Apport du broyage mécanique des prélèvements per-opératoires et de la PCR pan-bactérienne dans le diagnostic des infections de prothèse articulaire de hanche et de genou

Introduction : Les infections ostéo-articulaires sur prothèse (IOAP) sont un enjeu majeur de santé publique. Leur diagnostic est capital pour assurer une prise en charge optimale des patients. L objectif de cette étude était double, évaluer les performances de la méthode de culture classique après préparation des prélèvements per-opératoires par broyage mécanique et comparer la technique de PCR pan-bactérienne à la culture conventionnelle. Méthodes : Une étude prospective a été menée sur des patients opérés pour un descellement de prothèse de hanche ou de genou pour cause septique ou non. Pour chaque patient, des prélèvements ont été réalisés à visée bactériologique : les prélèvements habituellement recommandés traités de manière classique et 2 échantillons supplémentaires prétraités par broyage mécanique avant la mise en culture. Ces prélèvements ont ensuite été testés en PCR universelle. Résultats : De novembre 2012 à juin 2013, l analyse des prélèvements des 24 patients inclus n a pas montré d amélioration de la sensibilité de la culture par le broyage mécanique préalable des échantillons. En revanche, ce prétraitement a permis de réduire le délai de positivité des cultures, le risque de contamination et de favoriser la détection des Small colony variants . La PCR universelle, bien que moins sensible que la culture, présente un intérêt dans certaines situations spécifiques, notamment en cas d antibiothérapie préalable. Conclusion : Le broyage mécanique des prélèvements solides apparaît donc comme une technique intéressante pour optimiser le diagnostic des IOAP. Dans ce contexte, la PCR universelle doit s envisager en complément de la culture microbiologique.GRENOBLE1-BU Médecine pharm. (385162101) / SudocSudocFranceF

Tularemia treatment: experimental and clinical data

Tularemia is a zoonosis caused by the Gram negative, facultative intracellular bacterium Francisella tularensis. This disease has multiple clinical presentations according to the route of infection, the virulence of the infecting bacterial strain, and the underlying medical condition of infected persons. Systemic infections (e.g., pneumonic and typhoidal form) and complications are rare but may be life threatening. Most people suffer from local infection (e.g., skin ulcer, conjunctivitis, or pharyngitis) with regional lymphadenopathy, which evolve to suppuration in about 30% of patients and a chronic course of infection. Current treatment recommendations have been established to manage acute infections in the context of a biological threat and do not consider the great variability of clinical situations. This review summarizes literature data on antibiotic efficacy against F. tularensis in vitro, in animal models, and in humans. Empirical treatment with beta-lactams, most macrolides, or anti-tuberculosis agents is usually ineffective. The aminoglycosides gentamicin and streptomycin remain the gold standard for severe infections, and the fluoroquinolones and doxycycline for infections of mild severity, although current data indicate the former are usually more effective. However, the antibiotic treatments reported in the literature are highly variable in their composition and duration depending on the clinical manifestations, the age and health status of the patient, the presence of complications, and the evolution of the disease. Many patients received several antibiotics in combination or successively. Whatever the antibiotic treatment administered, variable but high rates of treatment failures and relapses are still observed, especially in patients treated more then 2–3 weeks after disease onset. In these patients, surgical treatment is often necessary for cure, including drainage or removal of suppurative lymph nodes or other infectious foci. It is currently difficult to establish therapeutic recommendations, particularly due to lack of comparative randomized studies. However, we have attempted to summarize current knowledge through proposals for improving tularemia treatment which will have to be discussed by a group of experts. A major factor in improving the prognosis of patients with tularemia is the early administration of appropriate treatment, which requires better medical knowledge and diagnostic strategy of this disease

A search for small noncoding RNAs in Staphylococcus aureus reveals a conserved sequence motif for regulation

