Identification of Cpgp40/15 Type Ib as the Predominant Allele in Isolates of Cryptosporidium spp. from a Waterborne Outbreak of Gastroenteritis in South Burgundy, France

ABSTRACT Cryptosporidium sp. isolates from a waterborne outbreak of diarrhea in France were analyzed by PCR-restriction fragment length polymorphism analysis and sequencing of the Cpgp40/15 locus. Ninety-one percent of the isolates were Cryptosporidium hominis type Ib. The results of this study and those of studies of other outbreaks suggest that the type Ib allele is the predominant allele associated with waterborne cryptosporidiosis.

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…

Speculation on whether a vaccine against cryptosporidiosis is a reality or fantasy

In this paper the authors question whether the development of a vaccine against cryptosporidiosis could be taken into consideration. The necessity and feasibility of such a vaccine for human and veterinary application is discussed. Developmental stages within the life cycle of the parasite that might act as possible targets for vaccine development are summarised, as well as the target antigens offered by molecular biology and immunology studies. Vaccination trials against cryptosporidiosis carried out so far, including the active and passive immunisation approach, are also overviewed. It seems that with respect to a Cryptosporidium vaccine two target groups can be considered: children of th…

Détection et identification de Fusarium spp. dans le réseau hydrique d’un centre hospitalier universitaire

Profiles and seasonal distribution of airborne fungi in indoor and outdoor environments at a French hospital

International audience; A one-year prospective survey of fungal air contamination was conducted in outdoor air and inside two haematological units of a French hospital. Air was sampled with a portable Air System Impactor. During this period of survey, the mean viable fungal load was 122.1 cfu/m(3) in outdoor air samples, and 4.1 and 3.9 cfu/m(3) in samples from adult and pediatric haematology units, respectively. In outdoor samples, Cladosporium was the dominant genus (55%) while in the clinical units, Penicillium sp. (23 to 25%), Aspergillus sp. (15 to 23%) and Bjerkandera adusta (11 to 13%) were the most frequently recovered airborne fungi. The outdoor fungal load was far higher in autumn…

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…

Hydro-contamination fongique par Fusarium spp. en milieu hospitalier pendant une période de construction

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…

Épidémiologie de populations de Fusarium oxysporum et F. dimerum en milieu hospitaliers à Dijon et Nancy

Fusarium oxysporum et F. dimerum sont des champignons d'origine tellurique présents dans de nombreux écosystèmes terrestres mais ils ont été récemment détectés dans les systèmes de distribution d'eau de bâtiments hospitaliers1. Une enquête épidémiologique incluant divers bâtiments hospitaliers sur différents sites, des complexes non-hospitaliers et des maisons individuelles a été menée pendant deux ans dans deux villes françaises, Dijon et Nancy. Les champignons ont été détectés seulement dans les canalisations de bâtiments hospitaliers et n'ont pas été détectés dans celles des autres immeubles ni dans l'eau du réseau urbain. Cette distribution surprenante s'explique par une combinaison de …

Mise en place d'un modèle in vivo de colonisation digestive stable à C. Abicans chez la souris immunocompétente

Les levures du genre Candida sont des agents pathogènes opportunistes responsables de candidoses invasives chez les sujets immunodéprimés, et sont associées à un taux de mortalité élevé. Elles représentent 8 à 15% des infections nosocomiales hématogènes et Candida albicans est l’espèce la plus fréquemment isolée en pathologie humaine. Initialement C. albicans appartient à la flore commensale intestinale, buccale et vaginale de l’homme. Ce commensalisme résulte d’un équilibre entre les propriétés biologiques de la levure et les systèmes de défense de l’hôte. La rupture de cet équilibre chez un patient fragilisé aura pour conséquence une colonisation intense des muqueuses favorisant un envahi…

Cellular interactions ofCandida albicanswith human oral epithelial cells and enterocytes

The human pathogenic fungus Candida albicans can cause systemic infections by invading epithelial barriers to gain access to the bloodstream. One of the main reservoirs of C. albicans is the gastrointestinal tract and systemic infections predominantly originate from this niche. In this study, we used scanning electron and fluorescence microscopy, adhesion, invasion and damage assays, fungal mutants and a set of fungal and host cell inhibitors to investigate the interactions of C. albicans with oral epithelial cells and enterocytes. Our data demonstrate that adhesion, invasion and damage by C. albicans depend not only on fungal morphology and activity, but also on the epithelial cell type an…

Adaptation inattendue de populations de Fusarium oxysporum et F. Dimerum au milieu aquatique urbain des conduites d'eau de bâtiments hospitaliers à Dijon et Nancyξ

