A temperature-type model for describing the relationship between fungal growth and water activity

Growth of Penicillium chrysogenum, Aspergillus flavus, Cladosporium cladosporioides and Alternaria alternata at their respective optimum temperatures was studied in Potato Dextrose Agar (PDA) medium at different water activities (a(w)) adjusted with glycerol. The growth rate (mu) was expressed as the increase in colony radius per unit of time. This paper extends the model that showed the relationship between temperature and bacterial growth rate developed by Rosso et al. [J. Theor. Biol. 162 (1993) 447] to describe the influence of a(w) on fungal development. An excellent correlation between the experimental data and the model predictions was obtained, the regression coefficients (r2) were …

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

Steroidal saponins from Asparagus acutifolius.

Abstract Six new steroidal saponins ( 1 – 6 ) were isolated from the roots of A. acutifolius L., together with a known spirostanol glycoside ( 7 ). Their structures were elucidated mainly by extensive spectroscopic analysis (1D and 2D NMR, FABMS and HRESIMS). Compounds 4 – 7 demonstrated antifungal activity against the human pathogenic yeasts C. albicans , C. glabrata and C. tropicalis with MICs values between 12.5 and 100 μg/ml.

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…

Mise au point d’un modèle de co-culture cellules entérocytes et d’un modèle de colonisation digestive stable chez la souris immuno-compétente permettant d’étudier les interactions cellulaires et moléculaires in vitro et in vivo de C. albicans avec la muqueuse digestive

National audience

Steroidal saponins and flavan-3-ol glycosides from Dioscorea villosa

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

Rbt1 Protein Domains Analysis in Candida albicans Brings Insights into Hyphal Surface Modifications and Rbt1 Potential Role during Adhesion and Biofilm Formation

Cell wall proteins are central to the virulence of Candida albicans. Hwp1, Hwp2 and Rbt1 form a family of hypha-associated cell surface proteins. Hwp1 and Hwp2 have been involved in adhesion and other virulence traits but Rbt1 is still poorly characterized. To assess the role of Rbt1 in the interaction of C. albicans with biotic and abiotic surfaces independently of its morphological state, heterologous expression and promoter swap strategies were applied. The N-terminal domain with features typical of the Flo11 superfamily was found to be essential for adhesiveness to polystyrene through an increase in cell surface hydrophobicity. A 42 amino acid-long domain localized in the central part o…

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 …

Candida albicans interaction with M cells in an in vitro model of the human intestinal Follicle Associated Epithelium (FAE)

National audience; Candida albicans (C. albicans) is a microorganism belonging to the commensal flora of the intestinal, oral and vaginal mucosal surfaces in healthy humans. This commensalism results from a balance between the virulence factors of the yeast and defense mechanisms of the host. However, disturbance of this balance in a vulnerable patient may result in intense mucosal colonization that promotes invasion of epithelial cells, translocation across the intestinal epithelial barrier and, eventually hematogenous dissemination. A better understanding of the mechanisms by which C. albicans interacts with the intestinal mucosa will improve our knowledge of the physiopathology of dissem…

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…

Antifungal steroid saponins from Dioscorea cayenensis.

From the rhizomes of Dioscorea cayenensis Lam.-Holl (Dioscoreaceae), the new 26- O- beta- D-glucopyranosyl-22-methoxy-3 beta,26-dihydroxy-25( R)-furost-5-en-3- O- alpha- L-rhamnopyranosyl-(1-->4)- alpha- L-rhamnopyranosyl-(1-->4)-[ alpha- L-rhamnopyranosyl-(1-->2)]- beta- D-glucopyranoside ( 1) was isolated together with the known dioscin ( 2) and diosgenin 3- O- alpha- L-rhamnopyranosyl-(1-->4)- alpha- L-rhamnopyranosyl-(1-->4)-[ alpha- L-rhamnopyranosyl-(1-->2)]- beta- D-glucopyranoside ( 3). Their structures were established on the basis of spectral data. Compound 2 exhibited antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata and C. tropicalis (MICs of …

A new ecdysteroid and other constituents from two Dioscorea species

Phytochemical investigation of the rhizome of Dioscorea dumetorum has led to the isolation by several chromatographic steps on normal and reversed phase silica gel of a new ecdysteroid, (20R)-5β,11α,20-trihydroxyecdysone (1), and two known ecdysteroids, ajugasterone C (2) and herkesterone (3). Their structures were determined by spectroscopic methods including 1D- and 2D-NMR (COSY, TOCSY, HSQC and HMBC). This is the first report on the occurrence of phytoecdysteroids in the Dioscoreaceae family. These compounds were devoid of antifungal activity against three Candida species (Candida albicans, Candida glabrata and Candida tropicalis, MIC > 200 μg/ml).

