A survey of dermatophytes isolated from human patients in the United States from 1993 to 1995

Cutaneous Fungal Infections Caused by Dermatophytes and Non-Dermatophytes: An Updated Comprehensive Review of Epidemiology, Clinical Presentations, and Diagnostic Testing

Cutaneous fungal infection of the skin and nails poses a significant global public health challenge. Dermatophyte infection, mainly caused by Trichophyton spp., is the primary pathogenic agent responsible for skin, hair, and nail infections worldwide. The epidemiology of these infections varies depending on the geographic location and specific population. However, epidemiological pattern changes have occurred over the past decade. The widespread availability of antimicrobials has led to an increased risk of promoting resistant strains through inappropriate treatment. The escalating prevalence of resistant Trichophyton spp. infections in the past decade has raised serious healthcare concerns on a global scale. Non-dermatophyte infections, on the other hand, present even greater challenges in terms of treatment due to the high failure rate of antifungal therapy. These organisms primarily target the nails, feet, and hands. The diagnosis of cutaneous fungal infections relies on clinical presentation, laboratory investigations, and other ancillary tools available in an outpatient care setting. This review aims to present an updated and comprehensive analysis of the epidemiology, clinical manifestations, and diagnostic testing methods for cutaneous fungal infections caused by dermatophytes and non-dermatophytes. An accurate diagnosis is crucial for effective management and minimizing the risk of antifungal resistance.

Dermatophytosis caused by Nannizzia nana (Microsporum nanum): a comprehensive review on a novel pathogen

Keratinophilic fungi are mostly soil-inhabiting organisms with occasional infections in humans and animals. Even though most dermatophytes are host-adapted, cross-species infections are common by zoophilic and geophilic dermatophytes. N. nana is considered an etiological agent of ringworm in pigs but has also been isolated from other animals, including humans. However, it also possesses many characteristics of geophilic dermatophytes including the ability to grow in soil. N. nana produces characteristic pear-shaped macroconidia and usually exhibits an ectothrix pattern of hair infection. It has been isolated from dermatitis lesions as well as from soil. N. nana infections in pigs are not of much concern as far as economy or health is concerned. But it has been associated with onychomycosis and gonathritis in humans, which are significant in human medicine. The shift in the predominance of dermatophytes in humans and the ability to evolve into a potential tinea pathogen necessitates more understanding of the physiology and genetics of N. nana. In this review, we have attempted a detailed analysis of the studies about N. nana, emphasizing growth and cultural characters, physiology, isolation, infection in humans and animals, molecular characterization and antifungal susceptibility.

Tinea blepharitis and follicular conjunctivitis in a child

Trichophyton tonsurans is a fungal species that frequently causes tinea capitis (ringworm), a skin infection found in children. We report a case of unilateral blepharoconjunctivitis due to tinea capitis in a previously healthy 8-year-old boy. Although no case of blepharitis or follicular conjunctivitis due to T. tonsurans has been previously reported, the findings are consistent with other rare causes of ringworm blepharitis. Emerging or chronic fungal blepharitis should be considered in the differential diagnosis of unilateral follicular conjunctivitis.

Real-Time PCR as an Alternative Technique for Detection of Dermatophytes in Cattle Herds

Dermatophytes are filamentous fungi with the ability to digest and grow on keratinized substrates. The ongoing improvements in fungal detection techniques give new scope for clinical implementations in laboratories and veterinary clinics, including the monitoring of the disease and carrier status. The technologically advanced methods for dermatophyte detection include molecular methods based on PCR. In this context, the aim of this study was to carry out tests on the occurrence of dermatophytes in cattle herds using qPCR methods and a comparative analysis with conventional methods. Each sample collected from ringworm cases and from asymptomatic cattle was divided into three parts and subjected to the real-time PCR technique, direct light microscopy analysis, and culture-based methods. The use of the real-time PCR technique with pan-dermatophyte primers detected the presence of dermatophytes in the sample with a 10.84% (45% vs. 34.17%) higher efficiency than direct analysis with light microscopy. Moreover, a dermatophyte culture was obtained from all samples with a positive qPCR result. In conclusion, it seems that this method can be used with success to detect dermatophytes and monitor cowsheds in ringworm cases and carriers in cattle.

