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See detailNon Digestible Oligosaccharides Modulate the Gut Microbiota to Control the Development of Leukemia and Associated Cachexia in Mice.
Bindels, Laure B.; Neyrinck, Audrey M.; Salazar, Nuria et al

in PloS one (2015), 10(6), 0131009

We tested the hypothesis that changing the gut microbiota using pectic oligosaccharides (POS) or inulin (INU) differently modulates the progression of leukemia and related metabolic disorders. Mice were ... [more ▼]

We tested the hypothesis that changing the gut microbiota using pectic oligosaccharides (POS) or inulin (INU) differently modulates the progression of leukemia and related metabolic disorders. Mice were transplanted with Bcr-Abl-transfected proB lymphocytes mimicking leukemia and received either POS or INU in their diet (5%) for 2 weeks. Combination of pyrosequencing, PCR-DGGE and qPCR analyses of the 16S rRNA gene revealed that POS decreased microbial diversity and richness of caecal microbiota whereas it increased Bifidobacterium spp., Roseburia spp. and Bacteroides spp. (affecting specifically B. dorei) to a higher extent than INU. INU supplementation increased the portal SCFA propionate and butyrate, and decreased cancer cell invasion in the liver. POS treatment did not affect hepatic cancer cell invasion, but was more efficient than INU to decrease the metabolic alterations. Indeed, POS better than INU delayed anorexia linked to cancer progression. In addition, POS treatment increased acetate in the caecal content, changed the fatty acid profile inside adipose tissue and counteracted the induction of markers controlling beta-oxidation, thereby hampering fat mass loss. Non digestible carbohydrates with prebiotic properties may constitute a new nutritional strategy to modulate gut microbiota with positive consequences on cancer progression and associated cachexia. [less ▲]

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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 ▲]

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See detailMicrobiological safety and quality aspects of the short supply chain: SWOT analysis of the Belgian case study
Verraes, Claire; Uyttendaele, Mieke; Clinquart, Antoine ULg et al

in British Food Journal (2015), 117(9), 2250-2264

Purpose – In recent years consumers in Belgium have shown a great interest for foods from the short supply chain. The difference with the conventional chain is that in the short supply chain the primary ... [more ▼]

Purpose – In recent years consumers in Belgium have shown a great interest for foods from the short supply chain. The difference with the conventional chain is that in the short supply chain the primary products are locally processed and sold directly by the producer to the consumer. The short supply chain has different microbiological quality and safety aspects in comparison with the conventional chain. The purpose of this paper is to evaluate these aspects. Design/methodology/approach – The methodology consists of analyzing the available scientific literature and results of microbiological analyses on foods from the short supply chain. Findings – The main findings were that Listeria monocytogenes was frequently detected (15 percent) in sampled raw dairy products whereas Salmonella was not isolated in 1,023 samples. Human pathogenic vero (cyto) toxin-producing Escherichia coli and Campylobacter spp. are potential hazards, in particular for products that are not thermally treated. Data with regard to E. coli counts showed a greater variability in products from the short supply chain compared to the conventional chain. Research limitations/implications – The paper discusses strengths and weaknesses with impact on microbial quality and safety in operation of food safety management in the short supply chain vs the conventional chain. Originality/value – This is the first paper that assesses the risks from the short supply chain vs the conventional chain and that makes recommendations for operators in the short supply chain [less ▲]

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See detailThe effects of xylo-oligosaccharides on performance and microbiota in broiler chickens.
De Maesschalck, C.; Eeckhaut, V.; Maertens, L. et al

in Applied and environmental microbiology (2015)

In broiler chickens, feed additives, including prebiotics, are widely used to improve gut health and to stimulate performance. Xylo-oligosaccharides (XOS) are hydrolytic degradation products of ... [more ▼]

