Dermatophytes are fungi responsible for a disease known as dermatophytosis. Biofilms are sessile microbial communities surrounded by extracellular polymeric substances (EPS) with increased resistance to antimicrobial agents and host defenses. This paper describes, for the first time, the characteristics of Trichophyton rubrum and T. mentagrophytes biofilms. Biofilm formation was analyzed by light microscopy, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) as well as by staining with crystal violet and safranin. Metabolic activity was determined using the XTT reduction assay. Both species were able to form mature biofilms in 72 h. T. rubrum biofilm produced more biomass and EPS and was denser than T. mentagrophytes biofilm. The SEM results demonstrated a coordinated network of hyphae in all directions, embedded within EPS in some areas. Research and characterization of biofilms formed by dermatophytes may contribute to the search of new drugs for the treatment of these mycoses and might inform future revisions with respect to the dose and duration of treatment of currently available antifungals.

Cryptococcosis is an important systemic mycosis and the third most prevalent disease in human immunodeficiency virus (HIV)-positive individuals. The incidence of cryptococcosis is high among the 25 million people with HIV/acquired immunodeficiency syndrome (AIDS), with recent estimates indicating that there are one million cases of cryptococcal meningitis globally per year in AIDS patients. In Cryptococcus neoformans, resistance to azoles may be associated with alterations in the target enzyme encoded by the gene ERG11, lanosterol 14α-demethylase. These alterations are obtained through mutations, or by overexpressing the gene encoding. In addition, C. gattii and C. neoformans present a heteroresistance phenotype, which may be related to increased virulence. Other species beyond C. neoformans and C. gattii, such as C. laurentii, have been diagnosed mainly in patients with immunosuppression. Infections of C. albidus have been isolated in cats and marine mammals. Recent evidence suggests that the majority of infections produced by this pathogen are associated with biofilm growth, which is also related with increased resistance to antifungal agents. Therefore, there is a great need to search for alternative antifungal agents for these fungi. The search for new molecules is currently occurring from nanoparticle drugs of plant peptide origin. This article presents a brief review of the literature regarding the epidemiology of cryptococcosis, as well as fungal resistance and new alternatives for treatment.

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Cryptococcus neoformans and C. gattii are fungal pathogens that are most commonly found in infections of the central nervous system, which cause life-threatening meningoencephalitis and can grow as a biofilm. Biofilms are structures conferring protection and resistance of microorganism to the antifungal drugs. This study compared the virulence of planktonic and biofilm cells of C. neoformans and C. gattii in Galleria mellonella model, as well as, the quantification of gene transcripts LAC1, URE1, and CAP59 by real time PCR. All three of the genes showed significantly increased expressions in the biofilm conditions for two species of Cryptococcus, when compared to planktonic cells. C. neoformans and C. gattii cells in the biofilm forms were more virulent than the planktonic cells in G. mellonella. This suggests that the biofilm conditions may contribute to the virulence profile. Our results contribute to a better understanding of the agents of cryptococcosis in the host-yeast aspects of the interaction.

Recebido em 8/2/08; aceito em 2/4/08; publicado na web em 29/4/08 ANTIFUNGAL SAPONINS FROM Swartzia langsdorffii. Chromatographic fractionation of the EtOH extract from the leaves of Swartzia langsdorffii afforded the pentacyclic triterpenes oleanolic acid and lupeol, and two saponins: oleanolic acid 3-sophoroside and the new ester 3-O-β-D-(6'-methyl)-glucopyranosyl-28-O-β-D-glucopyranosyl-oleanate. Their structures were elucidated from spectral data, including 2D NMR and HRESIMS experiments. Antifungal activity of all isolated compounds was evaluated, using phytopathogens Cladosporium cladosporioides and C. sphaerospermum, and human pathogens Candida albicans, C. krusei, C. parapsilosis and Cryptococcus neoformans.Keywords: Swartzia langsdorffii; saponins; antifungal activity. INTRODUÇÃOEspécies da família Fabaceae são amplamente distribuídas em regiões tropicais e subtropicais e divididas em três subfamílias: Caesalpinoideae, Mimosoideae e Papilionoideae.1 O gênero Swartzia pertence à subfamília Caesalpinoideae e inclui 150 espécies, distribuídas pelas Américas do Sul e Central e África. Na América do Sul, o centro de maior diversidade desse gênero está na região amazôni-ca. No Brasil, além da região amazônica, existe uma considerável representatividade de espécies na região sudeste. 1,2Swartzia langsdorffii pertence à subfamília Caesalpinoideae, e é popularmente conhecida como banana-de-papagaio, jacarandá-banana e jacarandá-de-sangue. Na região sudeste, é encontrada nos estados do Rio de Janeiro e de São Paulo nas formações florestais do complexo atlântico, principalmente na Serra do Mar.3 A árvore é ornamental, principalmente quando em flor, e seus frutos são muito procurados por várias espécies da fauna, que se alimentam do arilo suculento que envolve parcialmente a semente. Por essa razão, essa árvore é interessante para plantio em áreas degradadas para preservação permanente.3 O gênero Swartzia é caracterizado pela presença de isoflavonóides, saponinas triterpênicas e diterpenos aromáti-cos.2,4-7 Espécies deste gênero apresentam constituintes químicos com atividade antimicrobiana, 4 antifúngica, 5 moluscicida 6 e citotóxica, 2,7 o que mostra a importância da investigação adicional sobre aspectos fitoquímicos e/ou farmacológicos destas espécies. Em nosso programa de bioprospecção, o extrato de Swartzia langsdorffii destacou-se pela marcante atividade antifúngica frente a fitopatógenos e patógenos humanos. Os fungos são amplamente associados a doenças oportunistas e tem-se observado aumento no núme-ro de pacientes com alterações no estado imunológico associado ao vírus da imunodeficiência adquirida (HIV), à quimioterapia do cân-cer e transplante de órgãos e de sangue. Coincidindo com esse aumento de pacientes imunocomprometidos tem ocorrido um aumento da incidência de micoses sistêmicas humanas. 8 Cryptococcus neoformans, destacado como uma das principais infecções em pacientes aidéticos, e Candida sp, descrita em 20 a 40% de pacientes com câncer e em aproximadamente 25% dos pacientes que recebem transplan...

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ABSTRACT:The present study aimed to analyze the genetic similarity between genomic profiles of thirteen Klebsiella oxytoca and seven Klebsiella pneumoniae samples isolated from two different collections carried out in different places of dental offices. Random amplified polymorphic DNA (RAPD) technique and similarity coefficients (calculated by Sorensen-Dice and simple matching) were applied to determine their genetic profile of randomic DNA sequences. The majority of the isolates of K. pneumoniae and K. oxytoca presented similar coefficient values (≥ 0.80). Thus, it was possible to identify that strain dissemination occurred mainly via the hands of the surgeon-dentists and, finally, to determine the genetic similarity of the strains from dental office environments. KEY WORDS:Klebsiella oxytoca, Klebsiella pneumoniae, RAPD, dental office. CONFLICTS OF INTEREST:There is no conflict. CORRESPONDENCE TO:ROSEMEIRE CRISTINA LINHARI RODRIGUES PIETRO, Departamento de