HAL-Paris 13
Not a member yet
33893 research outputs found
Sort by
Quantifying the effects of antibiotic resistance and within-host competition on strain fitness in Streptococcus pneumoniae
No full textInternational audienceCompetition plays a key role in shaping the structure and diversity of bacterial populations. In many clinically important bacterial species, strains compete at multiple scales: at the between-host scale for new hosts to colonise, and at the within-host scale during co-colonisation. Characterising these multiple facets of competition plays an important role in understanding bacterial ecology. This is particularly relevant for antibiotic resistance, where competition between antibiotic-susceptible and resistant strains determines resistance dynamics. In this work, we perform survival analyses on a large longitudinal dataset of Streptococcus pneumoniae carriage to quantify how within-host competition affects the rates of clearance and establishment of pneumococcal strains. We find that the presence of a within-host competitor is associated with a 33% increase in clearance and a 54% reduction in establishment. Priority effects and serotype differences partially predict the outcomes of this within-host competition. Further, we quantify the effects of antibiotic resistance on between- and within-host components of fitness. Antibiotic consumption is associated with increased clearance rate for both susceptible and resistant strains, albeit to a higher extent in susceptible strains. In the absence of antibiotics, we find some evidence that resistance is associated with increased susceptibility to within-host competition, suggesting a fitness cost of resistance. Overall, our work provides quantitative insights into pneumococcal competition across scales and the role of this competition in shaping pneumococcal epidemiology
A "One Health" vision of rabies in Saint-Louis in 2024: a study on knowledge, attitudes, and practices among health providers
No full textInternational audienceIntroduction: rabies remains a major public health issue in Senegal, with Saint-Louis being one of the most affected regions in 2022. Diagnostic challenges, gaps in case management, and inadequate attitudes and practices among health providers and the population contribute to the increasing risk. This study aimed to assess the knowledge, attitudes, and practices (KAP) of human and animal health providers regarding rabies in the Saint-Louis district. Methods: data were collected using a questionnaire developed on KoboToolbox and analyzed using R software version 4.3.3. This was a cross-sectional and analytical study conducted from July 15 to 28, 2024, with a sample of 161 human and animal health providers. The analyses included descriptive, bivariate, and multivariate assessments of variables, taking into account group comparisons. Results: two out of five participants (41.0%) had sufficient knowledge about rabies, 38.5% demonstrated a positive attitude, while 31.1% adopted good practices in the event of an animal bite. Multivariate analysis revealed that animal health providers were 7.64 times more likely to have sufficient knowledge about rabies compared to their human health counterparts (p = 0.083). Human and animal health providers with sufficient knowledge were 3.41 times more likely to adopt a positive attitude towards rabies (95% CI: [1.01-12.70]). Additionally, human and animal health providers with a positive attitude were 3.23 times more likely to implement good practices in response to an animal bite (95% CI: [1.08-10.70]). Conclusion: the study highlights the need to strengthen the training of human and animal health providers on rabies, emphasizing a "One Health" approach. Enhancing knowledge appears to be a critical lever for positively influencing attitudes and practices, thereby contributing to better management of this zoonosis
Des liaisons élastiques transitoires au frottement : étude complète d'une équation du quatrième ordre pénalisée avec retard
No full textInternational audienceIn this paper we consider a fourth order nonlinear parabolic delayed problem modeling a quasi-instantaneous turn-over of linkages in the context of cell-motility. The model depends on a small parameter ε which represents a typical time scale of the memory effect. We first prove global existence and uniqueness of solutions for ε fixed. This is achieved by combining suitable fixed-point and energy arguments and by uncovering a nonlocal in time, conserved integral quantity. After giving a complete classification of steady states in terms of elliptic functions, we next show that every solution converges to a steady state as . When , we then establish convergence results on finite time intervals, showing that the solution tends in a suitable sense towards the solution of a parabolic problem without delay. Moreover, we establish the convergence of energies as , which enables us to show that, for ε small enough, the -dependent problem inherits part of the large time asymptotics of the limiting parabolic problem
Les pratiques numériques des mouvements sociaux, entre autonomie communicationnelle et dépendance institutionnelle
No full textInternational audienceLa médiatisation des mouvements sociaux s’est transformée sous l’influence des technologies numériques, au point que certaines mobilisations ont fait le pari de s’émanciper des logiques traditionnelles de représentation en s’appuyant sur une communication en ligne. Jusqu’à quel point l’usage des plateformes numériques a-t-il permis de remplir cet objectif
Increasing Evidence Supports the Benefits of Rapid Uptitration of the Neurohormonal Blockade in HFmrEF/HFpEF Patients With AHF
No full textInternational audienceNo abstract availabl
Cloxacillin versus cefazolin for meticillin-susceptible Staphylococcus aureus bacteraemia (CloCeBa): a prospective, open-label, multicentre, non-inferiority, randomised clinical trial
