Les médiateurs de l'immunité anti-candida : outils d'analyse physiopathologique et intérêt diagnostique

Candida albicans, digestive tract endo-saprophyte, is responsible of superficial and invasive infections. Invasive candidiasis (IC) is a persistent public health with an attributable mortality of 40% in intensive care unit and an exponential morbidity related to the antifungals consumption and extended hospital stays of patients. This medico-economic impact is mainly related to diagnostic difficulties. Indeed, neither clinical symptoms nor the imaging are specific of IC. Biological diagnosis remains complex and often late. Conventional tests (blood culture) have a low sensitivity, and non-culture based methods often lack sensitivity or specificity. In this context, it’s necessary to develop new diagnostic strategies to improve the early diagnosis, to identify patients with high risk of infection and to lead the prescription of an appropriate antifungal therapy. Our work has focused on two circulating anti-Candida immunity mediators, mannose-binding lectin (MBL) and anti-protein antibodies (Ab) in relation to IC diagnosis. Regarding the detection of antibodies, we produced six recombinant proteins (Hwp1, Eno1, Hsp90, FBA1, Mp65 and Sod5) overexpressed during the C. albicans pathogen phase and developed five prototypes of EIA. The association of these biomarkers with the detection of circulating mannan (Mn) revealed three proteins with high diagnostic performances. For a specificity fixed arbitrarily at 80%, the sensitivity of combinations of Fba1-Ab/Mn, Hwp1-Ab/Mn and Hsp90-Ab/Mn were 84%, 84% and 81%, respectively. The average delay of positivity was 5 days before isolation of Candida from blood culture. Odds ratios associated with these three combinations of markers were 108, 65 and 77 for Fba1-Ab/Mn, Hwp1-Ab/Mn and Hsp90-Ab/Mn, respectively. Our findings on serum MBL have shown i) dynamic evolution of MBL levels during IC, ii) direct interaction with circulating cell wall mannan and iii) susceptibility to colonization in MBL deficient patients. Besides quantitative aspects, we have developed a model for assessing the MBL functionality by surface plasmon resonance (SPR) involving whole cells, fungal cell wall glycans from C. albicans cell wall or synthetic oligommanosides. This model was used to better characterize the epitopes recognized by MBL and showed the interaction of this lectin with a panel of Candida species commonly isolated in human pathology.These mediators of innate or humoral immunity open new clinical perspectives in terms of diagnostic or prognosis of IC. These findings may participate to improve our understanding of IC pathophysiology and to optimize management of patients.Candida albicans, endo-saprophyte du tube digestif, est responsable d’infections superficielles ou invasives. Les candidoses invasives (CI) constituent un problème persistant de santé publique avec une mortalité attribuable de 40% en réanimation et une morbidité exponentielle liée à la consommation d’antifongiques ou aux séjours prolongés des patients. Cet impact médico-économique est principalement lié aux difficultés diagnostiques. En effet, ni la symptomatologie, ni l’imagerie ne sont spécifiques des CI. Le diagnostic biologique demeure complexe et souvent tardif. Les tests conventionnels (hémoculture) sont peu sensibles, et les tests alternatifs à la culture manquent souvent de sensibilité ou de spécificité. Dans ce contexte, il est nécessaire de développer de nouvelles stratégies diagnostiques en mesure d’améliorer la précocité du diagnostic, d’identifier les sujets à haut risque d’infection et de permettre la mise en place d’un traitement antifongique approprié. Notre travail a porté sur deux médiateurs circulants de l’immunité anti-Candida, la mannose-binding lectin (MBL) et les anticorps anti- proteines (Ab) en relation le diagnostic des CI.En ce qui concerne la détection d’anticorps, nous avons produit 6 protéines recombinantes (Hwp1, Eno1, Hsp90, Fba1, Mp65 et Sod5), surexprimées pendant la phase pathogène de C. albicans et développés 5 prototypes de tests EIA. L’association de ces biomarqueurs avec la détection du mannane circulant (Mn) par EIA a permis d’identifier 3 protéines à fort potentiel diagnostique. Pour une spécificité fixée arbitrairement à 80%, la sensibilité des associations Fba1-Ab/Mn, Hwp1-Ab/Mn et Hsp90-Ab/Mn étaient de 84%, 84% et 81% respectivement. Le délai moyen de positivité était de 5 jours avant l’isolement de Candida d’hémoculture. Les Odds ratios associés aux trois combinaisons de marqueurs étaient de 108, 65 et 77 pour Fba1-Ab/Mn, Hwp1-Ab/Mn et Hsp90-Ab/Mn.En ce qui concerne la MBL, nous avons montré i) une évolution dynamique de la MBL au cours des CI, ii) une interaction directe avec le mannane pariétal de levure ainsi qu’une iii) prédisposition à la colonisation chez les patients déficients en MBL. Outre les aspects quantitatifs, nous avons mis en place un modèle d’évaluation fonctionnels de la MBL par resonance plasmonique de surface (SPR) en impliquant des cellules entières ou des glycannes fongiques issus de la paroi de C. albicans ou des oligommanosides de synthèse. Ce modèle nous a permis de mieux caractériser les épitopes reconnus par la MBL et de montrer l’interaction de cette lectine avec un panel d’espèces Candida communément isolées en pathologie humaine.Ces médiateurs de l’immunité humorale ou innée permettent d’envisager des perspectives cliniques en termes diagnostique ou pronostique. Ils permettent également d’améliorer notre compréhension de la physiopathologie des CI et d’optimiser la prise en charge des patients

