R Ducatelle

Ghent University, Gand, Flemish, Belgium

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Publications (497)1132.96 Total impact

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    ABSTRACT: Inflammatory bowel disease (IBD) is a chronic inflammation of the digestive tract, characterized by dysbiosis of the intestinal microbiota. Probiotics have been suggested as a strategy to reduce active disease or extend remission. We isolated and characterized the butyrate-producing strain Butyricicoccus pullicaecorum 25-3T and identified it as a potential probiotic for patients with IBD. To evaluate the safety of 25-3T for use in humans, we conducted a standard acute oral toxicity test and a 28-day repeated oral dose toxicity test. The complete genome of B. pullicaecorum 25-3T was sequenced to search for virulence factors and antibiotic resistance determinants. The minimum inhibitory concentration (MIC) of 21 antimicrobials was determined. Results showed no adverse effects in the oral toxicity tests. B. pullicaecorum 25-3T is resistant against aminoglycosides and trimethoprim. The genome of 25-3T contains no virulence factors, one gene related to harmful metabolites and 52 sequences with high similarity to antimicrobial and toxic compound resistance genes, that did not correspond with a resistant phenotype. This first report of a safety assessment of a butyrate-producing strain from Clostridium cluster IV shows that B. pullicaecorum 25-3T is a non-pathogenic strain, but carries antibiotic resistance genes with the risk of transfer, that need further investigation.
    Food and Chemical Toxicology 10/2014; 72:129–137. DOI:10.1016/j.fct.2014.06.024 · 2.61 Impact Factor
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    ABSTRACT: Both mycotoxin contamination of feed and Clostridium perfringens-induced necrotic enteritis have an increasing global economic impact on poultry production. Especially the Fusarium mycotoxin deoxynivalenol (DON) is a common feed contaminant. This study aimed at examining the predisposing effect of DON on the development of necrotic enteritis in broiler chickens. An experimental Clostridium perfringens infection study revealed that DON, at a contamination level of 3,000 to 4,000 µg/kg feed, increased the percentage of birds with subclinical necrotic enteritis from 20±2.6% to 47±3.0% (P<0.001). DON significantly reduced the transepithelial electrical resistance in duodenal segments (P<0.001) and decreased duodenal villus height (P = 0.014) indicating intestinal barrier disruption and intestinal epithelial damage, respectively. This may lead to an increased permeability of the intestinal epithelium and decreased absorption of dietary proteins. Protein analysis of duodenal content indeed showed that DON contamination resulted in a significant increase in total protein concentration (P = 0.023). Furthermore, DON had no effect on in vitro growth, alpha toxin production and netB toxin transcription of Clostridium perfringens. In conclusion, feed contamination with DON at concentrations below the European maximum guidance level of 5,000 µg/kg feed, is a predisposing factor for the development of necrotic enteritis in broilers. These results are associated with a negative effect of DON on the intestinal barrier function and increased intestinal protein availability, which may stimulate growth and toxin production of Clostridium perfringens.
    PLoS ONE 09/2014; 9(9):e108775. DOI:10.1371/journal.pone.0108775 · 3.53 Impact Factor
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    ABSTRACT: A number of Helicobacter species cause gastrointestinal or hepatic disease in humans, including H. pylori, gastric non-H. pylori helicobacters from animal origin and enterohepatic Helicobacter species. Little is known on the presence of Helicobacter species in great apes, our closest living relatives and potential reservoirs of microorganisms that might emerge in humans. The aim of the present study was to investigate the presence of gastric and enterohepatic Helicobacter species in African chimpanzees and gorillas. Fresh fecal samples were collected from wild endangered chimpanzees and critically endangered western lowland gorillas from different African National Parks, as well as wild-born captive animals from primate sanctuaries. Intact Helicobacter bacteria were demonstrated in feces by fluorescence in situ hybridization. Screening using a Helicobacter genus-specific PCR revealed the presence of Helicobacter DNA in the majority of animals in all groups. Cloning and sequencing of 16S rRNA gene fragments revealed a high homology to sequences from various zoonotic enterohepatic Helicobacter species, including H. cinaedi and H. canadensis. A number of gorillas and chimpanzees also tested positive using PCR assays designed to amplify part of the ureAB gene cluster and the hsp60 gene of gastric helicobacters. Phylogenetic analysis revealed the presence of a putative novel zoonotic gastric Helicobacter taxon/species. For this species, we propose the name ‘Candidatus Helicobacter homininae’, pending isolation and further genetic characterization. The presence of several Helicobacter species not only implies a possible health threat for these endangered great apes, but also a possible zoonotic transmission of gastric and enterohepatic helicobacters from these primate reservoirs to humans.
