Candida parapsilosis endocarditis: a comparative review of the literature

Fungal endocarditis (FE) is an uncommon disease, and while accounting for only 1.3-6% of all cases of infectious endocarditis, it carries a high mortality risk. Although Candida albicans represents the main etiology of FE, C. parapsilosis is the most common non-albicans species. We report the case of a 32-year-old man with a history of prior intravenous drug (IVD) use hospitalized with endocarditis due to C. parapsilosis and review all 71 additional cases documented in the literature. A retrospective analysis of the 72 C. parapsilosis cases compared to 52 recently reviewed cases of C. albicans endocarditis was conducted to identify organism-specific clinical peculiarities. The most common predisposing factor for C. parapsilosis endocarditis (41/72; 57.4%) involved prosthetic valves followed by IVD use (12/72; 20%). Peripheral embolic and/or hemorrhagic events occurred in 28/64 (43.8%) patients, mostly in cerebral and lower limb territories. Overall mortality was 41.7%. Combined surgical and clinical treatment was associated with a lower mortality. Few patients received the newer antifungal agents, and it would appear that more experience is required for their use in the treatment of C. parapsilosis endocarditis.

Capacidade de adesão e formação de biofilme de Candida ssp. isoladas da cavidade oral de pacientes transplantados renais na presença do extrato de Eugenia uniflora

Candidiasis is a major oral manifestation in kidney transplant patients. Candida spp. possess essential virulence factors which contribute for the infectious process, including the ability to adhere to epithelial cells and biofilm formation. The extract obtained from the leaves of Eugenia uniflora [acetone: water (7:3, v/v)] has demonstrated antifungal activity against Candida spp. This study evaluated the influence of the extract of E. uniflora in adhesion to human buccal epithelial cells (HBEC) and biofilm formation of 42 strains of Candida spp. isolated from the oral cavity of kidney transplant patients. Candida spp. strains belonging to a culture collection were reactivated and phenotypically re-identified by classical and molecular methods (genotyping ABC and RAPD), when necessary, to complete the identification to the species level. For the virulence tests evaluated in vitro, yeasts were grown in the presence and absence of 1000 g/mL of the extract. A ratio of 10: 1 (Candida spp. cells x HBECs) was incubated for 1 hour at 37 ° C, 200 rpm, fixed with 10% formalin and the number of Candida cells adhered to 150 HBEC determined by optical microscope. Biofilms were formed on polystyrene microplates in the presence or absence of the extract. The quantification was performed with crystal violet staining at 570 nm. All isolates were viable and exhibited phenotypic characteristics suggestive of each species identified. Two strains presumptively identified as Candida dubliniensis belonged to this species as determined with genotyping ABC, while strains identified as belonging to the Candida parapsilosis species complex were differentiated by RAPD genotyping. Candida albicans was found to be the most adherent species to the buccal epithelia, while C. tropicalis showed remarkable biofilm formation.We could detect that the extract of E. uniflora was able to reduce adhesion to HBEC for both Candida albicans and non-Candida albicans Candida species. On the other hand, only 16 Candida spp. strains (36 %) showed reduced biofilm formation. However, two highly biofilm producer strains of C. tropicalis had an expressive reduction in biofilm formation. This study reinforces the idea that besides growth inhibition, E. uniflora may interfere with the expression of some virulence factors of Candida spp., and may be possibly applied in the future as a novel antifungal agent.

Étude comparative entre la quantité de Candida spp. présente sur le palais et sur la pièce prothétique chez les patients porteurs d'une prothèse complète au maxillaire supérieur

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Étude comparative entre la quantité de Candida spp. présente sur le palais et sur la pièce prothétique chez les patients porteurs d'une prothèse complète au maxillaire supérieur

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

In vitro anti-Candida activity of Glycyrrhiza glabra L.

