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See detailDetection, isolation and characterization of Fusobacterium gastrosuis sp. nov. colonizing the stomach of pigs
De Witte, C.; Flahou, B.; Ducatelle, R. et al

in Systematic & Applied Microbiology (in press)

Nine strains of a novel Fusobacterium sp. were isolated from the stomach of 6-8 months old and adult pigs. The isolates were obligately anaerobic, although they endured 2 hours exposure to air ... [more ▼]

Nine strains of a novel Fusobacterium sp. were isolated from the stomach of 6-8 months old and adult pigs. The isolates were obligately anaerobic, although they endured 2 hours exposure to air. Phylogenetic analysis based on 16S rRNA and gyrase B genes demonstrated that the isolates showed high sequence similarity with Fusobacterium mortiferum, Fusobacterium ulcerans, Fusobacterium varium, Fusobacterium russii and Fusobacterium necrogenes, but formed a distinct lineage in the genus Fusobacterium. Comparative analysis of the genome of the type strain of this novel Fusobacterium sp. confirmed that it is different from other recognized Fusobacterium spp. DNA-DNA hybridization, fingerprinting and genomic %GC determination further supported the conclusion that the isolates belong to a new, distinct species. The isolates were also distinguishable from these and other Fusobacterium spp. by phenotypical characterization. The strains produced indole and exhibited proline arylamidase and glutamic acid decarboxylase activity. They did not hydrolyse esculin, did not exhibit pyroglutamic acid arylamidase, valine arylamidase, α-galactosidase, β-galactosidase, β-galactosidase-6-phosphate or α-glucosidase activity nor produced acid from cellobiose, glucose, lactose, mannitol, mannose, maltose, raffinose, saccharose, salicin or trehalose. The major fatty acids were C16 : 0 and C18 : 1ω9c. The name Fusobacterium gastrosuis sp. nov. is proposed for the novel isolates with the type strain CDW1(T) (= DSM 101753(T) = LMG 29236(T)). We also demonstrated that Clostridium rectum and Fusobacterium mortiferum represent the same species, with nomenclatural priority for the latter. [less ▲]

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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 ▲]

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See detailHigh-throughput sequencing analysis reveals the genetic diversity of different regions of the murine norovirus genome during in vitro replication
Mauroy, Axel ULg; Taminiau, Bernard ULg; Nezer, Carine et al

in Archives of Virology (in press)

In this study, we report the genetic diversity and nucleotide mutation rates of five representative regions of the murine norovirus genome during in vitro passages. The mutation rates were similar in ... [more ▼]

In this study, we report the genetic diversity and nucleotide mutation rates of five representative regions of the murine norovirus genome during in vitro passages. The mutation rates were similar in genomic regions encompassing partial coding sequences for non-structural (NS) 1-2, NS5, NS6, NS7 proteins within open reading frame (ORF) 1. In a region encoding a portion of the major capsid protein (VP1) within ORF2 (also including the ORF4 region) and a portion of the minor structural protein (VP2), the mutation rates were estimated to be at least one order of magnitude higher. The VP2 coding region was found to have the highest mutation rate. [less ▲]

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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 ▲]

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See detailIdentification of bacterial strains isolated from the traditional date product "Btana" produced in south regions of Algeria
Abekhti, Abdelkader; Taminiau, Bernard ULg; Kihal, Mabrouk et al

in Folia Microbiologica (in press)

Eleven samples of the traditional date product " Btana" prepared by direct (DBM) and indirect method (UBM) were analysed to characterize their bacterial diversity. A total of 42 representative isolates ... [more ▼]

Eleven samples of the traditional date product " Btana" prepared by direct (DBM) and indirect method (UBM) were analysed to characterize their bacterial diversity. A total of 42 representative isolates have been chosen for molecular identification. 16S rRNA gene sequencing revealed the presence of 20 species within 30.9% belonged to the genus Bacillus, 28.6% of the Staphylococcus, and Enterococcus genus. Within the minority represented species, two isolates were identified as Paenibacillus (isolated from UBM exclusively), Streptococci salivarius, Lactobacillus sakei and Klebsiella pneumoniae. Preliminary results indicate that IBM is more selective for spore former bacilli contrary to DBM that show more diversity in the bacterial flora with a prevalence of Enterococcus. API ZYM test showed that the bacilli species have a weak hydrolase activity. [less ▲]

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See detailLooking for phosphate-accumulating bacteria in activated sludge processes : a multidisciplinary approach
Tarayre, Cédric ULg; Charlier, Raphaëlle; Delepierre, Anissa ULg et al

in Environmental Science and Pollution Research (2017)

Over the past decades, an increasing need in renewable resources has progressively appeared. This trend concerns not only fossil fuels but also mineral resources. Wastewater and sewage sludge contain ... [more ▼]

Over the past decades, an increasing need in renewable resources has progressively appeared. This trend concerns not only fossil fuels but also mineral resources. Wastewater and sewage sludge contain significant concentrations in phosphate and can be considered as a fertilizer source of the utmost importance. In wastewater treatment plants, the biological uptake of phosphate is performed by a specific microbiota: the phosphate-accumulating organisms. These microorganisms are recovered in sewage sludge. Here, we aimed to investigate the occurrence of phosphate accumulators in four wastewater treatment plants. A 16S metagenetic analysis identified the main bacterial phyla extracted from the aerobic treatment: α-Proteobacteria, β-Proteobacteria, and Sphingobacteria. An enrichment stage was performed to stimulate the specific growth of phosphate-accumulating bacteria in an acetate medium. An analysis of metabolic activities of sulfur and phosphorus highlighted strong modifications related to phosphorus and much less distinguishable effects with sulfur. A solid acetate medium containing 5-Br-4-Cl-3-indolyl phosphate was used to select potential phosphate-accumulating bacteria from the enriched consortia. The positive strains have been found to belong in the genera Acinetobacter, Corynebacterium, and Pseudomonas. Finally, electron microscopy was applied to the strains and allowed to confirm the presence of polyphosphate granules. Some of these bacteria contained granules the size of which exceeded 100 nm. [less ▲]

