References of "Delcenserie, Véronique"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailAssessment of bacterial superficial contamination in classical or ritually slaughtered cattle using metagenetics and microbiological analysis
Korsak Koulagenko, Nicolas ULg; Taminiau, Bernard ULg; Hupperts, Caroline et al

in International Journal of Food Microbiology (in press)

The aim of this study was to investigate the influence of the slaughter technique (Halal vs. Classical slaughter) on the superficial contamination of cattle carcasses, by using traditional microbiological ... [more ▼]

The aim of this study was to investigate the influence of the slaughter technique (Halal vs. Classical slaughter) on the superficial contamination of cattle carcasses, by using traditional microbiological procedures and 16S rDNA metagenetics. The purpose was also to investigate the neck area to identify bacteria originating from the digestive or the respiratory tract. Twenty bovine carcasses (10 from each group) were swabbed at the slaughterhouse, where both slaughtering methods are practiced. Two swabbing areas were chosen: one “legal” zone of 1,600 cm2 (composed of zones from rump, flank, brisket and forelimb) and locally on the neck area (200 cm2). Samples were submitted to classical microbiology for aerobic Total Viable Counts (TVC) at 30°C and Enterobacteriaceae counts, while metagenetic analysis was performed on the same samples. The classical microbiological results revealed no significant differences between both slaughtering practices; with values between 3.95 and 4.87 log CFU/100 cm2 and 0.49 and 1.94 log CFU/100 cm2, for TVC and Enterobacteriaceae respectively. Analysis of pyrosequencing data showed that differences in the bacterial population abundance between slaughtering methods were mainly observed in the “legal” swabbing zone compared to the neck area. Bacterial genera belonging to the Actinobacteria phylum were more abundant in the “legal” swabbing zone in “Halal” samples, while Brevibacterium and Corynebacterium were encountered more in “Halal” samples, in all swabbing areas. This was also the case for Firmicutes bacterial populations (families of Aerococcaceae, Planococcaceae). Except for Planococcoceae, the analysis of Operational Taxonomic Unit (OTU) abundances of bacteria from the digestive or respiratory tract revealed no differences between groups. In conclusion, the slaughtering method does not influence the superficial microbiological pattern in terms of specific microbiological markers of the digestive or respiratory tract. However, precise analysis of taxonomy at the genus level taxonomy highlights differences between swabbing areas. Although not clearly proven in this study, differences in hygiene practices used during both slaughtering protocols could explain the differences in contamination between carcasses from both slaughtering groups. [less ▲]

Detailed reference viewed: 21 (8 ULg)
Full Text
Peer Reviewed
See detailUse of a metagenetic approach to monitor the bacterial microbiota of “Tomme d’Orchies” cheese during the ripening process
Ceugniez, Alexandre; Taminiau, Bernard ULg; Coucheney, Françoise et al

in International Journal of Food Microbiology (in press)

The study of microbial ecosystems in artisanal foodstuffs is important to complete in order to unveil its diversity. The number of studies performed on dairy products has increased during the last decade ... [more ▼]

The study of microbial ecosystems in artisanal foodstuffs is important to complete in order to unveil its diversity. The number of studies performed on dairy products has increased during the last decade, particularly those performed on milk and cheese derivative products. In this work, we investigated the bacterial content of "Tomme d'Orchies" cheese, an artisanal pressed and uncooked French cheese. To this end, a metagenetic analysis, using Illumina technology, was utilized on samples taken from the surface and core of the cheese at 0, 1, 3, 14 and 21 days of ripening process. In addition to the classical microbiota found in cheese, various strains likely from environmental origin were identified. A large difference between the surface and the core content was observed within samples withdrawn during the ripening process. The main species encountered in the core of the cheese were Lactococcus spp. and Streptococcus spp., with an inversion of this ratio during the ripening process. Less than 2.5% of the whole population was composed of strains issued from environmental origin, as Lactobacillales, Corynebacterium and Brevibacterium. In the core, about 85% of the microbiota was attributed to the starters used for the cheese making. In turn, the microbiota of the surface contained less than 30% of these starters and interestingly displayed more diversity. The predominant genus was Corynebacterium sp., likely originating from the environment. The less abundant microbiota of the surface was composed of Bifidobacteria, Brevibacterium and Micrococcales. To summarize, the “Tomme d’Orchies” cheese displayed a high diversity of bacterial species, especially on the surface, and this diversity is assumed to arise from the production environment and subsequent ripening process. [less ▲]

