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PubMed1997

Significance of non-dermatophyte moulds and yeasts in onychomycosis.

In a multicentre, randomised, double-blind, 48-week clinical trial, 118 patients with toe-nail onychomycosis were given terbinafine (250 mg daily) or placebo for 12 weeks, followed by 12 weeks of observation. Non-responders were offered 12 further weeks of terbinafine (250 mg daily) from week 28. Each patient had 8-12 consecutive nail specimens collected from the same nail, allowing for an assessment of the fungal nail flora from 1,321 nail specimens. By week 48, the overall mycological cure rate for terbinafine patients was 94%. 64% of patients had an underlying dermatophyte infection with at least 1 non-dermatophyte mould or yeast isolated from at least 1 specimen. These contaminants often overgrow or mask the presence of a dermatophyte. In only 2.5% of all patients was the same non-dermatophyte isolated from 2 or more consecutive specimens, probably representing secondary colonisation which exploits nutrients released by the underlying dermatophyte. The presence of incidental non-dermatophyte contaminants or secondary colonisers did not affect treatment outcome, and in this study treatment of the primary dermatophyte pathogen with terbinafine cleared the nails from infection in all cases. 80% of patients remained mycologically negative after 2 years.

Administration, Oral↗

PubMed2005

Production of a growth dependent metabolite active against dermatophytes by Streptomyces rochei AK 39.

BACKGROUND & OBJECTIVE: Dermatophytes responsible for causing dermatophytoses in humans have acquired resistance to certain antimycotic drugs. We isolated naturally occurring actinomycetes with an ability to produce metabolites having antimycotic property. The timecourse of antifungal metabolite production in terms of arbitrary units (AU) under optimum conditions was studied. METHODS: Water and soil samples were collected from various locations. The actinomycetes were isolated on starch casein medium and screened for their antifungal activity against yeasts and molds including dermatophytes. One promising isolate which showed a unique, stable and interesting property of inhibiting only dermatophytes was selected and characterized. Optimization of antifungal metabolite production in terms of AU using Trichphyton rubrum as target was done. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values of the culture supernatant from the isolate and that of griseofulvin were determined for all dermatophytes. RESULTS: Of the 218 actinomycete isolates, 14 per cent produced the metabolites having antifungal activity. The selected actinomycete, identified as Streptomyces rochei AK 39 produced metabolite, which was active against only dermatophytes whereas yeasts and other molds were resistant to it. Starch casein medium was found to be good for inducing antifungal activity in the isolate. The maximum antifungal metabolite production (400 AU/ml) was achieved in the late log phase, which remained constant during the stationery phase, and it was extracellular in nature. The MIC and MFC values of the culture supernatant from the isolate against the dermatophytes were within the range 1.25 to 5 and 1.25 to 10 AU/ml respectively. INTERPRETATION & CONCLUSION: The metabolite from Streptomyces rochei AK 39 was produced during late log phase and was active against only dermatophytes with a greater potency than griseofulvin. However, this needs further investigation using purified powdered form of the active component.

Actinobacteria↗

PubMedDate not supplied

Etiologic agents of dermatophyte infection in Lebanon.