Anti-candida immune mediators : pathophysiological analysis tools and diagnosis interest

Candida albicans, endo-saprophyte du tube digestif, est responsable d’infections superficielles ou invasives. Les candidoses invasives (CI) constituent un problème persistant de santé publique avec une mortalité attribuable de 40% en réanimation et une morbidité exponentielle liée à la consommation d’antifongiques ou aux séjours prolongés des patients. Cet impact médico-économique est principalement lié aux difficultés diagnostiques. En effet, ni la symptomatologie, ni l’imagerie ne sont spécifiques des CI. Le diagnostic biologique demeure complexe et souvent tardif. Les tests conventionnels (hémoculture) sont peu sensibles, et les tests alternatifs à la culture manquent souvent de sensibilité ou de spécificité. Dans ce contexte, il est nécessaire de développer de nouvelles stratégies diagnostiques en mesure d’améliorer la précocité du diagnostic, d’identifier les sujets à haut risque d’infection et de permettre la mise en place d’un traitement antifongique approprié. Notre travail a porté sur deux médiateurs circulants de l’immunité anti-Candida, la mannose-binding lectin (MBL) et les anticorps anti- proteines (Ab) en relation le diagnostic des CI.En ce qui concerne la détection d’anticorps, nous avons produit 6 protéines recombinantes (Hwp1, Eno1, Hsp90, Fba1, Mp65 et Sod5), surexprimées pendant la phase pathogène de C. albicans et développés 5 prototypes de tests EIA. L’association de ces biomarqueurs avec la détection du mannane circulant (Mn) par EIA a permis d’identifier 3 protéines à fort potentiel diagnostique. Pour une spécificité fixée arbitrairement à 80%, la sensibilité des associations Fba1-Ab/Mn, Hwp1-Ab/Mn et Hsp90-Ab/Mn étaient de 84%, 84% et 81% respectivement. Le délai moyen de positivité était de 5 jours avant l’isolement de Candida d’hémoculture. Les Odds ratios associés aux trois combinaisons de marqueurs étaient de 108, 65 et 77 pour Fba1-Ab/Mn, Hwp1-Ab/Mn et Hsp90-Ab/Mn.En ce qui concerne la MBL, nous avons montré i) une évolution dynamique de la MBL au cours des CI, ii) une interaction directe avec le mannane pariétal de levure ainsi qu’une iii) prédisposition à la colonisation chez les patients déficients en MBL. Outre les aspects quantitatifs, nous avons mis en place un modèle d’évaluation fonctionnels de la MBL par resonance plasmonique de surface (SPR) en impliquant des cellules entières ou des glycannes fongiques issus de la paroi de C. albicans ou des oligommanosides de synthèse. Ce modèle nous a permis de mieux caractériser les épitopes reconnus par la MBL et de montrer l’interaction de cette lectine avec un panel d’espèces Candida communément isolées en pathologie humaine.Ces médiateurs de l’immunité humorale ou innée permettent d’envisager des perspectives cliniques en termes diagnostique ou pronostique. Ils permettent également d’améliorer notre compréhension de la physiopathologie des CI et d’optimiser la prise en charge des patients.Candida albicans, digestive tract endo-saprophyte, is responsible of superficial and invasive infections. Invasive candidiasis (IC) is a persistent public health with an attributable mortality of 40% in intensive care unit and an exponential morbidity related to the antifungals consumption and extended hospital stays of patients. This medico-economic impact is mainly related to diagnostic difficulties. Indeed, neither clinical symptoms nor the imaging are specific of IC. Biological diagnosis remains complex and often late. Conventional tests (blood culture) have a low sensitivity, and non-culture based methods often lack sensitivity or specificity. In this context, it’s necessary to develop new diagnostic strategies to improve the early diagnosis, to identify patients with high risk of infection and to lead the prescription of an appropriate antifungal therapy. Our work has focused on two circulating anti-Candida immunity mediators, mannose-binding lectin (MBL) and anti-protein antibodies (Ab) in relation to IC diagnosis. Regarding the detection of antibodies, we produced six recombinant proteins (Hwp1, Eno1, Hsp90, FBA1, Mp65 and Sod5) overexpressed during the C. albicans pathogen phase and developed five prototypes of EIA. The association of these biomarkers with the detection of circulating mannan (Mn) revealed three proteins with high diagnostic performances. For a specificity fixed arbitrarily at 80%, the sensitivity of combinations of Fba1-Ab/Mn, Hwp1-Ab/Mn and Hsp90-Ab/Mn were 84%, 84% and 81%, respectively. The average delay of positivity was 5 days before isolation of Candida from blood culture. Odds ratios associated with these three combinations of markers were 108, 65 and 77 for Fba1-Ab/Mn, Hwp1-Ab/Mn and Hsp90-Ab/Mn, respectively. Our findings on serum MBL have shown i) dynamic evolution of MBL levels during IC, ii) direct interaction with circulating cell wall mannan and iii) susceptibility to colonization in MBL deficient patients. Besides quantitative aspects, we have developed a model for assessing the MBL functionality by surface plasmon resonance (SPR) involving whole cells, fungal cell wall glycans from C. albicans cell wall or synthetic oligommanosides. This model was used to better characterize the epitopes recognized by MBL and showed the interaction of this lectin with a panel of Candida species commonly isolated in human pathology.These mediators of innate or humoral immunity open new clinical perspectives in terms of diagnostic or prognosis of IC. These findings may participate to improve our understanding of IC pathophysiology and to optimize management of patients

