Epidemiology of Candida albicans infections and role of non-Candida-albicans yeasts.
ABSTRACT Infections of the skin and the mucous membranes due to Candida species may occur either in immuncompromised or in non-immuncompromised patients. This is in contrast to systemic candidiasis (e.g. candidemia) which is only seen in severely immunocompromised patients. Bloodstream infections caused by Candida species are increasingly recognized in critical ill adult and pediatric individuals, with significant associated morbidity and mortality. Candida albicans is the single most common fungal species causing nosocomial infections. However, non-Candida albicans spp., including fluconazole-less-susceptible Candida glabrata, have become more common pathogens. In some patient populations such as hematological (neutropenic) patients Non-C. albicans species are detected much more frequently as compared to non-neutropenic patients in the intensive care. Non-C. albicans species are more likely to occur in patients, who receive or have received antifungal therapy with azoles (e.g. fluconazole). In this review the current epidemiological trends in mucosal and invasive candidiasis are discussed with regard to the role of non-Candida albicans species as the causative agent in immunocompromised patients.
- SourceAvailable from: Chantal Guillard[Show abstract] [Hide abstract]
ABSTRACT: We have investigated the antimicrobial effects of photocatalysis on the yeast model Saccharomyces cerevisiae. To accurately study the antimicrobial mechanisms of the photocatalytic process, we focused our investigations on two questions: the entry of the nanoparticles in treated cells and the fate of the intracellular environment. Transmission electronic microscopy (TEM) did not reveal any entry of nanoparticles within the cells, even for long exposure time, despite degradation of the cell wall space and deconstruction of cellular compartments. Contrary to proteins located at the periphery of the cells, intracellular proteins did not disappear uniformly. Disappearance or persistence of proteins from the pool of oxidized intracellular isoforms was not correlated to their functions. Altogether our data suggested that photocatalysis induces the establishment of an intracellular oxidative environment. This hypothesis was sustained by the detection of an increased level of superoxide ions (O2 (°-)) in treated cells and by greater cell cultivability for cells expressing oxidant stress response genes during photocatalytic exposure. The increase in intracellular ROS, which was not connected to the entry of nanoparticles within the cells or to a direct contact with the plasma membrane, could be the result of an imbalance in redox status amplified by chain reactions. Moreover, we expanded our study to other yeast and filamentous fungi and pointed out that, contrary to the S. cerevisiae laboratory model, some environmental strains are very resistant to photocatalysis. This could be related to the cell wall composition and structure.Applied and Environmental Microbiology 09/2014; · 3.95 Impact Factor
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ABSTRACT: Because of the need for more effective and less harmful antifungal therapies, and interest in the synthesis of new carboximidamides, the goal of this study was to determine the antifungal and anti-enzyme activities of some new pyrazole carboximidamides and their cytotoxicity. For this purpose, tests were performed to evaluate: minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC); production of proteinases and phospholipase, and cytotoxicity of the extracts. Data were analyzed by ANOVA and Tukey Tests (α = 5%). The results were: MIC and MFC ≥ 62.5 μg/mL (C. albicans, C. parapsilosis, C. famata, C. glabrata, and Rhodotorula mucillaginosa) and MIC and MFC ≥ 15.6 μg/mL (C. lipolytica). The values of proteinase and phospholipase (Pz) of C. albicans before and after exposure to the compounds were: 0.6 (±0.024) and 0.2 (±0.022) and 0.9 (±0.074) and 0.3 (±0.04), respectively. These proteinase results were not significant (p = 0.69), but those of phospholipase were (p = 0.01), and 15.6 μg/mL was the most effective concentration. The cytotoxicity means were similar among the tests (p = 0.32). These compounds could be useful as templates for further development through modification or derivatization to design more potent antifungal agents. Data from this study provide evidence that these new pyrazole formulations could be an alternative source for the treatment of fungal infections caused by Candida. However, a specific study on the safety and efficacy of these in vivo and clinical trials is still needed, in order to evaluate the practical relevance of the in vitro results.Molecules 01/2014; 19(5):5806-5820. · 2.43 Impact Factor
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ABSTRACT: Minor species of the Candida albicans complex may cause overestimation of the epidemiology of C. albicans, and misidentifications could mask their implication in human pathology. Authors determined the occurrence of minor species of the C. albicans complex (C. africana, C. dubliniensis and C. stellatoidea) among Yaoundé HIV-infected patients, Cameroon. Stool, vaginal discharge, urine and oropharyngeal samples were analysed by mycological diagnosis. Isolates were identified by conventional methods and mass spectrometry (MS; carried out by the matrix-assisted laser desorption–ionisation time-of-flight MS protocol). Candida albicans isolates were thereafter submitted to the PCR amplification of the Hwp1 gene. The susceptibility of isolates to antifungal drugs was tested using the Clinical and Laboratory Standards Institute M27-A3 protocol. From 115 C. albicans obtained isolates, neither C. dubliniensis nor C. stellatoidea was observed; two strains of C. africana (422PV and 448PV) were identified by PCR electrophoretic profiles at 700 bp. These two C. africana strains were vaginal isolates. The isolate 448PV was resistant to ketoconazole at the minimal inhibitory concentration of 2 μg ml−1, and showed reduced susceptibility to amphotericin B at 1 μg ml−1. This first report on C. africana occurrence in Cameroon brings clues for the understanding of the global epidemiology of this yeast as well as that of minor species of the C. albicans complex.Mycoses 10/2014; · 1.28 Impact Factor