Effects of the essential oil of Thymus vulgaris L. Against Cryptococcus neoformans

Cryptococcus neoformans is an encapsulated yeast found in the environment, responsible for causing of meningoencephalitis in patients with a compromised immune system. In Brazil, cryptococcosis is the second cause of death among systemic mycoses. The limited efficacy of the available antifungal drugs used in its treatment has encouraged the search for therapeutic alternatives, such as medicinal plants. Thymus vulgaris, popularly known as thyme, is an aromatic plant whose essential oil (EO) possesses antifungal properties. The aim of this study was to assess the action of T. vulgaris EO on C. neoformans clinical isolates. This oil was analyzed by gas chromatography/mass spectrometry (GC/MS), which showed that its main components were thymol, ρ-cymene and linalool. Microdilution broth tests showed that this EO was effective against fungal isolates, with minimum inhibitory concentrations (MICs) ranging from 32 to 128 µg/mL. In vitro interaction tests between this oil and fluconazole (FCZ) showed no potentiation of the antifungal action of this drug. Its effect on mitochondrial metabolism of fungal cells was also evaluated and results demonstrated alterations on the mitochondrial enzyme activity of fungal cells only at concentrations >1,024 µg/mL. The results of the action of this EO on human erythrocytes indicated that it has low cytotoxic activity at MIC values. This investigation describes the antifungal action of T. vulgaris, showing its potential in the development of alternatives in the treatment of C. neoformans

Pimenta pseudocaryophyllus inhibits virulence factors and promotes metabolic changes in Candida yeast

Introduction This is the first study to examine the in vitro susceptibility and the expression of virulence factors in Candida species in the presence of Pimenta pseudocaryophyllus (Gomes) L.R. Landrum (Myrtaceae), a Brazilian plant known as paucravo. Additionally, the mechanisms of action of the crude ethanol extract and the ethyl acetate and aqueous fractions of this plant were investigated. Methods The in vitro susceptibility of Candida was tested using the broth microdilution method, whereas an XTT reduction assay was used for biofilms. Adherence was determined by counting the number of yeast cells that adhered to 100 oral epithelial cells, and hyphal formation was verified in the hyphal induction medium M199. Flow cytometry with propidium iodide and FUN-1 was performed to assess the mechanism of action. Results The results revealed that the crude ethanol extract and the ethyl acetate and aqueous fractions of P. pseudocaryophyllus inhibited the growth of Candida isolates at a minimal inhibitory concentration (MIC) ranging from 64 to 256µg/mL, whereas the 50% sessile minimal inhibitory concentration (SMIC50) ranged from 512 to >1,024µg/mL. Adherence and hyphal formation were significantly reduced in the presence of the crude ethanol extract and both fractions. Although cell membrane injury was detected, the predominant mechanism of action appeared to be the alteration of yeast metabolism, as demonstrated by flow cytometry. Conclusions Our results indicated that antifungal activity reduced the expression of virulence factors in yeast via the alteration of yeast metabolism, suggesting that the crude extract of P. pseudocaryophyllus and its fractions may contain novel antifungal agents. .

Clinical and microbiological features of cryptococcal meningitis

Introduction In this study, the clinical features, underlying diseases and clinical outcomes of patients with cryptococcosis were investigated. In addition, a molecular analysis of the Cryptococcus neoformans species complex isolated from these patients was performed. Methods A prospective study of 62 cases of patients with cryptococcal infection was conducted at the Hospital de Doenças Tropicais de Goiás Dr. Anuar Auad from 2009-2010. Cryptococcal meningitis cases were diagnosed by direct examination and cerebrospinal fluid (CSF) sample culture. The profiling of these patients was assessed. The CSF samples were submitted to India ink preparation and cultured on Sabouraud dextrose agar, and C. neoformans was identified by the production of urease, a positive phenoloxidase test and assimilation of carbohydrates. C. neoformans and C. gattii isolates were distinguished by growth on L-canavanine-glycine-bromothymol blue medium, and molecular analysis was conducted via PCR fingerprinting reactions using M13 and (GACA)4 primers. Results From the 62 patients with cryptococcosis, 71 isolates of CSF were obtained; 67 (94.4%) isolates were identified as C. neoformans var. grubii/VNI, and 4 (5.6%) were identified as C. gattii/VGII. Of these patients, 53 had an HIV diagnosis. The incidence of cryptococcosis was higher among patients 20-40 years of age, with 74.2% of the cases reported in males. Cryptococcus-related mortality was noted in 48.4% of the patients, and the symptoms were altered sensorium, headache, fever and stiff neck. Conclusions The high morbidity and mortality observed among patients with cryptococcosis demonstrate the importance of obtaining information regarding the epidemiological profile and clinical course of the disease in the State of Goiás, Brazil. .

