F-02: Antibiothérapies anti-SARM dans le traitement probabiliste des bactériémies à Staphylococcus aureus au CHU d'Angers

Introduction – objectifs La résistance à la méticilline du Staphylococcus aureus (SA) ne cesse de diminuer en France. Nous avons évalué la prescription des antibiothérapies probabilistes dans les bactériémies à SA et leur impact clinique. Matériels et méthodes Il s’agit d’une étude rétrospective incluant les bactériémies à Staphylococcus aureus sur le CHU d’Angers entre novembre 2012 et septembre 2013 avec recueil de l’antibiothérapie prescrite au rendu « cocci gram (CG)+ », à J5, hospitalisation depuis plus de 5 jours ou dans les six derniers mois, signes de gravité clinique, mortalité à J5. Résultats Nous avons inclus 146 épisodes de bactériémies. A l’annonce de CG+, 10 patients étaient décédés, 38,2 % ont reçu un anti-SARM (n = 52), 54,4 % un anti-SASM (n = 74), 7,4 % aucun antibiotique (n = 10). Parmi les bactériémies à SARM (n = 23), 60,9 % (n = 14) ont reçu une antibiothérapie initiale à visée SARM contre 36,3 % (n = 41) pour les bactériémies à SASM (n = 113) (OR = 2,71, p = 0,03). Cette adaptation semble influencée par une hospitalisation récente (OR = 1,82 ; p = 0,33) et la présence de signes de gravité (OR = 1,87, p = 0,23). Dans 21,4 % (n = 6) des bactériémies à SASM, l’antibiothérapie anti-SARM n’a pas été désecaladée. La mortalité à J5 est 13 %. L’absence d’antibiothérapie dans les 24 premières heures (OR = 2,97 ; p = 0,046) et une prescription de C3G (OR = 5,2, p = 0,05) en monothérapie augmentent le risque de décès à J5. Conclusion L’antibiothérapie initale semble adaptée à l’histoire et la présentation des patients. L’initiation sans délai, la visée staphylococcique et la désescalade sont les éléments importants du traitement

Neisseria oralis sp. nov., isolated from healthy gingival plaque and clinical samples

A polyphasic analysis was undertaken of seven independent isolates of Gram-negative cocci collected from pathological clinical samples from New York, Louisiana, Florida and Illinois and healthy subgingival plaque from a patient in Virginia, USA. The 16S rRNA gene sequence similarity among these isolates was 99.7–100 %, and the closest species with a validly published name was Neisseria lactamica (96.9 % similarity to the type strain). DNA–DNA hybridization confirmed that these isolates are of the same species and are distinct from their nearest phylogenetic neighbour, N. lactamica. Phylogenetic analysis of 16S and 23S rRNA gene sequences indicated that the novel species belongs in the genus Neisseria. The predominant cellular fatty acids were C16 : 0, summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH) and C18 : 1ω7c. The cellular fatty acid profile, together with other phenotypic characters, further supports the inclusion of the novel species in the genus Neisseria. The name Neisseria oralis sp. nov. (type strain 6332T = DSM 25276T = LMG 26725T) is proposed

New <i>Methyloceanibacter</i> diversity from North Sea sediments includes methanotroph containing solely the soluble methane monooxygenase

Marine methylotrophs play a key role in the global carbon cycle by metabolizing reduced one-carbon compounds that are found in high concentrations in marine environments. Genome, physiology and diversity studies have been greatly facilitated by the numerous model organisms brought into culture. However, the availability of marine representatives remains poor. Here, we report the isolation of four novel species from North Sea sediment enrichments closely related to the Alphaproteobacterium Methyloceanibacter caenitepidi. Each of the newly isolated Methyloceanibacter species exhibited a clear genome sequence divergence which was reflected in physiological differences. Notably one strain R-67174 was capable of oxidizing methane as sole source of carbon and energy using solely a soluble methane monooxygenase and represents the first marine Alphaproteobacterial methanotroph brought into culture. Differences in maximum cell density of >1.5 orders of magnitude were observed. Furthermore, three strains were capable of producing nitrous oxide from nitrate. Together, these findings highlight the metabolic and physiologic variability within closely related Methyloceanibacter species and provide a new understanding of the physiological basis of marine methylotrophy

Network-based identification of feedback modules that control RhoA activity and cell migration

Cancer cell migration enables metastatic spread causing most cancer deaths. Rho-family GTPases control cell migration, but being embedded in a highly interconnected feedback network, the control of their dynamical behavior during cell migration remains elusive. To address this question, we reconstructed the Rho-family GTPases signaling network involved in cell migration, and developed a Boolean network model to analyze the different states and emergent rewiring of the Rho-family GTPases signaling network at protrusions and during extracellular matrix-dependent cell migration. Extensive simulations and experimental validations revealed that the bursts of RhoA activity induced at protrusions by EGF are regulated by a negative-feedback module composed of Src, FAK, and CSK. Interestingly, perturbing this module interfered with cyclic Rho activation and extracellular matrix-dependent migration, suggesting that CSK inhibition can be a novel and effective intervention strategy for blocking extracellular matrix-dependent cancer cell migration, while Src inhibition might fail, depending on the genetic background of cells. Thus, this study provides new insights into the mechanisms that regulate the intricate activation states of Rho-family GTPases during extracellular matrix-dependent migration, revealing potential new targets for interfering with extracellular matrix-dependent cancer cell migratio

A comprehensive investigation into the production of gamma-aminobutyric acid by Limosilactobacillus fermentum NG16, a tuna gut isolate

Abstract Gamma-aminobutyric acid (GABA), a four-carbon non-protein amino acid, is widely known to have multiple physiological functions. The present study aimed to investigate the cultivation parameters for GABA production by a lactic acid bacteria (LAB) strain isolated from a tuna gut sample. Among 60 tuna gut LAB, only 7 Limosilactobacillus fermentum isolates, i.e. NG01, NG12, NG13, NG14, NG16, NG23, and NG27, were capable of GABA fermentation, with NG16 being the most potent GABA producer. The GABA production by isolate NG16 was therefore thoroughly characterised. The optimal batch culture conditions for GABA production were an initial cell density of 5×106 CFU mL−1, a monosodium glutamate concentration of 2, an initial pH of 7, a fermentation temperature of 35 °C, and an incubation time of 96 h. Under this cultivation conditions, NG16 produced a maximum GABA yield of 25.52 ± 0.41 mM

Evaluation d’une procédure de recherche rétrospective des infections du site opératoire au Centre Hospitalier Universitaire d’Angers

National audienc