No full textInternational audienceBACKGROUND: Although widely used, cefazolin efficacy for the treatment of meticillin-susceptible Staphylococcus aureus (MSSA) bacteraemia has not thus far been investigated in a clinical trial. In this study, we aimed to compare the efficacy and safety of cefazolin with that of cloxacillin in patients with MSSA bacteraemia. METHODS: We conducted an open-label, non-inferiority, randomised clinical trial in 21 university and non-university hospitals in France in adults (aged ≥18 years) with MSSA bacteraemia, without intravascular implant or suspicion of CNS infection. Participants were randomly assigned (1:1) to receive intravenously cefazolin (25-50 mg/kg every 8 h) or cloxacillin (25-50 mg/kg every 4-6 h) for the first 7 days of therapy using computer-generated blocks of various sizes and stratification on vascular-access associated bacteraemia and centre. Subsequent treatment was left to the choice of the investigator (total duration ≥14 days). The primary endpoint was a composite of sterile blood cultures at day 3 (day 5 for endocarditis) without relapse of bacteraemia, survival, and clinical success at day 90, and was assessed in the intention-to-treat population. A non-inferiority margin of 12% was chosen. This trial is registered on ClinicalTrials.gov (NCT03248063) and is complete. FINDINGS: Between Sept 5, 2018, and Nov 16, 2023, 315 participants were enrolled and assigned to cefazolin (n=158) or cloxacillin (n=157); 12 participants were excluded from analysis in the cefazolin group, and 11 in the cloxacillin group (final population of 146 in each group). Mean age was 62·7 years (SD 16·4), 215 (74%) participants were male, and race or ethnicity data were not collected. Median Pitt score was 0 (IQR 0-0). The primary endpoint was met in 109 (75%) of 146 participants in the cefazolin group versus 108 (74%) of 146 participants in the cloxacillin group (treatment difference -1%; 95% CI -11 to 9; p=0·012). At the end of study treatment, 22 (15%) of 146 participants assigned to cefazolin and 40 (27%) of 146 participants assigned to cloxacillin had had a serious adverse event (p=0·010). Acute kidney injury occurred more frequently in participants assigned to cloxacillin (15 [12%] of 128) than in those assigned to cefazolin (one [1%] of 134; p=0·0002). INTERPRETATION: Cefazolin constitutes an alternative to cloxacillin for the treatment of MSSA bacteraemia, offering non-inferior clinical efficacy and potentially enhanced tolerability. FUNDING: French Ministry of Health
Local distribution of rational points in flag varieties
No full textGiven a flag variety X defined over Q and a point x in X(R), we study approximations to x by points v in X(Q), and show that, with an appropriate rescaling, those approximations equidistribute when x is chosen randomly according to a Lebesgue measure on X(R), or when x is defined over Q and satisfies some non-degeneracy condition.</div
A Constraint Opinion Model
No full textInternational audienceThis paper introduces a generalised opinion model that extends the standard DeGroot model by representing agents' opinions and influences as soft constraints rather than single real values. This allows for modelling scenarios beyond the scope of the DeGroot model, such as agents sharing partial information and preferences, engaging in discussions on multiple topics simultaneously, and representing opinions with different degrees of uncertainty. By considering soft constraints as influences, the proposed model captures also situations where agents impose conditions on how others' opinions are integrated during belief revision. Finally, the flexibility offered by soft constraints allows us to introduce a novel polarisation measure that takes advantage of this generalised framework
Galectin-3/CD146 interaction promotes renal damage and systemic inflammation after acute kidney injury
No full textInternational audienceAbstract Galectin-3 (Gal-3) expression is abnormally increased after renal ischemic injury, in various studies, further promoting tissue damage. Gal-3 may interact with the endothelial layer to induce inflammation during renal injury, linking the systemic and tissue compartments. However, this mechanism has not been investigated after acute kidney injury (AKI). To this end, wild-type (WT) and Gal-3-/- mice underwent renal ischemia followed by reperfusion (rIR). Bone marrow transplantation was used to differentiate Gal-3 expression in renal tissue from systemic bone marrow cells. WT mice were injected with recombinant Gal-3 to study systemic issues. Gal-3 expression was assessed by immunofluorescence, western blot, and scRNAseq. Systemic pathways were analyzed with plasma proteomics. Immunofluorescence and scRNAseq showed increased Gal-3 expression after rIR, in different tubular segments and infiltrating immune cells within damaged kidneys. In bone marrow transplanted mice, renal dysfunction, damage, and inflammation were higher when Gal-3 was expressed in renal tissue. Gal-3 upregulation was associated with endothelial activation and renal inflammation after rIR, both of which were prevented in Gal-3-/- mice. Similar results were confirmed by plasma proteomics, as these mice showed reduced endothelial damage and rIR-associated inflammatory pathways. Systemic injection of recombinant Gal-3 increased the endothelial adhesion molecule CD146 expression in the kidney, without promoting renal injury. Interestingly, isolated renal tubules showed increased Gal-3 levels, interacting with CD146 to promote cytokine secretion and immune cell infiltration in the kidney. Thus, Gal-3 may promote endothelial activation via direct interaction with the endothelial activation marker CD146 after AKI, leading to renal injury and further systemic inflammation
Les recherches participatives dans la co-production des sciences et des savoirs
No full textQuel diagnostic faire sur les pratiques de la recherche participative ? Quels sont ses enjeux éthiques et institutionnels ? Les actions concrètes menées au sein de l'IRD contribuent à la fois à structurer une communauté de pratiques, à définir les garanties de l'intégrité des recherches et à instaurer la confianceentre les chercheurs et les publics concernés