    Veterinary Microbiology 09/2014; 174(1-2). DOI:10.1016/j.vetmic.2014.08.032 · 2.73 Impact Factor
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    ABSTRACT: Background Information on the genetic events leading to thyroid cancer in dogs is lacking.Hypothesis/Objectives Upregulation of the PI3K/Akt pathway has an important role in the tumorigenesis of thyroid carcinoma in dogs.AnimalsFifty-nine dogs with thyroid carcinoma and 10 healthy controls.Methods Quantitative RT-PCR was performed for VEGFR-1, VEGFR-2, EGFR, PIK3CA, PIK3CB, PDPK1, PTEN, AKT1, AKT2, COX-2, and CALCA. Mutation analysis was performed for known hotspots of RAS (N, K, H), PIK3CA, BRAF, RET, and for the entire coding region of PTEN.ResultsForty-three dogs (73%) had follicular cell thyroid carcinoma (FTC) and 16 dogs (27%) had medullary thyroid carcinoma (MTC). The relative mRNA expressions of VEGFR-1 (P < .001), VEGFR-2 (P = .002), PDPK1 (P < .001), AKT1 (P = .009), and AKT2 (P < .001) were increased in FTC, and those of EGFR (P < .001), VEGFR-1 (P = .036), and PIK3CA (P = .019) were increased in MTC when compared to normal thyroid glands. Mutation analysis of K-RAS identified 2 activating missense mutations, which also have been described in thyroid cancer of humans. A G12R substitution was present in 1 FTC and an E63K substitution was present in 1 MTC. No functional mutations were found in the sequenced regions of H-RAS, N-RAS, PIK3CA, BRAF, RET, and PTEN.Conclusions and Clinical ImportanceThe increased expression of several genes associated with PI3K/Akt signaling suggests the involvement of this pathway in the pathogenesis of thyroid carcinoma in dogs, warranting further research on pathway activation and gene amplification. The mutations most frequently associated with thyroid cancer in humans are rare in dogs.
    Journal of Veterinary Internal Medicine 09/2014; 28(6). DOI:10.1111/jvim.12435 · 2.22 Impact Factor
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    ABSTRACT: Background Prognostic markers for dogs with thyroid tumors are limited.Hypothesis/Objectives To identify clinical, pathologic, and immunohistochemical prognostic factors for dogs with thyroid tumors.AnimalsSeventy dogs with thyroid neoplasia.Methods Retrospective study. Dogs with thyroid neoplasia were included when follow-up information and formalin-fixed paraffin-embedded tumor samples were available. Immunohistochemistry (IHC) was performed for thyroglobulin, calcitonin, Ki-67, and E-cadherin. Correlation of tumor variables (diameter, volume, localization, scintigraphic uptake, thyroid function, IHC) with local invasiveness and metastatic disease was performed on all tumor samples. Forty-four dogs treated by thyroidectomy were included in a survival analysis.ResultsFifty dogs (71%) had differentiated follicular cell thyroid carcinoma (dFTC) and 20 (29%) had medullary thyroid carcinoma (MTC). At diagnosis, tumor diameter (P = .007; P = .038), tumor volume (P = .020), tumor fixation (P = .002), ectopic location (P = .002), follicular cell origin (P = .044), and Ki-67 (P = .038) were positively associated with local invasiveness; tumor diameter (P = .002), tumor volume (P = .023), and bilateral location (P = .012) were positively associated with presence of distant metastases. Forty-four dogs (28 dFTC, 16 MTC; stage I–III) underwent thyroidectomy. Outcome was comparable between dogs with dFTC and MTC. Macroscopic (P = .007) and histologic (P = .046) vascular invasion were independent negative predictors for disease-free survival. Although time to presentation, histologic vascular invasion and Ki-67 were negatively associated with time to metastases, and time to presentation was negatively associated with time to recurrence, no independent predictors were found. E-cadherin expression was not associated with outcome.Conclusions and Clinical ImportancePrognostic factors have been identified that provide relevant information for owners and clinicians.
