L. Abarca

Collaborative Evaluation of Optimal Antifungal Susceptibility Testing Conditions for Dermatophytes

ABSTRACT A multicenter study was conducted to define the most suitable testing conditions for antifungal susceptibility of dermatophytes. Broth microdilution MICs of clotrimazole, itraconazole, and terbinafine were determined in three centers against 60 strains of dermatophytes. The effects of inoculum density (ca. 103 and 104 CFU/ml), incubation time (3, 7, and 14 days), endpoint criteria for MIC determination (complete [MIC-0] and prominent [MIC-2] growth inhibition), and incubation temperature (28 and 37°C) on intra- and interlaboratory agreement were analyzed. The optimal testing conditions identified were an inoculum of 104 CFU/ml, a temperature of incubation of 28°C, an incubation period of 7 days, and MIC-0.

Phylogeny of chrysosporia infecting reptiles: proposal of the new family Nannizziopsiaceae and five new species

We have performed a phenotypic and phylogenetic study of a set of fungi, mostly of veterinary origin, morphologically similar to the Chrysosporium asexual morph of Nannizziopsis vriesii (Onygenales, Eurotiomycetidae, Eurotiomycetes, Ascomycota). The analysis of sequences of the D1-D2 domains of the 28S rDNA, including representatives of the different families of the Onygenales, revealed that N. vriesii and relatives form a distinct lineage within that order, which is proposed as the new family Nannizziopsiaceae. The members of this family show the particular characteristic of causing skin infections in reptiles and producing hyaline, thin- and smooth-walled, small, mostly sessile 1-celled conidia and colonies with a pungent skunk-like odour. The phenotypic and multigene study results, based on ribosomal ITS region, actin and β-tubulin sequences, demonstrated that some of the fungi included in this study were different from the known species of Nannizziopsis and Chrysosporium and are described here as new. They are N. chlamydospora, N. draconii, N. arthrosporioides, N. pluriseptata and Chrysosporium longisporum. Nannizziopsis chlamydospora is distinguished by producing chlamydospores and by its ability to grow at 5 °C. Nannizziopsis draconii is able to grow on bromocresol purple-milk solids-glucose (BCP-MS-G) agar alkalinizing the medium, is resistant to 0.2 % cycloheximide but does not grow on Sabouraud dextrose agar (SDA) with 3 % NaCl. Nannizziopsis arthrosporioides is characterised by the production of very long arthroconidia. Nannizziopsis pluriseptata produces 1- to 5-celled sessile conidia, alkalinizes the BCP-MS-G agar and grows on SDA supplemented with 5 % NaCl. Chrysosporium longisporum shows long sessile conidia (up to 13 μm) and does not produce lipase.

Brief communication: Extracellular enzymatic activities of dermatophytes

Eighty dermatophyte strains belonging to the genera Trichophyton, Microsporum, Epidermophyton and Chrysosporium were screened for their ability to produce extracellular enzymes using a semiquantitative method. The results obtained vary significantly when the studied genera are observed separately, though the enzyme β-galactosidase was detected in none of the four studied genera.

Antifungal activity of some mediterranean algae.

SummaryThe antifungal activity of 15 mediterranean algae species on some dermatophyte strains (Epidermophyton floccosum, Microsporum canis, M. gypseum and Trichophyton mentagrophytes) and pathogenic yeasts (Candida albicans, C. guillermondii, C. krusei, C. tropicalis and Torulopsis glabrata) has been tested following a modification of Auberts technique.Among the algae species studied, Falkenbergia rufolanosa is the most active in front of all the fungi tested.

Variability of biochemical characteristics in strains of Trichophyton mentagrophytes

The characteristics of 23 strains of Trichophyton mentagrophytes isolated from clinical samples, were studied. Sabouraud agar was the most adequate medium to inhance at their utmost the different taxonomical features. Variability of enzymatic reactions in strains of T. mentagrophytes was observed.

Sensitivity of some strains of the genus Epidermophyton to different antifungal agents

The inhibitory activity of some antifungal agents against 17 strains of genus Epidermophyton have been studied. The behaviour of Epidermophyton stockdaleae against antifungal agents tested is clearly different from that observed in the strains belonging to Epidermophyton floccosum, since all of the latter were sensitive to the antifungal agents used and the geophilic species showed resistance to griseofulvin, isoconazole, natamycin and nystatin, and intermediate sensitivity to ketoconazole and miconazole. The low sensitivity of E. stockdaleae (and other geophilic dermatophytes) to antifungal agents could be a problem in the current therapy if further studies or case reports demonstrate their pathogenic role.

Contribution to the study of Aspergillus fumigatus Fresenius

Abstract50 strains of Aspergillus fumigatus were studied for enzymatic and physiologic profile. Proteolytic and lipolytic activity were lacking. Various ribonucleases and sacchrolytic enzymes were found.