1% lactic acid (surface application). Results of this study indicate that potassium lactate and lactic acid can be used to control the growth and/or survival of Campylobacter sp. on boneless chicken breasts.

The second study eliminated the 1.5% potassium lactate and 0.2% and 0.3% lactic acid treatments and chicken breasts were not inoculated with Campylobacter sp.. This 4oC shelf life study occurred over 32 days, testing for Campylobacter species, psychrotrophic bacteria, as well as testing for sensory perceptions of color and odor changes in the chicken. The most effective treatment was the 2% potassium lactate-0.1% lactic acid surface treatment, demonstrating the most inhibition against both target populations. This treatment also had the greatest impact upon the odor of the chicken breasts. This treatment had the greatest difference from control samples, which was achieved by the inhibition of spoilage organisms on the chicken breasts.
Master of Science

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17

Arumugaswamy, Ramakrishnaswamy. "Studies on the presence and survival of campylobacter species in the Sydney rock oyster (Crassostrea commercialia) /." View thesis, 1985. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20031205.122556/index.html.

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18

Mabogo, Rudzani David Lesly. "The prevalence and survival of Campylobacter, Salmonella and Listeria species in poultry processing plant." Thesis, University of the Western Cape, 2004. http://etd.uwc.ac.za/index.php?module=etd&amp.

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The organisms in this study were chosen due to their associations with foods and their potential as food borne pathogens. Food borne diseases are an import public health problem in most countries. Bacteria of the genera Campylobacter, Salmonella and Listeria can be transported by poultry and poultry products to humans. Gastroenteritis, typhoid fever, diarrhea, dysentery may originate from the infection. This study was undertaken to determine the incidence of pathogens in a poultry processing plant using polymerase chain reaction and conventional tests and to determine the formation and survival of biofilm cells of food pathogens in trisodium phosphate.

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19

Thomas, James Christopher. "An investigation of factors influencing the survival of Campylobacter species in the aquatic environment." Thesis, University of Wolverhampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241640.

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20

Arumugaswamy, Ramakrishnaswamy, Hawkesbury Agricultural College, and Faculty of Food and Environmental Sciences. "Studies on the presence and survival of campylobacter species in the Sydney rock oyster (Crassostrea commercialia)." THESIS_FES_XXX_Arumugaswamy_R.xml, 1985. http://handle.uws.edu.au:8081/1959.7/412.

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A direct enrichment procedure has been developed for selectively recovering low numbers of Campylobacter jejuni and Campylobacter coli from oyster tissue. This procedure makes use of a selective enrichment step, using a broth medium composed of 2% proteose peptone, 1% yeast extract, 0.2% potassium L-aspartate, 0.25% sodium chloride as basal medium (PYA broth)plus 0.2% bacteriological charcoal, polymyxin (5000 IU/ litre), cefoperazone(30 mg/litre), trimethoprim (10 mg/litre), cycloheximide (50 mg/litre), sodium pyruvate (0.25g/litre), sodium metabisulphate (0.25g/litre) and ferrous sulphate (0.25g/litre). In this study the procedure has been used to study the occurrence of thermophilic campylobacters in Sydney rock oysters. Seventy nine samples were screened during the winter months of April to July in 1985. Approximately 8% of the samples contained C.jejuni and 6% of the samples were positive for C.coli. The survival of C.jejuni and C.coli in the Sydney rock oyster was also investigated and results discussed. In contaminated shell stock stored at 20 and 30 degrees Centigrade, C.jejuni and C.coli survived for periods varying from 2 to 9 days. The failure of the organism to multiply in oyster tissue at any of these temperatures studied is an important phenomenon.
Master of Science (Hons)

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21

Hurtado, Ana Isabel. "Large-subunit ribosomal RNA gene of Helicobacter and Campylobacter species : its role in genotypic identification and typing." Thesis, Queen Mary, University of London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265831.

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22

Messelhäußer, Ute Christine. "Nachweis von Shiga Toxin-bildenden Escherichia coli und thermophilen Campylobacter species bei Almkühen und in auf Almen produzierten Lebensmitteln." Diss., lmu, 2005. http://nbn-resolving.de/urn:nbn:de:bvb:19-33991.