    Journal of Veterinary Internal Medicine 09/2014; 28(6). DOI:10.1111/jvim.12436 · 2.22 Impact Factor
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    ABSTRACT: Strains LMG 27428(T) and LMG 27427 were isolated from the caecal content of a chicken and produced butyric, lactic and formic acid as major metabolic end products. The genomic DNA G+C content of strain LMG 27428(T) was 40.4 mol% and 38.8 mol% for LMG 27427. On the basis of 16S rRNA gene sequence similarity, both strains were most closely related to the generically misclassified Streptococcus pleomorphus ATCC 29734(T). Strain LMG 27428(T) could be distinguished from S. pleomorphus ATCC 29734(T) based on higher lactic acid and less formic acid production in M2GSC medium, a higher DNA G+C content and absence of acid phosphatase, leucine, arginine, leucyl glycine, pyroglutamic acid, glycine and histidine arylamidase activity while strain LMG 27428 was biochemically indistinguishable from S. pleomorphus. The novel genus Faecalicoccus within the family Erysipelotrichaceae is proposed to accommodate strain LMG 27428(T) = (DSM 26963(T)) as Faecalicoccus acidiformans sp. nov. and strain LMG 27427 (DSM 26962) as Faecalicoccus pleomorphus comb. nov.. Furthermore, the nearest phylogenetic neighbours of the genus Faecalicoccus are the generically misclassified Eubacterium cylindroides DSM 3983(T) (94.4 % 16S rRNA sequence similarity to the type strain) and Eubacterium biforme DSM 3989(T) (92.7 % 16S rRNA sequence similarity to the type strain). We present genotypic and phenotypic data that allow the differentiation of each of these taxa and formally propose to reclassify these generically misnamed Eubacterium species as Faecalitalea cylindroides comb. nov. (DSM 3983(T) = ATCC 27803(T) = JCM 10261(T)) and Holdemanella biformis comb. nov. (DSM 3989(T) = ATCC 27806(T) = CCUG 28091(T)), respectively.
    International Journal of Systematic and Evolutionary Microbiology 09/2014; 64(Pt 11). DOI:10.1099/ijs.0.064626-0 · 2.80 Impact Factor
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    ABSTRACT: In the last two decades, outbreaks of equine viral arteritis (EVA) have been reported in Europe, but little is known about these European isolates of equine arteritis virus (EAV). EAV European strain (08P178, EU-1 clade) isolated from one of these recent outbreaks is able to cause clinical signs on experimental infection. The aim of the present study was to investigate the microscopical lesions induced by this isolate after experimental infection of ponies. Animals were killed at 3, 7, 14 and 28 days post infection (dpi). At 3 dpi, lesions were essentially restricted to the respiratory tract and intestines and were characterized by mild multifocal epithelial degeneration and associated mononuclear cell infiltration. Lesions were more severe at 7 dpi and by 14 dpi, respiratory lesions were even more severe and lymphoplasmacytic infiltrates extended to other organs. At 28 dpi, lesions were still present in the viscera. In all specimens the most prominent histological change was intraepithelial, subepithelial and perivascular lymphoplasmacytic infiltration, ranging from mild and multifocal to extensive and diffuse. No signs of arterial damage such as infarcts, haemorrhages or necrosis were found. In conclusion, infection of naïve animals with the European 08P178 strain of EAV is associated with inflammation, but not arteritis.
