Caractérisation d'une nouvelle espèce bactérienne responsable d'infection de plaie de morsure (intérêts et limites des techniques d'identification moléculaire)

LYON1-BU Santé (693882101) / SudocRENNES1-BU Santé (352382103) / SudocSudocFranceF

Un cas typique d'intoxication volontaire par l'éthylène glycol

Le cas d'une intoxication volontaire aiguë par l'éthylène glycol, utilisé en tant que substitut à l'alcool chez un patient éthylique chronique, est rapporté. Un suivi des taux plasmatiques d'éthylène glycol (EG) par une méthode enzymatique et de son principal metabolite, l'acide glycolique (AG), par une méthode spectrophotométrique est présenté. Les concentrations maximales observées sont de 3,43 g/L pour l'EG et de 1,12 g/L pour l'AG. La demi-vie d'élimination calculée de l'éthylène glycol (7,4 heures) est conforme au résultats de la littérature lors de la mise en œuvre d'un traitement antidotique (fomépizole) et d'une épuration extra-rénale ; d'autre part, l'ampleur du trou anionique et le taux de glycolates sont superposables

Entropy production and field synergy principle in turbulent vortical flows

The heat transfer in turbulent vortical flows is investigated by three different physical approaches. Vortical structures are generated by inclined baffles in a turbulent pipe flow, of three different configurations. In the first, the vortex generators are aligned and inclined in the flow direction (called the reference geometry); in the second, a periodic 45 degrees rotation is applied to the tab arrays (alternating geometry); the third is the reference geometry used in the direction opposite to the flow (reversed geometry). The effect of the flow structure on the temperature distribution in these different configurations is analyzed. The conventional approach based on heat-transfer analysis using the Nusselt number and the enhancement factor is used to determine the efficiency of these geometries relative to other heat exchangers in the literature. The effect of vorticity on the Nusselt number is clearly demonstrated, and so as to highlight the respective roles of the coherent structures and the turbulence, a new parameter is defined as the ratio of the vortex circulation to the turbulent viscosity. The relative contribution of the radial convection to heat transfer appears to increase with Reynolds number. The effect of mixing performance on the temperature distribution is investigated by the field synergy method. A global parameter, namely the intersection angle between the velocity and temperature gradient, is defined in order to compare performances. Finally, an analysis of energetic efficiency by entropy production, involving both heat transfer and pressure losses, is carried out to determine the overall performance of the heat exchangers. All these approaches lead to the same conclusion: that the reversed geometry presents the best heat transfer coefficient and the best energetic efficiency. The reference geometry shows the worst performance, and the alternating array has intermediate performance. (C) 2011 Elsevier Masson SAS. All rights reserved

Propionibacterium namnetense sp. nov., isolated from a human bone infection

International audienceA polyphasic taxonomic study was performed on two Gram-positive-staining, anaerobic, pleomorphic, rod-shaped strains isolated from human bone and tissue samples. Sequencing of the 16S rRNA genes revealed that the strains belong to a novel species within the genus Propionibacterium, most closely related to Propionibacterium acnes subsp. acnes and Propionibacterium acnes subsp. elongatum with similarity values of 98.4 % and 98.1 %, respectively. In addition, protein-coding genes for rpoB, recA and gyrB clearly separated the novel organism from all species and subspecies of the genus Propionibacterium. However, a DNA–DNA hybridization analysis between the novel organism and the type strain P. acnes ATCC 6919[T] revealed a value of only 61.1 %. Furthermore, whole genome analysis using the program OrthoANI gave a value of 88.5 %, which is significantly below the cutoff value of 95 % for species delineation. The major fatty acids were iso-C 15 : 0 , anteiso-C 15 : 0 and iso-C 17 : 0. The DNA G+C content of the type strain was 59.7 mol%. When taken collectively, phenotypic, molecular genetic, chemotaxonomic and phylogenetic information demonstrate that the organism represents a distinct, albeit close relative of P. acnes On the basis of the results presented, the organism represents a novel member of the genus Propionibacterium for which the name Propionibacterium namnetense sp. nov. is proposed. The type strain is NTS 31307302[T] (=DSM 29427[T] =CCUG 66358[T])

