RESUMEN
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.
Asunto(s)
Arthrodermataceae/fisiología , Biopelículas/crecimiento & desarrollo , Hifa/ultraestructura , Trichophyton/fisiología , Análisis de Varianza , Arthrodermataceae/metabolismo , Violeta de Genciana , Microscopía Confocal , Microscopía Electrónica de Rastreo , Fenazinas , Especificidad de la Especie , Sales de Tetrazolio , Trichophyton/metabolismoRESUMEN
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.
Asunto(s)
Antifúngicos/uso terapéutico , Criptococosis/tratamiento farmacológico , Criptococosis/epidemiología , Cryptococcus/efectos de los fármacos , Farmacorresistencia Fúngica , Animales , Antifúngicos/farmacología , Gatos , Criptococosis/microbiología , Criptococosis/veterinaria , Cryptococcus/aislamiento & purificación , Descubrimiento de Drogas/métodos , Descubrimiento de Drogas/tendencias , HumanosRESUMEN
CLSI method M27-A3 is not available for use with dimorphic fungi, such as those of the Paracoccidioides genus. In this study, we developed a microdilution method and added the alamarBlue reagent to test the responses of Paracoccidioides brasiliensis and Paracoccidioides lutzii against amphotericin B and itraconazole antifungals. The test proved to be sensitive, practical, and inexpensive and can be used to monitor the activity of low-growth microorganisms and their response to various drugs.
Asunto(s)
Antifúngicos/farmacología , Oxazinas/metabolismo , Paracoccidioides/efectos de los fármacos , Coloración y Etiquetado/métodos , Xantenos/metabolismo , Anfotericina B/farmacología , Humanos , Itraconazol/farmacología , Pruebas de Sensibilidad Microbiana/métodos , Paracoccidioides/crecimiento & desarrollo , Paracoccidioides/metabolismoRESUMEN
The incidence of fungal infections has increased significantly, so contributing to morbidity and mortality. This is caused by an increase in antimicrobial resistance and the restricted number of antifungal drugs, which retain many side effects. Candida species are major human fungal pathogens that cause both mucosal and deep tissue infections. Recent evidence suggests that the majority of infections produced by this pathogen are associated with biofilm growth. Biofilms are biological communities with a high degree of organization, in which micro-organisms form structured, coordinated and functional communities. These biological communities are embedded in a self-created extracellular matrix. Biofilm production is also associated with a high level of antimicrobial resistance of the associated organisms. The ability of Candida species to form drug-resistant biofilms is an important factor in their contribution to human disease. The study of plants as an alternative to other forms of drug discovery has attracted great attention because, according to the World Health Organization, these would be the best sources for obtaining a wide variety of drugs and could benefit a large population. Furthermore, silver nanoparticles, antibodies and photodynamic inactivation have also been used with good results. This article presents a brief review of the literature regarding the epidemiology of Candida species, as well as their pathogenicity and ability to form biofilms, the antifungal activity of natural products and other therapeutic options.
Asunto(s)
Antifúngicos/uso terapéutico , Biopelículas , Productos Biológicos/uso terapéutico , Candida/fisiología , Candidiasis/tratamiento farmacológico , Candidiasis/epidemiología , Antifúngicos/clasificación , Biopelículas/efectos de los fármacos , Candida/clasificación , Candida/patogenicidad , HumanosRESUMEN
The pathogenic fungus, Histoplasma capsulatum, causes the respiratory and systemic disease 'histoplasmosis'. This disease is primarily acquired via inhalation of aerosolized microconidia or hyphal fragments of H. capsulatum. Evolution of this respiratory disease depends on the ability of H. capsulatum yeasts to survive and replicate within alveolar macrophages. It is known that adhesion to host cells is the first step in colonization and biofilm formation. Some microorganisms become attached to biological and non-biological surfaces due to the formation of biofilms. Based on the importance of biofilms and their persistence on host tissues and cell surfaces, the present study was designed to investigate biofilm formation by H. capsulatum yeasts, as well as their ability to adhere to pneumocyte cells. H. capsulatum biofilm assays were performed in vitro using two different clinical strains of the fungus and biofilms were characterized using scanning electron microscopy. The biofilms were measured using a 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium-hydroxide (XTT) reduction assay. The results showed that both the H. capsulatum strains tested were very efficient at adhering to host cells and forming biofilm. Therefore, this is a possible survival strategy adopted by this fungus.
