Inhibitory effect of proteinase K against dermatophyte biofilms: an alternative for increasing the antifungal effects of terbinafine and griseofulvin.

This study aimed to evaluate the effect of proteinase K on mature biofilms of dermatophytes, by assays of metabolic activity and biomass. In addition, the proteinase K-terbinafine and proteinase K-griseofulvin interactions against these biofilms were investigated by the checkerboard assay and scanning electron and confocal microscopy. The biofilms exposed to 32 µg ml-1 of proteinase K had lower metabolic activity and biomass, by 39% and 38%, respectively. Drug interactions were synergistic, with proteinase K reducing the minimum inhibitory concentration of antifungals against dermatophyte biofilms at a concentration of 32 µg ml-1 combined with 128-256 µg ml-1 of terbinafine and griseofulvin. Microscopic images showed a reduction in biofilms exposed to proteinase K, proteinase K-terbinafine and proteinase K-griseofulvin combinations. These findings demonstrate that proteinase K has activity against biofilms of dermatophytes, and the interactions of proteinase K with terbinafine and griseofulvin improve the activity of drugs against mature dermatophyte biofilms.

Atypical chlamydoconidium-producing Trichophyton tonsurans strains from Ceará State, Northeast Brazil: investigation of taxonomy by phylogenetic analysis and biofilm susceptibility.

Chlamydoconidium-producing Trichophyton tonsurans strains isolated in Northeastern Brazil have morphological features different from the classic description of this dermatophyte species. This study investigated the phylogenetic relationship of chlamydoconidium-producing T. tonsurans strains isolated in Northeastern Brazil. Also, the effect of terbinafine and farnesol on mature biofilms of T. tonsurans strains was evaluated. The mass spectra of T. tonsurans strains were investigated by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The ITS and LSU loci regions of rDNA and the partial ß-tubulin gene were sequenced and the phylogenetic tree was analysed. The effects of terbinafine and farnesol on mature T. tonsurans biofilms were evaluated through the analysis of metabolic activity, quantification of biomass and observation by scanning electron microscopy. MALDI-TOF MS spectra of the chlamydoconidium-producing T. tonsurans strains differed from the spectrum of the control strain (ATCC 28942), presenting an intense ion peak at m/z 4155 Da. Phylogenetic tree analysis showed that the chlamydoconidium-producing strains isolated in Northeastern Brazil are allocated to a single cluster, differing from strains isolated from other countries. As for mature T. tonsurans biofilms, farnesol reduced biomass and metabolic activity by 64.4 and 65.9 %, respectively, while terbinafine reduced the biomass by 66.5 % and the metabolic activity by 69 %. Atypical morphological characteristics presented by chlamydoconidium-producing T. tonsurans strains result from phenotypic plasticity, possibly for adaptation to environmental stressors. Also, farnesol had inhibitory activity against T. tonsurans biofilms, demonstrating this substance can be explored for development of promising anti-biofilm drugs against dermatophytes.

In vitro and ex vivo biofilms of dermatophytes: a new panorama for the study of antifungal drugs.

This study describes an ex vivo model that creates an environment for dermatophyte biofilm growth, with features that resemble those of in vivo conditions, designing a new panorama for the study of antifungal susceptibility. Regarding planktonic susceptibility, MIC ranges were 0.125-1 µg ml-1 for griseofulvin and 0.000097-0.25 µg ml-1 for itraconazole and terbinafine. sMIC50 ranges were 2->512 µg ml-1 for griseofulvin and 0.25->64 µg ml-1 for itraconazole and terbinafine. CLSM images demonstrated a reduction in the amount of cells within the biofilm, but hyphae and conidia were still observed and biofilm biomass was maintained. SEM analysis demonstrated a retraction in the biofilm matrix, but fungal structures and water channels were preserved. These results show that ex vivo biofilms are more tolerant to antifungal drugs than in vitro biofilms, suggesting that environmental and nutritional conditions created by this ex vivo model favor biofilm growth and robustness, and hence drug tolerance.

Ex vivo biofilm-forming ability of dermatophytes using dog and cat hair: an ethically viable approach for an infection model.