Detailed reference viewed: 17 (1 ULg)
Full Text
See detailMetabolites from media supplemented with 3’-sialyllactose and fermented by bifidobacteria have an antivirulent effect against intestinal pathogens
Bondue, Pauline ULg; Daube, Georges ULg; Delcenserie, Véronique ULg

Poster (2016, October 21)

Complex oligosaccharides from human milk (HMO) promote growth of Bifidobacterium bifidum. Oligosaccharides from cow milk (BMO), similar to HMO, are mainly represented in colostrum by 3’-sialyllactose ... [more ▼]

Complex oligosaccharides from human milk (HMO) promote growth of Bifidobacterium bifidum. Oligosaccharides from cow milk (BMO), similar to HMO, are mainly represented in colostrum by 3’-sialyllactose (3’SL). Bifidobacterium crudilactis, a species from bovine origin and encoding for β galactosidases and α-glucosidases, could be able to metabolise them. Also, fermentation products could have antivirulent activity against intestinal pathogens. This study focused on capacity of bifidobacteria to metabolise 3’SL and on potential antivirulent effect of cell-free spent media (CFSM) against pathogenic bacteria. B. bifidum BBA1 and B. crudilactis FR/62/B/3 isolated respectively from breastfed children feces and cow raw milk cheese were grown on media supplemented with 3’SL as sole source of carbon. Next, CFSM effects were tested against virulence gene expression using ler and hilA promoter activity of luminescent constructs of Escherichia coli 0157:H7 ATCC 43888 and Salmonella Typhimurium SA 941256, respectively. The effect was confirmed on wild type strains of E. coli O157:H7 ATCC 43890 and S. Typhimurium ATCC 14028 using RT-qPCR. Both strains were able to grow in presence of 3’SL. CFSM resulted in under-expression of hilA and ler genes for the luminescent constructs and in under-expression of ler (ratios of -15.4 and -8.1) and qseA (ratios of -2.1 and -3.1) genes for the wild type strain of E. coli O157:H7. No effect was observed with S. Typhimurium. Little is known about CFSM metabolites and they have to be isolated and identified. The potential synbiotic effect between 3’SL and bifidobacteria will be tested using the Shime®, a human gastrointestinal model. [less ▲]

Detailed reference viewed: 10 (0 ULg)
Full Text
Peer Reviewed
See detailIn vitro screening of mare's milk antimicrobial effect and antiproliverative activity.
Guri, Anilda; Paligot, Michèle; Crevecoeur, Sébastien ULg et al

in FEMS Microbiology Letters (2016), 363(2), 1-7

The aims of this study were to examine the effect of mare's milk on virulence gene expression of Salmonella Typhimurium and observe its potential activity on proliferation of adenocarcinoma Caco-2 cells ... [more ▼]

The aims of this study were to examine the effect of mare's milk on virulence gene expression of Salmonella Typhimurium and observe its potential activity on proliferation of adenocarcinoma Caco-2 cells. Different supernatants of mare's milk, raw or heat-treated at 65°C for 15 s or 30 min, were studied. The changes in hilA gene expression of Salmonella Typhimurium in presence of mare's milk supernatants were assessed using a reporter luminescent strain. A significant decrease in hilA gene expression was observed with all tested supernatants. Virulence gene expression was then assessed using qPCR on a wild-type strain of Salmonella Typhimurium. A significant decrease of hilA and ssrB2 gene expression was observed with raw milk supernatants but not with heat-treated supernatants. The same supernatants were administered to Caco-2 cells to measure their proliferation rate. A significant reduction of proliferative effect was observed only with raw milk supernatants. This study reports that raw mare's milk was able to modulate virulence gene expression of Salmonella Typhimurium and exerts antiproliferative effects on Caco-2 cells. These results may offer new approaches for promoting gastrointestinal health. [less ▲]

