Maria Lúcia Scroferneker

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.

Fasciola hepatica infection in cattle and buffaloes in the State of Rio Grande do Sul, Brazil

We examined 482 livers, 377 from cattle and 105 from buffaloes slaughtered at a meat packing plant between April 1999 and November 1999, in Viamao, a town in the state of Rio Grande do Sul, in southern Brazil. The cattle slaughtered at the meat packing plant belonged to eleven towns: Cachoeira do Sul, Cachoeirinha, Capivari do Sul, Charqueadas, Encruzilhada do Sul, Ibiraiaras, Palmares do Sul, Pantâno Grande, Rio Pardo, Tupancireta and Viamao. The buffaloes belonged to the following towns: Encruzilhada do Sul, Ibiraiaras, Parobe, Santo Antonio da Patrulha, and Uruguaiana. The occurrence rate of Fasciola hepatica was 10.34% for cattle in seven of the eleven towns included in the study (63.6%) and 20% for buffaloes in four of the five towns (80%). In terms of age, the occurrence rate was 81% for buffaloes with up to two years of life and 19% for buffaloes older than two years. The livestock from Cachoeira do Sul, Capivari do Sul, Ibiraiaras and Tupancireta were not infected with bovine fascioliasis, and the buffaloes from Uruguaiana were not infected either. The studied areas may represent important endemic regions to fasciolosis, showing that zoonotic areas should be investigated.

In vitro susceptibility of chromoblastomycosis agents to five antifungal drugs and to the combination of terbinafine and amphotericin B

Chromoblastomycosis is a chronic mycosis that affects the skin and subcutaneous tissues caused by several genera of dematiaceous fungi. There is not a treatment of choice. Thus, tools that help guide clinical practice are fundamental. In this sense, antifungal activity tests in vitro could be useful. However, trials with chromoblastomycosis agents are scarce. The aim of this study was to evaluate both the in vitro susceptibility of 60 chromoblastomycosis agents to five antifungals and the combination of amphotericin B (AMB) and terbinafine (TRB). TRB, itraconazole (ITZ) and ketoconazole (KTZ) were, in this order, the drugs which showed better activity against the chromoblastomycosis agents. The less active drugs were voriconazole (VRZ) and AMB. The more differentiated group was Exophiala spinifera. Cladophialophora carrionii and Fonsecaea spp. are significantly more susceptible to KTZ than Phialophora verrucosa, whereas C. carrionii is significantly more sensitive to VRZ than P. verrucosa and E. spinifera. Assays in this direction allow the knowledge of the susceptibility of the causative agents which may help the management of patients with this disease. This study includes the largest number of these agents and of genera found in the literature.

Phenotypic aspects of oral strains of Candida albicans in children with down's syndrome

The aim of this article is to characterize the biological aspects of oral strains of C. albicans in children with Downs syndrome. These yeasts were analyzed as to their macromorphological and enzymatic aspects and were tested as to their in vitro susceptibility to antifungal drugs using broth microdilution to determine the minimum inhibitory concentration (MIC). The morphotyping revealed that all oral C. albicans isolates from children with Downs syndrome promoted the formation of fringes regardless of size, while the control group presented smaller fringes. All oral C. albicans strains produced proteinase, but those with phospholipolytic activity showed greater enzyme capacity in the test group. In vitro susceptibility showed that all oral C. albicans isolates were sensitive to the drugs used.

Perfil de suscetibilidade a antifúngicos de dermatófitos isolados de pacientes com insuficiência renal crônica

BACKGROUND The prevalence of dermatophytosis in the general population is high, particularly in patients with chronic renal failure. Treatment requires the use of topical and/or systemic antifungal drugs. The efficacy of antifungal agents for the treatment of dermatophytosis has yet to be evaluated. Studies evaluating the in vitro activity of antifungal agents are rare, particularly in filamentous fungi. OBJECTIVE To evaluate the susceptibility profile of different species of dermatophytes isolated from patients with chronic renal failure to nine antifungal drugs available on the market for the treatment of dermatophytosis. METHODS Twenty-six isolates of dermatophytes obtained from patients with chronic renal failure were analyzed with respect to their susceptibility to nine antifungal agents (ketoconazole, ciclopirox olamine, fluconazole, griseofulvin, itraconazole, miconazole, piroctone olamine, terbinafine and tioconazole), using the broth microdilution method proposed by the Clinical and Laboratory Standards Institute (CLSI) and adapted for dermatophytes. RESULTS Of the antifungal agents tested, the best results in terms of sensitivity were found with terbinafine and tioconazole, while the antifungal activity of fluconazole was found to be weak, particularly against strains of M. gypseum. Ciclopirox olamine, although less effective than terbinafine, also yielded satisfactory results. CONCLUSIONS In general, the sensitivity profile of the antifungal agents tested in this study was similar to results obtained in previous studies, confirming the need to determine which species is causing the dermatophytosis given that antifungal susceptibility varies from one species to another. Furthermore, the present findings show the importance of conducting in vitro sensitivity tests, since the sensitivity profile may differ among isolates of the same species.

