Alexandre Meneghello Fuentefria

Isolation of a lipase-secreting yeast for enzyme production in a pilot-plant scale batch fermentation

The production of lipase by twenty-nine yeasts isolated from the phylloplane of Hibiscus rosa-sinensis was evaluated. The highest lipase producers were Pseudozyma hubeiensis HB85A, Debaryomyces occidentalis-like HB83 and Cryptococcus sp. HB80. P. hubeiensis HB85A batch fermentations were carried out in a bioreactor and lipase production improved 3.2-fold as compared to flask submerged cultures. The production process was significantly reduced from 48 h (in flasks) to 18 h (in the bioreactor). The better hydrolytic activity was achieved with C16 p-nitrophenyl ester. Maximal activity was observed at pH 7.0, the optimum temperature was 50 degrees C at pH 7.0 and the enzyme was stable at 30 and 40 degrees C. The lipolytic activity was stimulated by Mg(2+), K(+) and Ba(2+) salts and EDTA and slightly inhibited by Ca(2+) salts. Non-ionic detergents such as Triton X-100, Tween 80 and Tween 20 strongly stimulated lipase activity, whereas SDS inhibited it. The lipase was stable in iso-octane and hexane at 80%.

Epidemiological profile of cryptococcal meningitis patients in Rio Grande do Sul, Brazil.

Cryptococcosis is a major opportunistic mycosis which has meningitis as its most frequent clinical presentation and can be fatal in the absence of antifungal therapy. The aetiological agents are Cryptococcus neoformans, which affects mainly immunocompromised subjects, and C. gattii, the aetiologic agent for cryptococcosis in healthy individuals. A recent outbreak of cryptococcosis on Vancouver Island, Canada, raised the level of concern about the epidemiology of this disease. In Brazil, between 1980 and 2002, six per cent of AIDS patients had cryptococcosis in course at the time of diagnosis. To identify the profile of cryptococcal meningitis patients in Rio Grande do Sul (RS), Brazil, a retroactive study was realized using data from patients registered at Laboratório Central de Saúde Pública IPB-LACEN/RS from 2000 to 2005. Most of the patients were men (77.12%), Caucasian (83.5%), median age between thirty and thirty-nine years old (46.24%) and HIV positive (95%).

Trichosporon insectorum sp. nov., a new anamorphic basidiomycetous killer yeast.

Three killer yeasts, isolated from the gut of insects in Panama and artisanal cheese in Brazil, were shown to be related to the Ovoides clade of the genus Trichosporon. Sequencing of the D1/D2 region of the LSU rDNA and physiological characterization revealed a distinct taxonomic position in relation to known species of the genus. Conspecificity of the three killer isolates was reinforced by similar M13 fingerprinting and killer profiles. We propose a new species in this genus: Trichosporon insectorum. The type strain is CBS 10422(T) (syn. NRRL Y-48120). This anamorphic species produces arthroconidia but not appressoria, and its killer character seems to be associated with dsRNA.

Imidazolium salts as antifungal agents: strong antibiofilm activity against multidrug-resistant Candida tropicalis isolates

The in vitro activity of the imidazolium salt C16MImCl against planktonic and biofilm cells of multidrug‐resistant isolates of Candida tropicalis was evaluated, both in solution and applied on a commercial catheter surface. This was determined by inhibition and susceptibility assays of biofilm and planktonic cells. In both cases, C16MImCl prevented in vitro biofilm formation of C. tropicalis strains, including multidrug‐resistant ones. Outstanding performances were observed, even at extremely low concentrations. Furthermore, this is the first report of the antifungal lock property of C16MImCl, using a tracheal catheter as the test specimen to mimic a clinical in vivo condition. As such, C16MImCl has been identified as a promising antimicotic pharmaceutical candidate for the treatment of candidiasis infections.

In vitro evaluation of the acquisition of resistance, antifungal activity and synergism of Brazilian red propolis with antifungal drugs on Candida spp.

To evaluate the ability of Candida parapsilosis and Candida glabrata to develop phenotypic resistance to a benzophenone enriched fraction obtained from Brazilian red propolis (BZP‐BRP) as compared to fluconazole (FLC). To investigate possible synergy between BZP‐BRP and FLC and anidulafungin (AND).