Bioinformatic analysis of the intergenic regions of Staphylococcus aureus predicted multiple regulatory regions. From this analysis, we characterized 11 novel noncoding RNAs (RsaA‐K) that are expressed in several S. aureus strains under different experimental conditions. Many of them accumulate in the late-exponential phase of growth. All ncRNAs are stable and their expression is Hfq-independent. The transcription of several of them is regulated by the alternative sigma B factor (RsaA, D and F) while the expression of RsaE is agrA-dependent. Six of these ncRNAs are specific to S. aureus, four are conserved in other Staphylococci, and RsaE is also present in Bacillaceae. Transcriptomic and proteomic analysis indicated that RsaE regulates the synthesis of proteins involved in various metabolic pathways. Phylogenetic analysis combined with RNA structure probing, searches for RsaE‐mRNA base pairing, and toeprinting assays indicate that a conserved and unpaired UCCC sequence motif of RsaE binds to target mRNAs and prevents the formation of the ribosomal initiation complex. This study unexpectedly shows that most of the novel ncRNAs carry the conserved C−rich motif, suggesting that they are members of a class of ncRNAs that target mRNAs by a shared mechanis

The Signal Peptide of Staphylococcus aureus Panton Valentine Leukocidin LukS Component Mediates Increased Adhesion to Heparan Sulfates

Staphylococcus aureus necrotizing pneumonia is a severe disease caused by S. aureus strains carrying the Panton Valentine leukocidin (PVL) genes (lukS-PV & lukF-PV) encoded on various bacteriophages (such as phiSLT). Clinical PVL+ strains isolated from necrotizing pneumonia display an increased attachment to matrix molecules (type I and IV collagens and laminin), a phenotype that could play a role in bacterial adhesion to damaged airway epithelium during the early stages of necrotizing pneumonia (J Infect Dis 2004; 190: 1506–15). To investigate the basis of the observed adhesion of S. aureus PVL+ strains, we compared the ability of PVL+ and their isogenic PVL− strains to attach to various immobilized matrix molecules. The expression of recombinant fragments of the PVL subunits and the addition of synthetic peptides indicated that the processed LukS-PV signal peptide (LukS-PV SP) was sufficient to significantly enhance the ability of S. aureus to attach to extracellular matrix (ECM) components. Furthermore, we showed that adhesion to ECM components was inhibited by heparin and heparan sulfates (HS) suggesting that in vivo, HS could function as a molecular bridge between the matrix and S. aureus expressing the LukS-PV signal peptide. Site directed mutagenesis, biochemical and structural analyses of the LukS-PV signal peptide indicate that this peptide is present at the S. aureus surface, binds to HS in solid phase assay, and mediates the enhanced S. aureus matrix component adhesion. Our data suggests that after its cleavage by signal peptidase, the signal peptide is released from the membrane and associates to the cell wall through its unique C-terminus sequence, while its highly positively charged N-terminus is exposed on the bacterial surface, allowing its interaction with extracellular matrix-associated HS. This mechanism may provide a molecular bridge that enhances the attachment of the S. aureus PVL+ strains to ECM components exposed at damaged epithelial sites

Staphylococcus aureus RNAIII Binds to Two Distant Regions of coa mRNA to Arrest Translation and Promote mRNA Degradation

Staphylococcus aureus RNAIII is the intracellular effector of the quorum sensing system that temporally controls a large number of virulence factors including exoproteins and cell-wall-associated proteins. Staphylocoagulase is one major virulence factor, which promotes clotting of human plasma. Like the major cell surface protein A, the expression of staphylocoagulase is strongly repressed by the quorum sensing system at the post-exponential growth phase. Here we used a combination of approaches in vivo and in vitro to analyze the mechanism used by RNAIII to regulate the expression of staphylocoagulase. Our data show that RNAIII represses the synthesis of the protein through a direct binding with the mRNA. Structure mapping shows that two distant regions of RNAIII interact with coa mRNA and that the mRNA harbors a conserved signature as found in other RNAIII-target mRNAs. The resulting complex is composed of an imperfect duplex masking the Shine-Dalgarno sequence of coa mRNA and of a loop-loop interaction occurring downstream in the coding region. The imperfect duplex is sufficient to prevent the formation of the ribosomal initiation complex and to repress the expression of a reporter gene in vivo. In addition, the double-strand-specific endoribonuclease III cleaves the two regions of the mRNA bound to RNAIII that may contribute to the degradation of the repressed mRNA. This study validates another direct target of RNAIII that plays a role in virulence. It also illustrates the diversity of RNAIII-mRNA topologies and how these multiple RNAIII-mRNA interactions would mediate virulence regulation