Dermatologic Problems Commonly Seen by the Allergist/Immunologist

Allergists/immunologists see a variety of skin disorders, some of which have a known immunologic basis whereas others do not. We review the prevalence, etiology, clinical presentation, and effective and low-cost care of common dermatologic conditions seen in outpatient practices. Conditions discussed include pityriasis alba, seborrheic dermatitis, rosacea, acne, tinea infections, intertrigo, lichen planus, tinea versicolor, lichen simplex chronicus, scabies, pityriasis rosea, keratosis pilaris, and seborrheic keratosis. An understanding of frequently encountered cutaneous diseases and their therapies will help provide immediate access to treatment and improve the experience for both the affected patient and the clinician.

Epidemiology of Trichophyton verrucosum infection in Rennes University Hospital, France: A 12-year retrospective study

Trichophyton verrucosum is a zoophilic dermatophyte, known as a causative agent of inflammatory mycoses of the skin and the scalp in humans. In this study, we reviewed all cases of T. verrucosum infection diagnosed in our laboratory over a 12-year period, to determine epidemiological and clinical characteristics. Among 18,340 samples analyzed, 5,186 cultured positive with dermatophytes (2674 patients), of which 64 samples (41 patients) were positive for T. verrucosum. Our data show that there was a strong influence of age on the type of lesion, with children and adults presenting more frequently with tinea capitis and skin infections, respectively (P < .0001). Infection of children and adults resulted more frequently from indirect and direct exposure to cattle, respectively (P < .01). We observed a marked increase of cases over the last 4 years, with a correlation of the number of cases and the mean annual rainfall (P < .05), suggesting that increasing humidity favors cattle infection, and thereby, human infection. Whether this increase is the consequence of climate changes remains to be determined but should be considered.

The Changing Face of Dermatophytic Infections Worldwide

Dermatophytes evolve along with the geography and socioeconomic conditions. Epidermophyton floccosum, Microsporum audouinii and Trichophyton schoenleinii acted as the major pathogens of superficial fungal diseases 100 years ago, but their frequency decreased dramatically since the middle of the twentieth century and they are limited to some less-developed countries nowadays; meanwhile, frequency of Trichophyton rubrum, Trichophyton interdigitale, Trichophyton tonsurans and Microsporum canis increased gradually, and these fungi have become the major species globally. Some other dermatophytes, i.e., Trichophyton violaceum, Trichophyton verrucosum and Microsporum ferrugineum, are mainly endemic in some parts of Africa, Asia and Europe. At present, T. rubrum is the leading pathogen for skin and nail fungal infections, whereas M. canis, T. tonsurans and T. violaceum present as the predominant dermatophytes involved in tinea capitis. Population mobility, changes in human lifestyle and advents of antifungal drugs will continually drive the dermatophyte evolution in the skin microenvironment. Comprehensive observation is needed to better understand this kind of organisms and prospect the trends of their changes in future.

Epidemiological and clinical pattern of dermatomycoses in rural India

Superficial fungal infections are most common in tropical and subtropical countries. In this study, 297 suspected superficial fungal infection cases were identified among 15,950 patients screened. The collected samples (skin, nail, and hair) were subjected to direct microscopy with potassium hydroxide and cultured on Sabourauds dextrose agar to identify the fungal species. The prevalence of superficial fungal infection was 27.6% (82/297), dermatophytosis was 75.6% (62/82), and non-dermatophytosis was 24.4% (20/82). Among the isolated dermatophytes, Trichophyton rubrum was the commonest species (79%) and Candida (60%) the commonest non-dermatophytic species. Tinea corporis was the commonest (78%) clinical presentation.