BACKGROUND: Dermatophytes are common and cause important human fungal infections in many parts of the world, including Lebanon. The prevalence of these fungi, however, tends to vary with time and geographic location. In our region, studies on the prevalence of dermatophytoses and the distribution of the various dermatophyte species involved are rare. In Lebanon, only one study was published on this subject over the last forty years. OBJECTIVES: This study was undertaken to shed light on the types and prevalence of dermatophytes recovered at the American University of Beirut Medical Center (AUBMC), and to compare the findings with those of the only study from the same hospital published in the early 1960s. METHODS: Records from the clinical microbiology section were reviewed for the patients on whom dermatophyte cultures were requested between 1996 and 2002. All positive cultures were identified and analyzed. RESULTS: Among 1631 submitted specimens for culture (one per patient), 208 (12.7%) yielded 11 species of dermatophytes, dominated by Trichophyton spp. (89.9%), followed by Microsporum spp. (9.1%), Epidermophyton floccosum (0.4%) and Trichosporum beigelii (0.4%). The male to female ratio was almost 1:1, and the age range was 1 to 77 yrs for both sexes; 14% were children (< or = 15 yrs). The most commonly recovered species were: T. tonsurans (54.8%), T. mentagrophytes (24.5%), M. canis (7.7%), T. rubrum (5.3%) and T. verrucosum (4%). The distribution of infection according to body sites was : tinea unguium (44.2%), tinea corporis (43.2%), tinea capitis (7.7%) and tinea pedis (4.8%). Compared to the previous study from AUBMC in 1962, the current study showed an overall lower prevalence of dermatophytoses (12.7 vs 18.5%, p = 0.001) and variations in the prevalence rates of the dermatophyte species involved (dominated by T. tonsurans and T. mentagrophytes in the current study compared to E. floccosum and T. rubrum recovered in 1962). Based on the source of infection the current study showed higher transmission from human to human (anthropophylic) (86.5 vs 66.3%) and animal to human (zoophylic) (12.5 vs 1.1 %), but lower transmission from soil to human (geophylic) (1% vs 32.6%). CONCLUSIONS: The prevalence of dermatophytoses remains high in this country. The recognition of the changing prevalence in the causative dermatophyte species should help with the treatment approach and for potential implementation of control measures.

Adolescent↗

PubMed1997

Dermatophytes isolated from domestic animals in Barcelona, Spain.

This retrospective study deals with the main samples studied at the Mycology Diagnostic Service of the Faculty of Veterinary Science of Barcelona: animals with suspected dermatophytosis. Over a ten-year period from 1986 to 1995, 136 dermatophytes were identified from dog and cat cultures submitted for identification and from specimens submitted for mycological examination from a variety of other domestic animals. The most frequent dermatophytes isolated were Microsporum canis (55.9%), Trichophyton mentagrophytes var. mentagrophytes (27.2%), Microsporum gypseum (7.4%) and Trichophyton verrucosum (7.4%). The identity of the dermatophytes from dog and cat cultures submitted for identification was M. canis (77.8%), T. mentagrophytes (13.3%) and M. gypseum (8.9%). Dermatophytes were cultured from 15 of 105 (14.3%) canine specimens and 19 of 56 (33.9%) feline specimens submitted for mycological examination during this period. Microsporum canis was the most common species isolated (73.3% and 94.7% respectively). The percentage of positive microscopic examinations of the specimens of hair in culture positive submissions from dogs and cats was 58.8%. There was a high proportion of positive cultures from both dogs and cats less than 1 year of age, and in some breeds of dogs, but there was no significant difference between the sexes. Although dermatophytes were more frequently isolated in autumn and winter months, no significant difference was detected in the seasonal distribution of the canine and feline dermatophytosis. Trichophyton mentagrophytes was the most prevalent dermatophyte in rabbits and T. verrucosum in ruminants. Other isolated species were T. equinum and M. equinum from horses.

Animals↗

PubMed1998

Dermatophytes isolated from selected ruminants in India.

A survey was carried out in different areas of Uttar Pradesh for isolating and identifying dermatophytes from ruminants. Out of 102 skin scrapings, collected from various animals, 4/22 cattle, 1/9 buffalo, 14/44 sheep and 2/28 goats were KOH positive. In respect of the cattle, the culture positive samples yielded one strain each of Trichophyton mentagrophytes, T. rubrum, T. simii and two strains of Microsporum gypseum. From the buffaloes examined, only one case yielded a dermatophyte and it was identified as T. mentagrophytes. In respect of the sheep, two samples were culture positive and the dermatophyte was T. mentagraphytes (2). Of the 28 goat scrapings, only two harboured dermatophytes viz., M. gypseum and T. mentagrophytes. Fungi other than dermatophytes isolated from the ruminants were Alternaria species, Aspergillus species, Beauveria bassiana, Chrysosporium keratinophilum, Curvularia species, Penicillium species, Pseudoarachniotus roseus and T. terrestre. Isolation of T. rubrum from the skin lesion of one of the cattle is noteworthy, since this dermatophyte is better known as an anthrophilic species.

Animals↗

PubMed1997

Molecular determination of dermatophyte fungi using the arbitrarily primed polymerase chain reaction.

