In vitro determination of the susceptibility of Malassezia furfur biofilm to different commercially used antimicrobials.

Malassezia furfur is a yeast known as the etiological agent of seborrheic dermatitis. We evaluated the action of five different antimicrobials (amphotericin B, chloramphenicol, ketoconazole, fluconazole, and nystatin) on inhibiting biofilm formation and removing biofilm already formed by M. furfur. The assays were carried out using the microdilution method, and scanning electron microscopy images were used to analyze the biofilm structure. According to the results obtained, the percentage of inhibition was higher for chloramphenicol, followed by ketoconazole, nystatin, and amphotericin B. Regarding the eradication of the biofilm formed, the highest percentage was chloramphenicol, followed by ketoconazole and nystatin. Amphotericin B did not affect biofilm eradication, whereas fluconazole did not cause significant changes inhibiting or removing M. furfur biofilm. Therefore, except for fluconazole, all evaluated antimicrobials had inhibiting effects on the biofilm of M. furfur, either in its formation and/or eradication. Although the results achieved with chloramphenicol have been highlighted, further in vitro and in vivo studies are still needed in order to include this antimicrobial in the therapy of seborrheic dermatitis due to its toxicity, especially to the bone marrow.

Synergism Between Essential Oils and Evaluation of Their Activities with a Focus on Malassezia furfur Control.

Seborrheic dermatitis is a chronic inflammatory disease caused by Malassezia yeast species that affects the regions of the body where the sebaceous glands are present. The combined use of different essential oils (EOs) can increase their spectrum of action. Thus, the present study aimed to evaluate the action of EOs alone and in combination with each other on M. furfur, in planktonic and biofilm form, and their anti-inflammatory and mutagenic potential, in addition to the effects on the viability of cells lines. Of the 40 evaluated EOs, 22 showed activity against M. furfur at 0.5 - 2.0 mg/mL concentrations. Among the most active species, a blend of essential oils (BEOs) composed of Cymbopogon martini (Roxb.) Will. Watson (MIC = 0.5 mg/mL) and Mentha × piperita L. (MIC = 1.0 mg/mL) was selected, which showed a synergistic effect against yeast when evaluated through the checkerboard assay. The fungicidal activity was maintained by the addition of anti-inflammatory oil from Varronia curassavica Jacq. to BEOs. The BEOs also showed activity in the inhibition of biofilm formation and in the eradication of the biofilm formed by M. furfur, being superior to the action of fluconazole. Furthermore, it did not show mutagenic potential and did not interfere with the cell viability of both evaluated cell lines (HaCaT and BMDMs). TNF-α levels were reduced only by C. martini; however, this property was maintained when evaluating BEOs. BEOs had no effect on IL-8 levels. Thus, the BEOs may be indicated for alternative treatments against seborrheic dermatitis.

ORIGEN GEOGRÁFICO Y BOTÁNICO DE MIELES DE Apis mellifera (APIDAE) EN CUATRO DEPARTAMENTOS DE COLOMBIA / Geographical and Botanical Origin of Apis mellifera (APIDAE) Honey in four Colombian Departments

El objetivo de este trabajo fue determinar marcadores palinológicos que permitieran caracterizar el origen geográfico y botánico de mieles provenientes de los departamentos de Boyacá, Cundinamarca, Santander y Magdalena. Se realizaron análisis melisopalinológicos de 184 muestras de miel procedentes de 131 apiarios. Se determinaron diferencias significativas entre tipos de mieles mediante un análisis discriminante y comparando la composición de especies entre las muestras. En total se encontraron 297 especies distribuidas en 69 familias, dentro de las cuales las más representativas fueron Mimosa sp., Cecropiasp., Eucalyptus sp., Piper sp. y Quercus humboldtii . Las familias más importantes fueron Fabaceae, Asteraceae,Myrtaceae, Rubiaceae, Fagaceae, y Melastomataceae. Se lograron determinar seis grupos de mieles diferenciadas por su origen geográfico: altiplano Cundiboyacense, Medio Chicamocha, Sumapaz, Bajo Chicamocha, Sierra Nevada de Santa Marta y provincia Comunera; también se encontraron diferencias entre las mieles de las regiones andinas y subandinas. Dentro de los tipos de mieles diferenciadas por origen botánico predominaron las mieles monoflorales de Trifolium Pratense, Coffeaarabica, Eucalyptus sp., Inga sp. y Heliocarpus americanus, mieles oligoflorales de asteráceas y mezclas de mielato de Q. humboldtii y néctar floral (Eucalyptus sp. tipo Brassicaceae, asteráceas). La información de este trabajo junto con la obtenida en análisis fisicoquímicos y sensoriales servirá de base para que los apicultores puedan solicitar la denominación de origen de estas mieles.

The aim of this work was to find palynological markers which permit differentiate honeys from the departments of Boyacá, Cundinamarca, Santander and Magdalena, by its geographical and botanical origin. Melissopalynological analyses were made of 184 honey samples obtained from 131 localities. A discriminant analysis and comparisons between the species composition of honey samples were made to find geographical and botanical origin differences. A total of 297 pollen species distributed in 69 families was found, being Mimosa sp., Cecropiasp., Eucalyptus sp., Piper sp. and Quercus humboldtii the most representatives. The major families were Fabaceae, Asteraceae, Myrtaceae, Rubiaceae, Fagaceae and Melastomataceae. Six honey groups differentiated by its geographical origin were found: Altiplano Cundiboyacense, Medio Chicamocha, Sumapaz, Bajo Chicamocha, Sierra Nevada de Santa Marta and Comunera Province. In a broader scale, honeys from the Andean and sub-Andean regions could be differentiated as well. Between the honey types differentiated by its botanical origin, the most important were monofloral honeys of Trifolium Pratense, Coffeaarabica, Eucalyptus sp., Inga sp. and Heliocarpus americanus, Asteraceae oligofloral honeys and mixtures of Q. humboldtii honeydew and floral nectar (Eucalyptus sp., Brassicaceae Type, Asteraceae). This information in addition to the obtained by physicochemical and sensorial analysis, may be the basis to acquire honeys´ origin denomination.