Comparative Whole-Genome Phylogeny of Animal, Environmental, and Human Strains Confirms the Genogroup Organization and Diversity of the Stenotrophomonas maltophilia Complex

International audienceThe Stenotrophomonas maltophilia complex (Smc) comprises opportunistic environmental Gram-negative bacilli responsible for a variety of infections in both humans and animals. Beyond its large genetic diversity, its genetic organization in genogroups was recently confirmed through the whole-genome sequencing of human and environmental strains. As they are poorly represented in these analyses, we sequenced the whole genomes of 93 animal strains to determine their genetic background and characteristics. Combining these data with 81 newly sequenced human strains and the genomes available from RefSeq, we performed a genomic analysis that included 375 nonduplicated genomes with various origins (animal, 104; human, 226; environment, 30; unknown, 15). Phylogenetic analysis and clustering based on genome-wide average nucleotide identity confirmed and specified the genetic organization of Smc in at least 20 genogroups. Two new genogroups were identified, and two previously described groups were further divided into two subgroups each. Comparing the strains isolated from different host types and their genogroup affiliation, we observed a clear disequilibrium in certain groups. Surprisingly, some antimicrobial resistance genes, integrons, and/or clusters of attC sites lacking integron-integrase (CALIN) sequences targeting antimicrobial compounds extensively used in animals were mainly identified in animal strains. We also identified genes commonly found in animal strains coding for efflux systems. The result of a large whole-genome analysis performed by us supports the hypothesis of the putative contribution of animals as a reservoir of Stenotrophomonas maltophilia complex strains and/or resistance genes for strains in humans.IMPORTANCE Given its naturally large antimicrobial resistance profile, the Stenotrophomonas maltophilia complex (Smc) is a set of emerging pathogens of immunosuppressed and cystic fibrosis patients. As it is group of environmental microorganisms, this adaptation to humans is an opportunity to understand the genetic and metabolic selective mechanisms involved in this process. The previously reported genomic organization was incomplete, as data from animal strains were underrepresented. We added the missing piece of the puzzle with whole-genome sequencing of 93 strains of animal origin. Beyond describing the phylogenetic organization, we confirmed the genetic diversity of the Smc, which could not be estimated through routine phenotype- or matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF)-based laboratory tests. Animals strains seem to play a key role in the diversity of Smc and could act as a reservoir for mobile resistance genes. Some genogroups seem to be associated with particular hosts; the genetic support of this association and the role of the determinants/corresponding genes need to be explored

Assessment of Factors Associated With Community-Acquired Extended-Spectrum β-Lactamase–Producing <i>Escherichia coli</i> Urinary Tract Infections in France

International audienceIMPORTANCE Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is considered a leading pathogen contributing to the global burden of antimicrobial resistance. OBJECTIVE To better understand factors associated with the heterogeneity of community-acquired ESBL-producing E coli urinary tract infections (UTIs) in France. DESIGN, SETTING, AND PARTICIPANTS This cross-sectional study performed from January 1 to December 31, 2021, was based on data collected via PRIMO (Surveillance and Prevention of Antimicrobial Resistance in Primary Care and Nursing Homes), a nationwide clinical laboratory surveillance system in France. Strains of E coli isolated from community urine samples from January 1 to December 31, 2019, from 59 administrative departments of metropolitan France were included. MAIN OUTCOMES AND MEASURES Quasi-Poisson regression models were used to assess the associations between several ecological factors available on government and administration websites between 2010 and 2020 (demographic population structure, living conditions, baseline health care services, antibiotic consumptions, economic indicators, animal farming density, and environmental characteristics) and the number of ESBL-producing E coli strains isolated from urine samples of individuals with community-acquired UTI in 2019