A search for small noncoding RNAs in Staphylococcus aureus reveals a conserved sequence motif for regulation

Bioinformatic analysis of the intergenic regions of Staphylococcus aureus predicted multiple regulatory regions. From this analysis, we characterized 11 novel noncoding RNAs (RsaA‐K) that are expressed in several S. aureus strains under different experimental conditions. Many of them accumulate in the late-exponential phase of growth. All ncRNAs are stable and their expression is Hfq-independent. The transcription of several of them is regulated by the alternative sigma B factor (RsaA, D and F) while the expression of RsaE is agrA-dependent. Six of these ncRNAs are specific to S. aureus, four are conserved in other Staphylococci, and RsaE is also present in Bacillaceae. Transcriptomic and proteomic analysis indicated that RsaE regulates the synthesis of proteins involved in various metabolic pathways. Phylogenetic analysis combined with RNA structure probing, searches for RsaE‐mRNA base pairing, and toeprinting assays indicate that a conserved and unpaired UCCC sequence motif of RsaE binds to target mRNAs and prevents the formation of the ribosomal initiation complex. This study unexpectedly shows that most of the novel ncRNAs carry the conserved C−rich motif, suggesting that they are members of a class of ncRNAs that target mRNAs by a shared mechanism

Reuse of medical face masks in domestic and community settings without sacrificing safety: Ecological and economical lessons from the Covid-19 pandemic

The need for personal protective equipment increased exponentially in response to the Covid-19 pandemic. To cope with the mask shortage during springtime 2020, a French consortium was created to find ways to reuse medical and respiratory masks in healthcare departments. The consortium addressed the complex context of the balance between cleaning medical masks in a way that maintains their safety and functionality for reuse, with the environmental advantage to manage medical disposable waste despite the current mask designation as single-use by the regulatory frameworks. We report a Workflow that provides a quantitative basis to determine the safety and efficacy of a medical mask that is decontaminated for reuse. The type IIR polypropylene medical masks can be washed up to 10 times, washed 5 times and autoclaved 5 times, or washed then sterilized with radiations or ethylene oxide, without any degradation of their filtration or breathability properties. There is loss of the antiprojection properties. The Workflow rendered the medical masks to comply to the AFNOR S76-001 standard as “type 1 non-sanitory usage masks”. This qualification gives a legal status to the Workflow-treated masks and allows recommendation for the reuse of washed medical masks by the general population, with the significant public health advantage of providing better protection than cloth-tissue masks. Additionally, such a legal status provides a basis to perform a clinical trial to test the masks in real conditions, with full compliance with EN 14683 norm, for collective reuse. The rational reuse of medical mask and their end-of-life management is critical, particularly in pandemic periods when decisive turns can be taken. The reuse of masks in the general population, in industries, or in hospitals (but not for surgery) has significant advantages for the management of waste without degrading the safety of individuals wearing reused masks

Late Gothic Sculpture in Savoie : Workshops, Artists and Clientele in Chambéry and its vicinity : between 1480 and 1530

Malgré la rareté des sources à Chambéry et dans sa région, les critères d’existence d’un foyer artistique dans la ville et ses alentours au tournant des XVe et XVIe siècles peuvent être réunis. Un important corpus d'une quarantaine de sculptures produit au cours de quelques décennies entre 1480 et 1530 atteste l'activité locale de sculpteurs. L'analyse des œuvres permet de distinguer l'activité de plusieurs ateliers et d'envisager un mode de production. De nombreuses occasions d'échanges entre milieux artistiques chambériens, genevois et septentrionaux peuvent aussi être mises en lumière. Dans cet espace, autour de 1500, la présence d'une clientèle variée et un contexte religieux dynamique ont favorisé le développement d'un langage artistique originale.Despite the paucity of documentary evidence arguing in favour of the existence of much sculpting activity in and near Chambéry, the criteria needed to establish the presence of an artistic hub in the town and its vicinity at the turn of the XV and XVI centuries can be shown. The existence of a large body of sculptures, consistent both in style and iconography, produced over a few decades between 1480 and 1530, is testament to the activity of sculptors in the region. An analysis has led to identifying the activity of various artists' workshops, and to understanding of the way in which these works were produced. Many opportunities for contact between the art worlds of Chambéry, Geneva and Northern countries can also be identified. Within this space, a varied clientele as well as a dynamic religious context have supported the development of an original local artistic production

