Five-hour diagnosis of dermatophyte nail infections with specific detection of Trichophyton rubrum

A rapid two-step DNA extraction method and a multiplex PCR for the detection of dermatophytes in general and Trichophyton rubrum specifically were developed and evaluated with DNA extracted from pure cultures and from clinically diseased nails. DNA from the following dermatophytes was used: Epidermophyton floccosum, Microsporum audouinii, Microsporum canis, Microsporum gypseum, Microsporum nanum, Trichophyton mentagrophytes, Trichophyton rubrum, Trichophyton schoenleinii, Trichophyton soudanense, Trichophyton terrestre, Trichophyton tonsurans, Trichophyton verrucosum, and Trichophyton violaceum. Human DNA and DNA from the following nondermatophyte fungi were included as controls: Alternaria, Aspergillus niger, Candida albicans, Candida glabrata, Candida krusei, Malassezia furfur, Saccharomyces cerevisiae, and Scopulariopsis brevicaulis. A total of 118 nail samples received for routine microscopy and culture for dermatophytes were subsequently tested by the two PCRs separately and in a multiplex format. Using DNA extracted from pure cultures and the pan-dermatophyte PCR, the T. rubrum-specific PCR sequentially and in a multiplex format correctly detected all dermatophytes and additionally correctly identified T. rubrum. Comparison of the traditional diagnostic evaluation (microscopy and culture) of nail samples with PCR on DNA directly extracted from the nails showed excellent agreement between PCR and microscopy, but the number of samples with dermatophyte species identification was increased considerably from 22.9% to 41.5%, mainly due to the identification of T. rubrum by PCR in microscopy-positive but culture-negative samples. In conclusion, this 5-hour diagnostic test was shown to increase not only the speed but also the sensitivity of investigation for nail dermatophytosis.     

Fungi on the claws of buffalo and cow in Egypt

The frequency of occurrence of fungi in 120 claw samples of buffalo and cow from different localities at Assiut governorate was determined. Thirty-seven species which belong to twenty genera were collected from the two substrates and the most common genera were Chrysosporium (eleven species of Chrysosporium were isolated). Aspergillus and Scopulariopsis. From the preceding genera Chrysosporium sulfureum was common on cow claws but C. merdarium was slightly dominant on buffalo claws than on cow claws. Aspergillus flavus and A. niger were dominant on buffalo claws, but Scopulariopsis brevicaulis was prevalent on cow claws. Also other dermatophytes were isolated such as Trichophyton terrestre, T. rubrum, Histoplasma capsulatum, Phialophora gougerotii and Microsporum distortum.     

Onychomycosis in Morocco: experience of the parasitology and medical mycology laboratory from Rabat children hospital (1982-2003)

Cases of onychomycosis diagnosed by mycological examination in the parasitology and mycology laboratory (Children Hospital, Rabat, Marocco) over the 22-year period, between 1982 and 2003, have been reviewed. 17,177 dermatophytes have been isolated in 4,940 patients. Dermatophytes presented 61.46% of onychomycosis, yeasts Candida albicans were responsible in 25.5%, moulds in 1.53% and for 12% fungi identification was not determined (positive direct examination or negative direct examination and culture despite typical clinical aspect). The most frequent dermatophyte was Trichophyton rubrum (83.6%), followed by Trichophyton violaceum var. glabrum (9%) and Trichophyton mentagrophytes var. interdigitale (6.9%). Candida albicans was the prevalent yeast. Moulds were mainly Fusarium spp. (47%), followed Scopulariopsis brevicaulis (16%) and Aspergillus spp. (12%). Dermatophytes and moulds most commonly infected the toenails, yeasts the fingernails.     

Application of PCR to distinguish common species of dermatophytes

This report describes the application of PCR fingerprinting for the identification of species and varieties of common dermatophytes and related fungi utilizing as a single primer the simple repetitive oligonucleotide (GACA)(4). The primer was able to amplify all the strains, producing species-specific profiles for Microsporum canis, Microsporum gypseum, Trichophyton rubrum, Trichophyton ajelloi, and Epidermophyton floccosum. Intraspecific variability was not observed for these species. Instead, three different profiles were observed in the Trichophyton mentagrophytes group.     