Strategic Approach, Advances, and Challenges in the Development and Application of the SIT for Area-Wide Control of Aedes albopictus Mosquitoes in Reunion Island

International audienceSimple Summary: Aedes albopictus is a well-established competent arbovirus vector in Reunion Island, a French overseas territory in the Indian Ocean, occurring in a range of natural to urban environments where it represents a major threat to public health. Following the 2006 Chikungunya outbreak and periodic occurrence of dengue epidemics, the sterile insect technique (SIT) emerged as the most environment-friendly option for integration with the current vector control strategy that relies mainly on the elimination of breeding sites and insecticide applications. This paper describes the trajectory that has been followed in assessing the feasibility of SIT against Ae. albopictus in Reunion Island, and reviews some of the main achievements since 2009. These include essential scientific information so far obtained on the biology and ecology of Ae. albopictus, and the development of the requisite technological capabilities for the production and release of sexually competitive sterile males. Furthermore, it also draws attention to the strategies established to streamline the decision-making process, including an awareness campaign to enhance public understanding, efforts to secure public acceptance and regulatory validation of SIT pilot testing for small-scale suppression of wild Ae. albopictus in selected urban sites on the island. Abstract: The global expansion of Aedes albopictus, together with the absence of specific treatment and vaccines for most of the arboviruses it transmits, has stimulated the development of more sustainable and ecologically acceptable methods for control of disease transmission through the suppression of natural vector populations. The sterile insect technique (SIT) is rapidly evolving as an additional tool for mosquito control, offering an efficient and more environment-friendly alternative to the use of insecticides. Following the devastating chikungunya outbreak, which affected 38% of the population on Reunion Island (a French overseas territory in the southwest of the Indian Ocean), there has been strong interest and political will to develop effective alternatives to the existing vector control strategies. Over the past 10 years, the French Research and Development Institute (IRD) has established an SIT feasibility program against Ae. albopictus on Reunion Island in collaboration with national and international partners. This program aimed to Insects 2020, 11, 770 2 of 25 determine whether the SIT based on the release of radiation-sterilized males is scientifically and technically feasible, and socially acceptable as part of a control strategy targeting the local Ae. albopictus population. This paper provides a review of a multi-year and a particularly broad scoping process of establishing the scientific and technological feasibility of the SIT against Ae. albopictus on Reunion Island. It also draws attention to some prerequisites of the decision-making process, through awareness campaigns to enhance public understanding and support, social adoption, and regulatory validation of the SIT pilot tests