The aim of this study was to establish an ex vivo model for dermatophyte biofilm growth, using hair from dogs and cats. Strains of Microsporum canis, M. gypseum, Trichophyton mentagrophytes and T. tonsurans were assessed for in vitro and ex vivo biofilm production. All T. mentagrophytes and T. tonsurans isolates and 8/12 M. canis and 1/7 M. gypseum isolates formed biofilms in vitro, while all tested isolates presented biofilm growth on ex vivo models. T. mentagrophytes and M. canis formed more homogeneous and better-structured biofilms with greater biomass production on cat hair but T. tonsurans formed more biofilm on dog hair. Confocal and scanning electron microscopy demonstrated fungal hyphae colonizing and perforating the hair shaft, abundant fungal conidia, biofilm extracellular matrix and biofilm water channels. The present study demonstrated an ex vivo model for the performance of studies on biofilm formation by dermatophytes, using dog and cat hair.

Paródias no ensino de microbiologia: a música como ferramenta pedagógica / Parodies in the teaching of microbiology: music as a pedagogical tool / Parodias en la enseñanza de la microbiología: la música como herramienta pegagógica

Atividades lúdicas, como as paródias, são estratégias didáticas motivadoras para a aprendizagem e configuram-se como forma criativa e crítica de trabalhar o aprendizado. O presente artigo objetiva descrever o processo de construção e divulgação de paródias como instrumento facilitador para transmissão e assimilação de conteúdos microbianos, no âmbito do projeto de extensão ‘Musicalizando a Biologia’, vinculado ao Curso de Ciências Biológicas a distância da Universidade Estadual do Ceará/Universidade Aberta do Brasil. Trata-se de relato de experiência da produção de três paródias na qual foi possível estabelecer os critérios e os conteúdos, bem como a escolha de músicas populares que viriam a facilitar a fixação da melodia e da letra contendo as ideias que se queria transmitir. Os resultados indicam que a utilização dessa ferramenta pode oferecer contribuições significativas para o ensino e favorecer a aprendizagem dos conteúdos em microbiologia.

Fun activities, such as parodies, are among the creative teaching strategies that can motivate learning and critical analysis. This article describes the process of constructing and diffusion of parodies as aninstrument for transmission and assimilation of the technical concepts involving microbiology, in the project called ‘Musicalizando a Biologia’ (musicalization of biology), associated with the distance education undergraduate course in biology offered by University of Ceará/Open University of Brazil. It is a experience report of the production of three parodies, through which it was possible to establish the criteria, as well as the choice of popular melodies to facilitate memorization of the content and ideas. The results indicate that the use of this tool can make significant contributions to teaching and favoring the learning of concepts of microbiology.

Actividades lúdicas, como parodias, son estrategias de enseñanza motivadoras y se configuran como forma creativa y crítica para trabajar el aprendizaje. Este artículo describe el proceso de construcción y divulgación de parodias como facilitador para la transmisión y asimilación de contenido microbiano dentro del proyecto denominado ‘Musicalizando a Biologia’, vinculado a el curso de ciencias biológicas a distancia de la Universidad del Estado de Ceará/Universidad Abierta de Brasil. Se trata de un relato de experiencia de la producción de tres parodias, por la cual fue posible establecer los criterios y contenidos, así como la elección de canciones populares que facilitasen la memorización de la melodía y de la letra con las ideas que se quería transmitir. Los resultados indican que el uso de esta herramienta puede ofrecer contribuciones significativas a la enseñanza y favorecer el aprendizaje de contenidos en microbiología.

Fungal biodiversity of air in hospitals in the city of Fortaleza, Ceará, Brazil / Biodiversidade fúngica do ar de hospitais da cidade de Fortaleza, Ceará, Brasil

Objectives: To monitor the environment in specific areas of three tertiary hospitals in Fortaleza - CE, seeking to report the presence of potentially pathogenic fungi for patients and staff, contributing to a better risk assessment in these hospitals. Methods: In the period from December, 2005 to November, 2006, air samples from three public hospitals were collected monthly, which resulted in 180 air samples originated in 15 hospitals. The biological specimens were collected using the passive method of sedimentation, with exposure of Petri dishes containing Sabouraud agar supplemented with antibiotic. The dishes were incubated for 10 days (28°C) and all fungal colonies developed were subsequently identified. Results: 10,608 colonies were isolated, belonging to 16 genera, the most common being Aspergillus, Penicillium, Candida, Curvularia and Trichoderma. There were no statistically significant relationships between the total number of colonies and the characteristics of each environment studied, except for three of those. Conclusion: The difference in fungal concentrations in the air of these hospitals is possibly more related to instability of human activities, such as overpopulated settings and construction works, than to climatic variations observed in the period.

