285 research outputs found

    La brucellose bovine en Afrique centrale. II. Etude clinique et épidémiologique : particularités régionales et problèmes de l'élevage semi-intensif

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    L'étude clinique et épidémiologique de la brucellose bovine en Afrique centrale permet de préciser certains points: - La symptomatologie est dominée par les problèmes articulaires et synoviaux, mais l'avortement est également très fréquent, puisqu'il survient chez près de la moitié des femelles malades. Cet accident est une des composantes essentielles des pertes économiques, qui seront évaluées ultérieurement. - L'hygroma du genou, lésion très caractéristique dans cette région du monde, est réparti selon une fréquence très régulière. Il pourra servir de base à une méthode rapide d'enquête. L'importance de la brucellose est directement liée au système d'élevage, l'unité épidémiologique étant, avant tout, constituée par le troupeau gardé en commun durant la nuit. La forme épizootique apparaît dans certaines conditions, en élevage semi-intensif notamment, lorsqu'aucune mesure de prophylaxie n'est instauré

    Curbing methicillin-resistant Staphylococcus aureus in 38 French hospitals through a 15-year institutional control program

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    BACKGROUND: The Assistance Publique-Hôpitaux de Paris (AP-HP) institution administers 38 teaching hospitals (23 acute care and 15 rehabilitation and long-term care hospitals; total, 23 000 beds) scattered across Paris and surrounding suburbs in France. In the late 1980s, the proportion of methicillin resistance among clinical strains of Staphylococcus aureus (MRSA) reached approximately 40% at AP-HP.METHODS: A program aimed at curbing the MRSA burden was launched in 1993, based on passive and active surveillance, barrier precautions, training, and feedback. This program, supported by the strong commitment of the institution, was reinforced in 2001 by a campaign promoting the use of alcohol-based hand-rub solutions. An observational study on MRSA rate was prospectively carried out from 1993 onwards. RESULTS: There was a significant progressive decrease in MRSA burden (-35%) from 1993 to 2007, whether recorded as the proportion (expressed as percentage) of MRSA among S aureus strains (41.0% down to 26.6% overall; 45.3% to 24.2% in blood cultures) or incidence of MRSA cases (0.86 down to 0.56 per 1000 hospital days). The MRSA burden decreased more markedly in intensive care units (-59%) than in surgical (-44%) and medical (-32%) wards. The use of ABHR solutions (in liters per 1000 hospital days) increased steadily from 2 L to 21 L (to 26 L in acute care hospitals and to 10 L in rehabilitation and long-term care hospitals) following the campaign. CONCLUSION: A sustained reduction of MRSA burden can be obtained at the scale of a large hospital institution with high endemic MRSA rates, providing that an intensive program is maintained for a long period

    Single-Nucleotide Polymorphism Genotyping Identifies a Locally Endemic Clone of Methicillin-Resistant Staphylococcus aureus

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    We developed, tested, and applied a TaqMan real-time PCR assay for interrogation of three single-nucleotide polymorphisms that differentiate a clade (termed ‘t003-X’) within the radiation of methicillin-resistant Staphylococcus aureus (MRSA) ST225. The TaqMan assay achieved 98% typeability and results were fully concordant with DNA sequencing. By applying this assay to 305 ST225 isolates from an international collection, we demonstrate that clade t003-X is endemic in a single acute-care hospital in Germany at least since 2006, where it has caused a substantial proportion of infections. The strain was also detected in another hospital located 16 kilometers away. Strikingly, however, clade t003-X was not found in 62 other hospitals throughout Germany nor among isolates from other countries, and, hence, displayed a very restricted geographical distribution. Consequently, our results show that SNP-typing may be useful to identify and track MRSA clones that are specific to individual healthcare institutions. In contrast, the spatial dissemination pattern observed here had not been resolved by other typing procedures, including multilocus sequence typing (MLST), spa typing, DNA macrorestriction, and multilocus variable-number tandem repeat analysis (MLVA)

    Comparison and evaluation of experimental mediastinitis models: precolonized foreign body implants and bacterial suspension inoculation seems promising