The severity and frequency of opportunistic fungal infections still growing, concomitantly to the increasing rates of antimicrobial drug’s resistance. Natural matrices have been used over years due to its multitude of health benefits, including antifungal potential. Thus, the present work aims to evaluate the anti-Candida potential of the phenolic extract and individual phenolic compounds of Glycyrrhiza glabra L. (licorice), by disc diffusion assay, followed by determination of the minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) for both planktonic cells and biofilms. Licorice extract evidenced inhibitory potential against the nineteen tested Candida strains, but no pronounced effect was observed by testing the most abundant individual phenolic compounds. Candida tropicalis strains were the most sensible, followed by Candida glabrata, Candida parapsilosis and, then, Candida albicans. Lower MIC and MFC values were achieved to C. glabrata and C. tropicalis, which confirms its susceptibility to licorice extract; however, for C. tropicalis strains a higher variability was observed. Anti-biofilm potential was also achieved, being most evident in some C. glabrata and C. tropicalis strains. In general, a twice concentration of the MIC was necessary for planktonic cells to obtain a similar potential to that one observed for biofilms. Thus, an upcoming approach for new antifungal agents, more effective and safer than the current ones, is stablished; notwithstanding, further studies are necessary in order to understand its mechanism of action, as also to assess kinetic parameters.

Estudio de la patogenicidad de Candida y de la actividad de los fármacos antifúngicos en un modelo animal en Caenorhabditis elegans

171 p.

Candida duobushaemulonii: an emerging rare pathogenic yeast isolated from recurrent vulvovaginal candidiasis in Brazil

The aim of this study was to identify Candida species isolated from women diagnosed with recurrent vulvovaginal candidiasis (RVVC) and their partners; and to evaluate the fluconazole (FLZ) susceptibility of the isolates. In a period of six years, among 172 patients diagnosed with vulvovaginal candidiasis, 13 women that presented RVVC and their partners were selected for this investigation. The isolates were obtained using Chromagar Candida medium, the species identification was performed by phenotypic and molecular methods and FLZ susceptibility was evaluated by E-test. Among 26 strains we identified 14 Candida albicans , six Candida duobushaemulonii, four Candida glabrata , and two Candida tropicalis . Agreement of the isolated species occurred in 100% of the couples. FLZ low susceptibility was observed for all isolates of C. duobushaemulonii (minimal inhibitory concentration values from 8-> 64 μg/mL), two C. glabrata isolates were FLZ-resistant and all C. albicans and C. tropicalis isolates were FLZ-susceptible. This report emphasises the importance of accurate identification of the fungal agents by a reliable molecular technique in RVVC episodes besides the lower antifungal susceptibility profile of this rare pathogen C. duobushaemulonii to FLZ.

Colonización oral por Candida y su relación con la presencia de caries y/o enfermedad periodontal crónica en población adulta del País Vasco

250 p.

Highly effective fungal inactivation in He+O2 atmospheric-pressure nonequilibrium plasmas

Highly effective (more than 99.9%) inactivation of a pathogenic fungus Candida albicans commonly found in oral, respiratory, digestive, and reproduction systems of a human body using atmospheric-pressure plasma jets sustained in He+ O2 gas mixtures is reported. The inactivation is demonstrated in two fungal culture configurations with open (Petri dish without a cover) and restricted access to the atmosphere (Petri dish with a cover) under specific experimental conditions. It is shown that the fungal inactivation is remarkably more effective in the second configuration. This observation is supported by the scanning and transmission electron microscopy of the fungi before and after the plasma treatment. The inactivation mechanism explains the experimental observations under different experimental conditions and is consistent with the reports by other authors. The results are promising for the development of advanced health care applications.

Mixture models of nucleotide sequence evolution that account for heterogeneity in the substitution process across sites and across lineages

