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See detailContribution à l’identification de l’agent étiologique de l’entéropathie épizootique du lapin
Huybens, Nathalie ULg

Doctoral thesis (2012)

Epizootic rabbit enteropathy (ERE) is a pathology of the digestive system inducing economic loss in rabbit husbandry throughout Europe. The aetiological agent is unknown at the present time but a ... [more ▼]

Epizootic rabbit enteropathy (ERE) is a pathology of the digestive system inducing economic loss in rabbit husbandry throughout Europe. The aetiological agent is unknown at the present time but a reference inoculum (TEC4) reproduces the pathology. This inoculum contains an extremely rich bacterial flora. Several methods were used to reduce this bacterial flora while retaining virulence: centrifugation on discontinuous sucrose gradient, cellular adherence and treatment with chloroform/ethanol, antibiotics and an acid buffer. The flora of the obtained fractions were analyzed using traditional bacteriological techniques: identification of cultivable species, counting of colony forming units (CFU) and direct bacterioscopic exam after Gram coloration. Then, molecular biology was used to compare inocula, fractions and negative control. Three methods were used to find sequences present in virulent inocula and absent from non virulent inocula and negative controls. Twenty-two restriction enzymes were used to compare the 16SrDNA restriction profile (Amplified Ribosomal DNA Restriction Analysis or ARDRA). Hypervariable regions V3 and V6 to V8 were studied by Denaturating Gradient Gel Electrophoresis (DGGE). Finally, Random Amplification of Polymorphic DNA (RAPD) was used on the inocula, fractions and negative controls. Only the RAPD allow the obtainment of sequences specific to virulent inoculum. Unfortunately, a study on field samples did not confirm the link between the sequences and ERE. For one of the two identified sequences, a bacterial strain carrier was isolated. The strain was inoculated into rabbits but no clinical signs of ERE were observed. Samples of stools, blood and serum were collected during an experimental ERE infection. The evolution of fecal bacterial flora was studied using DGGE to follow the evolution of flora over the course of the disease. Unfortunately, neither specific bands nor specific band patterns appeared to be linked to the disease. Seven bacterial species were detected in the blood samples of three inoculated rabbits at day two post inoculation, confirming the hypothesis that bacteriemia occurs early on ERE infection. Finally, six fractions were analysed by pyrosequencing of the 16SrDNA gene. The aim was to find one or several species present in the virulent inocula but absent or less numerous in the nonvirulent inocula and control. The richness and diversity of all the inocula is equal or superior to human feces. As expected, the flora identified by pyrosequencing was different from the cultivable flora. However, no genera or species was specifically linked to the virulent inocula. The resolution of this technique was inadequate to identify the aetiological agent of ERE. A higher number of samples and sequences could at best restrain the identification to one genus. [less ▲]

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See detailEpizootic rabbit enteropathy: comparison of PCR-based RAPD fingerprints from virulent and non-virulent samples
Huybens, Nathalie ULg; Houeix, Julien ULg; Licois, Dominique et al

in Veterinary Journal (2011), 190(3), 416-417

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See detailEpizootic rabbit enteropathy inoculum (TEC4) antibiograms and antibiotic fractionation
Huybens, Nathalie ULg; Houeix, Julien ULg; Licois, Dominique et al

in Veterinary Research Communications (2011), 35

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See detailMolecular biology techniques to analyze complex Bactrian populations
Huybens, Nathalie ULg; Mainil, Jacques ULg; Marlier, Didier ULg

in Annales de Médecine Vétérinaire (2009), 153(2), 112-128

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See detailINOCULATION AND BACTERIAL ANALYSES OF FRACTIONS OBTAINED FROM THE REFERENCE INOCULUM TEC4 WHICH EXPERIMENTALLY REPRODUCES EPIZOOTIC RABBIT ENTEROPATHY
Huybens, Nathalie ULg; Houeix, Julien ULg; Licois, D. et al

in World Rabbit Science (2009), 17(4), 185-193

The aetiology of epizootic rabbit enteropathy (ERE) is still unknown despite ten years of continuous research. A putative bacterial aetiology is the basis of current research. The fractionation of the ... [more ▼]