    Journal of Comparative Pathology 08/2014; DOI:10.1016/j.jcpa.2014.04.008 · 1.10 Impact Factor
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    ABSTRACT: Helicobacter (H.) suis is a world-wide spread pathogen which not only colonizes the stomach of pigs, but is also the most prevalent gastric non-H. pylori Helicobacter (NHPH) species in humans. H. suis infections are associated with gastric lesions both in pigs and in humans. Recently, the presence of viable H. suis bacteria has been demonstrated in minced pork, suggesting that manipulation or consumption of contaminated pig meat is a possible route of transmission of this zoonotic agent. The main goal of this study was to determine the extent of pork carcass contamination with H. suis at slaughter. In two consecutive studies, the occurrence of H. suis DNA was assessed in scalding water, head and mouth swabs, mesenteric lymph nodes, palatine tonsils and on the chest, shoulder and ham region of pork carcasses from three slaughterhouses using qPCR with ureA gene based H. suis-specific primers. H. suis DNA was detected on carcasses in all slaughterhouses, in 8.3% of all 1083 samples. It was found in all sampled matrices, except for the palatine tonsils and scalding water samples. Contamination levels of dressed pork samples did not exceed 184 genomic equivalents per 100cm(2) (shoulder, ham) or 300cm(2) (chest). All positive PCR products were subjected to sequence analysis of the ureA gene to confirm the identification of H. suis bacteria. Using multilocus sequence typing (MLST) on a selection of the positive samples, 5 unique sequence types (STs) could be assigned. Multiple H. suis strains were present on samples derived from one specific pig herd. Since H. suis DNA was detected in 11% (n: 90) of the mesenteric lymph nodes derived at the slaughterhouse, it was determined whether these organisms can colonize the mesenteric lymph nodes after experimental infection. Despite high-level colonization of the porcine stomachs with the H. suis strain, no H. suis DNA was detected in the mesenteric lymph nodes at four weeks after experimental infection. This might indicate that its presence in these tissues of slaughtered pigs is due to contamination during the slaughter process, but further studies are necessary to confirm this. In conclusion, we demonstrate a relatively high prevalence of H. suis on pork carcasses.
    International Journal of Food Microbiology 07/2014; 187C:73-76. DOI:10.1016/j.ijfoodmicro.2014.06.016 · 3.16 Impact Factor
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    ABSTRACT: Necrotic enteritis in broilers is caused by Clostridium perfringens type A strains that produce the NetB toxin. It is one of the gastrointestinal diseases in poultry that has gained worldwide importance during the last decade due to efforts to improve broiler performance. Prevention strategies include avoiding predisposing factors, such as coccidiosis, and in-feed supplementation with a variety of feed additives. However, vaccination with modified toxin or other secreted immunogenic proteins seems a logical preventive tool for protection against a toxin-producing bacterium. Formalin-inactivated crude supernatant has been used initially for vaccination. Several studies have been carried out recently to identify the most important immunogenic and protective proteins that can be used for vaccination. These include the NetB toxin, as well as a number of other proteins. There is evidence that immunization with single proteins is not protective against severe challenge and that combinations of different antigens are needed. Most published studies have used multiple dosage vaccination regimens that are not relevant for practical use in the broiler industry. Single vaccination regimens for day-old chicks appear to be non-protective. This review describes the history of vaccination strategies against necrotic enteritis in broilers and gives an update on future vaccination strategies that are applicable in the field. These may include breeder hen vaccination, in ovo vaccination and live attenuated vectors to be used in feed or in drinking water.