Molecular Epidemiology of Agents of Human Chromoblastomycosis in Brazil with the Description of Two Novel Species

The human mutilating disease chromoblastomycosis is caused by melanized members of the order Chaetothyriales. To assess population diversity among 123 clinical strains of agents of the disease in Brazil we applied sequencing of the rDNA internal transcribed spacer region, and partial cell division cycle and β-tubulin genes. Strains studied were limited to three clusters divided over the single family Herpotrichiellaceae known to comprise agents of the disease. A Fonsecaea cluster contained the most important agents, among which F. pedrosoi was prevalent with 80% of the total set of strains, followed by 13% for F. monophora, 3% for F. nubica, and a single isolate of F. pugnacius. Additional agents, among which two novel species, were located among members of the genus Rhinocladiella and Cyphellophora, with frequencies of 3% and 1%, respectively.

Playing with cellular and humoral immunity

An interesting and easy game for the teaching of immunology was developed by the authors. Previously distributed figure cards are used by students that have to ask questions of each other. Most students considered the game to be interesting (97.7%) and declared that it helped them to understand the subject. The authors emphasise the importance of improving the quality of teaching using visual memory, fun and competition.

Sucesso terapêutico da terbinafina em um caso de esporotricose

Sporotrichosis is a chronic subacute infection caused by fungi belonging to the Sporothrix Complex. In the present clinical case, nasal sporotrichosis was treated with potassium iodide. This was unsuccessful, and the treatment was restarted with a combination of potassium iodide and itraconazole. This however resulted in a further recurrence of the infection. The mycological cultures were tested in vitro for antifungal activity to assist in treatment. Terbinafine, an antifungal drug, produced the best results and was therefore used for the rest of the treatment course, with no recurrence after two years of its completion. In addition, both cultures were compared using RAPD and different fragment patterns were observed. This indicated that the isolates were either different or indicated a microevolutionary process of this microorganism.

A game for teaching antimicrobial mechanisms of action

Background: Alternative teaching tools have proved to enhance students’ interest and knowledge skills. Aim: To integrate basic Bacteriology with mechanisms of action of antimicrobial agents. Methods: The board has 121 squares, including squares with question marks and antimicrobial agents. Each student receives a card with a clinical case, identification of the bacterium and its resistance to antimicrobials. The student rolls a dice and moves the corresponding number of squares. The game depends on the dice values rolled, the bacterial resistance profile, and the questions the student has to answer each time he/she lands on a question mark. Previously, the students were given a lecture about the subject. On the day of the game, students answered a pre-test and a post-test. The paired t-test was used for the statistical analysis. Results: The game was applied to 78 students of the Medicine and Pharmacy undergraduate courses of the Universidade Federal do Rio Grande do Sul, Brazil. There was an increase in the number of right answers and a decrease in the number of unknown answers. There were no significant differences between the courses. Conclusion: The game could be applied to other undergraduate courses in the field of Health Sciences.

Secretion of five extracellular enzymes by strains of chromoblastomycosis agents

The gelatinase, urease, lipase, phospholipase and DNase activities of 11 chromoblastomycosis agents constituted by strains of Fonsecaea pedrosoi, F. compacta, Phialophora verrucosa, Cladosporium carrionii, Cladophialophora bantiana and Exophiala jeanselmei were analyzed and compared. All strains presented urease, gelatinase and lipase activity. Phospholipase activity was detected only on five of six strains of F. pedrosoi. DNase activity was not detected on the strains studied. Our results indicate that only phospholipase production, induced by egg yolk substrate, was useful for the differentiation of the taxonomically related species studied, based on their enzymatic profile.