Scedosporium inflatum, an emerging pathogen.

The salient morphologic and physiologic characteristics of 18 isolates of Scedosporium inflatum, a newly reported human pathogen, were compared with those of the morphologically similar fungi Scedosporium apiospermum, Scopulariopsis brevicaulis, and Scopulariopsis brumptii. The formation by S. inflatum of annelloconidia in wet clumps at the apices of annellides with swollen bases was found to be the most useful characteristic in differentiating this potential pathogen.     

Invasive Scopulariopsis brevicaulis infection in an immunocompromised patient and review of prior cases caused by Scopulariopsis and Microascus species

Scopulariopsis species and their Microascus teleomorphs are cosmopolitan fungi that are uncommonly associated with invasive disease. This report describes a case of fatal disseminated Scopulariopsis brevicaulis disease in a patient with diffuse large B cell lymphoma who underwent high-dose chemotherapy followed by a matched unrelated donor stem cell transplant. This case is compared with 32 prior cases of proven invasive Scopulariopsis (Microascus) infections reported in the literature. A focus of this report is the diagnostic methods utilized which included histopathology and culture with both micromorphologic and genotypic procedures employed to confirm the species identification.     

The occurrence of keratinophilic fungi in sewage sludge from Egypt.

The keratinophilic fungi of 40 sewage sludge samples from Upper Egypt were studied using a goat hair-baiting technique. 43 species representing 22 genera were isolated, 17 species of which were dermatophytes and closely related fungi: Chrysosporium state of Arthroderma tuberculatum, C. asperatum, C. georgii, C. indicum, C. keratinophilum, C. pseudomerdarium, C. queenslandicum, Chrysosporium state of Thielavia sepedonium, C. tropicum, Microsporum cookei, M. gypseum, Myceliophthora anamorph of Corynascus novoguineensis, M. vellerea and Trichophyton terrestre. 26 species of cycloheximide resistant fungi were collected and these included members of Acremonium, Aspergillus, Alternaria, Chaetomium, Cladosporium, Cunninghamella, Emericella, Fusarium, Geotrichum, Penicillium and others.     

An animal model for cell-mediated immune responses to dermatophytes.

Guinea pigs infected with three species of dermatophytes were tested for cell-mediated immune responses, including delayed cutaneous hypersensitivity, lymphocyte transformation (LT), macrophage migration inhibition (MMI), and passive transfer of hypersensitivity. The patterns of reinfection disease were also analyzed as an index of altered host immunity. The fungi tested represented the three genera of dermatophytes (Trichophyton, Microsporum, and Epidermophyton), and included zoophilic and anthropophilic species. Microsporum vanbreuseghemii, the zoophilic species, produced the most virulent infection, and Epidermophyton floccosum, previously considered obligately anthropophilic, produced the mildest infection. The clinical stages of reinfection were condensed for all three species, and all infected animals manifested delayed-type cutaneous hypersensitivity to homologous antigen, which persisted up to 12 months. There was a significant MMI and LT by cells from infected animals exposed to homologous antigen. Cutaneous hypersensitivity was transferred by splenic, lymph node, and peritoneal exudate cells from infected donors. The severity of primary infection correlated with the duration and magnitude of reinfection symptoms, and with the persistence of hypersensitivity. These results indicate that there are systemic CMI responses to these fungi which usually do not invade beyond the keratinized layers of skin, hair, and nails.     

Keratinophilic fungi from the duck nails in Egypt

The mycoflora of one hundred and sixty of duck nail samples, collected from the duck Farm, Faculty of Agriculture, Assiut University, were examined. Using the soil plate technique and Sabouraud's dextrose agar, thirty six species appertaining to twenty genera of keratinophilic fungi were isolated. Chrysosporium was the genus most frequently isolated (50% of the samples). Aspergillus and Penicillium occurred in low incidences (13.1 and 12.5% of total samples). Trichophyton rubrum was found to colonize few of the duck nail samples (2.5%) as well as some other fungal species previously reported as pathogenic to man and animals (Aspergillus fumigatus, Scopulariopsis brevicaulis and Paecilomyces lilacinus).     