Detailed reference viewed: 24 (11 ULg)
Full Text
Peer Reviewed
See detailExploring the bacterial diversity of Belgian steak tartare using metagenetics and qPCR analysis
Delhalle, Laurent ULg; Korsak Koulagenko, Nicolas ULg; Taminiau, Bernard ULg et al

in Journal of Food Protection (2016), 79(2), 220-229

Steak tartare is a popular meat dish in Belgium. It is prepared with raw ground minced beef and eaten with sauce, vegetables, and spiced. Since it contains raw meat, steak tartare is highly prone to ... [more ▼]

Steak tartare is a popular meat dish in Belgium. It is prepared with raw ground minced beef and eaten with sauce, vegetables, and spiced. Since it contains raw meat, steak tartare is highly prone to bacterial spoilage. The objective of this study was to explore the bacterial flora diversity in steak tartare in Belgium according to the source and to determine which bacteria are able to grow during the shelf life. A total of 58 samples from butchers’ shops, restaurants, sandwich shops and supermarkets were collected. These samples were analyzed using 16S rDNA metagenetics, a classical microbiological technique, and quantitative real-time PCR (qPCR) targeting the Lactobacillus genus. Samples were analyzed at the beginning and at the end of their shelf life, except for those from restaurants and sandwich shops analyzed only at the purchase date. Metagenetic analysis identified up to 180 bacterial species and 90 genera in some samples. But only seven bacterial species were predominant in the samples, depending on the source: Brochothrix thermosphacta, Lactobacillus algidus, Lactococcus piscium, Leuconostoc gelidum, Photobacterium kishitani, Pseudomonas spp. and Xanthomonas oryzae. With this work, an alternative method is proposed to evaluate the total flora in food samples based on the number of reads from metagenetic analysis and the results of qPCR. The degree of underestimation of aerobic plate counts (APCs) at 30°C estimated with the classical microbiology method was demonstrated in comparison with the proposed culture independent method. Compared to culture-based methods, metagenetic analysis combined with qPCR targeting Lactobacillus provides valuable information for characterizing the bacterial flora of raw meat. [less ▲]

Detailed reference viewed: 230 (41 ULg)
Full Text
Peer Reviewed
See detailGrowth and Freeze-Drying Optimization of Bifidobacterium crudilactis
Tanimomo, Jean; Delcenserie, Véronique ULg; Taminiau, Bernard ULg et al

in Food and Nutrition Sciences (2016), 7

Bifidobacterium crudilactis FR62/b/3 belongs to a new population of bifidobacteria isolated from raw milk and raw milk cheese. The objective of this work was to study the large scale culture of the stain ... [more ▼]

Bifidobacterium crudilactis FR62/b/3 belongs to a new population of bifidobacteria isolated from raw milk and raw milk cheese. The objective of this work was to study the large scale culture of the stain and its stability in a dry formulation. Growth rate of Bifidobacterium crudilactis FR62/b/3 was optimal at a pH of 5.0 and a temperature of 37˚C. At a temperature growth of 33˚C and a pH of 5.0, the stationary phase was reached after 22 h, the viable cell number and the mean dry biomass concentration were respectively of 8.3 × 109 CFU/mL and of 2.1 g/L. Resistance of Bifidobacterium crudilactis FR62/b/3 to freeze-drying and effect of a variety of cryoprotectants to maintain the viability were also evaluated. Sorbitol was the most suitable cryoprotectant for freeze-drying as well as storage whereas sucrose and monosodium glutamate were only efficient during storage. [less ▲]

Detailed reference viewed: 23 (6 ULg)
Full Text
See detailOptmization of culture media for Bifidobacterium bifidum and Bifidobacterium crudilactis and study of the antimicrobial effect of culture supernatants
Bondue, Pauline ULg; Delcenserie, Véronique ULg; Crevecoeur, Sébastien ULg et al

Poster (2015, October)

Complex oligosaccharides from human milk (HMO) contribute to infant health. Bifidobacteriumbifidum mainly found in breast-fed infant microbiota has all the enzymatic machinery for degradation of HMO. On ... [more ▼]