In broiler chickens, feed additives, including prebiotics, are widely used to improve gut health and to stimulate performance. Xylo-oligosaccharides (XOS) are hydrolytic degradation products of arabinoxylans that can be fermented by the gut microbiota. In the current study it was aimed to analyze the prebiotic properties of XOS when added to the broiler diet. Administration of XOS to chickens, on top of a wheat/rye-based diet, significantly improved the feed conversion ratio. XOS significantly increased villus length in the ileum. It also significantly increased numbers of lactobacilli in the colon and Clostridium cluster XIVa in the caeca. Moreover, the number of gene copies encoding the key bacterial enzyme for butyrate production, butyryl-CoA:acetate CoA-transferase, was significantly increased in the caeca of chickens administered XOS. In this group of chickens, at species level, Lactobacillus crispatus and Anaerostipes butyraticus were significantly increased in abundance in the colon and caecum, respectively. In vitro fermentation of XOS revealed cross-feeding between L. crispatus and A. butyraticus. Lactate, produced by L. crispatus during XOS fermentation, was utilized by the butyrate-producing Anaerostipes species. These data show the beneficial effects of XOS on broiler performance when added to the feed, which potentially can be explained by stimulation of butyrate-producing bacteria through cross-feeding of lactate and subsequent effects of butyrate on gastrointestinal function. [less ▲]

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See detailThermophilic and cellulolytic consortium isolated from composting plants improves anaerobic digestion of cellulosic biomass: toward a microbial resource management approach
Kinet, Romain ULg; Destain, Jacqueline ULg; Hiligsmann, Serge ULg et al

in Bioresource Technology (2015)

A cellulolytic consortium was isolated from a composting plant in order to boost the initial hydrolysis step encountered in anaerobic digestion. Improvement of the cellulose degradation, as well as biogas ... [more ▼]

A cellulolytic consortium was isolated from a composting plant in order to boost the initial hydrolysis step encountered in anaerobic digestion. Improvement of the cellulose degradation, as well as biogas production, was observed for the cultures inoculated with the exogenous consortium. Metagenomics analyses pointed out a weak richness (related to the number of OTUs) of the exogenous consortium induced by the selective pressure (cellulose as sole carbon source) met during the initial isolation steps. Main microbial strains determined were strictly anaerobic and belong to the Clostridia class. During cellulose anaerobic degradation, pH drop induced a strong modification of the microbial population. Despite the fact that richness and evenness were very weak, the exogenous consortium was able to adapt and to maintain the cellulolytic degradation potential. This important result point out the fact that simplified microbial communities could be used in order to increase the robustness of mixed cultures involved in environmental biotechnology. [less ▲]

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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 ▲]

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See detailDetecting microbial patterns in relation to soil agricultural practices and the plant development stage
Degrune, Florine ULg; Dufrêne, Marc ULg; Taminiau, Bernard ULg et al

Poster (2014, December 02)

Agricultural practices have a strong impact on soil bacteria and fungi. Furthermore, microbial community composition can change with the stage of plant development. We are interested in exploring these ... [more ▼]

Agricultural practices have a strong impact on soil bacteria and fungi. Furthermore, microbial community composition can change with the stage of plant development. We are interested in exploring these effects in relation to changes induced by agriculture and plant stage in soil conditions. Some bacteria are influenced only by the plant stage, which induces changes in soil humidity, pH, nitrates, and carbon. We would thus expect these bacteria to be highly sensitive to these parameters. Other bacteria are affected only by the tillage practice applied. Further study is needed to identify the soil parameters responsible for this effect. The plant stage also has a great impact on fungal community composition. [less ▲]

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See detailP180: Intérêt de la modulation du microbiote intestinal par les oligosaccharides non digestibles dans le contrôle de la leucémie et de la cachexie cancéreuse
Bindels, L.B.; Neyrinck, A.M.; Salazar, N. et al

in Nutrition Clinique et Metabolisme (2014, December), 28(S1), 162

Il est à présent clairement établi que l’ensemble des bactéries présentes dans l’intestin (le microbiote intestinal) est capable d’influencer l’homéostasie énergétique et immunitaire de son hôte. Nous ... [more ▼]

Il est à présent clairement établi que l’ensemble des bactéries présentes dans l’intestin (le microbiote intestinal) est capable d’influencer l’homéostasie énergétique et immunitaire de son hôte. Nous avons testé l’hypothèse selon laquelle une modulation du microbiote intestinal par des oligosaccharides issus de la pectine (POS) ou de l’inuline (INU) permet d’interférer avec la progression de la leucémie et des désordres métaboliques associés. [less ▲]

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See detailDiversity of Clostridium difficile isolates from humans and animals
Rodriguez Diaz, Cristina ULg; Taminiau, Bernard ULg; Korsak Koulagenko, Nicolas ULg et al

Scientific conference (2014, October 17)

Clostridium difficile is an important cause of infectious diarrhea in hospitals. The major risk factors for the development of nosocomial C. difficile associated disease include antibiotic therapy and ... [more ▼]