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See detailChemical composition and antimicrobial activity of essential oils of Ocimum basilicum, Ocimum canum and Ocimum gratissimum in function of harvesting time
Mith, Hasika; Yayi-Ladékan, Eléonore; Dosso Sika Kpoviessi, Salomé et al

in Journal of Essential Oil-Bearing Plants [=JEOBP] (2016), 19(6), 1413-1425

The chemical composition of essential oils obtained by hydrodistillation from aerial parts of Ocimum basilicum, Ocimum canum and Ocimum gratissimum from Benin as affected by harvesting time, were analyzed ... [more ▼]

The chemical composition of essential oils obtained by hydrodistillation from aerial parts of Ocimum basilicum, Ocimum canum and Ocimum gratissimum from Benin as affected by harvesting time, were analyzed by GC-FID (Gas chromatography-Flame ionization detector) and GC-MS (Gas chromatography-Mass spectrometry). Based on the composition analysis, major components were as follows: estragol (43.0-44.7%) and linalool (24.6 29.8%) in O. basilicum oils; carvacrol (12.0-30.8%) and p-cymene (19.5-26.2%) in O. canum oils; thymol (28.3-37.7%) and γ-terpinene (12.5-19.3 %) in O. gratissimum oils. Disc diffusion and broth microdilution assays were used to evaluate the antibacterial activity of essential oils and their main components against two foodborne bacteria, Listeria monocytogenes and Salmonella enterica serotype Typhimurium. The tested oils and their components exhibited notable antimicrobial activities against L. monocytogenes and S. Typhimurium. The O. canum and O. gratissimum oils collected at 7h and 19h showed significant higher activities against L. monocytogenes and S. Typhimurium (MICs and MBCs 0.34 - 2.5 μL/mL) (p < 0.05), whereas O. basilicum showed lower activity (MICs and MBCs 2.0 - 8.0 μL/mL) at any daytime of harvest, the weakest being at 19h (MIC and MBC 12.0 - 32.0 μL/mL). The daytime of harvest can influence the composition of oils and their activities on bacteria. [less ▲]

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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 ▲]

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See detailDevelopment of an analytical method for the simultaneous measurement of 10 biogenic amines in food
Douny, Caroline ULg; Benmedjadi, Soumaya; Blaszczyk, Marie et al

Poster (2016, October 21)

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See detailConsumption patterns, bacteriological quality and risk factors for Salmonella contamination in meat-based meals consumed outside the home in Kigali, Rwanda
Niyonzima, Eugène; Ongol, Martin Patrick; Brostaux, Yves ULg et al

in Food Control (2016)

Meat-based meals are consumed as a source of animal proteins and constitute one of the leading vehicles for food borne infections in humans. The main objective of this study was to determine the ... [more ▼]

Meat-based meals are consumed as a source of animal proteins and constitute one of the leading vehicles for food borne infections in humans. The main objective of this study was to determine the consumption pattern and the bacteriological quality of meat-based meals consumed outside households in Kigali. A survey on meat consumption patterns was carried out in 400 households by using a questionnaire, whereas different meat-based meals were sampled from 150 snack bars and restaurants. Enumeration of hygiene indicator bacteria (total mesophilic bacteria and Escherichia coli) and the qualitative detection of Salmonella were carried out by using conventional culture methods. The results indicated that goat was the type of meat that was consumed the most outside the home in Kigali and the meat intake varied significantly (p ≤0.05) with the social category of the household. The average levels of total aerobic bacteria and E. coli in meat-based meals were found to be 4.7 and 1.4 log cfu/g, respectively, whereas Salmonella was detected in 11.7% of all meat-based meals. Eight factors mostly linked to the cooking treatments and hygienic handling practices for cooked meals were found to be significantly (p ≤ 0.05) associated with the risk of Salmonella occurrence in meat-based meals consumed outside the home in Kigali. The findings from this study strongly suggest the need for proper cooking and/or improvements in hygiene in the establishments selling ready-to-eat meat-based meals in Kigali, particularly those located in rural localities. [less ▲]

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See detailComparative analysis of the respiratory microbiota of healthy dogs and dogs with canine idiopathic pulmonary fibrosis
Roels, Elodie ULg; Taminiau, Bernard ULg; Darnis, Elodie ULg et al

in Journal of Veterinary Internal Medicine (2016, September)

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See detailStudy of the microbial diversity of microbial ring trials by metagenomic analysis : Quantification of alive bacteria by exclusion of dead bacteria
Fall, P.A.; Burteau, S.; Detry, E. et al

Poster (2016, July 19)

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See detailMetagenetics and predictive microbiology: a new tool to understand the kinetics of microbial subpopulations in Belgian white pudding
Cauchie, Emilie ULg; Gand, Mathieu; Kergourlay, Gilles et al

Poster (2016, July 18)

Detailed reference viewed: 36 (15 ULg)