Etudes des mécanismes moleculaires et cellulaires intervenant au cours de l'interaction de Candidi albicans avec les cellules intestinales caco-2 : rôle des tight junctions

Optimization of the preanalytical steps of matrix-assisted laser desorption ionization-time of flight mass spectrometry identification provides a flexible and efficient tool for identification of clinical yeast isolates in medical laboratories.

ABSTRACT We report here that modifications of the preanalytical steps of matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) identification of yeasts, with regard to the original protocol provided by the manufacturers, appear to be efficient for the reliable routine identification of clinical yeast isolates in medical laboratories. Indeed, when one colony was sampled instead of five and the protein extraction protocol was modified, the performance of MALDI-TOF MS was superior to that of the API ID 32C method (discrepancies were confirmed by using molecular identification), allowing the correct identification of 94% of the 335 clinical isolates prospec…

Dynamics of fungal colonization in a new medical mycology laboratory

International audience; Objective of the study. - Study of the spatio-temporal fungal colonization in a new medical mycology laboratory. Methods. - A 17-month survey of airborne fungal contamination was conducted in a new medical mycology laboratory at a tertiary care university hospital. This survey was implemented at three different periods: before the new premises were occupied (period A), during the move into the new laboratory (period B) and after resumption of the mycological activities in these new premises (period C). Results. - During period A, the airborne fungal load ranged from 2.3 to 6 cfu/m(3). The most frequently recovered airborne fungi were Penicillium spp. (75 to 100%). Du…

Adaptation de Candida albicans dans les tissus humains: du commensalisme à la pathogénicité

National audience; Candida albicans (C. albicans) est un micro-organisme eucaryote appartenant à la flore commensale des muqueuses de l’homme sain. Ce commensalisme résulte d’un équilibre entre la levure et les systèmes de défense de l’hôte. La rupture de cet équilibre chez un patient fragilisé (sujet infecté par le VIH, neutropénique, cancéreux, transplanté ou séjournant en service de réanimation) favorisera une colonisation intense des muqueuses, un envahissement de la barrière digestive et enfin la possibilité de dissémination hématogène. Les candidémies restent des infections graves puisque la mortalité directement attribuable à l’infection est estimée à 38%. Nos travaux ont d’abord por…

Enterocytes'tight junctions play a protective role in limiting invasion of Candida albicans into intestinal cells

National audience; C. albicans is a commensal yeast of the mucous membranes in healthy humans that can also be responsible for disseminated candidiasis, mainly originating from the digestive tract in vulnerable patients. Deciphering the cellular and molecular mechanisms of the interaction of C. albicans with enterocytes is necessary to better understand the basis of commensalism and pathogenicity of the yeast and to improve the management of disseminated candidiasis. In intestinal epithelia, E-cadherin is constitutive of the Adherens Junctions localized just below the Tight Junctions (TJs) which ensure impermeability of the intestinal barrier. We hypothesized the absence of endocytosis of C…

Mécanismes cellulaires et moléculaires de l'interaction de C-albicans avec les cellules épithéliales intestinales : rôle des Tight junctions

Fusarium species recovered from the water distribution system of a French university hospital

Abstract Dijon Hospital is a French tertiary care institution undergoing major renovation, and different microbiological controls revealed the presence of Fusarium spp. in the water distribution system. Because some Fusarium spp. can cause life-threatening opportunistic infections in immunocompromised patients, an 8-month survey was conducted in two hospital sites in order to evaluate the prevalence of the fungi in the water system. In 2 units of one hospital site, 100% of the samples of tap-water were positive, with high concentrations of Fusarium spp. (up to 10 5  cfu/L). In the second hospital site, 94% of samples were positive, but generally with lower concentrations. The analysis of tr…