Adamantylidene-substituted alkylphosphocholine TCAN26 is more active against Sporothrix schenckii than miltefosine

Sporotrichosis is the most frequent subcutaneous mycosis in the world and its increasing incidence has led to the search for new therapeutic options for its treatment. In this study, we demonstrated that three structural analogues of miltefosine (TCAN26, TC19, and TC70) showed inhibitory activity against Sporothrix schenckii sensu stricto and that TCAN26 was more active in vitro than miltefosine against several isolates. Scanning electron microscopy showed that S. schenckii exposure to TCAN26 resulted in cells that were slightly more elongated than untreated cells. Transmission electron microscopy showed that TCAN26 treatment induced loss of the regular cytoplasmic electron-density and altered the cell envelope (disruption of the cell membrane and cell wall, and increased cell wall thickness). Additionally, TCAN26 concentrations required to kill S. schenckii cells were lower than concentrations that were cytotoxic in mammalian cells, and TCAN26 was more selective than miltefosine. Thus, the adamantylidene-substituted alkylphosphocholine TCAN26 is a promising molecule for the development of novel antifungal compounds, although further investigations are required to elucidate the mode of action of TCAN26 in S. schenckii cells.

Silver nanoparticle production by the fungus Fusarium oxysporum: nanoparticle characterisation and analysis of antifungal activity against pathogenic yeasts

The microbial synthesis of nanoparticles is a green chemistry approach that combines nanotechnology and microbial biotechnology. The aim of this study was to obtain silver nanoparticles (SNPs) using aqueous extract from the filamentous fungus Fusarium oxysporum as an alternative to chemical procedures and to evaluate its antifungal activity. SNPs production increased in a concentration-dependent way up to 1 mM silver nitrate until 30 days of reaction. Monodispersed and spherical SNPs were predominantly produced. After 60 days, it was possible to observe degenerated SNPs with in additional needle morphology. The SNPs showed a high antifungal activity against Candida and Cryptococcus , with minimum inhibitory concentration values ≤ 1.68 µg/mL for both genera. Morphological alterations of Cryptococcus neoformans treated with SNPs were observed such as disruption of the cell wall and cytoplasmic membrane and lost of the cytoplasm content. This work revealed that SNPs can be easily produced by F. oxysporum aqueous extracts and may be a feasible, low-cost, environmentally friendly method for generating stable and uniformly sized SNPs. Finally, we have demonstrated that these SNPs are active against pathogenic fungi, such as Candida and Cryptococcus .

Performance of methods for identification of yeasts isolated fromblotted water: High prevalence of Candida parapsilosis / Desempenho dos métodos de identificação de leveduras de águaengarrafada: alta prevalência deCandida parapsilosis

Yeasts of the Candida genus can colonize epithelium and mucosa of the vertebrate organisms; howeverthese can cause infection in a broad range of body sites. Candida species also can be found in drinking water and they are considered as a potential indicator of water quality. In this study were evaluated three methods to identify yeasts isolated from blotted water (seminested PCR, culture on CHROMagar Candida medium, and Candifast identification system). For this propose, we used 27 isolates fromblotted water and compared with 22 clinical isolates from vaginal fluid. Seminested PCR has shown specificity and sensitivity for identification of the Candida species. Candida albicans and Candida parapsilosis were the prevalent species from vaginal fluid and blotted water, respectively. Culture onCHROMagar and Candifast system had low agreement with snPCR (40.9% and 45.5%, respectively) in the yeasts identification from vaginal fluid. On the other hand, CHROMagar Candida can be used in the presumptive identification of yeasts isolated from bottled water and it had agreement’s percentage of 81.5% with snPCR method.

Leveduras do gênero Candida podem colonizar epitélio e mucosa dos organismos vertebrados, entretanto, podem causar infecções em vários lugares do corpo. Espécies de Candida, também, podem ser encontradas em água e são consideradas um potencial indicador da qualidade de água. Neste trabalho, foram avaliados três métodos de identificação de leveduras isoladas de água engarrafada (seminestedPCR, cultura no meio CHROMagar Candida e sistema de identificação Candifast). Foram utilizados 27 isolados de água engarrafada e comparados com 22 isolados clínicos de fluido vaginal. Seminested PCR tem mostrado especificidade e sensibilidade para a identificação das espécies de Candida. Candida albicans e Candida parapsilosis foram as espécies prevalentes do fluido vaginal e da água engarrafada,respectivamente. Cultura em CHROMagar e o sistema Candifast tiveram baixa concordância com snPCR(40,9% e 45,5%, respectivamente) na identificação de leveduras de fluido vaginal. Em contrapartida, CHROMagar Candida pode ser usado em identificação presuntiva de leveduras de água engarrafada apresentando concordância de 81,5% com o método snPCR.