Clostridium difficile is an important cause of infectious diarrhea in hospitals. The major risk factors for the development of nosocomial C. difficile associated disease include antibiotic therapy and increasing age. In animals, as pigs, calves and horses, C. difficile also seems to be an important cause of enteric disease. The main objective of this study was to characterize and compare animal and human C. difficile strains with respect to the PCR-ribotype and the antibiotic resistance. Multilocus sequence typing (MLST) and multiple-Locus Variable number tandem repeat analysis (MLVA) were performed in order to study clonal relationships of the isolates. Human C. difficile isolates were obtained from care home residents and hospitalized patients. Animal isolates were collected from stool samples and carcasses of pigs and cattle at slaughter. An identification of the strains was performed by PCR-ribotyping. Further characterization was performed by antibiotic resistance, MLST and MLVA analysis. A neighbourd-joining phylogenetic three was constructed in order to determine the correlation between human and food isolates. A great variety of PCR ribotypes was found among the animal isolates, including PCR ribotypes 078 and 014. The most prevalent PCR-ribotypes in the nursing home were PCR-ribotypes 027 and 020. A high resistance to moxifloxacin, erythromycin, gentamicin and clindamycin was detected for some of the strains. Phylogenetic analysis showed that human and animal isolates with the same PCR-ribotype cluster in the same lineage, suggesting a potential risk of interspecies transmission. [less ▲]

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See detailEvaluation of morphological and functional characteristics of Carnobacterium maltaromaticum isolated from vacuum-packaged beef with long shelf life
Didimo Imazaki, Pedro Henrique ULg; Tahiri, Assia ULg; Ndedi Ekolo, François ULg et al

Poster (2014, October 17)

Carnobacterium maltaromaticum is a lactic acid bacterium, and many lactic acid bacteria associated with meat are known for their bactericidal or bacteriostatic activity against other strains, species or ... [more ▼]

Carnobacterium maltaromaticum is a lactic acid bacterium, and many lactic acid bacteria associated with meat are known for their bactericidal or bacteriostatic activity against other strains, species or genera of bacteria. The presence of certain lactic acid bacteria adapted to a low temperature in fresh meat could extend the shelf life and improve the microbial stability and safety of this product. The aim of this study was to perform a morphological and functional characterization of a C. maltaromaticum strain with a potential bioprotective effect isolated from vacuum packaged beef with very long shelf life. The morphological, biochemical and enzymatic profiles, the influence of different temperatures and atmospheres, and the microbial stability of fresh beef inoculated with the C. maltaromaticum strain were evaluated. The isolated C. maltaromaticum strain presented similar morphological, biochemical and enzymatic profiles as those of two reference strains (LMG 11393 and LMG 22902). Among the studied conditions, a temperature of +12 °C and an atmosphere poor in oxygen were optimal for the growth of C. maltaromaticum. Vacuum packing is therefore suitable for this bacterium. An antimicrobial effect against Enterobacteriaceae was highlighted on inoculated fresh meat stored under N2. The functional characterization of this isolate will be further pursued by a genotypic characterization. Special attention will be taken to study its bioprotective properties. [less ▲]

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See detailRelatedness of human, animal and food Clostridium difficile strains
Rodriguez Diaz, Cristina ULg; Taminiau, Bernard ULg; Avesani, Véronique et al

Poster (2014, September 18)

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See detailModelling the development of potential spoilage and biopreservative microorganisms on precooked pasta in different conditions of temperature based on classical microbiology and 16S rDNA metagenomic
Gand, Mathieu ULg; Cargnel, Mickaël ULg; Kergourlay, Gilles ULg et al

Poster (2014, September)

An important way to prevent the spoilage of food is the respect of the cold chain during the storage. While the temperature instructions are generally respected during process and distribution of food ... [more ▼]