Comparação do perfil de suscetibilidade entre isolados clínicos de Candida spp. orais e vulvovaginais no Sul do Brasil

INTRODUCAO: Nos ultimos anos, o oportunismo das candidiases vem se tornando cada vez mais recorrente e de dificil tratamento, principalmente em virtude da emergencia de novas especies, bem como devido a diminuicao a suscetibilidade aos antifungicos. O sucesso do tratamento das infeccoes causadas por Candida depende cada vez mais do conhecimento da especie e do seu perfil de sensibilidade. OBJETIVOS: Esse estudo teve por objetivo realizar uma investigacao do perfil de suscetibilidade de amostras de candidiase oral e vulvovaginal, de pacientes residentes no oeste de Santa Catarina, aos antifungicos anfotericina B, fluconazol e miconazol. MATERIAL E METODOS: A suscetibilidade de 60 cepas de Candida spp. foi avaliada frente aos antifungicos. As determinacoes das concentracoes inibitorias minimas e concentracoes fungicidas minimas foram realizadas com base no documento M27-A2 do Clinical and Laboratory Standards Institute (CLSI). RESULTADOS: No presente estudo foi observado alto indice de resistencia para o fluconazol e para a anfotericina B. O miconazol foi o antifungico que demonstrou melhor eficacia sobre as cepas testadas. DISCUSSAO: As amostras dessa regiao do estado de Santa Catarina demonstram baixa suscetibilidade aos antifungicos, o que explica a alta taxa de recidivas nas infeccoes, mas alerta para a emergencia de cepas com resistencia adquirida. CONCLUSAO: A previa avaliacao por testes de suscetibilidade in vitro deve nortear a conduta de um tratamento antifungico efetivo para os casos de candidiase de repeticao, principalmente em locais de alta prevalencia desta infeccao oportunista, como no oeste de Santa Catarina.

Imidazolium Salts as Antifungal Agents: Activity Against Emerging Yeast Pathogens, Without Human Leukocyte Toxicity

This study demonstrates the excellent in vitro antifungal activity profile of imidazolium ionic liquids (ILs) against species of opportunistic human mycoses. Several ILs were identified as more effective and less harmful than commercially available antifungal medications. Frequently, emerging yeast pathogens are resistant against commercial antifungal agents and, as a consequence, this class of imidazolium ILs represents a promising breakthrough in their treatment.

Imidazolium salts with antifungal potential against multidrug-resistant dermatophytes.

To investigate the antidermatophytic action of a complementary set imidazolium salts (IMS), determining structure‐activity relationships and characterizing the IMS toxicological profiles.

Assessment of the genotoxic impact of pesticides on farming communities in the countryside of Santa Catarina State, Brazil

The aim of this study was to assess the use of pesticides on farms located in the Lambedor River watershed in Guatambu, State of Santa Catarina, as well as to determine, by micronucleus testing, the risk of genotoxic impact. Samples from locally collected Cyprinus carpio, Hypostomus punctatus, Rhamdia quelen and Oreochromis niloticus gave evidence of a mean increase in micronuclei frequency from 6.21 to 13.78 in 1,000 erythrocytes, a clear indication of the genotoxic potenciality of pesticide residues in regional dams, and their significant contribution to local environmental contamination.

Synthesis of isosteric triterpenoid derivatives and antifungal activity.

Dermatomycoses are among the most widespread and common superficial and cutaneous fungal infections in humans. There is an urgent need to develop efficient and non‐toxic antimycotic agents with a specific spectrum of activity. Triterpenes have been demonstrated to exhibit a wide range of biological activities, including antifungal activities. In this study, through hemisynthesis, we aimed to obtain triterpene‐isosteric molecules from betulinic and ursolic acids to improve the antifungal activity and spectrum of action of these compounds. Six compounds were resynthesized and tested against eleven mucocutaneous and cutaneous mycotic agents. The results of the susceptibility assays were expressed as the minimal inhibitory concentration (MIC). The MIC values of the piperazinyl derivatives of ursolic and betulinic acids that were active against pathogenic yeasts were in the range of 16–32 μg/mL and 4–16 μg/mL, respectively, whereas fungicidal effects were observed at concentrations ranging from 16 to 128 μg/mL and 8 to 128 μg/mL, respectively. The piperazinyl derivative of betulinic acid exhibited an antifungal profile similar to that of terbinafine and was the most effective derivative against dermatophytes. This strategy led to a promising candidate for the development of a new antifungal agent.