    Avian Pathology 07/2014; DOI:10.1080/03079457.2014.939942 · 2.04 Impact Factor
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    ABSTRACT: Consumption of contaminated poultry meat is still an important cause of Salmonella infections in humans and there is a need for control methods that protect broilers from day-of-hatch until slaughter age against infection with Salmonella. Colonisation-inhibition, a concept in which a live Salmonella strain is orally administered to day-old chickens and protects against subsequent challenge, can potentially be used as control method. In this study, the efficacy of a Salmonella Typhimurium ΔhilAssrAfliG strain as a colonisation-inhibition strain for protection of broilers against Salmonella Typhimurium was evaluated. Administration of a Salmonella Typhimurium ΔhilAssrAfliG strain to day-old broiler chickens decreased faecal shedding and strongly reduced caecal and internal organ colonisation of a Salmonella Typhimurium challenge strain administered one day later using a seeder bird model. In addition, it was verified whether a colonisation-inhibition culture could be developed that protects against both Salmonella Enteritidis and Typhimurium. Therefore, the Salmonella Typhimurium ΔhilAssrAfliG strain was orally administered simultaneously with a Salmonella Enteritidis ΔhilAssrAfliG strain to day-old broiler chickens, which resulted in a decreased caecal and internal organ colonisation for both a Salmonella Enteritidis and a Salmonella Typhimurium challenge strain short after hatching, using a seeder bird model. The combined culture was not protective against Salmonella Paratyphi B varietas Java challenge, indicating serotype-specific protection mechanisms. The data suggest that colonisation-inhibition can potentially be used as a versatile control method to protect poultry against several Salmonella serotypes.
    Vaccine 06/2014; 32(36). DOI:10.1016/j.vaccine.2014.06.077 · 3.49 Impact Factor
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    ABSTRACT: VC2002, isolated from postweaning multisystemic wasting syndrome (PMWS)-affected pig, is a mixture of two porcine circovirus genotype 2b (PCV2b) viruses, K2 and K39. Preliminary experiments disclosed short-term adverse effects of K39, but not K2, on porcine foetuses. These findings led to the hypothesis that infection of immuno-incompetent foetuses with K2 confers a status of immunotolerance, and postnatal super-infection with K39 triggers PMWS. To explore this hypothesis, nine 55-day-old foetuses were inoculated in utero (three with K2-10(4.3)TCID50, three with K39-10(4.3)TCID50 and three with medium), and foeto-pathogenicity examined. At 21 days post-inoculation (dpi), K2 did not induce pathology, whereas pathological effects of K39 were evident. Twenty-four 45-day-old foetuses were subsequently inoculated to examine the long-term effect of K2, including six with K2-high dose-10(4.3)TCID50, six with K2-low dose-10(2.3)TCID50 and 12 mock-inoculated controls. Both doses resulted in five mummified foetuses and one live-born piglet each (69dpi). K2 was recovered from all mummies. K2 and K2-specific antibodies were not detected in serum of the two live-born piglets at birth, indicating full control of K2 infection. The K2-low dose-infected piglet was immunostimulated at day 2, but not the K2-high dose-infected piglet. Both non-stimulated and stimulated K2-infected piglets were super-inoculated with K39 at day 6 or 8 (taken as 0 days post super-inoculation). Low viral replication was observed in the non-stimulated K2-K39 piglet (up to 10(3.3)TCID50/g; identified as K39). In contrast, viral replication was extremely high in the stimulated K2-K39 piglet (up to 10(5.6)TCID50/g) and identified as K2, indicating that K2 infection is controlled during foetal life, but emerges after birth upon immunostimulation. However, none of the piglets showed any signs of PMWS.