Molecular phylogenetic studies of homologous sequences of nucleotides often assume that the underlying evolutionary process was globally stationary, reversible, and homogeneous (SRH), and that a model of evolution with one or more site-specific and time-reversible rate matrices (e.g., the GTR rate matrix) is enough to accurately model the evolution of data over the whole tree. However, an increasing body of data suggests that evolution under these conditions is an exception, rather than the norm. To address this issue, several non-SRH models of molecular evolution have been proposed, but they either ignore heterogeneity in the substitution process across sites (HAS) or assume it can be modeled accurately using the distribution. As an alternative to these models of evolution, we introduce a family of mixture models that approximate HAS without the assumption of an underlying predefined statistical distribution. This family of mixture models is combined with non-SRH models of evolution that account for heterogeneity in the substitution process across lineages (HAL). We also present two algorithms for searching model space and identifying an optimal model of evolution that is less likely to over- or underparameterize the data. The performance of the two new algorithms was evaluated using alignments of nucleotides with 10 000 sites simulated under complex non-SRH conditions on a 25-tipped tree. The algorithms were found to be very successful, identifying the correct HAL model with a 75% success rate (the average success rate for assigning rate matrices to the tree's 48 edges was 99.25%) and, for the correct HAL model, identifying the correct HAS model with a 98% success rate. Finally, parameter estimates obtained under the correct HAL-HAS model were found to be accurate and precise. The merits of our new algorithms were illustrated with an analysis of 42 337 second codon sites extracted from a concatenation of 106 alignments of orthologous genes encoded by the nuclear genomes of Saccharomyces cerevisiae, S. paradoxus, S. mikatae, S. kudriavzevii, S. castellii, S. kluyveri, S. bayanus, and Candida albicans. Our results show that second codon sites in the ancestral genome of these species contained 49.1% invariable sites, 39.6% variable sites belonging to one rate category (V1), and 11.3% variable sites belonging to a second rate category (V2). The ancestral nucleotide content was found to differ markedly across these three sets of sites, and the evolutionary processes operating at the variable sites were found to be non-SRH and best modeled by a combination of eight edge-specific rate matrices (four for V1 and four for V2). The number of substitutions per site at the variable sites also differed markedly, with sites belonging to V1 evolving slower than those belonging to V2 along the lineages separating the seven species of Saccharomyces. Finally, sites belonging to V1 appeared to have ceased evolving along the lineages separating S. cerevisiae, S. paradoxus, S. mikatae, S. kudriavzevii, and S. bayanus, implying that they might have become so selectively constrained that they could be considered invariable sites in these species.

Oral Immune Defense against Chronic Hyperplastic Candidosis

Candida yeast species are widespread opportunistic microbes, which are usually innocent opportunists unless the systemic or local defense system of the host becomes compromised. When they adhere on a fertile substrate such as moist and warm, protein-rich human mucosal membrane or biomaterial surface, they become activated and start to grow pseudo and real hyphae. Their growth is intricately guided by their ability to detect surface defects (providing secure hiding , thigmotropism) and nutrients (source of energy, chemotropism). The hypothesis of this work was that body mobilizes both non-specific and specific host defense against invading candidal cells and that these interactions involve resident epithelial cells, rapidly responding non-specific protector neutrophils and mast cells as well as the antigen presenting and responding den-dritic cell lymphocyte plasma cell system. It is supposed that Candida albicans, as a result of dar-winistic pressure, has developed or is utilizing strategies to evade these host defense reactions by e.g. adhering to biomaterial surfaces and biofilms. The aim of the study was to assess the host defense by taking such key molecules of the anti-candidal defense into focus, which are also more or less characteristic for the main cellular players in candida-host cell interactions. As a model for candidal-host interaction, sections of chronic hyperplastic candidosis were used and compared with sections of non-infected leukoplakia and healthy tissue. In this thesis work, neutrophil-derived anti-candidal α-defensin was found in the epithelium, not only diffusely all over in the epithelium, but as a strong α-defensin-rich superficial front probably able to slow down or prevent penetration of candida into the epithelium. Neutrophil represents the main host defence cell in the epithelium, to which it can rapidly transmigrate from the circulation and where it forms organized multicellular units known as microabscesses (study I). Neutrophil chemotactic inter-leukin-8 (IL-8) and its receptor (IL-8R) were studied and were surprisingly also found in the candidal cells, probably helping the candida to keep away from IL-8- and neutrophil-rich danger zones (study IV). Both leukocytes and resident epithelial cells contained TLR2, TLR4 and TLR6 receptors able to recognize candidal structures via utilization of receptors similar to the Toll of the banana fly. It seems that candida can avoid host defence via stimulation of the candida permissive TLR2 instead of the can-dida injurious TLR4 (study V). TLR also provides the danger signal to the immune system without which it will not be activated to specifically respond against candidal antigens. Indeed, diseased sites contained receptor activator of nuclear factor kappa B ligand (RANKL; II study), which is important for the antigen capturing, processing and presenting dendritic cells and for the T lymphocyte activation (study III). Chronic hyperplastic candidosis provides a disease model that is very useful to study local and sys-temic host factors, which under normal circumstances restrain C. albicans to a harmless commensal state, but failure of which in e.g. HIV infection, cancer and aging may lead to chronic infection.