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23

Purdy, Desmond. "Construction of a promotor probe vector incorporating bacterial luciferase and its use in oxidative stress studies in Campylobacter species." Thesis, University of Reading, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308056.

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24

Rodgers, Diana Elizabeth. "An investigation of red-billed seagulls (Larus novaehollandiae scopulinus) as reservoirs of Campylobacter species, and the potential risk to human health." Thesis, University of Canterbury. Department of Plant and Microbial Sciences, 2000. http://hdl.handle.net/10092/4248.

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Campylobacter species carriage by Red-billed gulls fluctuated with seasonality. For instance, 250/0 of gulls sampled in May 1999 and 84.2% of gulls sampled in February 2000, were identified as carriers of Campylobacter species. Quantitative measurements identified bacterial loads of between 2.2 x 10² and 9.4 x 10³ CFU g⁻¹ of gull faeces. Genotypic techniques were used to determine relatedness between 76 clinical, 83 gull and three water Campylobacter isolates. 126 isolates were confirmed as C. jejuni or C. coli by PCR methods, using thermophilic Campylobacter-specific primers amplifying a 222 bp fragment of the 23S rRNA gene. Of these, 121 were shown to be C. jejuni and five C. coli based on cadF PCR. The remaining 36 isolates were presumptively identified as C. lari based on negative hippurate hydrolysis and nalidixic acid sensitivity. The amplification of the 23S rRNA gene, and amplification failure of the cadF and ceuE genes, supported identification. The pathogenic potential of each isolate was investigated through the detection of the virulence determinants flaA (flagellin structural gene), cadF (fibronectin adhesin gene) and ciaB (cell internalisation gene), at the transcriptional level. 96% of clinical isolates and 53.5% of environmental isolates generated PCR amplicons for all three loci. This suggested that some isolates of gull origin possessed at least some of the genes necessary for the initiation of campylobacteriosis. flaA-specific primers were applied to all samples, with 77.8% generating a 1.7 kb amplicon. RFLP analysis, using DdeI, distinguished 50 flaA profiles, with flaA type 2 being the most common type identified in this study. flaA RFLPs were diverse in isolates of environmental origin with 42% demonstrating unique profiles. In comparison, 19.7% of clinical isolates demonstrated unique profiles. SixflaA types were shared between both clinical and environmental isolates, these being types 2, 6, 7, 11, 16 and 35. This suggested either a common source of the pathogen or a bi-directional exchange of Campylobacter between human and gull populations. This technique was highly discriminatory with a D value of 0.96. PCR using gmhA-specific primers was applied to 35 flaA-grouped C. jejuni and C. coli isolates. 82.9% generated either a 0.9 kb or 1.6 kb band. Five gmhA types were generated using DdeI, the most common of these types being gmhA 1. gmhA 1 was shared between clinical and environmental isolates, supporting flaA clonality. PFGE, using SmaI, was applied to isolates belonging to the two largest flaA groups, 2 and 16, in an attempt to further assess relationships. This technique was discriminatory with a D value of 0.93. Additionally, C. jejuni survival in the soil environment was investigated. Persistence of culturability was largely a function of temperature. Cells were recovered by culture at 35 days in sand held at 4°C, at 7.5 days in sand held at 25°C, and at 54 hours in sand held at 37°C. This persistence, especially at decreased temperatures, suggested the potential for pathogen transmission from sand reservoirs into animal and human populations. The detection of C. jejuni DNA was also greatly affected by the microcosm temperature. At all three temperatures tested, DNA was detected after culturability was lost. By comparison, naked C. jejuni DNA demonstrated reduced temporal persistence. This suggested that C. jejuni may persist in a 'viable but non-culturable' state in sand that may contribute to the environmental cycling of the pathogen.

