Current Knowledge of Trichosporon spp. and Trichosporonosis

Trichosporon spp. are basidiomycetous yeast-like fungi found widely in nature. Clinical isolates are generally related to superficial infections. However, this fungus has been recognized as an opportunistic agent of invasive infections, mostly in cancer patients and those exposed to invasive medical procedures. It is possible that the ability of Trichosporon strains to form biofilms on implanted devices, the presence of glucuronoxylomannan in their cell walls, and the ability to produce proteases and lipases are all factors likely related to the virulence of this genus and therefore may account for the progress of invasive trichosporonosis. Disseminated trichosporonosis has been increasingly reported worldwide and represents a challenge for both diagnosis and species identification. Phenotypic identification methods are useful for Trichosporon sp. screening, but only molecular methods, such as IGS region sequencing, allow the complete identification of Trichosporon isolates at the species level. Methods for the diagnosis of invasive trichosporonosis include PCR-based methods, Luminex xMAP technology, and, more recently, proteomics. Treating patients with trichosporonosis remains a challenge because of limited data on the in vitro and in vivo activities of antifungal drugs against clinically relevant species of the genus. Despite the mentioned limitations, the use of antifungal regimens containing triazoles appears to be the best therapeutic approach.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo, Lab Especial Micol, Disciplina Infectol, BR-04023062 São Paulo, BrazilUniv Fed Rio Grande do Norte, Lab Micol Med Mol, Dept Anal Clin Toxicol, BR-59072970 Natal, RN, BrazilUniversidade Federal de São Paulo, Lab Especial Micol, Disciplina Infectol, BR-04023062 São Paulo, BrazilFAPESP: 2005/02006-0FAPESP: 2005/04442-1FAPESP: 2007/08575-1CNPq: 308011/2010-4CAPES: PNPD 02640-09-0Web of Scienc

Advances in microbial diagnosis: using mass spectrometry for proteomics and genomics applications

Since the last two decades mass spectrometry (MS) has been applied to analyse the chemical cellular components of microorganisms, providing rapid and discriminatory proteomic profiles for their species identification and, in some cases, subtyping. The application of MS for the microbial diagnosis is currently well-established. The remarkable reproducibility and objectivity of this method is based on the measurement of constantly expressed and highly abundant proteins, mainly important conservative ribosomal proteins, which are used as markers to generate a cellular fingerprint. Mass spectrometry based on matrix-assisted laser desorption ionization-time of flight (MALDI- TOF) technique has been an important tool for the microbial diagnostic. However, some technical limitation concerning both MALDI-TOF and its used protocols for sample preparation have fostered the research of new mass spectrometry systems (e.g. LC MS/MS). LC MS/MS is able to generate online mass spectra of specific ions with further online sequencing of these ions, which include both specific proteins and DNA fragments. In this work a set of data for yeasts and filamentous fungi diagnostic obtained through an international collaboration project involving partners from Argentina, Brazil, Chile and Portugal will be presented and discussed

Extracellular enolase of Candida albicans is involved in colonization of mammalian intestinal epithelium

Enolase is secreted by C. albicans and is present in its biofilms although its extracellular function is unknown. Here we show that extracellular enolase mediates the colonization of small intestine mucosa by C. albicans. Assays using intestinal mucosa disks show that C. albicans adhesion is inhibited, in a dose dependent mode, either by pretreatment of intestinal epithelium mucosa disks with recombinant C. albicans enolase (70% at 0.5 mg/ml enolase) or by pretreatment of C. albicans yeasts with anti-enolase antibodies (48% with 20 µg antiserum). Also using flow cytometry, immunoblots of conditioned media and confocal microscopy we demonstrate that enolase is present in biofilms and that the extracellular enolase is not an artifact due to cell lysis, but must represent functional secretion of a stable form. This is the first direct evidence that C. albicans extracellular enolase mediates colonization on its primary translocation site. Also, because enolase is encoded by a single locus in C. albicans, its dual role peptide, as glycolytic enzyme and extracellular peptide, is a remarkable example of gene sharing in fungi

Impact of MALDI-TOF MS in clinical mycology: progress and barriers in diagnostics

[Excerpt] The science of microbial identification can be considered to have arisen from the seminal work of the Dutch microbiologist Antonie van Leeuwenhoek. He provided the pioneering microscopic work in 1683 using rudimentary equipment to support the studies of the equally important French microbiologist Louis Pasteur, who described the biological functions of microbes. In Germany, Robert Koch demonstrated the aetiology of the infectious disease process in humans. The search for the accurate identification of microbial pathogens became crucial for underpinning medicine in treating diseases. Florentine Pier Antonio Micheli published the Nova Plantarum Genera in 1729, which is an illustrated work detailing approximately 1900 ‘plant’ species. Of these, about 900 were fungi and lichenized fungi. In fact, Micheli specialized in microfungi and is notable for having defined several important genera including Aspergillus. Even now, classical mycological identifications are performed by some of those classical methods based on micro‐ and macromorphology (Simões et al., 2013). [...](undefined)info:eu-repo/semantics/publishedVersio

Species diversity, antifungal susceptibility and phenotypic and genotypic characterisation of Exophiala spp. infecting patients in different medical centres in Brazil

The Exophiala genus is responsible for many superficial and invasive infections resulting from black fungi. Identification of Exophiala at the species level is based on morphological observations complemented by molecular tests. The aim of this study was to identify 23 clinical isolates of Exophiala spp. and evaluate the antifungal susceptibility to seven different agents. Molecular identification was based on an analysis of ITS region of rDNA using genomic databases. The micromorphology was evaluated by microculture and scanning electron microscopy. The susceptibility tests were performed using the antifungal agents 5-fluorocytosine (5-FC), amphotericin B (AMB), itraconazole (ITC), voriconazole (VRC), posaconazole (PSC), caspofungin (CFG) and terbinafine (TRB). The ITS analysis identified 100% of the following isolates as: E.dermatitidis (8), E.xenobiotica (6), E.bergeri (4), E.oligosperma (3), E.spinifera (1) and E.mesophila (1). The antifungal susceptibility tests showed that the triazoles compounds were in vitro the most active agents against Exophiala. ITS sequencing enabled the accurate identification of the 23 tested isolates. The triazoles, particularly itraconazole and posaconazole, exhibited MIC values lower than AMB, CAS and 5-FC. Although the guidelines do not indicate AMB for treatment against Exophiala spp., this study showed activity for all of the tested species, except E.mesophila.Coordenacao de Aperfeicoamento de Pessoal em Nivel SuperiorCAPESUniv Fed Sao Paulo, Lab Especial Micol, Disciplina Infectol, Sao Paulo, BrazilFundacao Oswaldo Ramos, Hosp Rim, Sao Paulo, BrazilUniv Fed Espirito Santo, CIMM, Dept Patol, Vitoria, BrazilUniv Fed Alfenas, Inst Ciencias Biomed, Dept Microbiol & Imunol, Alfenas, BrazilUniv Fed Sao Paulo, Lab Especial Micol, Disciplina Infectol, Sao Paulo, BrazilCAPES: PNPD 23038.007393/2011-11Web of Scienc