Objetivos: Monitorar o ambiente em áreas específicas de três hospitais terciários da cidade de Fortaleza ? CE, buscando relatar a presença de fungos potencialmente patogênicos para pacientes e funcionários, contribuindo para uma melhor avaliação de riscos nesses hospitais. Métodos: No período de dezembro/2005 a novembro/2006, foram realizadas coletas mensais de amostras do ar de três hospitais públicos, que resultaram em 180 amostras de ar oriundas de 15 ambientes hospitalares. Os espécimes biológicos foram coletados através do método da sedimentação passiva, com exposições de placas de Petri, contendo ágar Sabouraud, suplementado com antibiótico. As placas foram incubadas por 10 dias (28°C), com a posterior identificação de todas as colônias fúngicas desenvolvidas. Resultados: Isolaram-se 10.608 colônias, pertencentes a 16 gêneros, sendo os mais frequentes Aspergillus, Penicillium, Candida, Curvularia e Trichoderma. Não se observaram relações estatisticamente significativas entre o número total de colônias e as características de cada ambiente analisado, com exceção de três ambientes. Conclusão: A diferença na concentração fúngica do ar desses hospitais possivelmente está mais relacionada com desequilíbrios das atividades humanas, tais como ambientes superpovoados e obras de construção, do que com as variações climáticas observadas no período em análise.

Fungal microbiota of the hair coat of laboratory animals / Microbiota fúngica da pelagem de animais de laboratório

With the refining of handling techniques for laboratory animals kept in animal rooms in which different work rules are followed,it is fundamental to evaluate the microbiota of the raising environment, as well as of the animals in this environment. It isknown that several saprobe fungi are isolated from hair and skin of experimental animals, being potentially pathogenic inspecific situations. The aim of this research was to determine the fungal microbiota on the coats of laboratory animals fromthe Central Animal Room of the University of Ceará. Samples of hair and skin of 355 healthy animals (150 rats, 150 mice, 40guinea pigs and 15 hamsters) were analyzed. Samples were collected by vigorously brushing the back of the animals andthen cultured on Sabourauds dextrose and Mycosel agar. Species identification was based on the analysis of the macroscopicappearance of colonies and microscopy features of the fungi. Development of fungi was observed in 63.95% of the animals.The most frequent fungi were: Scopulariopsis brevicaulis (34.7%), Aspergillus sp. (30%) and Penicillium sp. (16.7%). Inconclusion, fungal microbiota on coat of these animals is diversified, and saprobe fungi occurs in a great number of experimentalanimals

Com o afinamento das técnicas de manejo de animais de laboratório mantidos em biotérios que seguem diferentes normas de trabalho, é fundamental que se avalie a microbiota dos ambientes de criação, bem como dos animais que deles fazem parte. É sabido que várias espécies fúngicas sapróbias são isoladas da pele e pelos de animais experimentais, podendo em situações específicas ser potencialmente patogênicas. A presente pesquisa objetivou conhecer a microbiota fúngica da pelagem de animais de laboratório do Biotério Central da UECE. Para tanto, foram analisadas amostras de pele e pelos de 355 animais clinicamente saudáveis (150 ratos, 150 camundongos, 40 cobaias e 15 hamsters). As amostras foram coletadas mediante escovação vigorosa do dorso desses animais e semeadas em ágar Sabouraud dextrose e ágar Mycosel, sendo a identificação das espécies baseada na análise das características macro e microscópicas das colônias fúngicas. Houve o desenvolvimento de fungos em 63,95% dos animais. Os fungos mais incidentes foram: Scopulariopsis brevicaulis (34,7%), Aspergillus sp. (30%) e Penicillium sp. (16,7%). Frente aos resultados obtidos, conclui-se que a microbiota fúngica da pelagem desses animais é bem diversificada, ficando evidente a ocorrência de fungos sapróbios em grande número de animais experimentais

Epidemiologia e ecologia das dermatofitoses na cidade de Fortaleza: o Trichophyton tonsurans como importante patógeno emergente da Tinea capitis / Epidemiology and ecology or dematophytosis in Fortaleza city: Trichophyton tonsurans as an important emergent pathogen of Tinea capitis

As dermatofitoses säo os distúrbios infecciosos de pele mais comuns do mundo. Na presente pesquisa foram avaliados 2.297 pacientes com lesöes clínicas sugestivas de dermatofitoses das quais, 534 (23,2 por cento) mostraram-se positivas para dermatófitos. Destes, o T. rubrum foi a espécie mais prevalente (49,6 por cento; p