An important way to prevent the spoilage of food is the respect of the cold chain during the storage. While the temperature instructions are generally respected during process and distribution of food products, it is not always the case with the consumers. Indeed, a few persons reach the right temperature level required for a safe storage of foodstuffs in their refrigerator. Besides, the food can sometimes spend a few hours in ambient temperature between the buying in the supermarket and the storage in cold temperature. In this study, we propose to model the growth of microorganisms on precooked pasta, stored in different conditions of temperature that reflect the situations described above (constant 4°C, constant 8°C, constant 12°C, 1/3 4°C – 2/3 8°C, 1/3 4°C – breach during 4h at 20°C – 2/3 8°C and 1/3 8°C – breach during 4h at 20°C – 2/3 8°C. The product was surface inoculated with potential spoilage and biopreservative strains (Lactococcus piscium, Leuconostoc mesenteroides and Leuconostoc citreum). Analyses by classical microbiology and V1-V3 16S rDNA metagenomics were done each day until the out of date of the food matrix. The transition from 4 to 8°C and the breach at 20°C during 4h have clearly boosted the growth of the microorganisms. The metagenomic analysis was a powerful tool to follow separately each population in each condition of storage. The results of this communication show the importance of keeping the foodstuffs in 4°C or lower in the refrigerator with the goal to avoid the spoilage or the development of pathogens and the potential of metagenomics for selection of biopreservative strains. [less ▲]

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See detailMultilocus sequence typing analysis and antibiotic resistance of Clostridium difficile strains isolated from retail meat and humans in Belgium
Rodriguez Diaz, Cristina ULg; Taminiau, Bernard ULg; Avesani, Véronique et al

in Food Microbiology (2014), 42

Clostridium difficile has been isolated from food animals and meat, specially ground pork and ground beef. The recovered isolates were closely related to C. difficile human strains, indicating that ... [more ▼]

Clostridium difficile has been isolated from food animals and meat, specially ground pork and ground beef. The recovered isolates were closely related to C. difficile human strains, indicating that animals and food are possible transmission routes of human C. difficile infection. The main objective of this study was to characterize C. difficile isolates from retail meat and to compare with human isolates recovered from hospital patients in Belgium. Raw meat (beef and pork) was obtained from the retail trade. C. difficile was recovered from 2.3% of the beef samples and from 4.7% of the pork samples. A total of 4 different PCR-ribotypes were identified with a large percentage of types 078 and 014. Resistance to moxifloxacin and erythromycin was detected. The multi-locus sequence typing (MLST) analysis showed that meat and human isolates cluster in the same lineage. This study reveals the presence of toxigenic C. difficile in retail meat in Belgium with predominance PCR-ribotypes 078 and 014, which are among the four most prevalent ribotypes of C. difficile isolated from humans in Europe. [less ▲]

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See detailModelling the development of potential spoilage and biopreservative microorganisms on white pudding in different conditions of temperature based on classical microbiology and 16S rDNA metagenomic
Gand, Mathieu ULg; Cauchie, Emilie ULg; Kergourlay, Gilles ULg et al

Poster (2014, September)

An important way to prevent the spoilage of food is the respect of the cold chain during the storage. While the temperature instructions are generally respected during process and distribution of food ... [more ▼]

An important way to prevent the spoilage of food is the respect of the cold chain during the storage. While the temperature instructions are generally respected during process and distribution of food products, it is not always the case with the consumers. Indeed, a few persons reach the right temperature level required for a safe storage of foodstuffs in their refrigerator. Besides, the food can sometimes spend a few hours in ambient temperature between the buying in the supermarket and the storage in cold temperature. In this study, we propose to model the growth of microorganisms on white pudding, stored in different conditions of temperature that reflect the situations described above (constant 4°C, constant 8°C, constant 12°C, 1/3 4°C – 2/3 8°C, 1/3 4°C – breach during 4h at 20°C – 2/3 4°C and 1/3 4°C – breach during 4h at 20°C – 2/3 8°C. The product was surface inoculated with potential spoilage and biopreservative strains (Raoultella terrigena, Serratia quinivorans, Carnobacterium maltaromaticum, Lactobacillus oligofermentans, Lactobacillus nenjiangensis, Lactobacillus fuchuensis, Leuconostoc mesenteroides, lactococcus lactis and Lactobacillus graminis). Analyses by classical microbiology and V1-V3 16S rDNA metagenomics were done each day until the out of date of the food matrix. The transition from 4 to 8°C and the breach at 20°C during 4h have clearly boosted the growth of the microorganisms. The metagenomic analysis was a powerful tool to follow separately each population in each condition of storage. The results of this communication show the importance of keeping the foodstuffs in 4°C or lower in the refrigerator with the goal to avoid the spoilage or the development of pathogens and the potential of metagenomics for selection of biopreservative strains. [less ▲]

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See detailCarnobacterium maltaromaticum isolated from vacuum-packed beef with long shelf life: morphological and functional characterization
Didimo Imazaki, Pedro Henrique ULg; Tahiri, Assia ULg; Ndedi Ekolo, François et al