Dermatophytes are keratinophilic fungi capable of causing dermatophytosis (commonly known as tinea or ringworm) in humans and animals. Previously, we reported the differentiation of the common dermatophytes Trichophyton rubrum, T. mentagrophytes and T. tonsurans using a random primer 5'-ACCCGACCTG-3' (OPAA11) in the arbitrarily primed polymerase chain reaction (AP-PCR). In the present study, by examining additional dermatophytes including eight Microsporum spp., 16 Trichophyton species/subspecies and Epidermophyton floccosum using both OPAA11 and a second random decamer 5'-GAGAGCCAAC-3' (OPD18) in AP-PCR, we show that except for T. rubrum and T. gourvilli, and three T. mentagrophytes varieties, most of the dermatophyte fungi investigated formed distinct DNA band patterns on gel electrophoresis. The amplification of specific DNA bands in AP-PCR appeared to be independent of culture variations shown by dermatophyte isolates. These results provide the basis for the rapid identification of dermatophytes at the genetic level, supplementing existing laboratory methods and improving the diagnosis of human dermatophytosis.

Arthrodermataceae↗

PubMed2000

Application of PCR to the identification of dermatophyte fungi.

Infection of the keratinised tissues (skin, hair and nails) in man and animals by keratinophilic fungi (dermatophytes) results in dermatophytosis (also known as tinea or ringworm). As conventional laboratory procedures for the identification of dermatophytes are either slow or lack specificity, improved diagnostic methods are required. The application of nucleic acid amplification technology has made rapid and precise identification of dermatophytes possible. Recent studies have shown that when one of the four random primers (OPAA11, OPD18, OPAA17 and OPU15) was used in arbitrarily primed PCR (AP-PCR), up to 20 of the 25 dermatophyte species or subspecies under investigation could be distinguished on the basis of characteristic band patterns detected in agarose gel electrophoresis. A combination of two random primers (OPD18 and OPAA17) used in separate reaction tubes identified 23 of the 25 dermatophyte species or subspecies examined. AP-PCR provides a rapid and practical tool for identification of dermatophyte isolates that is independent of morphological and biochemical characteristics and thus enhances laboratory diagnosis of dermatophytosis.

Animals↗

PubMed2006

In vitro and in vivo effects of lufenuron on dermatophytes isolated from cases of canine and feline dermatophytoses.

Lufenuron is a benzyl-urea phenol compound that inhibits chitin synthesis and is used as an insecticide. Its efficacy in the therapy of dermatophytosis in dogs and cats was evaluated in several clinical studies, with contradictory results. We assessed the in vitro susceptibility of dermatophytes isolated from dogs and cats to lufenuron, and the clinical response of skin lesions to the drug. Dermatophyte cultures isolated from clinical cases were exposed to lufenuron by three different methods: direct application and application of whole blood or subcutaneous tissue samples obtained from a lufenuron-treated healthy dog. No inhibition of dermatophyte growth was observed in any of the samples after 1 week of incubation. Eight dogs and six cats with skin lesions were included in the in vivo survey. Results indicated that six of seven skin lesions that were diagnosed as being caused by dermatophytes did not respond to lufenuron whereas six of seven skin lesions that were not caused by dermatophytes improved. We concluded that lufenuron, in the way it was administered in this study, had no inhibitory activity on dermatophytes in vitro or in vivo and its clinical use as an anti-fungal agent is questionable. An immunomodulatory effect of the drug is, however, possible.

Animals↗

PubMedDate not supplied

Enzyme patterns of dermatophytes.

Exoenzymes produced by common dermatophytes, in addition to their ability to cause cutaneous inflammation, are thought to contribute to fungal spread. To investigate the patterns of enzymes released by common dermatophytes as well as Scopulariopsis brevicaulis, the fungi were grown in liquid media containing either hair, stratum corneum, neopeptone or lipids, or in RPMI medium. Enzymes recovered from the culture supernatants were compared using the Api-zyme test. As a result, the widest range of enzymes was seen in protein-containing media, with a maximum of 13 enzymes stimulated by growth on hair. Dermatophytes in all protein media produced high levels of alkaline phosphatase, esterases and leucine arylamidase. In these media the highest total enzymatic activity was released by Microsporum canis, whereas the lowest was released by Epidermophyton floccosum. Although RPMI broth stimulated luxuriant growth of all species, recovery was limited to a maximum of six enzymes. In lipid medium E. floccosum and M. canis failed to grow. When comparing the various nutrients, Scopulariopsis released fewer enzymes than the dermatophytes and only minor quantities of alkaline phosphatase. We conclude that alkaline phosphatase, esterases and leucine arylamidase may be important for the parasitic growth of dermatophytes. The total enzymatic activity of dermatophytes appears to be correlated with the intensity of cutaneous inflammation. Furthermore, enzyme measurements may be helpful for species identification.

