Background : Dermatophytes are common in both developed and developing countries, the species involved and the resulting clinical entities vary geographically. Aim of study: To determine public health importance of dermatophytes with special regard to the distribution of the zoophilic species among the examined human cases. Methods: Patient specimens (dermatophytosis-like lesions) were mycologically examined using direct microscopic and cultural examinations. Results: The overall dermatophyte infection rates among the examined patients (260) were 81.5% and 61.9% by direct microscopic and cultural examinations, respectively. A total of 161 dermatophyte isolates were obtained from culturally positive human specimens. The most common isolated species were Trichophyton violaceum (60, 37.3%) and Microsporum canis (46, 28.6%), followed by Trichophyton rubrum (20, 12.4%), Trichophyton tonsurans (16, 9.9%) and Trichophyton mentagrophytes (11, 6.8%). The less frequently isolated species were Trichophyton verrucosum (3, 1.9%), Epidermophyton floccosum (3, 1.9%), Microsporum gypseum (1, 0.6%) and Microsporum audouinii (1, 0.6%). The current study further revealed that out of 161 culturally positive patients, 61 (37.9%) had contact with pet animals, 6 (3.7%) had contact with farm animals, 7 (4.3%) had a history of rodent presence in or around their home and 87 (54%) had no contact with animals. Conclusions and recommendations: Although the anthropophilic species dominated the aetiology of human dermatophytosis in present study, the zoophilic species represented nearly one third of the totally obtained isolates, with the most important organisms being M. canis, T.mentagrophytes var. mentagrophytes and T. verrucosum. These findings indicate the necessity of human beings taking appropriate control measures when they are in contact with animals.
We previously developed an N-acetyl-D-glucosamine (GlcNAc) medium which induces Candida albicans to undergo a yeast-to-hyphal transition through a cAMP-PKA pathway. Microarray analysis demonstrated that 18 genes, including ALS3 that encodes a cell wall adhesion, were upregulated by 30-min incubation of yeast cells at 37°C in the GlcNAc medium. To investigate the differences between morphological transition and morphotype in C. albicans as a consequence of infection, this study utilized a silkworm infection model as an invertebrate mini-host. We prepared 3 different conditions of C. albicans cells in vitro by changing the incubation times in the GlcNAc medium: yeast-form cells at 0 min (Y0 cells), yeast-form cells in germination-ready state at 60 min (Y60 cells), and hyphal cells at 120 min (H120 cells), and compared their pathogenicities. We performed the infection study at various temperatures to find temperature-dependent virulence factors in vivo. Y60 cells in germination-ready state in the GlcNAc medium showed higher pathogenicity in vivo compared to Y0 and H120 cells at 30°C. Y60 cells proliferated in silkworms 24 h post-injection at 30°C, whereas the other 2 cell types did not. In vitro analysis demonstrated that Y60 cells, but not Y0 cells, germinated in the silkworm hemolymph at 30°C. However, Y0 and Y60 cells showed a similar degree of germination in the silkworm hemolymph at 37°C, although no significant difference in silkworm survival after infection with each cell type was observed at 37°C. These results suggested that the germination-ready state induced by the GlcNAc medium contributed to virulence in the silkworm.