Tinea faciei in a newborn due to Trichophyton tonsurans

We report here the first case of neonatal tinea faciei caused by Trichophyton tonsurans in mainland China. The mother of the infant had tinea corpris and tinea capitis while the father had tinea incongnito. The infections in the parents were mycologically confirmed to be due to Trichophyton tonsurans. Ttinea faciei in the infant was cured after two-week topical use of amorolfine cream. The mother ceased breastfeeding and took oral terbinafine for 4 weeks. No recurrence was observed in the infant during 12 months of follow-up.

The spectrum of fungal infections with a special reference to dermatophytoses in the capital area of Kuwait during 2000-2005: a retrospective analysis

BACKGROUND

Fungal infections constitute a major health problem all over the world. Signs and symptoms induced by various dermatophytic infections are difficult to distinguish clinically from each other. So, characterization by in vitro culture is required for appropriate diagnosis and treatment as well as to study the epidemiological characteristics in a region.

OBJECTIVES

The present retrospective work was aimed to study the spectrum of fungal infections of the skin, nails and hairs in the Capital area of Kuwait over a span of 5 years and to compare the results with those reported earlier from this region and other parts of the world. PATIENTS/MATERIALS: The study was conducted on 2,730 patients referred from dermatology outpatients to mycology laboratory suspected to have fungal infection over a 5-year period. Identification of dermatophyte isolates obtained was done by conventional microscopic examination in all patients, whereas culture techniques were performed for 1,593 of them.

RESULTS

Among 2,730 patients, 1,437 were men and 1,293 were women with a men to women ratio of 1.1:1. The age ranged from 3 months to 70 years (mean age 28.5 years). The clinical diagnosis of these patients was as follows: onychomycosis; tinea corporis; tinea capitis; tinea pedis; tinea cruris; tinea manum and tinea versicolor. Potassium hydroxide (KOH) examination showed positive results in 39% of all cases, whereas positive cultures were obtained in 29% of cultured specimens. Among dermatophytes, six species were isolated: Trichophyton mentagrophytes (39%), Microsporum canis (16%), Trichophyton rubrum (10%), Epidermophyton floccosum (6.2%), Trichophyton violaceum (2.4%) and Trichophyton verrucosum (0.4%). Trichophyton mentagrophytes was isolated from all body sites. Candida and Aspergillus niger were isolated on cycloheximide-free cultures in cases with onychomycosis.

CONCLUSIONS

Cutaneous fungal infections including dermatophytes remain prevalent in this part of the world. The most common isolate was T. mentagrophytes followed by Candida species. The least isolate was T. verrucosum. Species identification in relation to factors such as time, place and population is warranted in order to implement treatment regimens and to propose potential control measures.

Characteristics of superficial fungal infections in the Riyadh region of Saudi Arabia

BACKGROUND

The prevalence and characteristics of superficial fungal infections (SFIs) vary with climatic conditions, lifestyle, and population migration patterns. This study was undertaken to determine the characteristics of SFIs amongst patients visiting the dermatology clinic of Riyadh Military Hospital, Riyadh, Saudi Arabia, during the period 2003-2005.

METHODS

One hundred and nineteen patients with confirmed SFI (37 males and 82 females), aged between 5 months and 67 years, were included in this study. The diagnosis of SFI was based on clinical presentation confirmed by laboratory analysis. The type of mycotic pathogen and the site of infection were recorded as a function of age and sex.

RESULTS

Onychomycosis (40.3%) was the most frequent infection, followed by tinea capitis (21.9%), tinea pedis (16%), tinea cruris (15.1%), and tinea corporis (6.7%). Tinea capitis was most prevalent (15.1%) in children (male to female ratio, 1 : 1.57), whereas tinea pedis was most common (11.8%) in adults (male to female ratio, 1 : 2.5). Trichophyton mentagrophytes and Microsporum canis were the most common dermatophytes responsible for tinea infections, and T. mentagrophytes, Candida spp., and Aspergillus spp. were mainly responsible for onychomycosis.

