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Objectives: The aim of this study was to visualize the morphology of Candida albicans ATCC10231 in the absence and in the presence of amphotericin B at 0.4 μg/mL, to better understand the phenomenon responsible for a large portion of cases of treatment failure called "dormancy phenomenon". The main objective was to determine the morphological changes adopted by C. albicans in the lag phase extended before resuming normal growth., Materials and Methods: In order to define the morphological characteristics and surface properties of the cells in the absence and in the presence of amphotericin B at 0.4 μg/mL, cells were cultured in Sabouraud medium at 30°C, and the morphology index was determined by reference to the classification of forms in C. albicans determined by Merson-Davies and Odds. Then, the technique of scanning electron microscopy (SEM) coupled with image analysis was used to measure the surface and determined the morphological properties using the plugin analysis three-dimensional (3D) integrated into the ImageJ software., Results: The dormant phase in C. albicans ATCC10231 grown in Sabouraud liquid at 30°C in the presence of amphotericin B at 0.4 μg/mL extends to 21 hours. The index morphology obtained for the two samples (in the absence and presence of amphotericin B) indicates that the cell even in the presence of amphotericin B retains its yeast form (Mi<1.5) The analysis of microphotography obtained by scanning electron microscopy (SEM) has shown that the cell in the presence of amphotericin B is partially deformed; the deformation is estimated at 33.25%, with various changes in the cell surface., Conclusion: This study showed that the morphology of C. albicans ATCC10231 in the presence of amphotericin B at 0.4 μg/mL changes with partial deformation of the cell. This rate is insufficient to induce cell death, which partly explains the phenomenon of dormancy adopted by C. albicans prior to cell repair and resume normal growth., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Colonization of biomaterial by Candida species could be the first step of Candida infection. We examined the in vitro adherence capabilities of five Candida species to polyvinyl chlorure (PVC). Twenty stains were tested: C. albicans (9), C. glabrata (3), C. tropicalis (3), C. kefyr (4) and C. parapsilosis (1). The adherence to PVC was evaluated by direct microscopic examination. The results indicate that the adherence of C. albicans to PVC is similar to that of C. glabrata and C. tropicalis. Only C. kefyr adheres to a lower degree. We conclude that the adherence capabilities of non-albicans species were similar to that of C. albicans. There is a relationship between the adherence of Candida species and their abilities to colonize the biomaterial. The species, which are more adherent, are those, which are more virulent.

During infection by human immunodeficiency virus (HIV), oral pseudomembranous candidiasis frequency is high. Adherence of Candida albicans to epithelial cells constitutes one of the first step in the setting up of candidiasis. Adherence ability of Candida albicans to buccal epithelial cells (BEC) is estimated for 83 isolates. The yeasts are isolated from buccal swabs from HIV+ patients with clinical oropharyngeal candidiasis. Results show that Candida albicans ability to adhere to BEC is variable within isolates; it appears that most of the isolates are weakly adherent. In addition, adherence is not correlated with the serotype A or B of yeasts. We do not either observe any correlation between adherence capacity and sensibility of yeasts to fluconazole. Moreover, no correlation is observed between a group of 13 genetically identical isolates (analysed on 21 loci with isoenzymes method) and their adherence to BEC. Finally, Candida albicans virulence, which is studied in vivo on intravenously infected mouse model, does not seem to be correlated with capacity of each yeast to adhere on BEC in vitro.

Candida albicans is a versatile organism living as a commensal of the gastro-intestinal tract and having the ability to invade host tissues and to initiate serious diseases under the appropriate environmental conditions. The molecular basis for adherence, invasion, interactions with specific and non-specific immune factors have been studied in parallel to structural characteristics of the yeast. The main parasitologic features are closely linked to phenotypic variations. In this respect, mannoproteins are strongly involved in the cell wall variations. The study of the oligomannosidic repertoire represents one of the essential steps for the understanding of host-parasite relationships.

Candida albicans was grown in the darkness, at 28 degrees C, in a synthetic medium in which glucose and nitrogen concentrations were varied. Numeric appraisal of the chlamydospore index was possible only in the medium where glucose concentration was 0,08 g/1 or less. When the glucose concentration raised, pseudomycelial thalli bore numerous chlamydospores but sometimes also chains of cells with a dense granular content. These thalli bud yeast cells which separate and bud again in the medium. The different morphological aspects of the cultures are decribed, illustrated and classified according to the glucose and nitrogen concentration of the medium.

The taxonomical value of the specific distinction of C. albicans and C. stellatoidea was in mind, in the mycological study of: one homogenous group of 292 isolates of C. albicans and an other of 11 C. stellatoidae, of collection in majority. The growth in a liquid medium, the production: of chlamydospores, mycelium, pseudomycelium, germ-tubes, the fermentation and assimilation of carbohydrates, the tetrazolium-test, the actidione resistance and the maximal temperature for growth were the morpho-physiological characteristics studied. Were also reported some variations observed on two C. stellatoidea from which the type-strain of that species, cultured in two different laboratories.

Candida albicans is cultivated on rice cream decoction with glucose for chlamydospore production. A developmental stage refered as readiness is recognized. At this stage, the pseudomycelial thalli are able to produce chlamydospore in water without further stimulus by the sporulation medium. The greater the inoculum, the earlier appears the readiness. During the growth phase up to the readiness, the light is inhibiting the chlamydosporulation and favorising the yeast development. After the readiness, light still inhibits chlalmydospore formation.

Probably all pathogenic fungi can cause opportunistic infections in compromised hosts. This paper briefly reviews our knowledge on the saprophytic life - geographic distribution and habitat - of the most common pathogenic fungi. Some mycoses are of endogenous origin - e.g. Candida albicans is an endosaprophyte - others of epigenon origin - e.g. Pityrosporum ovale is an episaprophyte - but most mycoses are caused by fungi which have an exosaprophytic (or exosaprobic) life: one becomes infected after exposure to the saprobic source of the fungus. Nevertheless, it should be kept in mind that mycoses, e.g., cryptococcosis, coccidioidomycosis, and histoplasmosis, in compromised hosts are not necessarily the result of recent exposure but may be the result of the reactivation of latent or inactive forms.

Chlamydospore production by Candida albicans was investigated in rice cream decoction inoculated with a blastospore suspension. Effects of glucose, KH2PO4, (NH4)2SO4 and biotin addition were estimated using a "chlamydospore index" i.e. the mean-number of mature chlamydospores produced from a single blastospore development. If no other component was added, it appeared that better sporulation was obtained with both glucose concentration and inoculum size optimum (0.5 g/l and 7.8 X 10(3) blastospores/ml respectively). In glucose-KH2PO4 enriched medium, chlamydosporulation was the best with 0.5 g/l glucose and 0.5 g/l KH2PO4. The addition of biotin reduced the chlamydospore index at the concentrations tested (0.6 to 20 microgram/l). When glucose and (NH4)2SO4 were added together, it seemed that one of the C or N component had to be in low concentration for a good sporulation. The action of salts was also investigated; and finally a synthetic medium is proposed. The improvement of this medium is now in progress.