Archives de la peur

Qui sont les récidivistes pontissaliens livrés par les Cahiers des récidives correctionnelles de première Instance de l’arrondissement de Pontarlier ? Quelle est la spécificité de la prostitution pratiquée à Besançon, ville de garnison, où les filles sont victimes de la violence des soldats ? Le Petit Comtois livre le récit du crime à la Belle Époque où le lecteur retrouve les « assassins des villes ». Loin des représentations du crime, les procès retrouvés dans les arrêts de la cour d’assises du Doubs montrent la détresse des jeunes filles qui pratiquent l’infanticide au nom de leur honneur perdu. Dans l’attribution de la naturalisation, la République souhaite trouver chez les étrangers toutes les qualités qu’elle voudrait voir chez ses nationaux : la naturalisation est un honneur dont il faut assurer les charges. Cet ouvrage, dans un récit d’une grande cohérence, raconte la manière dont la Franche-Comté pense et vit les moments saillants de la pensée du mal et du malheur devenant particulièrement obsédante à la veille de la guerre de 1914. L’énumération de ces récits décline le registre noir des malheurs du temps qui s’accompagnent d’une promotion sans précédent de l’intériorisation de la conscience morale. Sous la Troisième République, ces Archives de la peur deviendront le creuset juridique, où se formalisera le droit social, qui incorporera à l’intérieur des drames et des souffrances le droit des personnes, que ce soit dans l’ordre des filiations, celui du travail ou de la nationalité

Field evaluation of seasonal trends in relative population sizes and dispersal pattern of Aedes albopictus males in support of the design of a sterile male release strategy

Abstract Background To develop an efficient sterile insect technique (SIT) programme, the number of sterile males to release, along with the spatial and temporal pattern of their release, has to be determined. Such parameters could be estimated from a reliable estimation of the wild population density (and its temporal variation) in the area to treat. Here, a series of mark-release-recapture experiments using laboratory-reared and field-derived Aedes albopictus males were carried out in Duparc, a selected pilot site for the future application of SIT in the north of La Reunion Island. Methods The dispersal, longevity of marked males and seasonal fluctuations in the population size of native mosquitoes were determined from the ratio of marked to unmarked males caught in mice-baited BG-Sentinel traps. The study was conducted during periods of declining population abundance (April), lowest abundance (September) and highest abundance (December). Results According to data collected in the first 4 days post-release, the Lincoln index estimated population size as quite variable, ranging from 5817 in April, to 639 in September and 5915 in December. Calculations of daily survival probability to 4 days after release for field and laboratory males were 0.91 and 0.98 in April, respectively, and 0.88 and 0.84 in September, respectively. The mean distance travelled (MDT) of released field males were 46 m, 67 m and 37 m for December, April and September experiments, respectively. For released laboratory males, the MDT was 65 m and 42 m in April and September, respectively. Conclusions Theoretically, the most efficient release programme should be started in July/August when the mosquito population size is the lowest (c.600 wild males/ha relative to 5000 wild males estimated for December and April), with a weekly release of 6000 males/ha. The limited dispersal of Ae. albopictus males highlights the nessecity for the widespread release of sterile males over multiple sites and in a field setting to avoid topographical barriers and anthropogenic features that may block the migration of the released sterile male mosquitoes

Comparison of Efficiency of BG-Sentinel Traps Baited with Mice, Mouse-Litter, and CO2 Lures for Field Sampling of Male and Female Aedes albopictus Mosquitoes

Determining the abundance and distribution of male mosquitoes in the wild and establishing species seasonality in candidate pilot sites is of particular interest with respect to the use of the sterile-male technique. With the knowledge that using mice as bait in BG-Sentinel traps effectively enhances Aedes albopictus male and female trapping success, the present study was designed to determine whether attractants derived from mouse odour blend could be a viable substitute for live mice to lure Ae. albopictus mosquitoes into traps. The effects of baiting BG-Sentinel traps with mice, carbon dioxide (CO2), and attractants derived from litter mouse odours (mouse litter (ML)) and a mouse odour blend (MOB) on the efficiency of trapping Ae. albopictus males and females were tested using a Latin square design. The BG-Sentinel trap baited with CO2 + ML caught a significantly larger number of mosquitoes compared to traps baited with mice only. The BG-Sentinel traps containing only CO2 or CO2 + MOB, however, did not catch significantly more mosquitoes compared to the other traps. The proportions of males caught in the BG-Sentinel traps did not differ significantly between the respective attractants. The results from this study confirm that CO2 bait is efficient to provide a reliable estimation method for Ae. albopictus adult male abundance in the wild, and suggest that mouse litter baits in combination with CO2 could be used to enhance Aedes trapping success in BG-Sentinel traps