Poster (2014, September)

This study was conducted as part of a research project on meat conservability, in particular vacuum packaged beef displaying very long shelf lives at a temperature close to the freezing point, and its ... [more ▼]

This study was conducted as part of a research project on meat conservability, in particular vacuum packaged beef displaying very long shelf lives at a temperature close to the freezing point, and its objective was to perform a morphological and functional characterization of C. maltaromaticum with potential bioprotective effect isolated from vacuum packaged long shelf life beef. The isolated C. maltaromaticum strain presented similar morphological, biochemical and enzymatic profiles as those of two reference strains (LMG 11393 and LMG 22902). Among the studied conditions, a temperature of +12 °C and an atmosphere poor in oxygen (100 % N2) were the optimal conditions for the growth of C. maltaromaticum. Nevertheless, growth on lower temperatures is also possible. After inoculation of beef samples with C. maltaromaticum and 7 days of storage under vacuum at −1 °C, no effect was observed on the total viable count and on the count of lactic acid bacteria. A reduction of Pseudomonas sp. and Brochothrix thermosphacta was observed during the first week of storage under vacuum conditions. After 7 days of subsequent storage of the same samples under modified atmosphere at +4 °C, the inoculant favored the growth of B. thermosphacta and inhibited the growth of Enterobacteriaceae under 100 % N2. No effect of the inoculant was observed when an atmosphere rich in oxygen was applied. The evaluation of the influence of different atmospheres showed that the growth of C. maltaromaticum was slower in an atmosphere containing O2 and CO2. Long-term storage under vacuum at low temperatures are therefore suitable for the growth of this bacterium. An antimicrobial effect against Enterobacteriaceae was highlighted on inoculated fresh meat stored under N2. The functional characterization of this strain will be further pursued by genotypic characterization. Special attention will be taken to study its bioprotective properties. [less ▲]

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See detailAntimicrobial and molecular analysis of Salmonella serovar Livingstone strains isolated from humans in Tunisia and Belgium
Guedda, Intissar; Taminiau, Bernard ULg; Ferjani, Asma et al

in Journal of Infection in Developing Countries [=JIDC] (2014), 8

Introduction: Salmonella Livingstone is one of the most common serotypes responsible for nosocomial outbreaks in Tunisia. In this study, 42 isolates of Salmonella Livingstone were analyzed. Most of these ... [more ▼]

Introduction: Salmonella Livingstone is one of the most common serotypes responsible for nosocomial outbreaks in Tunisia. In this study, 42 isolates of Salmonella Livingstone were analyzed. Most of these were isolated from humans (31 strains from Tunisia and 9 strains from Belgium) and 2 isolates came from food products (beef and pork). Methodology: All strains were characterized by antibiogram, multilocus sequence typing (MLST), and virulotyping. This last technique was carried out by simple PCR of five chromosomal genes (agfA, hin/H2, iroB, phoP/Q, and slyA) and two plasmid genes (spvA and spvC). Results: All Tunisian strains were resistant to amoxicillin, amoxicillin-clavulanic acid, ticarcillin, cefalotin, gentamicin, and kanamycin. They were also resistant to third-generation cephalosporin antibiotics (cefotaxim and ceftazidim). Belgian isolates were susceptible to all antibiotics tested. Further to MLST analyses, Tunisian strains belonged to the same sequence type, ST543. For Belgian isolates, eight strains had a ST543 profile, two strains had a ST638 profile, and one strain had a ST457 profile. Analyses of the virulence gene contents showed that strains isolated in different years and from different origins had the same virulence profile. These carried all five chromosomal genes and lacked plasmid-located virulence genes spvA and spvC. Conclusions: A combination of different typing methods showed that the majority of Belgian strains and all Tunisian strains were closely related; they belonged to the same sequence type (ST543) and had the same virulence profile, but different antibiotic resistance profiles depended on the country of origin. [less ▲]

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See detailMorphological and functional characterization of Carnobacterium maltaromaticum isolated from vacuum-packed beef with long shelf life
Didimo Imazaki, Pedro Henrique ULg; Tahiri, Assia ULg; Ndedi Ekolo, François et al

Poster (2014, August)

The aim of this study was to perform a morphological and functional characterization of a Carnobacterium maltaromaticum strain with a potential bioprotective effect isolated from vacuum packaged long ... [more ▼]