Failure of ticks to transmit Scopulariopsis brevicaulis (Deuteromycota), a common filamentous fungal commensal of ticks

The capacity of ticks to transmit a fungus was examined by analyzing tick saliva, host tissue from feeding sites, and host blood for presence of Scopulariopsis brevicaulis (Sacc.) Bainier, an internal mycosymbiont of the American dog tick, Dermacentor variabilis (Say), and lone star tick, Amnblyomma americanum (L.). Although >85% of ticks were infected with S. brevicaulis, conidia presence was low (0-5% of samples) in microscopic observations and mycological culturing of saliva expressed from larvae, nymphs, and adults. Additionally, the recovery of S. brevicaulis from blood and tissue feeding sites from a rabbit where S. brevicaulis-positive adult ticks had attached and fed was not increased compared with control tissue where no feeding occurred, indicating that transmission does not occur by the blood-feeding route. Tick mouthparts were found to contain S. brevicaulis in addition to Penicillium glabrum (Wehmer) Westling, but these agents were sparse in isolations from the feeding sites, which makes it unlikely that ticks act frequently as a mechanical fungal vector.     

Use of the sensititre colorimetric microdilution panel for antifungal susceptibility testing of dermatophytes

The Sensititre YeastOne antifungal panel was used to test 49 dermatophytes belonging to the species Epidermophyton floccosum, Microsporum gypseum, Microsporum canis, Trichophyton tonsurans, Trichophyton rubrum, and Trichophyton mentagrophytes. The MICs of four antifungals obtained with the Sensititre YeastOne antifungal panel were compared with those obtained by the reference NCCLS microdilution method. The levels of agreement between the two methods (相似文献   

Keratinophilic fungi of animal and bird pens in Egypt

Samples were collected from 44 pens under animals and birds for the estimation of keratinophilic fungi using the hair-baiting technique. Thirty-nine species which belong to eighteen genera were recovered. Chrysosporium, Aspergillus, and Penicillium were the most frequent genera. From keratinophilic fungi, Myceliophthora anamorph of Corynascus sepedonium, Myceliophthora anamorph of Corynascus novoguinensis, Microsporum boullardii, M. gypseum, Trichophyton metagrophytes and Arthroderma sp. were recovered in different frequencies.     

In vitro and in vivo photosensitized inactivation of dermatophyte fungi by heterotricyclic dyes.

The ability of three heterotricyclic dyes to photosensitize dermatophyte fungi was studied with Trichophyton mentagrophytes and Microsporum gypseum. In vitro studies showed that methylene blue, neutral red, and proflavine were capable of killing these fungi when used in conjunction with broad-spectrum light. Proflavine, however, killed both fungi most rapidly and was used for further studies. Fungal killing by proflavine plus light was dependent on dye concentration, pH, light wavelength, and light intensity. Based on the in vitro studies, a treatment regimen was developed for in vivo use on experimentally infected animals. When treatment of guinea pigs inoculated with T. mentagrophytes was begun during fungal invasion, lesion formation at inoculated sites was either prevented or substantially reduced. When treatment was begun after lesion formation, however, light-plus-dyed treated sites showed only slightly faster curing than untreated sites.     