    Virologica Sinica 06/2014; 29(3). DOI:10.1007/s12250-014-3431-0
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    ABSTRACT: Helicobacter heilmannii is a zoonotic bacterium that has been associated with gastric disease in humans. In this study, mRNA expression of mucins was analyzed at several time-points in the stomach of BALB/c mice during a one year infection with this bacterium in which gastric disease progressed in severity. Markers for acid production by parietal cells and mucous metaplasia were also examined. In the first 9 weeks post-infection, mRNA expression of Muc6 was clearly upregulated in both the antrum and fundus of the stomach of H. heilmannii-infected mice. Interestingly, Muc13 was upregulated already at 1 day post-infection in the fundus of the stomach. Its expression level remained high in the stomach over the course of the infection. This mucin is, however, not expressed in a healthy stomach and a high expression of this mucin has so far only been described in gastric cancer. In the later stages of infection, mRNA expression of H(+)/K(+)-ATPase α/β and KCNQ1 decreased whereas the expression of Muc4, Tff2, Dmbt1 and PigR increased starting at 16 weeks post-infection onwards suggesting the existence of spasmolytic polypeptide-expressing metaplasia in the fundus of the stomach. Mucous metaplasia present in the mucosa surrounding low grade mucosa associated lymphoid tissue lymphoma-like lesions was also histologically confirmed. Our findings indicate that H. heilmannii infection causes severe gastric pathologies, alterations in the expression pattern of gastric mucins, such as Muc6 and Muc13, as well as a disruption in the gastric homeostasis by inducing loss of parietal cells resulting in the development of mucous metaplasia.
    Infection and Immunity 05/2014; 82(8). DOI:10.1128/IAI.01867-14 · 4.16 Impact Factor
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    ABSTRACT: Eggs contaminated with Salmonella Enteritidis are an important source of human foodborne Salmonella infections. Salmonella Enteritidis is able to contaminate egg white during formation of the egg within the chicken oviduct, and it has developed strategies to withstand the antimicrobial properties of egg white to survive in this hostile environment. The mechanisms involved in the persistence of Salmonella Enteritidis in egg white are likely to be complex. To address this issue, a microarray-based transposon library screen was performed to identify genes necessary for survival of Salmonella Enteritidis in egg white at chicken body temperature. The majority of identified genes belonged to the lipopolysaccharide biosynthesis pathway. Additionally, we provide evidence that the serine protease/heat shock protein (HtrA) appears essential for the survival of Salmonella Enteritidis in egg white at chicken body temperature.
    Poultry Science 05/2014; 93(5):1263-9. DOI:10.3382/ps.2013-03711 · 1.54 Impact Factor
  • Gastroenterology 05/2014; 146(5):S-834-S-835. DOI:10.1016/S0016-5085(14)63031-6 · 13.93 Impact Factor
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    ABSTRACT: Aortic rupture in horses is a rare condition. Although it is relatively common in the Friesian breed, only limited histopathologic information is available. Twenty Friesian horses (1-10 years old) were diagnosed with aortic rupture by postmortem examination. Ruptured aortic walls were analyzed with histology and immunohistochemistry. Based on the histologic and immunohistochemical findings, these cases were divided into 3 groups: acute (n = 4, 20%), subacute (n = 8, 40%), and chronic (n = 8, 40%). Features common to samples from horses in all groups included accumulation of mucoid material; disorganization and fragmentation of the elastic laminae; aortic medial smooth muscle hypertrophy; and medial necrosis of varying degrees, ranging from mild and patchy in the acute cases to severe midzonal necrosis in the chronic cases. Inflammation, most likely secondary to medial necrosis, varied from predominantly neutrophilic infiltrates in the media and periadventitial tissue in the acute group to the presence of mainly hemosiderophages in the periadventitial tissue in the chronic group. Medial fibrosis with aberrant collagen morphology was seen in the subacute group and, more commonly, in the chronic group. Only minimal changes were seen in the aortic vasa vasorum. Smooth muscle hypertrophy and accumulation of mucoid material were not related to the age of the lesions. The findings of this study suggest that a connective tissue disorder affecting elastin or collagen in the aortic media is potentially the underlying cause of aortic rupture in Friesian horses.
