Sandra Denise Camargo Mendes

Antifungal susceptibilities and identification of species of the Sporothrix schenckii complex isolated in Brazil.

Sporotrichosis is a subacute or chronic mycosis caused worldwide by the dimorphic species complex, Sporothrix schenckii. We studied 85 isolates recovered in Brazil to verify their identification and evaluate their in vitro antifungal susceptibility patterns. Based on phenotypic tests (microscopic features, ability to grow at 30°C and 37°C, colony diameters, as well as assimilation of sucrose and raffinose) and molecular assays (amplification of a fragment of the calmodulin gene), the strains were identified as S. schenckii, S. brasiliensis and S. globosa, with a predominance of S. schenckii isolates. There was 37.7% disagreement between the phenotypic and genotypic identification methodologies. In general, terbinafine was the most active drug, followed by ketoconazole and itraconazole, and the less active fluconazole and voriconazole. Five isolates (one S. globosa and four S. schenckii) were found to be itraconazole-resistant strains but, in general, there were no differences in the in vitro antifungal susceptibility profiles among the Sporothrix species.

(GTG)5 MSP-PCR Fingerprinting as a Technique for Discrimination of Wine Associated Yeasts?

In microbiology, identification of all isolates by sequencing is still unfeasible in small research laboratories. Therefore, many yeast diversity studies follow a screening procedure consisting of clustering the yeast isolates using MSP-PCR fingerprinting, followed by identification of one or a few selected representatives of each cluster by sequencing. Although this procedure has been widely applied in the literature, it has not been properly validated. We evaluated a standardized protocol using MSP-PCR fingerprinting with the primers (GTG)5 and M13 for the discrimination of wine associated yeasts in South Brazil. Two datasets were used: yeasts isolated from bottled wines and vineyard environments. We compared the discriminatory power of both primers in a subset of 16 strains, choosing the primer (GTG)5 for further evaluation. Afterwards, we applied this technique to 245 strains, and compared the results with the identification obtained by partial sequencing of the LSU rRNA gene, considered as the gold standard. An array matrix was constructed for each dataset and used as input for clustering with two methods (hierarchical dendrograms and QAPGrid layout). For both yeast datasets, unrelated species were clustered in the same group. The sensitivity score of (GTG)5 MSP-PCR fingerprinting was high, but specificity was low. As a conclusion, the yeast diversity inferred in several previous studies may have been underestimated and some isolates were probably misidentified due to the compliance to this screening procedure.

Evaluation of Zygosaccharomyces bailii BCV 08 as a co-starter in wine fermentation for the improvement of ethyl esters production

Zygosaccharomyces bailii BCV 08, a yeast isolated from red wine barrels in Brazil, was evaluated as co-starter in fermentations with Saccharomyces cerevisiae. Z. bailii BCV 08 was preliminarily shown to produce high levels of esters, and the production was optimized in bench and bioreactor scales using grape must. White wine vinifications were conducted with mixed cultures containing different proportions of Z. bailii BCV 08 and an enological strain of S. cerevisiae. In all trials that contained Z. bailii BCV 08, the production of ethyl esters was enhanced in comparison to the vinification control. Our results clearly show the potential of Z. bailii BCV 08 as a mixed starter with S. cerevisiae in order to increase the aromatic complexity of wine.

A case of Exophiala spinifera infection in Southern Brazil: Molecular identification and antifungal susceptibility

We report a case of an 80-year-old Brazilian man, farmer, with lesions on the dorsum of the hand. A direct mycological examination, cultivation and microculture slide observation was performed. The sequencing of ITS1-5.8S rDNA-ITS2 region was carried out and the etiological agent confirmed as Exophiala spinifera. The in vitro susceptibility of this isolate to antifungal agents alone and in combination was evaluated. This is the third case of phaeohyphomycosis caused by Exophiala spinifera in Brazil.

Melanin: Quantification and protection against oxidative stress in chromoblastomycosis agents

Chromoblastomycosis (CBM) is a chronic cutaneous and subcutaneous infection caused by melanized fungal species. We quantified the extractable melanin of 77 strains of CBM agents distributed within five genera. Moreover, resistance to oxidative stress was evaluated in strains exposed or not to the melanin inhibitor tricyclazole. The median percentage of melanin mass extracted from dry fungal mass varied from 0.69 (Rhinocladiella similis) to 3.81 (Phialophora americana). Inhibition of melanin synthesis decreased survival rates to hydrogen peroxide. Together, these data highlight the importance of melanin in CBM agents.

Environmental yeast communities in vineyards in the mountains of Santa Catarina State, Brazil

Yeasts were isolated from three vineyards located in the South Region of Brazil. A cross evaluation was carried out at the oldest vineyard of the study in Pinheiro Preto. Samples of grape berries, grapevine leaves and the soil, along with samples of the winery equipment and effluent, were collected. In the Serra do Marari and Campos Novos vineyards only samples of grape clusters were obtained. The 106 yeast isolates were identified by sequencing the D1/D2 domain of LSU rDNA or ITS1-5.8S-ITS2 region in 22 species. The values for the richness indices varied between the vineyards. A comparison of the taxonomic diversity of the yeasts from these regions using the reciprocal Simpson index showed a significant difference between the Serra do Marari and Campos Novos vineyards (5.72 ± 0.36 and 2.92 ± 0.36, respectively, p < 0.0001). The functional diversity was assessed in relation to the use of carbon and nitrogen sources by the yeasts isolated from each location. In general, we observed that the Pinheiro Preto and Campos Novos vineyards differed consistently from the Serra do Marari vineyard according to these indices (FAD2, FDc and Rao, p < 0.0001). The possible spreading of Saccharomyces cerevisiae from the winery to the vineyard in Pinheiro Preto was observed.