Isolation and identification of Candida species in patients with orogastric cancer: susceptibility to antifungal drugs, attributes of virulence in vitro and immune response phenotype.

BACKGROUND: Because of the inherent immunosuppression of cancer patients opportunistic infections by Candida spp, occur frequently. This study aimed to identify Candida species in the oral mucosa of 59 patients with orogastric cancer (OGC) and to analyze the immunological phenotype of these patients. METHODS: The yeasts were identified by MALDI-TOF mass spectrometry (MS). For all isolates, we performed phospholipases and proteinases assays, in vitro adherence to buccal epithelial cells (BEC), minimum inhibitory concentration of antifungal drugs and determined the cytokine profile by Cytometric Bead Array flow citometry assay. RESULTS: C. albicans was the most prevalent species in OGC patients (51.6 %) and control group (66.7 %). Candida spp. strains isolated from OGC patients exhibited better adherence to BEC (p = 0.05) than did the control group. Phospholipases production by Candida strains from OGC patients was lower (51.6 %) than in the control group (61.9 %). Proteinases were detected in 41.9 % and 4.8 % of the yeasts from OGC patients and control group, respectively. Significant differences were found in the serum of OGC patients compared to the control group for IL-2, IL-10, TNF-α, IFN-γ and IL-17. CONCLUSIONS: The results of this work suggest increased virulence of yeasts isolated from OGC patients and, that this may interfere with the immune phenotype.

Kinetics of oral colonization by Candida spp. during topical corticotherapy for oral lichen planus.

BACKGROUND: Oral candidiasis is an important side effect of topical corticotherapy. The purpose of this study was to assess oral mucosa colonization by five Candida species during topical corticotherapy and to investigate Candida spp. pathogenicity and in vitro susceptibility to fluconazole and amphotericin B. METHODS: Oral swabbing samples from 11 erosive oral lichen planus (OLP) patients were collected before (day 0) and at days 7 and 30 of topical corticotherapy. Conventional methods for identification and quantification of Candida species, quantitative PCR (qPCR), pathogenicity tests and in vitro susceptibility to fluconazole and amphotericin B assays were performed. RESULTS: Candida albicans was the most prevalent species in the oral mucosa after corticotherapy. Increased number of colony-forming units (CFU) and Candidaalbicans DNA copies were observed at day 30 of corticotherapy, despite no clinical evidence of candidiasis in any patient. Colony-forming units' count of Candida species was less sensitive than qPCR, but both methods positively correlated. No resistance to fluconazole or amphotericin B was observed. CONCLUSIONS: Topical corticoid used for oral erosive lichen planus treatment was associated with increase in Candida spp., in particular, C. albicans, in the oral cavity, independent of clinical manifestation of the disease.

Influence of oxidation state of sulfur on the dissociation of [Tz-(CH2)n-S(O)m-(CH2)n-Tz + Na+] adducts generated by electrospray ionization (Tz = tetrazole ring; n = 2, 3; m= 0, 1, 2).

Sodium adducts of six organosulfur-α,ω-ditetrazole compounds (Tz-(CH(2))(n)-S(O)(m)-(CH(2))(n)-Tz; where Tz = tetrazole ring; n = 2, 3; m = 0, 1, 2) were generated via electrospray ionization (ESI) and their fragmentation pattern assessed via collision-induced dissociation (CID). Two main dissociation channels were observed: (a) losses of N(2) and HN(3) from the tetrazole rings; (b) cleavage of the C-S bond. The sulfoxides pass predominantly through the second fragmentation pathway, but for the sulfides and sulfones the tetrazole ring fragmentation occurs. Theoretical calculations at the B3LYP/6-31 + G(d,p) level indicate that for all the adducts (sulfide, sulfoxide, and sulfone) the dissociation pathway that leads to product ions arising from loss of N(2) was the most exothermic. Based on these results and assumptions, it was postulated that the dissociation of the sulfoxide adducts occurs under kinetic control (N(2)-loss pathway via a much more energetic transition state). For the sulfide and sulfone adducts, on the other hand, the dissociation process takes place via a thermodynamically controlled process.

Biological activity of Cryptococcus neoformans and Cryptococcus gattii from clinical and environmental isolates / Atividade biológica de Cryptococcus neoformans e Cryptococcus gattii provenientes de isolados clínicos e ambientais

INTRODUCTION: Cryptococcus neoformans and Cryptococcus gattii are encapsulated basidiomycetous yeasts with worldwide distribution. They cause cryptococcosis with features of systemic infection, affecting the central nervous system, lungs and skin in humans and animals. These fungi present numerous virulence factors that allow them to invade the host and multiply, among which extracellular enzyme capacity and microbial adaptation to different temperatures are worth mentioning. OBJECTIVE: To evaluate the production of protease and investigate possible differences in thermotolerance and urease activity in clinical and environmental yeast isolates. MATERIAL AND METHODS: Culture methods and Pz analysis were applied to assess urease and protease, whereas the optical density method was used to analyze biological activity in thermotolerance. RESULTS: There was no significant results as to microbial growth at the tested temperatures (25º, 37º and 42ºC). It was observed that clinical specimens grew better than environmental ones at elevated temperatures. As to C. neoformans, the moderate production of urease enzyme prevailed in both clinical and environmental isolates within 24h or 48h. Moreover, there was significant production on the seventh day of reading. The best reading time for viewing protease production in both isolates and species was the seventh day: 96% clinical samples and 94% environmental isolates. CONCLUSION: Further studies are required in order to investigate the virulence factors of C. neoformans and C. gattii cerebrospinal isolates from patients with meningoencephalitis and environmental samples from Sergipe. Furthermore, a higher technical accuracy and statistical precision are indispensable.

INTRODUÇÃO: Cryptococcus neoformans e Cryptococcus gattii são leveduras encapsuladas basidiomicéticas com distribuição mundial. Causam criptococose com características de infecção sistêmica, afetando o sistema nervoso central, pulmão e pele em humanos e animais. Esses fungos possuem inúmeros fatores de virulência que permitem invadir o hospedeiro e se multiplicar, entre eles destacam-se a capacidade enzimática extracelular e a adaptação microbiana a diversas temperaturas. OBJETIVO: Avaliar a produção de proteinase por essas leveduras, de isolados clínicos e ambientais, além de verificar possíveis diferenças na termotolerância e na atividade da urease. MATERIAL E MÉTODOS: Para urease e proteinase, foi utilizado o sistema de cultivo e análise Pz. Já para atividade biológica em termotolerância, foi analisado o método de densidade óptica. RESULTADOS: Não há resultado significativo no crescimento, mesmo nas temperaturas testadas (25º, 37º e 42ºC). Foi verificado que, em temperaturas elevadas, as amostras clínicas cresceram melhor que as ambientais. Para C. neoformans, tanto nos isolados ambientais como nos clínicos, em 24h ou 48h, prevaleceu a produção moderada da enzima urease. Já no sétimo dia de leitura, houve produção significativa. O melhor tempo de leitura para visualização da produção de proteinase em ambos isolados e espécies foi no sétimo dia, sendo: 96% amostras clínicas e 94% ambientais. CONCLUSÃO: São necessários novos estudos acerca da determinação dos fatores de virulência de C. neoformans e C. gattii isolados de liquor oriundos de pacientes com meningoencefalite e amostras ambientais em Sergipe, além de maior acuidade técnica e precisão estatística dos resultados.