CONCLUSION

The prevalence of SFI was twofold greater in females than males. Children were most commonly affected by tinea capitis, whereas adults generally suffered from tinea pedis. The frequency of onychomycosis was nearly three times higher in adults. This study clearly shows that SFIs are of concern in both genders and in all age groups.

Analysis of the dermatophyte species isolated in the British Isles between 1980 and 2005 and review of worldwide dermatophyte trends over the last three decades

Infections of the skin, hair and nails by dermatophyte fungi are common in developed and developing countries alike. However, the species involved and the resulting clinical entities vary both geographically and with time. We have surveyed 15,333 dermatophytes obtained from primary isolations at the Mycology Reference Laboratory, Bristol, UK from 1980 through 2005. Several striking trends in dermatophyte prevalence were apparent over this period. The relative frequencies of isolations of Microsporum canis (cat and dog ringworm), Trichophyton verrucosum (cattle ringworm), T. mentagrophytes var. mentagrophytes (rodent ringworm) and Epidermophyton floccosum (a cause of human groin and foot infections) all decreased by 90%. Conversely, the contributions of T. tonsurans and T. violaceum (two anthropophilic scalp-infecting species) to total dermatophyte isolations increased by 1000% over the same period. Finally, T. rubrum and T. mentagrophytes var. interdigitale, the two common causes of foot infection comprised 80% of all dermatophytes isolated in 1980 and 90% of isolations in 2005. Similar trends in dermatophyte prevalence were evidenced throughout the British Isles, based on the voluntary reporting of isolations from a large number of British laboratories at 5-yearly intervals over the same period. The implications of these changing patterns of dermatophyte species, and the clinical entities they produce are discussed in the context of a review of worldwide dermatophyte isolations over the last three decades, with emphasis on the causal agents of tinea capitis.

Mycologic disorders of the skin

Cutaneous tissue can become infected when fungal organisms contaminate or colonize the epidermal surface or hair follicles. The skin can be a portal of entry for fungal infection when the epithelial barrier is breached or it can be a site for disseminated, systemic fungal disease. The two most common cutaneous fungal infections in small animals are dermatophytosis and Malassezia dermatitis. Dermatophytosis is a superficial cutaneous infection with one or more of the fungal species in the keratinophilic genera Microsporum, Trichophyton, or Epidermophyton. Malassezia pachydermatis is a nonlipid dependent fungal species that is a normal commensal inhabitant of the skin and external ear canal in dogs and cats. Malassezia pachydermatis is the most common cause of Malassezia dermatitis. The diagnosis and treatment of these cutaneous fungal infections will be discussed.

Survey of dermatophytes on clinically normal cats in the southeast of England

OBJECTIVES

To report the incidence of dermatophytes on the hair coat of asymptomatic cats in the southeast of England. Asymptomatic cats are often blamed for transmission of dermatophytes between animals and humans. This study may help to clarify whether cats are responsible for the increase in fungal infections among the human population.

METHODS

A total of 169 clinically healthy cats without any dermatological signs were sampled using the Mackenzie brush technique and cultured for dermatophytes. Thirty cats were from a closed colony and 139 were feral or from domestic households in the southeast of England.

RESULTS

The incidence of Microsporum canis and Trichophyton mentagrophytes in household and feral cats was 2.16 per cent for each dermatophyte. This survey shows little difference in the isolation rates of M. canis between the southeast and southwest of England, which was reported on in 1994.

CLINICAL SIGNIFICANCE

Given the low number of dermatophytes isolated, asymptomatic cats are unlikely to be responsible for the increasing incidence of human infection. Asymptomatic carriers with T. mentagrophytes in the hair coat have not been previously reported and may need to be considered when treating humans with trichophytosis.