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Scheik, Letícia Klein. "Potencial de formação de biofilme e suscetibilidade ao extrato metanólico de Butia odorata em isolados de Campylobacter jejuni." Universidade Federal de Pelotas, 2018. http://guaiaca.ufpel.edu.br:8080/handle/prefix/4122.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
O emprego das Boas Práticas de Fabricação na indústria de alimentos, como a higienização de superfícies, é importante para evitar a formação de biofilmes. Campylobacter jejuni, que é o principal agente etiológico da campilobacteriose, pode sobreviver em condições adversas no ambiente pela capacidade de formação de biofilme. As bactérias formadoras de biofilme podem adquirir resistência à compostos utilizados como sanitizantes na etapa de sanitização, como o cloreto de benzalcônio (CB). Assim, faz-se necessário a busca por novos compostos com ação antibacteriana que possam ser utilizados em alternativa aos sanitizantes sintéticos. Os extratos de plantas vêm sendo amplamente estudados devido às suas características antimicrobianas e por serem compostos naturais. O extrato metanólico de Butia odorata Barb. Rodr. (EMB) teve sua ação antibacteriana comprovada em estudos anteriores. Portanto, os objetivos deste estudo foram avaliar a influência da superfície, temperatura, atmosfera e co-cultura com Pseudomonas aeruginosa sobre a formação de biofilme de Campylobacter jejuni isolados de abatedouro de frangos da região sul do Rio Grande do Sul, bem como identificar a presença de alguns genes relacionados à formação de biofilme nesses isolados. Também objetivou-se avaliar a suscetibilidade desses isolados ao EMB e ao CB, através do teste qualitativo de disco difusão em ágar para o EMB, e da concentração inibitória mínima (CIM) e da concentração bactericida mínima (CBM) para o EMB e para o CB. A atmosfera não afetou a formação de biofilme monoespécie de C. jejuni tanto em poliestireno como em aço inoxidável. Houve maior formação de biofilme em temperaturas que não são as ótimas para a multiplicação d e C. jejuni. A forma como P. aeruginosa foi inoculada para formar biofilmes duoespécie com C. jejuni (concomitante ou pré-formado por P . aeruginosa), não influenciou a formação de biofilme pelos isolados. Nos biofilmes duo-espécie com P. aeruginosa, as maiores contagens de biofilme por C. jejuni em aço inoxidável ocorreram a 25 oC. Os sete isolados de C. jejuni avaliados possuem 10 genes envolvidos no processo de formação de biofilme, porém o gene katA não foi encontrado em três isolados, e o gene kpsM não foi encontrado em um isolado, o que não afetou a formação de biofilme por esses isolados. O EMB apresentou atividade antibacteriana contra os sete isolados no teste qualitativo de disco difusão em ágar, com halos de inibição acima de 23 mm. A CIM do EMB ficou entre 83,3 e 166,6 μL.mL-1, e a CBM foi o mesmo valor de CIM em todos os isolados. Já para o CB, o valor de CIM ficou entre 1 e 2 μg.mL-1, e a CBM variou entre 1 e 4 μg.mL-1 entre os isolados. Dessa forma, o EMB pode tornar-se uma boa alternativa ao CB empregado na etapa de sanitização em indústrias de alimentos.
The employment of good manufacturing practice in the food industry, as surfaces sanitization, is important to avoid the biofilm formation. Campylobacter jejuni, which is the main etiological agent of campilobacteriosis, can survives in adverse environmental conditions by capacity of biofilm formation. Biofilm forming bacteria can acquire resistance to compounds used as sanitizers in sanitization step, such as benzalkonium chloride (BC). Thereby, it is necessary the search for new compounds with antibacterial activity which can be used in alternative to syntetic sanitizers. The plants extracts have been widely studied due to it’s antimicrobial characteristics and for being natural compounds. The Butia odorata Barb. Rodr. methanolic extract (BME) had it’s antibacterial activity proven in studies performed previously. Therefore, the aims of this study were evaluate the factors that influence of surface, temperature, atmosphere and co-culture with Pseudomonas aeruginosa on biofilm formation in Campylobacter jejuni isolated from poultry slaughterhouse of Southern Rio Grande do Sul, Brazil, as well identify the presence of some genes related to biofilm formation in these isolates. Moreover, was aimed to evaluate the susceptibility of these isolates to the BME and to the BC, through the agar disc diffusion qualitative test for BME, and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for BME and BC. The atmosphere did not affected the monospecies biofilm formation both in polystyrene and stainless steel. There was greater biofilm formation in temperatures that are not the optimals for C. jejuni growth. The way how P. aeruginosa was inoculated to form dual-species biofilms with C. jejuni (concomitant or preformed by P. aeruginosa) did not influenced the biofilm formation by the isolates. In duo-species biofilms with P. aeruginosa, the higher biofilm counts of C. jejuni in stainless steel occurred at 25 oC. The seven isolates had 10 genes that are involved in biofilm formation process, but the katA gene was not found in three isolates, and the kpsM gene was not observed in one isolate, which did not affected the biofilm formation by these isolates. The BME presented antibacterial activity against the seven C. jejuni isolates tested in the qualitative test of agar disc diffusion, resulting in inhibition halos above of 23 mm. The MIC of BME ranged between 83,3 and 166,6 μL.mL-1, and the MBC was the same value that MIC in all isolates. Already for BC, the MIC value stay between 1 and 2 μg.mL-1, and the MBC value ranged between 1 and 4 μg.mL- 1 among isolates. In this way, the BME can become a good alternative to the BC employed in sanitization step in food industries.