Molecular analysis of inorganic nitrogen assimilation in yeasts

Assimilation of nitrate and various other inorganic nitrogen compounds by different yeasts was investigated. Nitrate, nitrite, hydroxylamine, hydrazine, ammonium sulphate, urea and L-asparagine were tested as sole sources of nitrogen for the growth of Candida albicans, C. pelliculosa, Debaryomyces hansenii, Saccharomyces cerevisiae, C. tropicalis, and C. utilis. Ammonium sulphate and L-asparagine supported the growth of all the yeasts tested except D. hansenii while hydroxylamine and hydrazine failed to support the growth of any. Nitrate and nitrite were assimilated only by C. utilis. Nitrate utilization by C. utilis was also accompanied by the enzymatic activities of NAD(P)H: nitrate oxidoreductase (EC 1.6.6.2) and NAD(P)H: nitrite oxidoreductase (EC 1.6.6.4), but not reduced methyl viologen-or FAD-nitrate oxidoreductases (EC 1.7.99.4). It is demonstrated here that nitrate and nitrite reductase activities are responsible for the ability of C. utilis to assimilate primary nitrogen.

Traditional medicinal uses and biological activities of some plant extracts of African Combretum Loefl., Terminalia L. and Pteleopsis Engl. species

In Africa various species of Combretum, Terminalia and Pteleopsis are used in traditional medicine. Despite of this, some species of these genera have still not been studied for their biological effects to validate their traditional uses. The aim of this work has been to document the ethnomedicinal uses of several species of Combretum and Terminalia in Mbeya region, south-western Tanzania, and to use this information for finding species with good antimicrobial and cytotoxic potential. During a five weeks expedition to Tanzania in spring 1999 sixteen different species of Combretum and Terminalia, as well as Pteleopsis myrtifolia were collected from various locations in the districts of Mbeya, Iringa and Dar-es-Salaam. Traditional healers in seven different villages in the Mbeya region were interviewed in Swahili and Nyakyusa on the medicinal uses of Combretum and Terminalia species shown to them. A questionnaire was used during the interviews. The results of the interviews correlated well between different villages, the same species being used in similar ways in different villages. Of the ten species shown to the healers six were frequently used for treatment of skin diseases, bacterial infections, diarrhea, oedema and wounds. The dried plants were most commonly prepared into hot water decoctions or mixed into maize porridge, Ugali. Infusions made from dried or fresh plant material were also common. Wounds and topical infections were treated with ointments made from the dried plant material mixed with sheep fat. Twenty-one extracts of six species of Combretum and four of Terminalia, collected from Tanzania, were screened for their antibacterial effects against two gram-negative and five gram-positive bacteria, as well as the yeast, Candida albicans, using an agar diffusion method. Most of the screened plants showed substantial antimicrobial activity. A methanolic root extract of T. sambesiaca showed the most potent antibacterial effects of all the plant species screened, and gave a MIC value of 0.9 mg/ml against Enterobacter aerogenes. Also root extracts of T. sericea and T. kaiserana gave excellent antimicrobial effects, and notably a hot water extract of T. sericea was as potent as extracts of this species made from EtOH and MeOH. Thus, the traditional way of preparing T. sericea into hot water decoctions seems to extract antimicrobial compounds. Thirty-five extracts of five species of Terminalia, ten of Combretum and Pteleopsis myrtifolia were screened for their antifungal effects against five species of yeast (Candida spp.) and Cryptococcus neoformans. The species differed from each other to their antifungal effects, some being very effective whereas others showed no antifungal effects. The most effective extracts showed antifungal effects comparable to the standard antibiotics itraconazol and amphotericin B. Species of Terminalia gave in general stronger antifungal effects than those of Combretum. The best effects were obtained with methanolic root extracts of T. sambesiaca, T. sericea and T. kaiserana, and this investigation indicates that decoctions of these species might be used for treatment of HIV-related fungal infections. Twenty-seven crude extracts of eight species of Combretum, five of Terminalia and Pteleopsis myrtifolia were evaluated for their cytotoxic effects against human cancer cell lines (HeLa, cervical carcinoma; MCF 7, breast carcinoma, T 24 bladder carcinoma) and one endothelial cell line (BBCE, bovine brain capillary endothelial cells). The most outstanding effects were obtained with a leaf extract of Combretum fragrans, which nearly totally inhibited the proliferation of T 24 and HeLa cells at a concentration of 25 ug/ml and inhibited 60 % of the growth of the HeLa cells at a concentration of 4.3 ug/ml. The species of Terminalia were less cytotoxically potent than the Combretum species, although T. sericea and T. sambesiaca gave good cytotoxic effects (< 30 % proliferation). In summary this study indicates that some of the species of Terminalia, Combretum and Pteleopsis, used in Tanzanian traditional medicine, are powerful inhibitors of both microbial and cancer cell growth. In depth studies would be needed to find the active compounds behind these biological activities.