Prevalence of Dermatophytic Fungal Infections in Children: A Recent Study in Anambra State, Nigeria

We conducted a recent survey of dermatological fungal infections amongst children in both urban and rural parts of Anambra State in the south-east geographical flank of Nigeria during the period January 2003 to December 2003. Samples were collected from 1624 children with clinically suggestive lesions and also between the ages of 4 and 16. Young children aged 7-11 and 4- 6 years had significantly higher incidences (P < 0.05) than their older colleagues aged 12-16 years among samples proved to be mycologically positive by microscopy, culture or both. There was a significant difference in the incidence of dermatophytoses amongst children in urban and rural areas investigated (P < 0.05). Tinea capitis was the predominant clinical type. Trichophyton tonsurans was the most prevalent etiological agent while Microsporum audouinii was the least in occurrence. We compared our result with a recent study in the northern geographical zone and observed that although incidence of dermatophytoses is higher in northern Nigeria, tinea capitis was the predominant clinical type in both regions. In addition, the etiological agents appear to vary from time to time in their occurrence and the reasons for these observations are discussed. A regular surveillance and assessment of the etiologic agent and its prevalence by medical mycologists is strongly recommended to facilitate monitoring, reduce/prevent transmission and spread of dermatophytes in countries like Nigeria where they constitute a public health problem.

Dermatophyte infections in the Ljubljana region, Slovenia, 1995-2002

We studied dermatophyte infections in patients, examined in the Mycological Laboratory of the Department of Dermatology, University Medical Centre Ljubljana during the period 1995-2002. A total of 42,494 samples were collected from 33,974 patients suspected to have dermatomycosis. Dermatophytes were identified in 8286 (71.2%) positive cultures. Microsporum canis was the most frequent dermatophyte isolated (46.8%), followed by Trichophyton rubrum (36.7%), T. mentagrophytes var. interdigitale (7.9%) and T. mentagrophytes var. mentagrophytes (4.9%). Less frequently isolated were M. gypseum, T. verrucosum, Epidermophyton floccosum, T. tonsurans and T. violaceum. The most common dermatophyte infections included tinea corporis, onychomycosis, tinea pedis and tinea faciei. Zoophilic dermatophytes were most commonly recovered from children and adolescents with tinea capitis, tinea corporis and tinea faciei. Anthropophilic species were identified mostly in adults with tinea pedis, onychomycosis and tinea inguinalis. During the period studied, we recorded a decline in the rate of M. canis infections, while infections produced by T. rubrum increased in frequency.

Characteristics of dermatophytoses among children in an area south of Tehran, Iran

The aim of this study was to determine the prevalence and etiological agents of dermatophytoses, and also their distribution according to age, gender, and body site among children in an area south of Tehran. A total of 382 children aged </=16 years suspected to have dermatophytic lesions were examined over a period of 3 years (1999-2001). The incidence rate of dermatophytoses was 6.6 per 100 000 person-years. Trichophyton violaceum was the most frequent isolate (28.3%) followed by Microsporum canis (15.1%), Epidermophyton floccosum (15.1%), T. rubrum (13.2%), T. mentagrophytes (11.3%), M. gypseum (7.5%), and T. verrucosum (5.7%). Tinea capitis (39.6%) was the most common type of infection, followed by tinea corporis (30.2%), tinea faciei (18.9%), and tinea manuum (7.5%).

Griseofulvin versus terbinafine in the treatment of tinea capitis: a meta-analysis of randomized, clinical trials

OBJECTIVE

Tinea capitis, a common pediatric infection in the United States, is caused mainly by Trichophyton species and affects many urban children. Although the current treatment of choice is oral griseofulvin, terbinafine has been shown to be variably effective in several comparative, randomized trials. The purpose of this study was to perform a meta-analysis of randomized, clinical trials comparing the efficacies of oral terbinafine and oral griseofulvin for the treatment of childhood tinea capitis.