Evaluation of MALDI-TOF mass spectrometry for the identification of medically-important yeasts in the clinical laboratories of Dijon and Lille hospitals

EA MERSInternational audienceConventional identification (CI) of yeasts is based on morphological, biochemical and/or immunological methods. Matrix-assisted laser desorption/ionization - time of flight (MALDI-TOF or MT-MS) mass spectrometry has been proposed as a new method for the identification of microorganisms. This prospective study compared the performance of MT-MS and CI for the identification of yeasts isolated from clinical samples. Sequencing of the internal transcribed spacer (ITS) regions of ribosomal DNA was used as the reference method in the analysis of a total of 1207 yeast isolates. Concordance between MT-MS and CI was observed for 1105 isolates (91.5%), while 74 isolates (6.1%) were misidentified. Molecular identification revealed that 73 of these 74 isolates were identified correctly by MT-MS and CI correctly identified the last one. Concordance between the two techniques was excellent for the medically-important species (98-100%), including the identification of closely-related species (Candida albicans/C. dubliniensis; C. inconspicua/C. norvegensis; C. parapsilosis/C. metapsilosis/C. orthopsilosis). Only 2.3% of isolates belonging to C. famata, C. lambica and C. magnoliae or to Geotrichum spp. and Trichosporon spp. were not identified by MT-MS. This investigation highlights the potential of MT-MS-based yeast identification as a reliable, time and cost-efficient alternative to CI

Enhancement of the BG-sentinel trap with varying number of mice for field sampling of male and female Aedes albopictus mosquitoes

International audienceBackground: Trapping male mosquitoes in the field is essential for the development of area-wide vector control programs with a sterile insect technique (SIT) component. To determine the optimal temporal and spatial release strategy, an estimation of the wild population density and its temporal dynamics is essential. Among the traps available for such data collection, the BG-Sentinel trap developed by the Biogents company uses a combination of visual cues, convection currents and olfactory signals. Although in numerous cases, this trap has shown high efficiency in sampling Aedes albopictus, in some cases low capture rates of Ae. albopictus males were recorded for the BG-sentinel mosquito trap baited with synthetic attractants.Methods: The effects of modifying the BG-sentinel trap (by adding one mouse, two or three live mice to the trap) on the efficiency of trapping Ae. albopictus males and females was tested. The experiment was carried out in three distinct areas on La Réunion that have been selected for pilot field testing of the release of sterile male Ae. albopictus mosquitoes. The effect of four types of attractant (including the generic BG-Lure, one mouse or two to three mice) in baited BGS traps was tested with a Latin square design in order to control for the variability of different sampling positions and dates.Results: At the three studied sites, the number of Ae. albopictus adults caught and the proportion of males per trap consistently increased with the number of mice present in the trap.Conclusions: The results from this study suggest that some new attractants derived from, or similar to, mouse odors could be developed and tested in combination with other existing attractive components, such as CO2 and heat, in order to provide a reliable estimation method for Ae. albopictus adult male abundance in the wil

Complementarity of empirical and process-based approaches to modelling mosquito population dynamics with Aedes albopictus as an example: Application to the development of an operational mapping tool of vector populations

International audienceMosquitoes are responsible for the transmission of major pathogens worldwide. Modelling their population dynamics and mapping their distribution can contribute effectively to disease surveillance and control systems. Two main approaches are classically used to understand and predict mosquito abundance in space and time, namely empirical (or statistical) and process-based models. In this work, we used both approaches to model the population dynamics in Reunion Island of the 'Tiger mosquito', Aedes albopictus, a vector of dengue and chikungunya viruses, using rainfall and temperature data. We aimed to i) evaluate and compare the two types of models, and ii) develop an operational tool that could be used by public health authorities and vector control services. Our results showed that Ae. albopictus dynamics in Reunion Island are driven by both rainfall and temperature with a non-linear relationship. The predictions of the two approaches were consistent with the observed abundances of Ae. albopictus aquatic stages. An operational tool with a user-friendly interface was developed, allowing the creation of maps of Ae. albopictus densities over the whole territory using meteorological data collected from a network of weather stations. It is now routinely used by the services in charge of vector control in Reunion Island