Complex oligosaccharides from human milk (HMO) contribute to infant health. Bifidobacteriumbifidum mainly found in breast-fed infant microbiota has all the enzymatic machinery for degradation of HMO. On the other hand, whey is rich in complex bovin milk oligosaccharides (BMO) very similar to HMO, including 3’-sialyllactose (3’SL). They are very likely to be metabolised by B. bifidum too, but also by B. crudilactis, a bovine origin strain. Fermentation of HMO or BMO by bifidobacteria can result in production of metabolites modulating virulence expression of several pathogenic bacteria. Two strains of bifidobacteria were used in this study: B. bifidum, isolated from breastfed infant feces and B. crudilactis, isolated from bovine raw milk. The ability of those strains to metabolise culture media enriched in glucose, whey and 3’SL has been assessed. Then, the obtained culture supernatant has been tested against virulence genes expression of E. coli O157:H7.  Both strains were able to grow in presence of BMO and 3’SL. B. crudilactis presented the best growth on all media. All culture supernatants obtained after supplementation with 3’SL resulted in significant under-expression of genes ler and qseA. The trend of genes stxB2 and luxS was also toward a down-regulation. BMO combined to some bovine or human origin bifidobacteria strains could be interesting synbiotics to maintain or restore the intestinal health of young children. These effects observed in vitro require further investigations to ensure repeatability in humans and to identify the exact nature of molecules obtained from fermentation media by B. bifidum and B. crudilactis. [less ▲]

Detailed reference viewed: 45 (2 ULg)
Full Text
Peer Reviewed
See detailUse of 16S rDNA Metagenetics and classical Microbiology to Assess the bacterial superficial Contamination Patterns in Bovines Classically Slaughtered or following the Halal Ritual
Korsak Koulagenko, Nicolas ULg; Taminiau, Bernard ULg; Hupperts, Caroline et al

Poster (2015, June 17)

In Belgium and in several European countries, two cattle slaughtering protocols exist: the classical method, that encompasses a stunning step before the sticking procedure, and the halal method, combining ... [more ▼]

In Belgium and in several European countries, two cattle slaughtering protocols exist: the classical method, that encompasses a stunning step before the sticking procedure, and the halal method, combining the stunning and the sticking in one single step. The main difference lies in the fact that, in the halal protocol, a single cut with a sharp knife is practiced directly on live cattle, instead of two cutting steps with two different knives for the sticking in the classical slaughtering technique. The unique section in the halal technique results generally in the cross section of trachea and esophagus of cattle. The aim of this study was to seek if the two slaughtering techniques were similar regarding the superficial contamination of carcasses, swabbed between 2 and 4 hours after the killing step. For this purpose, classical microbiological tests (TVC and Enterobacteriaceae) and 16S rDNA metagenetic analysis were carried out from 20 cattle carcasses (swabbing of “legal” zone – 1.600 cm2 – and in the neck area – 200 cm2). The classical microbiological results revealed no significant differences between the two slaughtering practices. Statistical analysis of pyrosequencing data showed that differences in bacterial population abundance between slaughtering methods were mainly found in the “legal” swabbing zone compared to the neck area. Bacterial genera belonging to Actinobacteria (Brevibacterium, Corynebacterium) were more aundant in “Halal” samples whereas populations from the Proteobacteria (Caulobacteraceae, Comamonadaceae, Bradyrhizobiaceae) and Firmicutes (Lactobacillus) were more abundand in the “classical” group. The analysis of OTU abundance of bacteria from the digestive or respiratory tract revealed no differences beteween groups. In conclusion, the slaughtering method does not influence the superficial microbiological pattern in terms of specific microbiological markers of the digestive or respiratory tract. However, precise analysis to the genus level underlines differences between methods, the legal swabbing zone being still the best sampling zone compared to the neckline. The next step will be the identification of precise contamination origin of the differences found between slaughtering methods. [less ▲]

Detailed reference viewed: 187 (11 ULg)
Full Text
See detailOptimisation de milieux de culture pour Bifidobacterium bifidum et Bifidobacterium crudilactis et étude de l’effet antimicrobien des surnageants de culture
Bondue, Pauline ULg; Delcenserie, Véronique ULg; Crevecoeur, Sébastien ULg et al

Poster (2015, June)

Modulé entre autre par notre alimentation, le microbiote intestinal influence notre santé. Un enfant allaité sera en meilleure santé qu’un enfant nourri avec des formulations commerciales. Ceci est ... [more ▼]