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    BACKGROUND: Post-sternotomy mediastinitis (PSM) is a devastating surgical complication affecting 1–3% of patients that undergo cardiac surgery. Staphylococcus aureus is one of the most commonly encountered bacterial pathogen cultured from mediastinal samples obtained from patients with PSM. A component of the membrane of the gram positive bacteria, lipoteichoic acid, stimulates the blood monocytes and macrophages to secrete cytokines, radicals and nitrogen species leading to oxido-inflammatory damage. This seems to be responsible for the high mortality rate in PSM. For the evaluation of the pathogenesis of infection or for the investigation of alternative treatment models in infection, no standard model of mediastinitis seems to be available. In this study, we evaluated four mediastinitis models in rats. METHODS: The rats were divided into four groups to form different infection models. Group A: A suspension of 1 × 10(7 )colony-forming units Staphylococcus aureus in 0,5 mL was inoculated from the right second intercostal space into the mediastinum. Group B: A hole was created in the right second intercostal space and a piece of stainless-steel implant with a length of 0.5 cm was inserted into the mediastinum and a suspension of 1 × 10(7 )cfu bacteria in 0,5 mL was administered via the tail vein. Group C: Precolonized stainless-steel implant was inserted into the mediastinum. Group D: Precolonized stainless-steel implant was inserted into the mediastinum and the bacteria suspension was also injected into the mediastinum. On the 10(th )day, rats were sacrificed and the extension of infection in the mediastenae was evaluated by quantitative cultures. Myeloperoxidase activity (MPO) and malondialdehyde (MDA) levels were determined in the sera to evaluate the neutrophil activation and assess the inflammatory oxidation. RESULTS: The degree of infection in group C and D were 83.3% and 100% respectively (P < 0.001). MDA levels were significantly higher in these two groups than the others (P < 0.001). CONCLUSION: Infected implants and high bacterial concentration administration were the two important components that played a significant role in the outcome of a successful infection in mediastinum in a rat model

    The epidemiology and transmission of methicillin-resistant Staphylococcus aureus in the community in Singapore: study protocol for a longitudinal household study.

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    BACKGROUND/AIM: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common multidrug-resistant organisms in healthcare settings worldwide, but little is known about MRSA transmission outside of acute healthcare settings especially in Asia. We describe the methods for a prospective longitudinal study of MRSA prevalence and transmission. METHODS: MRSA-colonized individuals were identified from MRSA admission screening at two tertiary hospitals and recruited together with their household contacts. Participants submitted self-collected nasal, axilla and groin (NAG) swabs by mail for MRSA culture at baseline and monthly thereafter for 6 months. A comparison group of households of MRSA-negative patients provided swab samples at one time point. In a validation sub-study, separate swabs from each site were collected from randomly selected individuals, to compare MRSA detection rates between swab sites, and between samples collected by participants versus those collected by trained research staff. Information on each participant's demographic information, medical status and medical history, past healthcare facilities usage and contacts, and personal interactions with others were collected using a self-administered questionnaire. DISCUSSION/CONCLUSION: Understanding the dynamics of MRSA persistence and transmission in the community is crucial to devising and evaluating successful MRSA control strategies. Close contact with MRSA colonized patients may to be important for MRSA persistence in the community; evidence from this study on the extent of community MRSA could inform the development of household- or community-based interventions to reduce MRSA colonization of close contacts and subsequent re-introduction of MRSA into healthcare settings. Analysis of longitudinal data using whole-genome sequencing will yield further information regarding MRSA transmission within households, with significant implications for MRSA infection control outside acute hospital settings

    Mapping and functional analysis of heterochromatin protein 1 phosphorylation in the malaria parasite Plasmodium falciparum

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    Previous studies in model eukaryotes have demonstrated that phosphorylation of heterochromatin protein 1 (HP1) is important for dynamically regulating its various functions. However, in the malaria parasite Plasmodium falciparum both the function of HP1 phosphorylation and the identity of the protein kinases targeting HP1 are still elusive. In order to functionally analyze phosphorylation of P. falciparum HP1 (PfHP1), we first mapped PfHP1 phosphorylation sites by liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis of native PfHP1, which identified motifs from which potential kinases could be predicted; in particular, several phosphorylated residues were embedded in motifs rich in acidic residues, reminiscent of targets for P. falciparum casein kinase 2 (PfCK2). Secondly, we tested recombinant PfCK2 and a number of additional protein kinases for their ability to phosphorylate PfHP1 in in vitro kinase assays. These experiments validated our prediction that PfHP1 acts as a substrate for PfCK2. Furthermore, LC-MS/MS analysis showed that PfCK2 phosphorylates three clustered serine residues in an acidic motif within the central hinge region of PfHP1. To study the role of PfHP1 phosphorylation in live parasites we used CRISPR/Cas9-mediated genome editing to generate a number of conditional PfHP1 phosphomutants based on the DiCre/LoxP system. Our studies revealed that neither PfCK2-dependent phosphorylation of PfHP1, nor phosphorylation of the hinge domain in general, affect PfHP1's ability to localize to heterochromatin, and that PfHP1 phosphorylation in this region is dispensable for the proliferation of P. falciparum blood stage parasites
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