ARN régulateurs bactériens (régulation de l'expression de la protéine A par l'ARNIII de Staphylococcus aureus)

LYON1-BU Santé (693882101) / SudocSudocFranceF

Régulation post-transcriptionnelle des gènes de virulence de staphylococcus aureus par un ARN régulateur, l'ARN III

La pathogénie des infections à Staphylococcus aureus est liée à la synthèse de nombreux facteurs de virulence. Leur expression est temporellement coordonnée au cours de l infection, par différents systèmes de régulation. Le système Agr accessory gene regulator est l un des mieux caractérisés. Son effecteur est un ARN régulateur de 514 nucléotides, l ARNIII. En phase post-exponentielle de croissance, il réprime l expression des gènes codant des protéines de paroi et active la synthèse des exoprotéines et des toxines. La régulation s effectue aux niveaux transcriptionnel et post-transcriptionnel. Le but de ce travail concerne la régulation post-transcriptionnelle des gènes cibles par l ARNIII. Le domaine 3 de l ARNIII inhibe l expression de la protéine A (spa) via un mécanisme de type antisens. Différentes approches (fusions traductionnelles, cartographie en solution, gel retard ) ont permis de montrer que le domaine 3 de l ARNIII, partiellement complémentaire du site de fixation au ribosome de l ARNm spa, forme un duplex étendu avec ce dernier et bloque sa traduction. Le duplex devient la cible d une ribonucléase (RNase III) conduisant à sa dégradation. Une approche bioinformatique a permis d identifier d autres gènes cibles du domaine 3 de l ARNIII, comme SA1000, protéine d adhésion, la coagulase, deux protéines homologues à l antigène sécrété SsaA (SA2353 et SA2093) et le facteur de transcription Rot. Un mécanisme de régulation analogue à celui de spa, a été validé pour l ensemble de ces facteurs, excepté pour Rot. L interaction implique plusieurs tiges-boucles de l ARN sans formation d un duplex étendu. Le domaine 3 de l ARNIII constitue à lui seul, un régulateur pléiotropique de l expression de facteurs de virulenceStaphylococcal pathogenesis is multifactorial, involving many virulence factors that are temporally regulated during the infection. The expression of most virulence factors is controlled by global regulators such as Agr ( accessory gene regulator ) which is the best characterized. The effector of the Agr system is a 514 nt regulatory RNA, RNAIII. During the post-exponential phase, RNAIII inhibits the expression of surface proteins and activates exoproteins and extracellular toxins. RNAIII controls virulence gene at the transcriptional and post-transcriptional levels. The aim of this study was to determine the post-transcriptional regulatory mechanism of targets genes by RNAIII. The 3 domain of RNAIII inhibits the synthesis of protein A using an antisens-RNA mechanism. Various technical approaches (translational fusions, probing in solution, gel shift,..) lead us to conclude that binding of RNAIII sequesters the Shine Dalgarno sequence of spa mRNA and induces rapid degradation by the double-strand specific RNase III. A bioinformatic approach was also used to predict new mRNA targets of the 3 domain of RNAIII. We have shown that several virulence factors, such as SA1000, a fibrinogen-like binding protein, the coagulase, two proteins homologous to the secretory antigen precursor SsaA (SA2353 and SA2093), and the repressor of toxins, Rot, are regulated by antisens regulatory mechanism similar to that described for spa. In addition, Rot is repressed by a mechanism involving multiple interactions with RNAIII without formation of an extended duplex. Hence, the 3 domain constitutes by itself a pleiotropic regulatory virulence domain of RNAIIILYON1-BU.Sciences (692662101) / SudocSudocFranceF