    Veterinary Pathology 04/2014; 52(1). DOI:10.1177/0300985814528219 · 2.04 Impact Factor
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    ABSTRACT: Necrotic enteritis in broiler chickens is associated with netB positive Clostridium perfringens type A strains. It is known that C. perfringens strains isolated from outbreaks of necrotic enteritis are more capable of secreting factors inhibiting growth of other C. perfringens strains than strains isolated from the gut of healthy chickens. This characteristic could lead to extensive and selective presence of a strain that contains the genetic make-up enabling to secrete toxins that cause gut lesions. This report describes the discovery, purification, characterization and recombinant expression of a novel bacteriocin, referred to as perfrin, produced by a necrotic enteritis-associated netB-positive C. perfringens strain. Perfrin is a 11.5 kDa C-terminal fragment of a 22.9 kDa protein and showed no sequence homology to any currently known bacteriocin. The 11.5 kDa fragment can be cloned into Escherichia coli, and expression yielded an active peptide. PCR detection of the gene showed its presence in 10 netB-positive C. perfringens strains of broiler origin, and not in other C. perfringens strains tested (isolated from broilers, cattle, sheep, pigs, and humans). Perfrin and NetB are not located on the same genetic element since NetB is plasmid-encoded and perfrin is not. The bacteriocin has bactericidal activity over a wide pH-range but is thermolabile and sensitive to proteolytic digestion (trypsin, proteinase K). C. perfringens bacteriocins, such as perfrin, can be considered as an additional factor involved in the pathogenesis of necrotic enteritis in broilers.
    Veterinary Research 04/2014; 45(1):40. DOI:10.1186/1297-9716-45-40 · 3.38 Impact Factor
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    ABSTRACT: Background Although the infection rate of Helicobacter suis is significantly lower than that of Helicobacter pylori, the H. suis infection is associated with a high rate of gastric mucosa-associated lymphoid tissue (MALT) lymphoma. In addition, in vitro cultivation of H. suis remains difficult, and some H. suis-infected patients show negative results on the urea breath test (UBT).Materials and Methods Female C57BL/6J mice were orally inoculated with mouse gastric mucosal homogenates containing H. suis strains TKY or SNTW101 isolated from a cynomolgus monkey or a patient suffering from nodular gastritis, respectively. The high-purity chromosomal DNA samples of H. suis strains TKY and SNTW101 were prepared from the infected mouse gastric mucosa. The SOLiD sequencing of two H. suis genomes enabled comparative genomics of 20 Helicobacter and 11 Campylobacter strains for the identification of the H. suis-specific nucleotide sequences.ResultsOral inoculation with mouse gastric mucosal homogenates containing H. suis strains TKY and SNTW101 induced gastric MALT lymphoma and the formation of gastric lymphoid follicles, respectively, in C57BL/6J mice. Two conserved nucleotide sequences among six H. suis strains were identified and were used to design diagnostic PCR primers for the detection of H. suis.Conclusions There was a strong association between the H. suis infection and gastric diseases in the C57BL/6 mouse model. PCR diagnosis using an H. suis-specific primer pair is a valuable method for detecting H. suis in gastric biopsy specimens.
    Helicobacter 03/2014; 19(4). DOI:10.1111/hel.12127 · 2.99 Impact Factor
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    ABSTRACT: P-glycoprotein (P-gp) plays a major role as an efflux pump for endogenous and exogenous substrates at the blood-brain barrier and is localized in the brain at the apical side of capillary endothelial cells. Bovine spongiform encephalopathy (BSE) is marked primarily by the build-up of protease resistant misfolded prion protein (PrPres) in the brain. In the present study, the relationship between P-gp and BSE was investigated. An increase in the expression of vascular Pgp in the obex was found inclassical BSE, more prominent in the pre-clinical cases. This upregulation of P-gp in the early stages of the disease might be a protective regulatory mechanism to increase the clearance of the abnormal PrPres protein in an attempt to protect the brain from the accumulation of PrPres.
