Caractéristiques et prise en charge contemporaine du rétrécissement aortique en Europe (l' étude Euro Heart Survey)

PARIS-BIUM (751062103) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocSudocFranceF

Équipe expérimentale : Étude des processus infectieux en confinement A1à A3 sur les animaux de rente, de laboratoire, de loisir et de la faune sauvage

Présentation du poster en 180 sec de l'activité des équipes expérimentation / élevage de la PFIENational audienc

Evaluation of phage cocktails to prevent avian colibacillosis

International audienceColibacillosis is the main bacterial disease in poultry and is treated mainly by antibiotics, which eventually led to the emergence of antibiotic resistant strains. Our objective was to evaluate the efficacy of two phage cocktails to prevent colibacillosis induced in chicks by the pathogenic strain BEN4358. The first cocktail was constituted of eight phages of different genus, four phages were able to replicate on BEN4358, leading to the death of the bacterial cells; three phages were not able to replicate on the strain, but were able to lyse bacterial cells by the action of virion-associated enzymes and one phage was not active on BEN4358. The second cocktail was composed of the four phages able to replicate on BEN4358. In a chicken embryo lethality assay, the cocktail of 8 phages allowed 90% of chicken embryos to survive an infection by BEN4358, in contrast to the control (BEN4358 only), which gave a survival rate of 0%. Then, embryonated chicken eggs were inoculated by the phage cocktails in the allantoic fluid at 16 days. At day 19, embryonated eggs were transferred from the egg incubator to isolators, where the chicks hatched. Strain BEN4358 was inoculated subcutaneously at one-day-old chicks. Even if phages were detected in chicks, the mortality between the non-treated and the phage-treated groups was 75% and 80%, respectively. There was no reduction in BEN4358 intestinal load. Same in vivo experimental scheme was conducted with the second cocktail and the chicks were challenged with a 10-fold reduced bacterial inoculum. There was no difference in the mortality rate between both groups; however, the mortality was delayed in the treated-group. Moreover, the intestinal BEN4358 load was statistically significantly lower in the phage-treated group (2.2x107 CFU/mL) compared to the non-treated group (1.3x108 CFU/mL).Thus, in ovo inoculated phage cocktails did not prevent colibacillosis but phages were transmitted to chicks and one cocktail reduced intestinal carriage

Endotoxemia affects citrulline, arginine and glutamine bioavailability

International audienceBACKGROUND:Sepsis considerably alters the intestinal barrier functions, which in turn modify the absorption and bioavailability of nutrients. However, the effects of septic shock on aminoacid (AAs) bioavailability are poorly documented. The aim of this study was to compare the bioavailability of citrulline, arginine and glutamine during endotoxemia.MATERIALS AND METHODS:Thirty-six rats were randomised into two groups: control and lipopolysaccharides (LPS). The LPS group received an intraperitoneal injection of endotoxins (7·5 mg/kg). After 12 h, each group was again randomised into three subgroups, each of which received an oral bolus of citrulline, arginine or glutamine (5·7 mmol/kg). Blood samples were collected at various times from 0 to 600 min after AA administration. The concentrations of citrulline, arginine, glutamine and their metabolites arginine and ornithine were measured to determine pharmacokinetic parameters Area Under Curve (AUC), C(max) and T(max).RESULTS:The AUC values of citrulline decreased in LPS rats [citrulline, control: 761 ± 67 and LPS: 508 ± 72 μmol min/mL (P = 0·02)]. Maximum concentrations of citrulline were also significantly decreased by endotoxemia (P = 0·01). The pharmacokinetic parameters of arginine and glutamine were not significantly modified by endotoxemia. The AUC value of arginine from citrulline conversion was diminished in endotoxemic rats. The other pharmacokinetic parameters of arginine were not significantly modified after arginine or citrulline supply in either group (control or LPS).CONCLUSION:Endotoxemia affects the bioavailability of AAs differently according to the amino acid considered. This feature may be important for nutritional strategy in ICU patients