National audience; Fusarium oxysporum et F. dimerum sont des champignons d'origine tellurique présents dans de nombreux écosystèmes terrestres mais ils ont été récemment détectés dans les systèmes de distribution d'eau de bâtiments hospitaliers. Une enquête épidémiologique incluant divers bâtiments hospitaliers sur différents sites, des complexes non-hospitaliers et des maisons individuelles a été menée pendant 2 ans dans deux villes françaises Dijon et Nancy. Les champignons ont été détectés seulement dans les canalisations de bâtiments hospitaliers et n'ont pas été détectés dans celles des autres immeubles ni dans l'eau du réseau urbain. Cette distribution surprenante s'explique par une c…

Les facteurs pronostiques de décès des candidémies chez les patients hospitalisés : une étude rétrospective dans un hôpital universitaire en France

Immunodetection of the microvillous cytoskeleton molecules villin and ezrin in the parasitophorous vacuole wall of Cryptosporidium parvum (Protozoa: Apicomplexa).

Microvilli - actin - villin - ezrin - Cryptosporidium parvum The sporozoites and merozoites of the Apicomplexan protozoan Cryptosporidium parvum (C. parvum) invade the apical side of enterocytes and induce the formation of a parasitophorous vacuole which stays in the brush border area and disturbs the distribution of microvilli. The vacuole is separated from the apical cytoplasm of the cell by an electron-dense layer of undetermined composition. In order to characterize the enterocyte cytoskeleton changes that occur during C. parvum invasion and development, we used both confocal immunofluorescence and immunoelectron microscopy to examine at the C.parvum-enterocyte interface the distributio…

Caspase-dependent apoptosis during infection with Cryptosporidium parvum

The protozoan parasite Cryptosporidium parvum causes persistent diarrhea and malnutrition in children and the diarrhea-wasting syndrome in AIDS. No therapy exists for eliminating the parasite in the absence of a healthy immune response. Although it had been reported that infection of intestinal cell lines with C. parvum leads to host cell death, the mechanisms of cytolysis have not been characterized. We show here that infection with C. parvum leads to typical apoptotic nuclear condensation and DNA fragmentation in host cells. Both nuclear condensation and DNA fragmentation are inhibited by a caspase inhibitor, showing that caspases are involved in this type of apoptosis. Finally, blocking …

Using a Multi-Locus Microsatellite Typing method improved phylogenetic distribution of Candida albicans isolates but failed to demonstrate association of some genotype with the commensal or clinical origin of the isolates.

EA MERS CT3 Enjeu 3; International audience; The dimorphic yeast Candida albicans is a component of the normal microflora at the mucosal surfaces of healthy individuals. It possesses an array of phenotypic properties considered as virulence traits that contribute to pathogenicity of the yeast in immuno-compromised patients. We addressed the question of the pathogenicity of lineages of C. albicans with regard to their genotype in three series of C. albicans isolates (a series of commensal isolates collected in healthy individuals, a group of bloodstream isolates and a group of non-bloodstream clinical isolates) using a Multi-Locus Microsatellite Typing (MLMT) approach based on the analysis o…

Adaptation of Fusarium oxysporum and Fusarium dimerum to the specific aquatic environment provided by the water systems of hospitals.

SPE IPM MERS EA; International audience; Members of the Fusarium group were recently detected in water distribution systems of several hospitals in the world. An epidemiological investigation was conducted over 2 years in hospital buildings in Dijon and Nancy (France) and in non-hospital buildings in Dijon. The fungi were detected only within the water distribution systems of the hospital buildings and also, but at very low concentrations, in the urban water network of Nancy. All fungi were identified as Fusarium oxysporum species complex (FOSC) and Fusarium dimerum species complex (FDSC) by sequencing part of the translation elongation factor 1- alpha (TEF-1a) gene. Very low diversity was …

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…

Profil épidémiologique et mycologique des dermatophytoses au CHU de Dijon (2007–2016)

International audience; IntroductionL’objectif de ce travail a été d’étudier le profil épidémiologique et mycologique des dermatophytoses diagnostiquées au laboratoire de parasitologie-mycologie du CHU de Dijon.Matériel et méthodesIl s’agit d’une étude rétrospective qui couvre une période de 10 ans (2007–2016). Seuls les examens mycologiques positifs pour les dermatophytes ont été pris en compte pour cette étude (genres Epidermophyton, Microsporum et Trichophyton).De janvier 2007 à août 2014, l’identification de ces micromycètes a été réalisée selon les caractères macro- et microscopiques des colonies fongiques. À partir de septembre 2014, leur identification a été réalisée par microscopie …

Candida albicansis able to use M cells as a portal of entry across the intestinal barrierin vitro

Candida albicans is the most frequent yeast responsible for systemic infections in humans. These infections mainly originate from the gastrointestinal tract where C. albicans can invade the gut epithelial barrier to gain access to the bloodstream. Along the gut, pathogens can use Microfold (M) cells as a portal of entry to cross the epithelial barrier. M cells are specialized cells mainly located in the follicule-associated epithelium of Peyer patches. In this study, we used scanning electron and fluorescence microscopy, adhesion and invasion assays and fungal mutants to investigate the interactions of C. albicans with M cells obtained in an established in vitro model whereby enterocyte-lik…