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26

Morgan, J. H. "Bacteriology of calf diarrhoea with special reference to Campylobacter." Thesis, University of Reading, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254444.

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27

Epps, Sharon V. R. "The Effect of Thymol-B-D-Glucopyranoside on the Reduction of Campylobacter Species in Food-Producing Animals." Thesis, 2013. http://hdl.handle.net/1969.1/151051.

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Abstract:

Campylobacter are a leading cause of bacterial derived foodborne illness. Thymol is a natural product that reduces survivability of Campylobacter in vitro. Results from animal studies, however, indicate that absorption or degradation within the stomach and small intestine may preclude delivery of thymol to the cecum and large intestine, the main sites of Campylobacter colonization. Presently, we compared the anti- Campylobacter activity of thymol against that of thymol-β-D-glucopyranoside (β-Dthymol), the latter suspected to be resistant to degradation and absorption in the proximal alimentary tract lacking β-glycosidase activity. When treated with 1 mM thymol, the survivability of Campylobacter coli and jejuni in vitro was reduced by 3.41 to 6.87 log_10 CFU mL-1 after 48-h pure culture and after co-culture, respectively. In the presence of a β-glycosidase-expressing Parabacteroides distasonis. Conversely, the survivability of C. coli and C. jejuni was reduced by 3.72 and 4.30 log_10 CFU mL-1, respectively, in cocultures treated with β-D-thymol, but not in pure cultures similarly treated. When tested in mixed cultures of porcine or bovine fecal microbes possessing endogenous β- glycosidase, C. coli and C. jejuni survivability was reduced by 3.26 and 2.50 log_10 CFU mL-1, respectively, whether treated with thymol or β-D-thymol. In mixed populations of avian crop and cecal microbes, C. jejuni survivability was reduced 1.41 to 2.32 log_10 CFU mL-1 whether treated with thymol or β-D-thymol. Thymol and β-D-thymol inhibited ammonia accumulation in mixed populations of porcine and mixed bovine fecal microbes which is consistent with free thymol’s purported role as a deaminase inhibitor. Conversely, thymol and β-D-thymol did not affect ammonia accumulation in mixed populations of avian gut microbes implicating population specific effects of these compounds. β-D-thymol, but not thymol, reduced accumulation of fermentation acids indicating the conjugate inhibited fermentation which may limit its application to the last meal or last few meals before harvest. Oral administration of 150 μmol β-D-thymol reduced C. jejuni in avian crop, but not in cecal contents; treatment with thymol was ineffective. These results indicate that β-D-thymol, or similar β-glycosides, may be a suitable candidate to escape absorption and degradation within the proximal alimentary and retain its anti-Campylobacter properties. Further research is needed to reduce such technology to practice.

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Messelhäußer, U. [Verfasser]. "Nachweis von Shiga-Toxin-bildenden Escherichia coli und thermophilen Campylobacter-Species bei Almkühen und in auf Almen produzierten Lebensmitteln / von Ute Christine Messelhäußer." 2005. http://d-nb.info/974406678/34.

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Specker, Marcus [Verfasser]. "Untersuchungen zum Vorkommen von Listerien, Salmonellen, Campylobacter und Staphylokokken in Rohmilch im Land Brandenburg / vorgelegt von Marcus Specker." 1996. http://d-nb.info/961937645/34.

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Dissertations / Theses on the topic 'Campylobacter species'

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