METHODS

The Medline database was searched for randomized, clinical studies comparing griseofulvin and terbinafine for the treatment of tinea capitis. Acceptance criteria included oral administration of griseofulvin for at least 6 weeks and the identification of a pathogenic dermatophyte from the scalp at the time of enrollment in the study. Scalp culture status at least 8 weeks after enrollment was used as the outcome. The common odds ratio (OR) with 95% confidence intervals (CIs), the Cochran-Mantel-Haenszel test for significance, and the Breslow-Day test for homogeneity were calculated.

RESULTS

Six articles that satisfied all inclusion criteria were identified. These studies were combined by using outcomes at 12 to 16 weeks after enrollment. The common OR was 0.86 (95% CI: 0.57-1.27). When the 5 studies that identified Trichophyton species as the predominant pathogen were combined, using outcomes 12 weeks after enrollment, the results nearly favored terbinafine (OR: 0.65 [95% CI: 0.42-1.01]). For outcomes at 8 weeks after enrollment, no difference was found between the agents (OR: 0.84 [95% CI: 0.54-1.32]). Consclusions.A 2- to 4-week course of terbinafine is at least as effective as a 6- to 8-week course of griseofulvin for the treatment of Trichophyton infections of the scalp. Griseofulvin is likely to be superior to terbinafine for the rare cases caused by Microsporum species.

PCR and PCR–RFLP techniques targeting the DNA topoisomerase II gene for rapid clinical diagnosis of the etiologic agent of dermatophytosis

BACKGROUND

We have focused on the DNA topoisomerase II genes of several pathogenic fungi, and developed polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (RFLP) methods targeting this gene for identification of dermatophytes.

OBJECTIVE

To assess the availability of the PCR-based identification for an etiologic study of dermatophytosis, by testing these PCR and PCR-RFLP methods for stability and reproducibility.

METHODS

Three hundred and fifty-six dermatophyte strains were isolated from 305 patients with tinea, and their genomic DNAs were used as templates for the PCR using primer mixes (PsT, PsME, dPsD1 or dPsD2) composed of gene-specific primers for identification of dermatophytes to the species level. The genomic DNAs of Trichophyton rubrum were further subjected to subrepeat element analysis of the nontranscribed spacer (NTS) of ribosomal DNA (rDNA).

RESULTS

In this study, six dermatophyte species (T. rubrum, Trichophyton mentagrophytes, Trichophyton tonsurans, Microsporum canis, Microsporum gypseum, and Epidermophyton floccosum) were obtained. In all cases, the identifications obtained from the PCR and PCR-RFLP targeting the DNA topoisomerase II gene coincided with those from the conventional morphological features-based identification technique. The sensitivity of the PCR-based identification was found to be a colony of approximately 3mm in diameter. Furthermore, T. rubrum was divided into three groups (17 types) on the basis of the sizes and numbers of the products generated from the TRS-1 region, and three types from the TRS-2 region.

CONCLUSION

The PCR and PCR-RFLP targeting the DNA topoisomerase II gene were rapid, stable, and reproducible for species identification of dermatophytes, and thus are convenient tools for an etiologic study of dermatophytosis.

Clinical and mycological status of theTrichophyton mentagrophytes(interdigitale) syndrome of chronic dermatophytosis of the skin and nails

The syndrome of tinea pedis caused by human-adapted Trichophyton mentagrophytes (interdigitale) can be recognized by two signs not characteristically seen in tinea pedis caused by T. rubrum and Epidermophyton floccosum:1 bullous > 2 mm vesicles in the thin skin of the plantar arch and along the sides of the feet and heel adjacent to the thick plantar stratum corneum,2 and white superficial onychomycosis. The relationship of the syndrome to zoophilic T. mentagrophytes remains in question.