Arthrodermataceae↗

PubMed1997

A new medium for the presumptive identification of dermatophytes.

A new medium, Dermatophyte Identification Medium (DIM) (trade mark pending), was specifically developed to eliminate problems of false-positive results associated with commercially marketed media, such as dermatophyte test medium (DTM). Previous investigations had demonstrated that DTM only partially suppressed growth of nondermatophytes and that several of these nondermatophytic fungi that were morphologically similar to dermatophytes caused false-positive results. Presumptive identification of an unknown isolate as a dermatophyte required only the transfer of a portion of the suspected colony recovered from the specimen to DIM. Positive results, evidenced by a change in the color of the medium, were observed within 24 to 48 h. In studies of over 500 isolates of dermatophytes and common nondermatophyte molds, as well as close to 600 yeast isolates, false-positive results were always associated with bacterial contamination of the mold isolates while false negatives were only observed with occasional isolates of Trichophyton verrucosum. DIM culture was an inexpensive, rapid, and accurate method for the presumptive identification of dermatophytes in the clinical mycology laboratory.

Arthrodermataceae↗

PubMed2001

Rapid discrimination among dermatophytes, Scytalidium spp., and other fungi with a PCR-restriction fragment length polymorphism ribotyping method.

Dermatomycoses are very common infections caused mainly by dermatophytes. Scytalidiosis is a differential mycological diagnosis, especially in tropical and subtropical areas. Since a culture-based diagnosis takes 2 to 3 weeks, we set up a PCR-restriction fragment length polymorphism (RFLP) method for rapid discrimination of these fungi in clinical samples. The hypervariable V4 domain of the small ribosomal subunit 18S gene was chosen as the target for PCR. The corresponding sequences from 19 fungal species (9 dermatophytes, 2 Scytalidium species, 6 other filamentous fungi, and 2 yeasts) were obtained from databases or were determined in the laboratory. Sequences were aligned to design primers for dermatophyte-specific PCR and to identify digestion sites for RFLP analysis. The reliability of PCR-RFLP for the diagnosis of dermatomycosis was assessed on fungal cultures and on specimens from patients with suspected dermatomycosis. Two sets of primers preferentially amplified fungal DNA from dermatophytes (DH1L and DH1R) or from Scytalidium spp. (DH2L and DH1R) relative to DNA from bacteria, yeasts, some other filamentous fungi, and humans. Digestion of PCR products with EaeI or BamHI discriminated between dermatophytes and Scytalidium species, as shown with cultures of 31 different fungal species. When clinical samples were tested by PCR-RFLP, blindly to mycological findings, the results of the two methods agreed for 74 of 75 samples. Dermatophytes and Scytalidium spp. can thus be readily discriminated by PCR-RFLP within 24 h. This method can be applied to clinical samples and is suited to rapid etiologic diagnosis and treatment selection for patients with dermatomycosis.

Ascomycota↗

PubMed2002

Survey of dermatophyte infections in the Lausanne area Switzerland.

BACKGROUND: The dermatophytes are important in the Swiss medical environment since 5-10% of consultations in dermatology concern mycotic infections. OBJECTIVE: To obtain information about the prevailing species of dermatophytes in the south-west of Switzerland and their pattern of infection. METHODS: An analysis was made of the dermatophytes isolated in the Department of Dermatology at the University Hospital of Lausanne and from samples collected in private practices of Switzerland during an 8-year period (1993-2000). The total number of samples sent for mycological analysis was 33,725. RESULTS: 4,193 cultures revealed a dermatophyte. Trichophyton rubrum was the most frequently isolated species accounting for 62.5% of the strains followed by T. mentagrophytes (24.5%) and Microsporum canis (5.0%). Less frequent isolates included Epidermophyton floccosum, M. langeroni, M. gypseum, T. soudanense, T. violaceum, T. verrucosum, T. gourvili and T. tonsurans. Analysis of the localisation of the isolated fungi confirms that the dermatophyte species have a predilection for certain body areas. CONCLUSIONS: The relative frequencies of isolation of the dermatophyte species partially depending of the record of the different tinea vary from one country to another. Our study reveals the importance of T. rubrum and the appreciable frequency of M. canis in the Swiss autochthonous population and the apparition of new species with immigrants.