Identificação de espécies de candida em saliva de profissionais da saúde / Identification of candida species on the saliva of the hospital workers / La identificación de las especies de candida en salivas de profesionales de salud

As espécies de Candida são de ocorrência comum na cavidade bucal sendo que estas leveduras estão presentes em cerca de 50% de indivíduos saudáveis, podendo este porcentual variar dependendo da população estudada. Os processos infecciosos causados por Candida variam de quadros clínicos benignos, a quadros graves e fatais como as infecções invasivas e disseminadas. Neste estudo foi avaliada a colonização de leveduras do gênero Candida em 312 amostras de saliva de profissionais do Hospital das Clínicas da Universidade Federal de Goiás, na cidade de Goiânia, Goiás, Brasil, durante o período de julho a dezembro de 2007. As espécies de Candida isoladas da saliva foram identificadas através da produção de tubo germinativo e de clamidoconídios, assimilação de carboidratos e cultivo em meio CHROMagar® Candida. Os profissionais estudados mostraram colonização por leveduras do gênero Candida em 61,9% das amostras analisadas, sendo isolados C. albicans (58,5%), C. parapsilosis (24,4%), C. krusei (8,3%) e C. famata (3,6%). A divulgação destes resultados pode servir como um auxílio para a prevenção e controle de candidíase bucal nos trabalhadores da área de saúde que vivem em contato constante com indivíduos altamente suscetíveis a infecções.

Candida species are of common occurrence in the buccal cavity and these yeasts are present in about 50% of healthy individuals. This percentage can change depending on the studied population. The infectious processes caused by Candida vary of benign clinical pictures, to serious and fatal pictures as the invasive infections and disseminated. In this study it was evaluated the colonization of yeasts of the Candida genus on 312 saliva sample of the hospital workers from ?Hospital das Clínicas da Universidade Federal de Goiás? in the city of Goiania-Goiás/Brazil, during the period from July to December of 2007. Candida species were identified by production of germ-tube, chlamydospore formation, assimilation sugar tests and culture on CHROMagar® Candida. The hospital workers analyzed presented colonization of the saliva by yeasts of the Candida genus in 61.9% from samples studied, being isolated C. albicans (58.5%), C. parapsilosis (24.4%), C. krusei (8.3%) and C. famata (3.6%). The publication of these results can serve as an aid for the prevention and control of oral candidiasis in the workers of the area of health that live in contact with individuals susceptible to infections.

Especies de Candida son de ocurrencia común en la cavidad bucal y estas levaduras están presentes en cerca del 50% de individuos sanos. La frecuencia varía, dependiendo de las personas investigadas. Los procesos infecciosos causados por Candida varían de cuadros clínicos benignos, a los cuadros serios y fatales como las infecciones invasivas y diseminadas. En este estudio ha sido evaluado la colonización de las especies de Candida en la saliva de los obreros del Hospital das Clínicas de la Universidad Federal de Goiás en Goiânia, Brasil, entre julio y diciembre de 2007. El trabajo se llevó a cabo con 312 muestras de saliva. Las especies de Candida aisladas de la saliva fueron identificadas a través de la formación de tubo germinal y de clamidoconídio, asimilación de carbohidratos y cultivo en CHROMagar® Candida. En nuestro estudio, 61.9% de los trabajadores analizados del hospital presentaron colonización de la saliva por las levaduras del género Candida, estar aislado C. albicans (58.5%), C. parapsilosis (24,4%), C. krusei (8,3%) y C. famata (3,6%). La divulgación de estos resultados puede servir como una ayuda para la prevención y control de candidíase bucal en los trabajadores del área de salud que viven en contacto constante con individuos susceptibles a las infecciones.