No abstract

Candida albicans and C. tropicalis obtained from whole saliva of patients presenting signs of oral candidosis were assayed for quantification of colony forming units, exoenzyme activity (phospholipase and proteinase) and antifungal drug sensitivity (amphotericin B, fluconazole and itraconazole) by the reference method of the Clinical and Laboratory Standards Institute. The number of colony forming units per milliliter varied according to the Candida species involved and whether a single or mixed infection was present. Proteinase activity was observed in both C. albicans and C. tropicalis, but phospholipase activity was noted only in C. albicans. In vitro resistance to antifungals was verified in both species, but C. tropicalis appears to be more resistant to the tested antifungals than C. albicans.

Typing methods to evaluate isolates in relation to their phenotypical and molecular characteristics are essential in epidemiological studies. In this study, Candida albicans biotypes were determined before and after storage in order to verify their stability. Twenty C. albicans isolates were typed by Randomly Amplified Polymorphic DNA (RAPD), production of phospholipase and proteinase exoenzymes (enzymotyping) and morphotyping before and after 180 days of storage in Sabouraud dextrose agar (SDA) and sterilised distilled water. Before the storage, 19 RAPD patterns, two enzymotypes and eight morphotypes were identified. The fragment patterns obtained by RAPD, on the one hand, were not significantly altered after storage. On the other hand, the majority of the isolates changed their enzymotype and morphotype after storage. RAPD typing provided the better discriminatory index (DI) among isolates (DI = 0.995) and maintained the profile identified, thereby confirming its utility in epidemiological surveys. Based on the low reproducibility observed after storage in SDA and distilled water by morphotyping (DI = 0.853) and enzymotyping (DI = 0.521), the use of these techniques is not recommended on stored isolates.

COSTA, K. R. C. Phenotypic and molecular aspects of adhesion and enzymatic activity of Candida sp recovered from patients with clinical signs of oral candidiasis. 2009. 122 f. Thesis (Doctoral Degree)

Enterobacter cloacae and E. aerogenes have been increasingly reported as important opportunistic pathogens. In this study, a high prevalence of multi-drug resistant isolates from Brazil, harboring several β-lactamase encoding genes was found. Several virulence genes were observed in E. aerogenes, contrasting with the E. cloacae isolates which presented none.

The wide spectrum of candidiasis and its clinical importance encourage the research with the purpose of clarifying the mechanisms of pathogenicity and identification of virulence factors of Candida sp. Therefore, the aim of this study was to verify the adhesion capacity, protease activity and genotypic diversity of oral C. albicans and C. tropicalis isolates. The adhesion ability to the extracellular matrix glycoproteins laminin and fibronectin was evaluated using the ELISA technique. The research of proteases was carried out in agar plate containing bovine albumin and through a quantitative method in buffer solution containing haemoglobin. Intra and interspecies polymorphisms was verified through random amplified polymorphic DNA (RAPD) technique. All C. albicans and C. tropicalis isolates binded to immobilised laminin and fibronectin. Ca33 and Ct13 isolates had relative adhesion index significantly higher than the other isolates for both glycoproteins (P < 0.001). Protease activity was observed in all isolates of C. albicans using either the semi-quantitative or quantitative assay. The protease activity of C. tropicalis was better detected through the quantitative assay. The genotypic diversity by RAPD revealed a heterogeneous population in both species. Nevertheless, C. tropicalis presented higher genetic variability than C. albicans strains.

We report herein the results of antifungal activity of fifteen 1,2,3-triazoles against Candida albicans, Candida krusei, Candida parapsilosis, Candida kefyr, Candida tropicalis, Candida dubliniensis, Tricophyton rubrum, Microporum canis and Aspergillus niger. All of the 1,2,3-triazoles were prepared from 1,3-dipolar cyclizations between aryl azides and alkynes catalyzed by Cu(I), and several of the compounds exhibited antifungal activity with low cytotoxicity. The results demonstrated the potential and importance of developing new 1,2,3-triazoles compounds with antifungal activity.

100% das C. albicans de ambos os grupos avaliados produziram as enzimas fosfolipase e proteinase em diferentes níveis de atividade. Os isolados de C. tropicalis não apresentaram produção da fosfolipase, com relação à proteinase 43,8% dos isolados de pacientes com lesão bucal foram positivos. Em relação aos testes de sensibilidade, a faixa da CIM para anfotericina B foi de 0,125-4µg/mL para os isolados de C. albicans e de 2-4 µg/mL para os de C. tropicalis, com o itraconazol o intervalo da CIM foi de 0,03-16µg/mL para as duas espécies e para o fluconazol a faixa da CIM foi de 0,125-≥64µg/mL para os isolados de C. albicans e de 0,25-≥64µg/mL para os de C. tropicalis. Com base nos resultados obtidos conclui-se que: a análise de saliva é sensível para detecção de leveduras tanto em pacientes com sinais clínicos de candidíase quanto em indivíduos saudáveis portadores da levedura; C. albicans foi à espécie mais isolada em ambos os grupos; todas os isolados de C. albicans foram produtores das enzimas fosfolipase e proteinase; nenhum isolado de C. tropicalis apresentou atividade da enzima fosfolipase. A maioria dos isolados de C. albicans e C. tropicalis foram sensíveis in vitro aos antifúngicos testados.