The aetiology of epizootic rabbit enteropathy (ERE) is still unknown despite ten years of continuous research. A putative bacterial aetiology is the basis of current research. The fractionation of the reference inoculum (TEC4) is a major step towards finding the potential bacterial agent(s). In this study, TEC4 was fractionated by different techniques: centrifugation on discontinuous sucrose gradient, cell adherence and chloroform/ethanol treatment. The different fractions were inoculated into SPF rabbits and analyzed with classical bacteriological techniques. ERE was reproduced with two of the six fractions obtained. Four species never previously cultured from TEC were identified in the process but, to date, none of them seems to be the aetiology of ERE. [less ▲]

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See detailIS EPIZOOTIC RABBIT ENTEROPATHY (ERE) A BACTERIAL DISEASE?
Huybens, Nathalie ULg; Houeix, Julien ULg; Szalo, Ioan Mihai ULg et al

in Proceeding of the 9th World Rabbit Congress (2008, June 12)

The etiology of epizootic rabbit enteropathy (ERE) is still unknown despite ten years of continuous research. A putative bacterial etiology is at the basis of current research. The fractionation of the ... [more ▼]

The etiology of epizootic rabbit enteropathy (ERE) is still unknown despite ten years of continuous research. A putative bacterial etiology is at the basis of current research. The fractionation of the reference inoculum (TEC4) is a major step to find the potential bacterial agent(s). In this study, TEC4 was fractionated with two techniques: centrifugation on discontinuous sucrose gradient then cell adhesion. Two selected fractions were inoculated to SPF rabbits and analyzed with classical bacteriological techniques. ERE was reproduced with both fractions. The 16S rDNA gene was amplified in all fractions and in three negative controls and subsequently analyzed with Restriction Fragment Length Polymorphism (RFLP) and Denaturating Gradient Gel Electrophoresis (DGGE). A difference in bacterial DNA composition was found between virulent and non-virulent fractions which reinforce the potential role of bacteria in the etiology of ERE. [less ▲]

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See detailAnalyses bactériologiques traditionnelles et moléculaires de l'inoculum de référence de l'entéropathie épizootique du lapin (TEC4) et de ses fractions
Huybens, Nathalie ULg

Master of advanced studies dissertation (2007)

Epizootic rabbit enteropathy is a digestive disease that induces huge economic losses in European rabbit production units. Its aetiology is still unknown but a reference inoculum (TEC4) can reproduce the ... [more ▼]

Epizootic rabbit enteropathy is a digestive disease that induces huge economic losses in European rabbit production units. Its aetiology is still unknown but a reference inoculum (TEC4) can reproduce the pathology. The aim of the study is to find a bacteria or a bacterial DNA sequence specific to this inoculum. The bacterial species found in TEC4 were separated by centrifugation on discontinuous sucrose gradient followed or not by a cellular adhesion sorting. The rabbit kidney cells adhering fractions can reproduce the pathology by inoculation on sensitive rabbits. The classical bacteriological and bacterioscopical analyses show a variation and a selection of the flora in the course of the fractionation. Restriction Fragment Length Polymorphism (RFLP) analysis with Acc I show a specific pattern for the fraction able to reproduce the pathology. [less ▲]

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See detailNouveaux animaux de compagnie : infections à Salmonella enterica et état sanitaire
Huybens, Nathalie ULg; Delleur, Valéry; Poulipoulis, Anastassios ULg et al

in Annales de Médecine Vétérinaire (2006), 150(4), 241-246

Human transmission of Salmonella enterica from new companion animals is usually suspected even though very few data according Salmonella infections in these animal species are available. The prevalence of ... [more ▼]

Human transmission of Salmonella enterica from new companion animals is usually suspected even though very few data according Salmonella infections in these animal species are available. The prevalence of Salmonella enterica infections in the digestive tract of 450 new companion animals ( 45 ferrets, 7 birds, 308 rodents, 82 rabbits and 8 reptiles) coming from pet shops or individual owners was determined by bacteriological examinations of anal swabs or pooled fresh faeces. Only one Salmonella Enteritidis strain was isolated from a ferret in a pet shop. The symptomatic or asymptomatic Salmonella carriage in ferrets, rodents and rabbits is thus not as frequent as what was suspected. [less ▲]

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