Analysis of dermatophyte flora at a private clinic in Sapporo during the period 1992 to 2001]

Statistical analysis was made of a total of 5530 patients (6798 cases) of dermatophytoses presenting at our private clinic during the period 1992 to 2001. The number of patients and cases represents 8.0% and 9.8% of the entire outpatient population during that time, respectively. Sex ratio (male/female) was 1.5. Among the 6798 dermatophytoses cases, tinea pedis was most frequent (65.8%), followed by tinea unguium (20.7%), tinea cruris (7.2%), tinea corporis (3.9%), tinea manuum (2.4%) and tinea barbae (0.04%). The incidence of tinea unguium increased, whereas that of tinea pedis, tinea cruris, and tinea corporis decreased during this ten year period, and 35.8% of dermatophytoses patients had more than two clinical subtypes simultaneously. Three thousand seven hundred ninety-five dermatophytes were isolated during the survey. : Trichophyton rubrum (TR)(79.4%), Trichophyton mentagrophytes (TM)(19.5%), Microsporum canis (MC)(0.7%), Epidermophyton floccosum (EF) (0.3%), and Microsporum gypseum (MG) (0.1%). Compared with our previous analysis reported for the period 1982 to 1991, the frequency of dermatophytoses increased, especially among aged individuals. Of the clinical subtypes, tinea pedis and tinea unguium were higher, but tinea cruris and tinea corporis were lower, and tinea capitis was not seen in the current survey. Among dermatophytes, TR was increased and other types of fungi were decreased. TR was 4.08 times more common than TM; this ratio is higher than our previous report.     

Keratinophilic fungi associated with rabbit claws in Egypt

Using the soil plate technique, thirty one species appertaining to twenty three genera were recovered from 160 samples of rabbit claws which were collected from a rabbit farm at Assiut. Of the true keratinophilic fungi Chrysosporium tropicum was the most prevalent where it colonized 56.25% of the samples. Microsporum gypseum was rarely isolated in this study. Among the non-keratinophilic fungi Penicillium funiculosum. P. jenseni and Paccilomyces lilacinus were of low incidence (20%, 19.37% and 14.37% of the samples, respectively).     

Dermatophytes from animals]

Dermatophytes from animal dermatophytoses were investigated, especially for their teleomorphs and molecular characteristics. Microsporum canis, M. equinum, M. gypseum, M. nanum, Trichophyton equinum, T. mentagrophytes complex, T. rubrum and T. verrucosum were isolated as the etiological agents of animal ringworm in Japan. They were morphologically and biochemically identified and their perfect states were examined. The teleomorph of M. canis was first obtained and reported as Nanizzia otae in 1975. The isolates of M. canis of which the teleomorph was confirmed were all "-" excepted two Japanese isolates. Mating experiments indicated that the isolates of M. gypseum were "+" or "-" of A. gypseum and A. incurvatum, respectively. Most of the isolates of T. mentagrophytes complex of which a perfect state was detected were A. vanbreuseghemii. One isolate from a monkey was A. simii and one from a rabbit was A. benhamiae. However, the teleomorph remained unknown in many isolates. Molecular characteristics in random amplification of polymorphic DNA and Southern hybridization analyses were found to be effective to differentiate the species of Microsporum. Nucleotide sequences of chitin synthase 1 (CHS1) gene of dermatophytes were also analyzed for their phylogenetic relatedness. The phylogenetic analysis revealed four clusters: the first cluster consisted of A. benhamiae, A. simii, A. vanbreuseghemii, T. mentagrophytes var. interdigitale, T. rubrum and T. violaceum; the second of A. fulvum, A. gypseum and A. incurvatum; the third of A. grubyi and A. otae; and the fourth of Epidermaphyton floccosum, providing useful information for the classification and understanding of their evolution.     

Saprophytic fungi isolated from animal and bird pens in Egypt

Forty-four samples collected from animal and bird pens were screened for their content of saprophytic fungi by using the dilution plate method. 76 species in addition to one variety of Aspergillus flavus belonging to 33 genera were recovered on three types of media: 20 genera and 49 species on Littman-oxgall agar, 19 genera and 41 species on cellulose- and 19 genera and 43 species on glucose-Czapek's agar. The most frequent genera were Aspergillus (21 species), Scopulariopsis (4 species) and Penicillium (10 species). Among the isolated fungi A. fumigatus, A. flavus, A. terreus, A. niger, A. sydowi, A. nidulans, S. brevicaulis, S. brumptii, P. chrysogenum and P. funiculosum were the most common species.     