Modulé entre autre par notre alimentation, le microbiote intestinal influence notre santé. Un enfant allaité sera en meilleure santé qu’un enfant nourri avec des formulations commerciales. Ceci est notamment dû à la présence d’oligosaccharides complexes dans le lait maternel (HMO). Les oligosaccharides ajoutés au lait maternisé sont d’origine végétale et leur structure est très éloignée de celle des HMO. Parce que les HMO ressemblent aux glycans de la paroi épithéliale, les pathogènes intestinaux infantiles s’y fixent et sont expulsés naturellement. Le lait de vache possède des oligosaccharides complexes (BMO), dont la structure est très similaire à celle des HMO. Les bifidobactéries rencontrées majoritairement dans les matières fécales d’un nourrisson devraient pouvoir métaboliser les BMO, tout comme celles isolées dans le lait de vache. Les objectifs de cette étude étaient d’étudier le potentiel de croissance de bifidobactéries d’origine bovine ou humaine sur des milieux de culture enrichis en lactosérum et BMO. Le deuxième objectif était de vérifier si le catabolisme de ces sucres complexes induisaient une synthèse de métabolites influençant l’expression de virulence de certains pathogènes tels qu’Escherichia coli O157 :H7. Une souche de Bifidobacterium bifidum, isolée à partir des matières fécales d’un nourrisson exclusivement allaité et une souche de Bifidobacterium crudilactis, isolée à partir de fromage au lait cru, ont été mises en culture dans des milieux contenant différentes sources d’hydrates de carbone (glucose, lactosérum naturellement riche en lactose et BMO, et 3’-syalillactose (3’SL)). Le 3’SL est un oligosaccharide complexe majoritaire parmi les BMO. Les surnageants des différents milieux de culture ont été prélevés et concentrés par lyophilisation puis mis en contact avec E. coli O157 :H7. L’expression relative de différents gènes de virulence d’E. coli O157:H7, fliC, ler, stx2b et luxS a été étudiée. Dans le futur, les BMO et certaines souches d’origine bovine ou humaine pourraient s’avérer être des compléments alimentaires intéressants pour maintenir ou rétablir la santé intestinale des jeunes enfants. [less ▲]

Detailed reference viewed: 73 (6 ULg)
Full Text
Peer Reviewed
See detailL’exploration du microbiote intestinal par les outils de la métagénomique au service de la santé animale et humaine
Taminiau, Bernard ULg; Rodriguez Diaz, Cristina ULg; Delhalle, Laurent et al

in Food Science and Law (2015), (4), 165-169

L’essor des nouvelles technologies de séquençage de l’ADN a, depuis une décennie, bouleversé les méthodologies et ouvert de nouvelles perspectives de recherche dans de nombreux domaines. La métagénétique ... [more ▼]

L’essor des nouvelles technologies de séquençage de l’ADN a, depuis une décennie, bouleversé les méthodologies et ouvert de nouvelles perspectives de recherche dans de nombreux domaines. La métagénétique et la métagénomique, appliquées à la microbiologie, a permis de changer la vision du monde scientifique face à l’omniprésence des populations microbiennes dans notre quotidien. Basées sur l’exploration de la biodiversité taxonomique et fonctionnelle des bactéries, de nombreuses recherches ayant pour but le contrôle et le management des écosystèmes microbiens ont vu le jour, dans le domaine de la santé, dans l’industrie mais également dans la gestion de notre environnement. Cette revue détaille et illustre brièvement les techniques métagénomiques actuelles. [less ▲]

Detailed reference viewed: 55 (8 ULg)
Full Text
Peer Reviewed
See detailGenome of Bifidobacteria and Carbohydrate Metabolism
Bondue, Pauline ULg; Delcenserie, Véronique ULg

in Korean Journal for Food Science of Animal Resources (2015)

Detailed reference viewed: 13 (3 ULg)
Full Text
See detailAntimicrobial Effects of Bifidobacteria from Human and Animal Origin
Delcenserie, Véronique ULg

Scientific conference (2015)