Asunto(s)
Células Epiteliales Alveolares/microbiología , Biopelículas , Histoplasma/patogenicidad , Células Epiteliales Alveolares/metabolismo , Adhesión Celular , Línea Celular , Histoplasma/metabolismo , Histoplasma/fisiología , Histoplasmosis/microbiología , Interacciones Huésped-Patógeno , Humanos , Microscopía Electrónica de Rastreo , Sales de Tetrazolio/metabolismoRESUMEN
Trichophyton rubrum is a dermatophyte, which can cause infections in human skin, hair and nail. Pothomorphe umbellata (L.) Miq. (Piperaceae) is a native Brazilian plant, in which phytochemical studies have demonstrated the presence of steroids, 4-nerolidylcatechol, sesquiterpenes and essential oils. The objective of this study was to analyze the in vitro activity of extracts and fractions of P. umbellata on resistant strains of T. rubrum. The microdilution plate method was utilized to test Tr1, H6 and ΔTruMDR2 strains of T. rubrum; ΔTruMDR2 strain was obtained from H6 by TruMDR2 gene rupture, which is involved in multiple drugs resistance. The highest antifungal activity to all strains was observed for dichloromethane and hexane fractions of the 70% ethanolic extract which showed minimal inhibitory concentration (MIC) and minimal fungicide concentration (MFC) of 78.13 µg/mL. This antifungal activity was also obtained by 70% ethanolic extract, which presented MIC and MFC of 78.13 µg/mL to ΔTruMDR2, whereas the MIC values for Tr1 and H6 were 78.13 and 156.25 µg/mL, respectively. Our results suggest the potential for future development of new antifungal drugs from P. umbellata, especially to strains presenting multiple resistance.
Asunto(s)
Antifúngicos/farmacología , Piperaceae/química , Extractos Vegetales/farmacología , Trichophyton/efectos de los fármacos , Antifúngicos/aislamiento & purificación , Brasil , Recuento de Colonia Microbiana , Evaluación Preclínica de Medicamentos , Farmacorresistencia Fúngica Múltiple/genética , Etanol , Cromatografía de Gases y Espectrometría de Masas , Eliminación de Gen , Genes Fúngicos , Hexanos , Cloruro de Metileno , Pruebas de Sensibilidad Microbiana , Extractos Vegetales/aislamiento & purificación , Solventes , Trichophyton/genéticaRESUMEN
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 (¡Ý 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.(AU)
Asunto(s)
Animales , Klebsiella oxytoca , Perfil Genético , Klebsiella pneumoniae , Consultorios OdontológicosRESUMEN
Infecções fúngicas sistêmicas são hoje importante causa de morbidade e mortalidade em pacientes imunossuprimidos ou com outras condições predisponentes. Candida albicans e as não-albicans são importante causa de infecções nosocomiais e vários destes agentes são menos suscetíveis às drogas antifúngicas, principalmente os azólicos, um fato que tem significado no tratamento destes pacientes. O moderno laboratório de micologia tem importante papel no esclarecimento destas infecções, incluindo sua detecção , identificação e a sensibilidade a drogas antifúngicas, bem como a análise epidemiológica. Neste estudo, foi comparada a distribuição de espécies de Candida relacionadas a fungemias e outras fontes, em quatro hospitais do Estado de São Paulo. Das 40 leveduras identificadas, C. albicans, C. parapsilosis e C. tropicalis foram isoladas, respectivamente, em 35 por cento, 50 por cento e 15 por cento, revelando uma tendência de ser maior a freqüência de espécies não-albicans. As fungemias foram causadas por C. parapsilosis (45,4 por cento). C. albicans (36,4 por cento) e C. tropicalis (18,2 por cento), o que revela um aumento de espécies não-albicans em relação a séries históricas. As três diferentes espécies foram incluídas em 6,3 e 4 biótipos diferentes, respectivamente para C.albicans, C.parapsilosis e C.tropicalis. Este estudo enfatiza a importância da avaliação de espécies de Candida especialmente em centros hospitalares com pacientes de risco.