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    ABSTRACT: Thyroid carcinoma is a common endocrine tumor in the dog. Local invasive growth frequently precludes surgical excision and, in up to 38% of dogs, the tumor has already metastasized by the time of diagnosis. Therefore, it is important to investigate new treatment modalities that may be useful for the large number of dogs with inoperable tumors or metastatic disease. To investigate the immunohistochemical expression of potential therapeutic targets in canine thyroid tumors. 74 dogs with thyroid neoplasia. Immunohistochemistry was performed for thyroglobulin, calcitonin, vascular endothelial growth factor (VEGF), p53, cycloxygenase-2 (cox-2), and P-glycoprotein (P-gp). Fifty-four (73%) tumors were classified as follicular cell thyroid carcinomas (FTCs) and 20 (27%) as medullary thyroid carcinomas (MTCs). Eighty percent of FTCs and all MTCs had a high percentage (76-100%) of neoplastic cells immunopositive for VEGF. Thirteen percent of FTCs and 50% of MTCs expressed cox-2. Seven percent of FTCs and 70% of MTCs expressed P-gp. No tumor was immunopositive for p53 expression. Expression of VEGF (P = .034), cox-2 (P = .013), and P-gp (P < .001) was significantly higher in MTCs compared to FTCs. VEGF is a potential therapeutic target in both FTC and MTC in dogs. Cox-2 and P-gp may be useful molecular targets in canine MTC.
    Journal of Veterinary Internal Medicine 02/2014; 28(2). DOI:10.1111/jvim.12330 · 2.22 Impact Factor
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    ABSTRACT: The objective of the study was to investigate the effect of feed restriction on the intestinal ecosystem and on the pathogenesis of experimental necrotic enteritis in broiler chicks. To induce subclinical necrotic enteritis, an experimental challenge model using a specific diet formulation, Gumboro vaccination, oral inoculation of broilers with a 10-fold dose of attenuated anticoccidial vaccine and multiple oral inoculations with a specific strain of Clostridium perfringens, was adapted,. Two hundred and forty day-old Cobb 500 broilers were randomly allocated to groups feed restricted, challenged, both feed restricted and challenged, and a negative control. From each bird, the intestines, gizzard and liver were collected and scored for gross lesions at 21, 22, 23 and 24 days of age. The intestinal digesta was collected for pH and viscosity determination. One caecum from each bird was taken for microbiological analysis. The application of feed restriction in birds challenged with C. perfringens reduced the necrotic enteritis lesion score significantly (P ≤ 0.05) and feed restriction significantly reduced (P ≤ 0.05) pH in the small intestine, the viscosity of the jejunum digesta as well as the C. perfringens counts in the caeca compared to the control. In conclusion, feed restriction of broilers has a positive effect on the intestinal ecosystem and a significant protective effect against necrotic enteritis in the subclinical experimental model.
    Avian Pathology 02/2014; DOI:10.1080/03079457.2014.889278 · 2.04 Impact Factor

Publication Stats

7k Citations
1,132.96 Total Impact Points

Institutions

  • 1981–2015
    • Ghent University
      • • Department of Pathology, Bacteriology and Avian Diseases
      • • Faculty of Veterinary Medicine
      • • Department of Pathology
      Gand, Flemish, Belgium
  • 2014
    • University of Tehran
      • Faculty of Veterinary Medicine
      Teheran, Tehrān, Iran
  • 1992–2011
    • Universitair Ziekenhuis Ghent
      Gand, Flanders, Belgium
  • 2009
    • Państwowy Instytut Weterynaryjny
      Puławy, Lublin Voivodeship, Poland
    • University of Helsinki
      • Institute of Biotechnology
      Helsinki, Southern Finland Province, Finland
  • 2007
    • University of Antwerp
      • Laboratory of Pathophysiology
      Antwerpen, Flanders, Belgium
  • 2004
    • Veterinary Research Institute, Brno
      Brünn, South Moravian, Czech Republic
  • 2001
    • Vrije Universiteit Brussel
      • Laboratory for Cell Genetics
      Bruxelles, Brussels Capital, Belgium
  • 1998
    • Veterinary and Agrochemical Research Centre
      Bruxelles, Brussels Capital Region, Belgium