Les cellules M : une porte d’entrée pour le franchissement de la barrière intestinale par Candida albicans

Candida albicans est un pathogene opportuniste pouvant provoquer des infections systemiques chez des patients immunodeprimes. L’origine de ces infections est principalement d’origine endogene, notamment a partir du tractus gastro-intestinal, ou le champignon peut penetrer a travers la barriere epitheliale intestinale pour gagner ensuite la circulation sanguine. Au niveau de la muqueuse intestinale, les enterocytes forment une monocouche de cellules assurant l’integrite et l’impermeabilite du tissu digestif. Au niveau des plaques de Peyer notamment, les cellules Microfold (ou cellules M) sont associees aux enterocytes et jouent un role important dans l’homeostasie digestive. En effet, ces ce…

A Clonal Lineage of Fusarium oxysporum Circulates in the Tap Water of Different French Hospitals.

ABSTRACT Fusarium oxysporum is typically a soilborne fungus but can also be found in aquatic environments. In hospitals, water distribution systems may be reservoirs for the fungi responsible for nosocomial infections. F. oxysporum was previously detected in the water distribution systems of five French hospitals. Sixty-eight isolates from water representative of all hospital units that were previously sampled and characterized by translation elongation factor 1α sequence typing were subjected to microsatellite analysis and full-length ribosomal intergenic spacer (IGS) sequence typing. All but three isolates shared common microsatellite loci and a common two-locus sequence type (ST). This S…

Failure to differentiate Cryptosporidium parvum from C. meleagridis based on PCR amplification of eight DNA sequences.

ABSTRACT In order to determine the specificities of PCR-based assays used for detecting Cryptosporidium parvum DNA, eight pairs of previously described PCR primers targeting six distinct regions of the Cryptosporidium genome were evaluated for the detection of C. parvum , the agent of human cryptosporidiosis, and C. muris , C. baileyi , and C. meleagridis , three Cryptosporidium species that infect birds or mammals but are not considered to be human pathogens. The four Cryptosporidium species were divided into two groups: C. parvum and C. meleagridis , which gave the same-sized fragments with all the reactions, and C. muris and C. baileyi , which gave positive results with primer pairs targ…

Ensemble de Ressources Biologiques dédiées à l'Agroécologie (INRA, Dijon). Mieux connaître, conserver et utiliser les ressources du sol.

National audience; Les spécificités de la problématique biodiversité dans le domaine agricole sont directement liées à l'ensemble des ressources génétiques, qu'elles soient microbiennes, végétales ou animales, et nécessitent la prise en compte de ces multiples composantes, leur fonctionnalité et leurs interactions pour en assurer la conservation et la valorisation. Gérer ces ressources biologiques consiste à les préserver in situ, mais aussi, à les inventorier, les caractériser et les évaluer, les conserver ex situ éventuellement, les régénérer et les diffuser ainsi que les connaissances afférentes. En collaboration avec le CRB Ferdinand Cabanne (http://www.crbferdinandcabanne.fr/) du CHU d…

Mise en place d’un modèle in vivo de colonisation digestive stable à C. albicans chez la souris immunocompétente

Evaluation of CandiSelect4, a new chromogenic medium for isolation and presumptive identification of Candida species from clinical specimens

Abstract In clinical laboratories, isolation of Candida species is generally based on the culture of specimens on Sabouraud dextrose agar. This strategy does not allow species identification on primary culture and makes it difficult to detect mixed cultures. Chromogenic media contain substrates that react specifically with different Candida species, and partly overcome these difficulties. Objectives The aim of this study was to compare two chromogenic media: (i) CandiSelect4 (C4), a new medium developed for direct identification of C. albicans and presumptive identification of C. krusei , C. tropicalis and C. glabrata (ii) CHROMagar Candida (CH), a medium licensed for direct identification …

Contamination des circuits d’alimentation en eau par Fusarium

La decouverte de micromycetes du genre Fusarium dans le reseau hydrique du CHU de Dijon nous a conduit a mettre en place un protocole hospitalier de recherche clinique (PHRC) dont l’objectif a ete de decrire en prospectif, dans le temps et dans l’espace, la contamination par Fusarium dans l’eau de 2 CHU francais (Dijon et Nancy), a des periodes d’activites de restructuration et de construction. Cette etude a ainsi permis de mettre en evidence la presence chronique de Fusarium spp. dans les circuits de distribution de l’eau de certains bâtiments hospitaliers. Nous avons en effet observe que ces micromycetes etaient « installes » dans le reseau, que leur densite de population variait au cours…