In ovo administration of a phage cocktail partially prevents colibacillosis in chicks

ABSTRACT: Avian pathogenic Escherichia coli (APEC) causes colibacillosis, the main bacterial disease in poultry leading to significant economic losses worldwide. Antibiotic treatments favor the emergence of multidrug-resistant bacteria, and preventive measures are insufficient to control the disease. There is increasing interest in using the potential of bacteriophages, not only for phage therapy but also for prevention and biocontrol. This study aimed to evaluate the efficacy of a phage cocktail administered in ovo to prevent avian colibacillosis in chicks. When 4 different phages (REC, ESCO3, ESCO47, and ESCO58), stable under avian physiological conditions, were combined and inoculated at 17 embryogenic days (ED), they were transmitted to the newly hatched chicks. In a second trial, the 4-phage cocktail was inoculated into the allantoic fluid at ED16 and after hatch 1-day-old chicks were challenged with the O2 APEC strain BEN4358 inoculated subcutaneously. Two phages (REC and ESCO3) were still detected in the ceca of surviving chicks at the end of the experiment (7-days postinfection). Chicks that received the phages in ovo did not develop colibacillosis lesions and showed a significant decrease in intestinal BEN4358 load (8.00 × 107 CFU/g) compared to the challenged chicks (4.52 × 108 CFU/g). The majority of the reisolated bacteria from the ceca of surviving chicks had developed full resistance to ESCO3 phage, and only 3 were resistant to REC phage. The partially or complete resistance of REC phage induced a considerable cost to bacterial virulence. Here, we showed that phages inoculated in ovo can partially prevent colibacillosis in 1-wk-old chicks. The reduction in the APEC load in the gut and the decreased virulence of some resistant isolates could also contribute to control the disease

Production of Germ-Free Fast-Growing Broilers from a Commercial Line for Microbiota Studies

International audienceStudies of the gut microbiota contribution to the host physiology and immunocompetence are facilitated by the availability of germ-free animal models, which are considered the gold standard. Nesting birds are ideal models for the production of germ-free animals since there is no need to raise their relatives under sterile conditions. Germ-free chickens are mainly generated from specific-pathogen-free (SPF) experimental lines, which are poorly representative of commercial chicken lines. The method proposed here allowed the production of germ-free chickens from the fast growing broiler line Ross PM3, commonly used by the poultry industry. Eggs were quickly collected after laying at a broiler breeder farm. They underwent a strict decontamination process from the collection to the introduction in a sterile egg hatching isolator. The chicks have been hatched and kept in these sterile isolators during the period necessary to control their sterility. Originally developed for an experimental SPF white leghorn line, the present protocol has been adapted not only to the Ross PM3 broiler line but also to quails. It therefore represents a robust and readily adaptable procedure to other poultry species and nesting birds of economic, biological or ecological relevance

In-vivo echo-navigated MR thermometry for real-time monitoring of cardiac radiofrequency ablation

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Two-Photon Initiating Efficiency of a Ditopic Alkoxynitrostilbene Reacting through a Self-Regenerative Mechanism

International audienceThe photophysical properties and the photoinitiating reactivity of a ditopic alkoxynitrostilbene were compared to those of its single branch chromophore used as a reference. Whereas a trivial additive effect is observed when considering the one-and two-photon absorption properties, a clear and very significant amplification has been highlighted for the photoreactivity of this free radical photoinitiator which was used as a hydrogen abstractor in presence of an aliphatic amine co-reactant. We indeed demonstrate that the proximity of two nitroaromatics moieties within the same molecular architecture gives rise to an original cycling mechanism based on a stepwise photo triggering of each photoredox center followed by a subsequent regenerative process. The combination of a high two-photon absorption cross-section (delta 780nm ≈ 330 GM) with a strong enhancement in photoreactivity makes this nitrostilbene bichromophore a very suitable candidate for two-photon polymerization applications