Évaluation du kit de PCR en temps réel MycoGENIE ® Pneumocystis jirovecii pour le diagnostic moléculaire de la pneumocystose

Pneumocystis jirovecii (Pj) est un champignon pathogene opportuniste strictement humain. Il colonise transitoirement et sans symptome l’arbre respiratoire des patients immunocompetents, et peut etre responsable d’infections pulmonaires severes chez les patients immunodeprimes. Le diagnostic biologique de pneumocystose repose sur la mise en evidence du pathogene a l’examen direct d’un prelevement pulmonaire profond. Si l’examen direct manque souvent de sensibilite, de nombreuses techniques de PCR se sont developpees pour ameliorer la sensibilite de detection du champignon. Les techniques de PCR quantitatives (qPCR) permettent de quantifier la charge fongique dans le prelevement, et potentiel…

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…

Prediction of conidial germination of Penicillium chrysogenum as influenced by temperature, water activity and pH.

M. SAUTOUR, A. ROUGET, P. DANTIGNY, C. DIVIES AND M. BENSOUSSAN. 2001 Aims: Conidial germination of Penicillium chrysogenum was carried out under operating conditions compatible with a pastries manufacturing process. Methods and Results: A range, limited by two experimental values, was defined for each environmental factor tested: temperature (15 or 25°C), water activity (0·75 or 0·85) and pH (3·5 or 5·5). A closed device was made, which maintained an equilibrium between water activity of the culture medium and atmospheric relative humidity during 25 days, to follow spore germination. The combined effects of temperature, water activity and pH on spore germination were studied by applying fa…

Steroidal saponins from Smilax medica and their antifungal activity.

Three new steroidal saponins (1-3) were isolated from the roots of Smilax medica, together with the known disporoside A (4). The structures of the new compounds were elucidated mainly by extensive spectroscopic analysis (1D and 2D NMR, FABMS, and HRESIMS). Compounds 1, 2, and 4 demonstrated weak antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata, and C.tropicalis, with MIC values between 12.5 and 50 microg/mL.

Ruling out nosocomial transmission of Cryptosporidium in a renal transplantation unit: case report

Background Cryptosporidium spp. is a ubiquitous parasite affecting humans as well as domestic and wild vertebrates, causing diarrhea in both immunocompetent and immunocompromised hosts worldwide. Its transmission occurs primarily by the fecal-oral route. In humans, C. parvum and C. hominis are the most prevalent species, whereas immunocompetent and immunocompromised individuals can also be infected by other zoonotic species. Renal transplant patients are prone to develop cryptosporidiosis, which can induce severe and life-threatening diarrhea. Case presentation We report here a series of nearly concomitant cases of acute symptomatic cryptosporidiosis in three renal transplant patients atten…

Oestrus ovis external ophtalmomyiasis : a case report in Burgundy France

Background External ophtalmomyiasis (EOM) is a zoonosis related to the presence of Oestrus ovis larvae at the ocular level in small ruminants (i.e. ovine, caprine). In humans, EOM is a rare cosmopolitan disorder, mostly described in warm and dry rural areas in patients living close to livestock areas. In metropolitan France (excluding Corsica), EOM is an exceptional disease with less than 25 cases recorded since 1917. Case presentation We report a case of EOM in a 19-years old man in the last week of September 2016 in Burgundy. Conclusion The diagnosis of an EOM in Burgundy, a French region described as cold and humid, is surprising and could be due to a more marked climatic warming during …

Sphingolipids and other constituents from Cordia platythyrsa

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 …

Infection pulmonaire invasive à Trichoderma longibrachiatum, à propos d’un cas

Introduction : Trichoderma longibrachiatum est un champignon filamenteux appartenant à la famille des hyalohyphomycètes, rarement isolé lors d’infections fongiques invasives chez l’Homme mais quelques cas ont déjà été décrits chez des sujets immunodéprimés. Observation : Un homme de 69 ans a développé un syndrome fébrile une semaine après la fin d’une chimiothérapie pour le traitement d’une leucémie aiguë myéloïde alors qu’il était en aplasie profonde (GB Aspergillus Galactomannan test), un scanner thoracique est réalisé. L’aspect scannographique (signe du halo) était évocateur d’une aspergillose pulmonaire invasive (API), motivant la réalisation d’un lavage broncho-alvéolaire (LBA). Le LBA…