Preseptal cellulitis caused by trichophyton (ringworm)

A 10-year-old boy with a past medical history significant for chicken pox at 7 years of age was referred to our eye center by an outside ophthalmologist for a 15-day history of worsening right-sided preseptal cellulitis. The patient reported photophobia, pruritus, and pain in the eyelid region. There appeared to be vesicular lesions on the eyelids. Empiric therapy with oral antibacterial and antiviral medications failed to resolve the preseptal cellulitis. Lid cultures revealed coagulase negative Staphylococcus, Streptococcal viridans, and a Trichophyton species of fungus. The infection was successfully treated with two courses of oral itraconazole. This is the first case of preseptal cellulitis caused by this dermatophyte that we could find in the literature.

Antimicrobial effect of resveratrol on dermatophytes and bacterial pathogens of the skin

The phytoalexin resveratrol is commonly found in food and drinks, including red wine, grapes, and peanuts. Many studies have shown that this compound has anti-inflammatory properties, and it has been ascribed as having health benefits that help to prevent cancer and coronary heart disease. A treatment that combines antimicrobial and anti-inflammatory actions may be desirable for alleviating many skin conditions that range in severity. Therefore, we evaluated the antimicrobial activity of resveratrol against bacteria and dermatophytes that are major etiologic agents of human skin infections. Using the broth microdilution protocol of the National Committee for Clinical Laboratory Standards (NCCLS) M7-A5, growth of the bacterial species Staphylococcus aureus, Enterococcus faecalis, and Pseudomonas aeruginosa was inhibited at 171-342 microg/mL of resveratrol in the solvent dimethyl sulfoxide. Using the NCCLS protocol M38-P, activity against the fungal species Trichophyton mentagrophytes, Trichophyton tonsurans, Trichophyton rubrum, Epidermophyton floccosum, and Microsporum gypseum was also tested. The growth of dermatophytes was inhibited at 25-50 microg/mL of resveratrol. Thus, this study indicates a novel application for resveratrol, a molecule of plant defense, to combat human fungal pathogens. Resveratrol and its analogs may have wide application to skin conditions that afflict a significant portion of our population, and may also have promising clinical potentials in diabetic wounds.

Amino acid- or protein-dependent growth of Trichophyton mentagrophytes and Trichophyton rubrum

Culture conditions were examined for Trichophyton mentagrophytes and Trichophyton rubrum, which are major pathogens involved in dermatophytosis. They grew well in Sabouraud's dextrose broth or RPMI 1640. Growth in phosphate-buffered yeast nitrogen base supplemented with glucose was very slow, although growth improved significantly with the addition of amino acids or proteins to the medium. The fungi could also grow using human nail fragments as the only source of nutrition. Examination of proteases by substrate gel electrophoresis indicated that distinct sets of proteases are secreted from the dermatophytes in two different media, Sabouraud's dextrose broth and nail fragments. A protease inhibitor, phenylmethanesulfonyl fluoride, inhibited the growth of the fungi on nail fragments, but it did not inhibit their growth in Sabouraud's dextrose broth.

[Epidemiology and ecology of dermatophytoses in the City of Fortaleza: Trichophyton tonsurans as important emerging pathogen of Tinea capitis]

Dermatophytosis is the most common skin infectious disturbance in the world. In this research 2,297 patients were evaluated with suspected clinical lesions of dermatophytosis. It was observed that, 534 (23.2%) patients tested positive for dermatophytes. T. rubrum was the most prevalent specie (49.6%; p < or = 0.05), followed by T. tonsurans (34.4%), M. canis (7%) and T. mentagrophytes (6.2%). When the species isolated was correlated with the respective anatomical localization, it was observed that T. tonsurans was the most frequent isolated in scalp lesions (73.9%; p < or = 0.01). On the other hand, T. rubrum was the main specie involved in body lesions (72.8%; p < or = 0.05). Therefore, in scalp infections it was observed that, there was an absolute prevalence of T. tonsurans. This evidence is different from the statistical data collected in the southeast and south of Brazil, as well as from other areas of the world, which still show M. canis as the most frequent microorganism isolated in Tinea capitis.