Arthrodermataceae↗

PubMed2003

Dermatophyte test medium culture for evaluating toenail infections in patients with diabetes.

OBJECTIVE: To evaluate the performance of the in-office dermatophyte test medium (DTM) culture when used to confirm the diagnosis of onychomycosis in diabetic patients. RESEARCH DESIGN AND METHODS: Nail samples from 184 diabetic patients who exhibited symptoms consistent with toenail onychomycosis were screened for dermatophyte fungal infection using DTM, potassium hydroxide evaluation, and central mycology laboratory culture tests. The diabetic patient group investigated in this study is a subset of a heterogeneous set of patients who participated in a nationwide survey designed to investigate the use of fungal culture tests by dermatologists, podiatrists, and primary care physicians described in detail elsewhere. The overall sensitivity of the DTM and central laboratory culture methods was estimated and compared. Sensitivity differences between DTM and central laboratory culture methods were tested for statistical significance using the McNemar statistic. RESULTS: DTM culture was positive in 102 of 184 patients (55%), while the central laboratory culture test detected the existence of fungal infection in 78 of 184 (42%). The two tests were in agreement (both positive or both negative) in 114 of 184 patients (62%). Central laboratory culture identified dermatophytes as the pathogen in 91% of positive cases. CONCLUSIONS: DTM is a convenient and inexpensive culture test that can be used to confirm dermatophyte infections in diabetic patients with presumed onychomycosis. We found this test to be well suited for use in the primary care setting. Because oral antifungal agents are effective against dermatophyte species, which cause the vast majority of nail infections, diagnosis of onychomycosis requires confirmation of dermatophyte infection only, not identification of genus and species. DTM fulfills this requirement and has a diagnostic yield comparable to central laboratory culture.

Arthrodermataceae↗

PubMed1993

Dermatophytes and keratin in patients with hereditary palmoplantar keratoderma. A mycological study.

Fourteen patients with hereditary palmoplantar keratoderma of the Unna Thost variety were included in the study. Dermatophytosis was found in 7 of the 14 patients. Six were affected with T. rubrum and one with T. mentagrophytes. The growth pattern of dermatophytes in keratin from the patients did not differ from that of normal control individuals. Keratin from patients with hereditary palmoplantar keratoderma was sterilized with ethylene gas and placed in the center of culture plates, previously broad inoculated with control dermatophytes or dermatophytes isolated from patients. An inhibition zone around the keratin was found in 42.9% of the control dermatophytes and in 83.4% of the patient cultures. The inhibition zone was only seen in cultures with T. rubrum and not in those with T. mentagrophytes. No significant difference in minimal inhibitory concentration values against ketoconazole between control dermatophytes and dermatophytes from patients was demonstrated.

Adult↗

PubMed2000

[Preventive effects of various socks against adhesion of dermatophytes to healthy feet].

We studied the preventive effects of socks against dermatophyte infection. Wearing various socks (cotton socks, nylon stockings, wool socks and "tabi"), a healthy volunteer walked on a bath mat on which a patient with tinea pedis had stepped earlier. The volunteer pressed her right foot with socks onto large agar medium (Foot-press method), then, took off the socks and performed the Foot-press method again. The number of colonies of isolated dermatophytes on the medium was counted. The number of isolated colonies from the sole after taking off the nylon stockings was larger than that from the foot wearing the stockings. Dermatophytes were also isolated from the sole after taking off cotton socks. In contrast, few dermatophytes were isolated from the sole after taking off wool socks or "tabi". On microscopic observation, fibers of the nylon stockings and cotton socks were seen to be loose enough for dermatophytes to pass through. In contrast with those socks, fibers of wool socks and "tabi" were tight or fluffy. In conclusion, the nylon stockings and cotton socks are unsatisfactory in preventing the adhesion of dermatophytes.