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…

Identification clinique par spectrométrie de masse MALDI-TOF des champignons filamenteux : construction de banques de données pour les dermatophytes et les Fusarium

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…

Action de la chlorhexidine sur l'expression de la virulence de

Abstract Candida albicans is an opportunistic yeast. Its pathogenicity is linked to the susceptibility of the host surface as well as to particular factors of the strain: adhesion, filamentous growth and secretion of proteolytic enzymes. Chlorhexidine digluconate is an antiseptic with fungicidal properties. The action of the antiseptic on the growth of the yeast shows a minimal inhibitory concentration (MIC) at 50 μg·mL−1 and a minimal fungicidal concentration (MFC) at 100 μg·mL−1. The consequences of antiseptic treatment are studied using two indicators of pathogenicity: filamentation and the secretion of acid proteinase. Concerning the morphological indicator, a complete inhibition of fil…

A New Phenanthrene Glycoside and Other Constituents from Dioscorea opposita

Phytochemical investigation of the rhizome of Dioscorea opposita has led to the isolation of a new phenanthrene glycoside, 3,4,6-trihydroxyphenanthrene-3-O-beta-D-glucopyranoside (1), and five known compounds, soyacerebroside I (2), adenosine (3), beta-sitosterol (4), palmitic acid (5) and palmitoyloleoylphosphatidylcholine (6). Their structures were determined by spectroscopic methods, including 1D- and 2D-NMR. Compounds 1-6 exhibited no antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata and C. tropicalis.

Steroidal saponins from the roots of Smilax aspera subsp. mauritanica

Two new steroidal saponins (1, 2) were isolated from the roots of Smilax aspera subsp. mauritanica (POIR.) ARCANG. (Liliaceae), together with the known curillin G (3), asparagoside E (4), asparoside A (5), asparoside B (6) and the phenolic compound resveratrol (7). Their structures were established mainly on the basis of 600 MHz 2D-NMR spectral data. 3 exhibited antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata and C. tropicalis (minimum inhibitory concentrations of 25, 25 and 50 microg/ml, respectively) whereas the other compounds were inactive.

Bioactive Steroidal Saponins from Smilax medica

Two new spirostanol saponins ( 1 and 2) were isolated from the roots of Smilax medica, together with the known smilagenin 3-O-beta-D-glucopyranoside (3). Their structures were determined by spectroscopic methods including 1D- and 2D-NMR experiments. Compounds 1 and 2 exhibited antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata and C. tropicalis (MICs between 6.25 and 50 microg/mL) whereas 3 was inactive.

A New Steroidal Saponin from Dioscorea cayenensis

The new 26-O-beta-D-glucopyranosyl-3beta,26-dihydroxy-20,22-seco-25(R)-furost-5-en-20,22-dione-3-O-alpha-L-rhamnopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->4)-[alpha-L-rhamnopyranosyl-(1-->2)]-beta-D-glucopyranoside (1), along with the known methyl protodioscin (2), asperoside (3) and prosapogenin A of dioscin (4) were isolated from the rhizomes of Dioscorea cayenensis LAM.-HOLL (Dioscoreaceae). Their structures were established mainly on the basis of 600 MHz 2D-NMR spectral data. 4 exhibited antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata and C. tropicalis (MICs of 20.8, 6.25, 25 microg/ml, respectively), whereas saponins 1-3 were inactive.

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…

Additional file 1: of Oestrus ovis external ophtalmomyiasis: a case report in Burgundy France

Figure S1. Parasite cycle of Oestrus ovis. Oestrus ovis exerts a strict parasitism of the nasal cavities of small sheep and goat ruminants. The viviparous females of Oestrus ovis deposit first-stage larvae (L1) directly in the nasal orifices of sheep and goats. L1 actively penetrate through the nasal orifices and colonize the cornets and septum where they will develop. Once located at the ethmoid level, L1 molt to stage 2 larvae (L2). L2 further ascend from the nasal cavity to the frontal sinuses where they molt to stage 3 larvae (L3). Thereafter, L3 are expelled from the nasal cavity of the host by sneezing via the nasal mucus that subsequently contaminate the soils. Then, L3 turn into a p…