The aim of this study was to perform a morphological and functional characterization of a Carnobacterium maltaromaticum strain with a potential bioprotective effect isolated from vacuum packaged long shelf life beef. The morphological, biochemical and enzymatic profiles, the influence of different temperatures and atmospheres, and the microbial stability of fresh beef inoculated with the C. maltaromaticum strain were evaluated. The isolated C. maltaromaticum strain presented similar morphological, biochemical and enzymatic profiles as those of two reference strains (LMG 11393 and LMG 22902). The growth of C. maltaromaticum was slower in an atmosphere containing O2 and CO2. Vacuum packing is therefore suitable for this bacterium. An antimicrobial effect against Enterobacteriaceae was highlighted on inoculated fresh meat stored under N2. The functional characterization of this isolate will be further pursued by a genotypic characterization to better understand its potential bioprotective effect. [less ▲]

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See detailProduction and microbiological evaluation of three types of "Dèguè", a local fermented drink made from milk in Benin
Tchekessi, Célestin; Bokossa, Auréole; Agbangla, Clément et al

in International Journal of Multidisciplinary and Current Research (2014), 2

This study consists to finalize some technologies for the production of a fermented drink called dèguè. This drink is widely consumed in Benin and other countries in sub-Saharan Africa. Following three ... [more ▼]

This study consists to finalize some technologies for the production of a fermented drink called dèguè. This drink is widely consumed in Benin and other countries in sub-Saharan Africa. Following three different technologies, we had produced three (03) types of dèguè respectively with maize flour, sorghum and millet. These types have been analyzed and their microbiological characteristics were evaluated. The microbiological analysis results obtained from the experiments have shown that lactic acid bacteria, yeasts and molds were the dominant microflora of dèguè and varied respectively 7.22log10UFC/g to 7.55log10UFC/g for lactic acid bacteria and 7.78log10UFC/g to 8.44log10UFC/g for yeasts and molds. Moreover, the statistical analysis of these results showed that there was no significant difference at 5% (p <0.05) between the three types of dèguè. The values of lactic acid bacteria obtained were consistent with the standard (≥ 107/g) attached to the yoghurt. No type contained neither total coliforms nor thermotolerant coliforms. The products (dèguès) were also free of pathogenic microorganisms such as Escherichia coli, Staphylococcus aureus and Salmonella. [less ▲]

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See detailHigh throughput sequencing analysis reveals genetic variability and selection pressure in different murine norovirus genomic regions during in vitro replication
Mauroy, Axel ULg; Taminiau, Bernard ULg; Nezer, Carine et al

Poster (2014, July)

Murine norovirus (MuNoV), a single stranded positive sense RNA virus belonging to the Caliciviridae family, is considered as a representative model for human norovirus infections, one of the most ... [more ▼]

Murine norovirus (MuNoV), a single stranded positive sense RNA virus belonging to the Caliciviridae family, is considered as a representative model for human norovirus infections, one of the most important etiological cause of both epidemic and sporadic gastroenteritis cases worldwide. Four open reading frames are described into its genome: ORF1 codes the non-structural (NS) proteins, including the viral RNA dependent RNA polymerase (RdRp); ORF2 codes the single capsid protein (VP1), wherein two domains are present: a relatively conserved domain (“shell”) and a more variable domain (“protruding”); ORF3 codes a minor structural protein; and ORF4, currently only found in viruses genetically related to MuNoV codes a virulence factor. In this study, we demonstrated by high throughput sequencing that, during serial passages of MuNoV in cell culture, the substitution rates, estimated by Bayesian inferences, did not significantly differ across the five targeted genomic regions except one. These rates were similar in four genomic regions encompassing partial non-structural 1-2 protein (NS1-2)-, NS5-, NS6-, NS7 (RdRp)- and VP1-coding sequences (coding the conserved part of the protein also including the ORF4 region). In the partial minor structural protein-coding region, this substitution rate was however estimated to be at least one log higher when expressed as substitution/site/day. The precise localisation of the detected nucleotide point mutations (substitution, deletion and insertion) were reported as well as the quantitative increase or decrease of the sequences harbouring them along ten cell culture passages. The non-silent amino acid mutations were also depicted in 3D models for four out of the five studied regions. These results have important implications for different norovirus research fields, especially in terms of diagnosis, classification methodology and genetic evolution. [less ▲]

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