Adult↗

PubMed2000

Dermatophyte test medium culture versus mycology laboratory analysis for suspected onychomycosis. A study of 100 cases in a geriatric population.

Onychomycosis is the most frequently encountered condition in podiatric practice in the United States. A variety of modalities are available to confirm the presumptive diagnosis of onychomycosis. This study was conducted to compare the results of in-office dermatophyte test medium cultures with those of mycology laboratory analysis for 100 cases of suspected onychomycosis in a geriatric population. The results demonstrated that 20% of the patients had dermatophyte involvement, 56% had saprophyte involvement, and 19% had yeast involvement. Only 50% of positive dermatophyte test medium cultures correlated with a positive microscopic fungal culture for dermatophytes. Given these results, it is questionable whether in-office dermatophyte test medium cultures should be routinely used in geriatric patients for the diagnosis of onychomycosis. The authors believe mycology laboratory testing with fluorescent potassium hydroxide preparations and microscopic fungal cultures to be superior to in-office dermatophyte test medium cultures for the diagnosis of onychomycosis in geriatric patients.

Aged↗

PubMed2002

An in-office diagnostic procedure to detect dermatophytes in a nationwide study of onychomycosis patients.

PURPOSE: To evaluate in-office dermatophyte test medium (DTM) culture as an alternative to traditional laboratory fungal culture for confirming a diagnosis of onychomycosis, and to determine the prevalence of dermatophytes as a cause of onychomycosis in patients not participating in a clinical trial. DESIGN: This nationwide multicenter prospective study enrolled 1100 adult patients with suspect onychomycosis. DTM and laboratory fungal culture results were compared for individual patients. METHODOLOGY: The 310 participating physicians obtained patient nail-bed specimens and divided them for testing by both diagnostic methods. The paired results of the two culture methods were compared using the kappa statistic. PRINCIPAL FINDINGS: Paired culture results were available for 975 of the 1100 enrolled patients. DTM results agreed with central laboratory cultures in 70 percent of cases. The kappa value of 0.40 indicated a moderate degree of correspondence between the two testing modalities. Overall, DTM culture indicated a dermatophyte in 616 patient specimens (56 percent) and central laboratory culture identified a dermatophyte in 528 of the specimens (48 percent). For the entire study population, dermatophytes were identified in 93 percent of the positive central laboratory cultures, confirming that dermatophytes caused the vast majority of the infections. The cost of each DTM culture was approximately $1, compared to $25 for each laboratory fungal culture. CONCLUSION: This study demonstrates that the in-office DTM culture for diagnosing onychomycosis has comparable utility to the traditional laboratory fungal culture, is less expensive, and yields faster results.

Adult↗

PubMed2004

Clinical identification of common species of dermatophytes by PCR and PCR-RFLP.

To find a fast and efficient way of identifying seven common dermatophytes in clinical practice, we used the techniques of polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (RFLP) targeting Topoisomerase II gene. The DNA of 7 dermatophytes, along with Candida albicans, Aspergillus terreus and Aspergillus flavus were amplified by consensus primer dPsD1. They were then subjected to a second PCR with primers dPsD2 and species-specific primers PsT and PsME separately. 6 of the products generated by dPsD2 were digested with restriction enzyme Hinc II. DNA fragments of 3390 bp and 2380 bp was amplified by using consensus primer dPsD1 and dPsD2 from the genomic DNA of each dermatophyte species separately. By combining the results of the two species-specific primer sets (PsT and PsME), all species of dermatophyte yielded unique sizes-set of PCR products expect for T. mentagrophytes and T. tonsurans. From the restriction profiles of Hinc II, 6 of the 7 dermatophytoses were diagnosed to species level including T. mentagrophytes and T. tonsurans. By combining the results of the PCR and PCR-RFLP, the 7 common dermatophytes can be identified to species level. It is conclude that the multiplex PCR and PCR-RFLP identification targeting the DNA topoisomerase II gene is rapid and efficient.

Arthrodermataceae↗