Characterization of Candida spp. isolated from vaginal fluid: identification, antifungal susceptibility, and virulence profile / Caracterização de Candida spp. isoladas de fluido vaginal: identificação, susceptibilidade antifúngica e perfil de virulência

A total of 101 (20.0%) yeast samples were isolated from vaginal fluids of 504 non-hospitalized patients in Maringá, Paraná State, Brazil and Candida albicans was more frequent specie (93.1%) identified by seminested PCR method. All the isolates were susceptible to amphotericin B and nystatin, and 93.1% of them were susceptible to fluconazole. The acid proteinase, hemolytic and phospholipase activities were observed in 99.0, 90.0, and 88.0% of Candida spp., respectively. Around 67.0% of the strains had adherence indexes of 0.5 to 1.5 yeasts by Vero cell, and most of them showed a hydrophilic profile. Correlation studies indicated hydrophilic yeasts presented higher adherence index, proteinase, and phospholipase activities; and a positive correlation between all enzymes was also observed. In addition, the isolates with high hemolytic activity were less susceptible to fluconazole and amphotericin B. These results of Candida prevalence and antifungal susceptibility corroborate with literature's datas and correlation between virulence factors and MIC values suggest Candida isolates from vaginal fluid less susceptible to antifungal and with higher extracellular enzymes production can be more virulent to cause tissue damage.

Cento e uma leveduras foram isoladas de fluido vaginal de 504 pacientes não hospitalizados em Maringá, Estado do Paraná, Brasil e Candida albicans foi a espécie mais freqüente (93,1%) identificada pelo método seminested PCR. Todos os isolados foram susceptíveis a anfotericina B e a nistatina, e 93,1 % susceptíveis ao fluconazol. Atividades da proteinase ácida, hemolisina, e fosfolipase foram observadas em 99,0, 90,0 e 88,0% dos isolados de Candida spp., respectivamente. Aproximadamente 67,0% das cepas apresentaram índices de aderência de 0,5 a 1,5 leveduras por célula Vero, sendo que a maioria dos isolados mostrou um perfil hidrofílico. Estudos de correlação indicaram que leveduras hidrofílicas apresentaram maiores índices de aderência e atividade da proteinase e fosfolipase; e uma correlação positiva entre todas as enzimas, também, foi observada. Adicionalmente, os isolados com alta atividade hemolítica foram menos susceptíveis aos fluconazol e a anfotericina B. Esses resultados de prevalência de leveduras do gênero Candida e de susceptibilidade aos antifúngicos corroboram com dados da literatura; e as correlações observadas entre os fatores de virulência e valores de CIM sugerem que Candida spp. isoladas de fluido vaginal menos susceptíveis aos antifúngicos e com alta produção de enzimas extracelulares podem ser mais virulentas para causar dano tecidual.

Terbinafine inhibits Cryptococcus neoformans growth and modulates fungal morphology

Cryptococcus neoformans is an encapsulated fungus that causes cryptococcosis. Central nervous system infection is the most common clinical presentation followed by pulmonary, skin and eye manifestations. Cryptococcosis is primarily treated with amphotericin B (AMB), fluconazole (FLC) and itraconazole (ITC). In the present work, we evaluated the in vitro effect of terbinafine (TRB), an antifungal not commonly used to treat cryptococcosis. We specifically examined the effects of TRB, either alone or in conjunction with AMB, FLC and ITC, on clinical C. neoformans isolates, including some isolates resistant to AMB and ITC. Broth microdilution assays showed that TRB was the most effective drug in vitro. Antifungal combinations demonstrated synergism of TRB with AMB, FLC and ITC. The drug concentrations used for the combination formulations were as much as 32 and 16-fold lower than the minimum inhibitory concentration (MIC) values of FLC and AMB alone, respectively. In addition, calcofluor white staining revealed the presence of true septa in hyphae structures that were generated after drug treatment. Ultrastructural analyses demonstrated several alterations in response to drug treatment, such as cell wall alterations, plasma membrane detachment, presence of several cytoplasmic vacuoles and mitochondrial swelling. Therefore, we believe that the use of TRB alone or in combination with AMB and azoles should be explored as an alternative treatment for cryptococcosis patients who do not respond to standard therapies.