Experimental systemic virulence of oral Candida dubliniensis isolates in comparison with Candida albicans, Candida tropicalis and Candida krusei

There are no previous studies on the comparative virulence of Candida dubliniensis with other non-albicans species. The aim of this study was to compare the virulence and infection kinetics of C. dubliniensis and other species. Candida albicans, C. dubliniensis, Candida tropicalis and Candida krusei (reference strains) were inoculated intravenously in mice. For infection kinetics evaluation, a group of five animals were sacrificed after 6 h, 3, 7, 14 and 21 days. Microbiological evaluations (liver, spleen, kidneys, lungs and brain) and histopathological examination of the kidney were performed. The results of virulence evaluation were analysed using Kaplan-Meier survival analysis (5%). Candida dubliniensis-inoculated mice survived for longer periods compared with those with C. albicans (P = 0.005). No differences were detected in relation to C. tropicalis (P = 0.326) and C. krusei (P = 0.317). Most of the organs were persistently colonised by C. albicans and C. dubliniensis even by day 21. Tendency of C. krusei clearance was observed in all organs. Fungal masses and renal lesions were observed after inoculation of C. albicans, C. dubliniensis and C. tropicalis. Within the limits of the study, data on survival rate and dissemination capacity suggest that C. dubliniensis is less virulent than C. albicans.

Research on Candida dubliniensis in a Brazilian yeast collection obtained from cardiac transplant, tuberculosis, and HIV-positive patients, and evaluation of phenotypic tests using agar screening methods

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Experimental pathogenicity of Candida albicans and Candida dubliniensis with continuous and discontinuous fringes morphotypes

A possible correlation between the presence of discontinuous fringes and high virulence has been previously suggested. The aim of this study was to compare the pathogenicity of Candida albicans and Candida dubliniensis with continuous and discontinuous fringes morphotypes on mice. For C. albicans, two discontinuous fringe morphotype isolates (PN 69, PN 74), two continuous fringe morphotype isolates (N 60, N 33) and one reference strain were used. For C. dubliniensis, three discontinuous fringe morphotype isolates (97487, 97464, 97519), two continuous fringe morphotype isolates (97040, 98026) and one reference strain were used. Swiss male mice were inoculated with a standardised suspension of the microorganisms and observed for 35 days. The pathogenicity of the isolates was analysed according to parameters proposed previously. Three isolates were considered pathogenic: PN 74, N 60 and 98026. Strain N 60 killed the highest amount of mice (80%). Animals inoculated with C. albicans did not show differences on survival estimate. Candida dubliniensis 98026 was more pathogenic than samples 97464 and 97519. on the other hand, the sample 97487 showed a higher pathogenicity when compared with 97040 (Kaplan-Meier test, P = 0.008). Strains with continuous fringe morphotypes were also associated with Candida sp. virulence in vivo.

Susceptibility of Candida albicans and Candida dubliniensis to erythrosine- and LED-mediated photodynamic therapy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Molecular fingerprinting methods for the discrimination between C-albicans and C-dubliniensis

Opportunistic fungal pathogens are becoming increasingly important causes of both community-acquired and nosocomial infections. The most important fungal pathogens are yeast species belonging to the genus Candida. These species show differences in levels of resistance to antifungal agents and mortality. Consequently, it is important to correctly identify the causative organism to the species level. Identification of Candida dubliniensis in particular remains problematic because of the high degree of phenotypic similarity between this species and Candida albicans. However, as the differences between both are most pronounced at the genetic level, several studies have been conducted in order to provide a specific and rapid identification fingerprinting molecular test. In most candidal infectious, no single DNA fingerprinting technique has evolved as a dominant method, and each method has its advantages, disadvantages and limitations. Moreover, the current challenge of these techniques is to compile standardized patterns in a database for interlaboratory use and future reference. This review provides an overview of most common molecular fingerprinting techniques currently available for discrimination of C. albicans and C. dubliniensis.

Phenotypic methods and commercial systems for the discrimination between C-albicans and C-dubliniensis

Candida dubliniensis is a recently described Candida species associated with oral candidosis that exhibits a high degree of phenotypic similarity to Candida albicans. However, these species show differences in levels of resistance to antimycotic agents and ability to cause infections. Therefore, accurate clinical identification of C. dubliniensis and C. albicans species is important in order to treat oral candidal infections. Phenotypic identification methods are easy-to-use procedures for routine discrimination of oral isolates in the clinical microbiology laboratory. However, C. dubliniensis may be so far underreported in clinical samples because most currently used identification methods fail to recognize this yeast. Phenotypic methods depend on growth temperature, carbon source assimilation, chlamydospore and hyphal growth production, positive or negative growth on special media and intracellular enzyme production, among others. In this review, some phenotypic methods are presented with a special emphasis on the discrimination of C. dubliniensis and C. albicans.

Efeitos da terapia fotodinâmica sobre a patogenicidade de Candida albicans e C dubliniensis na candidose bucal em ratos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Identificação de candida dubliniensis em cepas da micoteca da Faculdade de Odontologia de São José dos Campos/UNESP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Candida dubliniensis: prevalência na cavidade bucal de pacientes diabéticos, com câncer de mama e hansenianos e patogenicidade experimental

O objetivo deste estudo foi avaliar a presença de C. dubliniensis dentre isolados bucais de pacientes com Diabetes mellitus do tipo I (n=39) e II (n=36), hansenianos (n=38) e sob quimioterapia para o câncer de mama (n=30) e de respectivos indivíduos controle pareados quanto à idade, gênero e condições bucais. Um total de 479 isolados previamente identificados por testes fenotípicos (formação de tubo germinativo, produção de hifas/pseudohifas/clamidoconídeos, fermentação e assimilação de carboidratos) e identificadas como C. albicans/C. dubliniensis foram incluídos no estudo. A existência de C. dubliniensis dentre os isolados foi analisada usando protocolo validado de PCR multiplex. Foi também realizado estudo de patogenicidade experimental utilizando camundongos em modelo de infecção sistêmica, objetivando comparar a virulência e cinética de infecção de C. dubliniensis com outras espécies do gênero Candida. Um isolado (0.002%) de C. dubliniensis foi detectado entre os isolados do grupo controle. Esta espécie não foi encontrada dentre os isolados dos outros grupos de pacientes. C. dubliniensis foi menos virulenta para camundongos em relação a C. albicans e C. tropicalis e mais virulenta do que C. krusei. O estudo da cinética de infecção mostrou infecção persistente no rim e no fígado mesmo após 21 dias da inoculação de C. dubliniensis. Conclui-se que a detecção de C. dubliniensis dentre os isolados clínicos foi baixa e observada apenas no grupo controle. C. dubliniensis foi menos virulenta para camundongos que C. albicans e C. tropicalis e causou infecção prolongada no rim e no fígado

Yeasts isolated from a fungus-growing ant nest, including the description of Trichosporon chiarellii sp nov., an anamorphic basidiomycetous yeast

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Antimicrobial Properties and Cytotoxicity of an Antimicrobial Monomer for Application in Prosthodontics

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)