Molecular detection of Microsporum persicolor in soil suggesting widespread dispersal in central India.

A survey was conducted from 1999 to 2003 as part of a microbial biodiversity study on geophilic and keratinophilic fungi in central India. Among the keratinophilic fungi recovered were 82 isolates belonging to the dermatophyte genus Microsporum. Species were provisionally identified by morphology and confirmed by PCR-RFLP and sequencing of the ITS regions of rDNA. Microsporum persicolor appeared to be preponderant in central Indian soils, outnumbering the common geophilic species of Microsporum filvum and Microsporum gypseum. Three dinucleotide microsatellite markers were developed and their use revealed immense intraspecific variation among Indian populations of M. persicolor which would indicate that this species was not recently introduced into India. No correlation was established between the genotypes and the geographical location or the habitat of the isolates.     

Keratinophilic and saprophytic fungi isolated from students' nails in Egypt

In order to determine the presence of dermatophytes and saprophytes in healthy toe and finger nails, 120 students (60 male and 60 female) from preparatory schools at Sohag Governorate (Upper Egypt) were studied. 54 species in addition to 3 varieties belonging to 17 genera were isolated. Six species of true dermatophytes were collected: Microsporum audouinii var. rivalieri, M. cookei, Trichophyton mentagrophytes, T. simii, T. terrestre and T. verrucosum. Chrysosporium, a well-known keratinophilic genus, was prevalent and represented by 7 species (C. asperatum, C. indicum, C. keratinophilum, C. luteum, C. pannorum, C. tropicum and Chrysosporium state of Thielavia sepedonium). The commonest saprophytes in order of frequency were members of the genera Aspergillus, Penicillium, Alternaria, Scopulariopsis, Fusarium, Paecilomyces, Chaetomium, Syncephalastrum, Mucor, Rhizopus and Acremonium.     

Les dermatophytes : d’où viennent-ils ? Comment sont-ils devenus des parasites ?

Dermatophytes are widespread and varied florae that are distinguished by their ability to develop at the expense of a substrate, keratin, which is a complex protein that forms part of the composition of the skin, nails and hair. The hypothesis proposed a long time ago and recently confirmed by phylogenetic studies, is that dermatophytes originated in the soil and that pathogenic dermatophytes also evolved from soil-born nonpathogenic ancestors. Indeed, the Arthroderma genus is found in the soil during its teleomorphic sexual stage. Results of recent molecular analysis of dermatophytes lineages showed that the origin of parasitism (50 million years ago) corresponds to the early adaptive explosion of mammals. The same analysis led to remarkable discoveries on evolution towards parasitism. The pathway from soil to animal and to man, or from soil to man, is the usual phylogeny evolution of these fungi leading to progressive loss of reproduction, poor or attenuated conidiogenesis, and relative tolerance by the host. Although the epidemiological distinction between geophiles, zoophiles, and anthropophiles holds true, dermatophytes can be classified in two categories or lineages: (1) soil-associated-dermatophytes and; (2) non-soil-associated dermatophytes.The category of soil-associated dermatophytes includes some zoophiles and all pathogenic zoophiles, these species possess sexual reproduction, copious conidiation, the ability to perforate shed hair, vitamin independence, urease activity and other clinical and epidemiological features. Typical examples are Microsporum gypseum, Microsporum canis and zoophilic members of the T. mentagrophytes ss lat. complex. Non-soil-associated dermatophytes include some zoophiles and all anthropophiles are characterized by loss of some or all the above characters and are moving resolutely toward almost obligatory parasitism (T. verrucosum, M. audouinii, T. rubrum, T. tonsurans, T. soudanense, T. interdigitale, etc.). Clonal evolution of these anthropophice dermatophytes involves species diversification by means of a “speciation” process. It is interesting to note that in spite of lost sexual reproduction in anthropophilic dermatophytes, clonal lineages are able to survive and disseminate widely in humans (cf. the remarkable example of the T. rubrum complex). In medical mycology, dermatophytes represent an interesting model of evolution towards parasitism.