Detailed reference viewed: 13 (1 ULg)
Peer Reviewed
See detailShort communication: Evaluation of the microbiota of kefir samples using metagenetic analysis targeting the 16S and 26S ribosomal DNA fragments
Korsak Koulagenko, Nicolas ULg; Taminiau, Bernard ULg; Leclercq, Mathilde et al

in Journal of Dairy Science (2015), 98

Milk kefir is produced by fermenting milk in the presence of kefir grains. This beverage has several benefits for human health. The aim of this experiment was to analyze 5 kefir grains (and their products ... [more ▼]

Milk kefir is produced by fermenting milk in the presence of kefir grains. This beverage has several benefits for human health. The aim of this experiment was to analyze 5 kefir grains (and their products) using a targeted metagenetic approach. Of the 5 kefir grains analyzed, 1 was purchased in a supermarket, 2 were provided by the Ministry of Agriculture (Namur, Belgium), and 2 were provided by individuals. The metagenetic approach targeted the V1-V3 fragment of the 16S ribosomal (r)DNA for the grains and the resulting beverages at 2 levels of grain incorporation (5 and 10%) to identify the bacterial species population. In contrast, the 26S rDNA pyrosequencing was performed only on kefir grains with the aim of assessing the yeast populations. In parallel, pH measurements were performed on the kefir obtained from the kefir grains using 2 incorporation rates. Regarding the bacterial population, 16S pyrosequencing revealed the presence of 20 main bacterial species, with a dominance of the following: Lactobacillus kefiranofaciens, Lactococcus lactis ssp. cremoris, Gluconobacter frateurii, Lactobacillus kefiri, Acetobacter orientalis, and Acetobacter lovaniensis. An important difference was noticed between the kefir samples: kefir grain purchased from a supermarket (sample E) harbored a much higher proportion of several operational taxonomic units of Lactococcus lactis and Leuconostoc mesenteroides. This sample of grain was macroscopically different from the others in terms of size, apparent cohesion of the grains, structure, and texture, probably associated with a lower level of Lactobacillus kefiranofaciens. The kefir (at an incorporation rate of 5%) produced from this sample of grain was characterized by a lower pH value (4.5) than the others. The other 4 samples of kefir (5%) had pH values above 5. Comparing the kefir grain and the kefir, an increase in the population of Gluconobacter in grain sample B was observed. This was also the case for Acetobacter orientalis in sample D. In relation to 26S pyrosequencing, our study revealed the presence of 3 main yeast species: Naumovozymaspp., Kluyveromyces marxianus, and Kazachastania khefir. For Naumovozyma, further studies are needed to assess the isolation of new species. In conclusion, this study has proved that it is possible to establish the patterns of bacterial and yeast composition of kefir and kefir grain. This was only achieved with the use of high-throughput sequencing techniques. [less ▲]

Detailed reference viewed: 211 (19 ULg)
Full Text
Peer Reviewed
See detailThe impact of oregano (Origanum heracleoticum) essential oil and carvacrol on virulence gene transcription by Escherichia coli O157:H7
Mith, Hasika; Clinquart, Antoine ULg; Zhiri, Abdesselam et al

in FEMS Microbiology Letters (2015), 362

The aim of the current study was to determine, via reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis, the effect of oregano essential oil (Origanum heracleoticum) and ... [more ▼]

The aim of the current study was to determine, via reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis, the effect of oregano essential oil (Origanum heracleoticum) and carvacrol, its major component, on the expression of virulence-associated genes in enterohaemorrhagic Escherichia coli (EHEC) O157:H7 ATCC strain 35150. Both oregano oil and carvacrol demonstrated their efficacy firstly, by inhibiting the transcription of the ler gene involved in up regulation of the LEE2, LEE3 and LEE4 promoters and of attaching and effacing lesions and secondly by decreasing both Shiga toxin and fliC genes expression. In addition, a decrease in luxS gene transcription involved in quorum sensing was observed. These results were dose dependent and showed a specific effect of O. heracleoticum and carvacrol in downregulating the expression of virulence genes in EHEC O157:H7. These findings suggest that oregano oil and carvacrol have the potential to mitigate the adverse health effects caused by virulence gene expression in EHEC O157: [less ▲]

Detailed reference viewed: 61 (24 ULg)