Synthesis, spectral characterization, in-vitro microbiological evaluation and cytotoxic activities of novel macrocyclic bis hydrazone

A macrocyclic hydrazone Schiff base was synthesized by reacting 1,4-dicarbonyl phenyl dihydrazide with 2,6-diformyl-4-methyl phenol and a series of metal complexes with this new Schiff base were synthesized by reaction with Co(II), Ni(II) and Cu(II) metal salts. The Schiff base and its complexes have been characterized by elemental analyses, IR, H-1 NMR, UV-vis, FAB mass, ESR spectra, fluorescence, thermal, magnetic and molar conductance data. The analytical data reveal that the Co(II), Ni(II) and Cu(II) complexes possess 2:1 metal-ligand ratios. All the complexes are non-electrolytes in DMF and DMSO due to their low molar conductance values. Infrared spectral data suggest that the hydrazone Schiff base behaves as a hexadentate ligand with NON NON donor sequence towards the metal ions. The ESR spectral data shows that the metal-ligand bond has considerable covalent character. The electrochemical behavior of the copper(II) complex was investigated by cyclic voltammetry. The Schiff base and its complexes have also been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Shigella dysentery, Micrococcus, Bacillus subtilis, Bacillus cereus and Pseudomonas aeruginosa) and antifungal activities (Aspergillus niger, Penicillium and Candida albicans) by MIC method. The brine shrimp bioassay was also carried out to study their in-vitro cytotoxic properties. (C) 2009 Elsevier Masson SAS. All rights reserved.

Epidemiology of candidemia in Finland

Candida species are an important cause of nosocomial bloodstream infections in hospitalized patients worldwide, with associated high mortality, excess length of stay and costs. Main contributors to candidemias is profound immunosuppression due to serious underlying condition or intensive treatments leading to an increasing number of susceptible patients. The rank order of causative Candida species varies over time and in different geographic locations. The aim of this study was to obtain information on epidemiology of candidemia in Finland, to identify trends in incidence, causative species, and patient populations at risk. In order to reveal possible outbreaks and assess the value of one molecular typing method, restriction enzyme analysis (REA), in epidemiological study, we analyzed C. albicans bloodstream isolates in Uusimaa region in Southern Finland during eight years. The data from the National Infectious Disease Register were used to assess the incidence and epidemiological features of candidemia cases. In Helsinki University Central Hospital (HUCH) all patients with blood culture yielding any Candida spp. were identified from laboratory log-books and from Finnish Hospital Infection Program. All the patients with a stored blood culture isolate of C. albicans were identified through microbiology laboratory logbooks, and stored isolates were genotyped with REA in the National Institute for Health and Welfare (former KTL). The incidence of candidemia in Finland is globally relatively low, but increased between between 1990s and 2000s. The incidence was highest in males >65 years of age, but incidence rates for patients <1-15 years were lower during 2000s than during 1990s. In HUCH the incidence of candidemia remained low and constant during our 18 years of observation, but a significant shift in patient-populations at risk was observed, associated with patients treated in intensive care units, such as premature neonates and surgical patients. The predominating causative species in Finland and in HUCH is C. albicans, but the proportion of C. glabrata increased considerably. The crude one-month case fatality was constantly high between 28-33%. REA differentiated efficiently between C. albicans blood culture isolates and no clusters were observed in the hospitals involved, despite of abundant transfer of patients among them. Candida spp. are an important cause of nosocomial blood stream infections in Finland, and continued surveillance is necessary to determine the overall trends and patient groups at risk, and reduce the impact of these infections in the future. Molecular methods provide an efficient tool for investigation of suspected outbreak and should be available in the future in Finland, also.