Genetic diversity among Trichophyton mentagrophytes isolates using random amplified polymorphic DNA method.

Trichophyton mentagrophytes is a common cosmopolitan dermatophyte species composed of two varieties: T. mentagrophytes var. interdigitale (anthropophilic form) and T. mentagrophytes var. mentagrophytes (zoophilic form). We used a random amplified polymorphic DNA (RAPD) method to study the genetic diversity of 46 clinical isolates of the T. mentagrophytes complex collected from 38 patients with different geographical origins (Europe, Africa, South America). The T. mentagrophytes were isolated either from a unique lesion for 31 patients, including two patients living together, or from at least two sites for seven patients. Only one primer of 15 primers tested showed DNA polymorphism in the isolates, producing 23 distinct patterns belonging to three clusters. There was no specific cluster grouping isolates from the same geographical origin. The same pattern is shared by all the four T. mentagrophytes var. mentagrophytes and 13 of 42 T. mentagrophytes var. interdigitale. An identity of strains responsible for several lesions in seven individuals suggests an homogeneous T. mentagrophytes population in the case of multiple lesions. In contrast, the dissimilarity of two strains recovered from two patients living together argues against person-to-person transmission in that case. This study indicates that RAPD can be successfully applied to show genetic diversity among T. mentagrophytes isolates.     

Trichophyton mentagrophytes var. nodulare–Ein seltener Fußpilzerreger auf dem Vormarsch?

Background: The spectrum of organisms causing dermatophytoses is changing continuously. Patients/Methods: Two strains of Trichophyton mentagrophytes var. nodulare are characterized mycologically; both were isolated for the first time in our laboratory within the past 2 years from patients with tinea pedis. Results: Distinctive features of Trichophyton mentagrophytes var. nodulare are a bright yellow‐orange pigmentation of the thallus, a marked exudation of pigment, and the development of nodular bodies. Trichophyton mentagrophytes var. nodulare is an anthropophilic variety of Trichophyton mentagrophytes causing tinea and onychomycosis. Conclusions: Trichophyton mentagrophytes var. nodulare has been found only very rarely in Germany and is relatively unknown. An increased awareness of this dermatophyte is needed in order to track its possible spread.     

Animals as a Reservoir of Human Ringworm in New Zealand

Investigations in New Zealand have shown that animals are an important reservoir of human ringworm. Of 4,328 dermatophytes recovered from human lesions over the six-year period 1963-68, 1,579 (36.5%) were considered to be of animal origin–1,254 (29.0% total) Microsporum canis; 189 (4.4% total) Trichophyton erinacei; 86 (2.0% total) Trichophyton mentagrophytes; 46 (1.1%) Trichophyton verrucosum; 2 Microsporum distortum and 2 Trichophyton equinum var. autotrophicum. Human infection with zoophilic dermatophytes was more pronounced in the younger age groups, showed no marked sex distribution, and usually occurred at only a single exposed site on the body. Apart from the M. canis ringworms which occurred mainly between the months February to August (autumn, winter), no marked seasonal variations were observed. Of the 12 dermatophyte species recovered from 1,290 wild, domestic and laboratory animals examined between 1960-68, only nine were regarded as possessing parasitic properties. These were the zoophilic Microsporum canis, M. distortum, M. nanum, Trichophyton erinacei, T. equinum var. autotrophicum, T. gallinae, T. mentagrophytes, T. verrucosum, and the geophilic M. gypseum. Those regarded as essentially non-pathogenic were the geophilic M. cookei, T. ajelloi and T. terrestre. Apart from T. mentagrophytes which was recovered from a wide variety of animals, the remaining pathogenic dermatophytes displayed marked host specificities. T. mentagrophytes var. quinckeanum was not isolated from any of the human or animal specimens. It is confirmed that, in New Zealand, animals form an important reservoir of human ringworm. Direct contact with small domestic pets rather than larger farm animals is the main source of infection. Of the small wild animals, hedgehogs (Erinaceus europaeus) appear most important.     

The first case of tinea faciei caused by Trichophyton mentagrophytes var. erinacei isolated in Chile

Background Trichophyton mentagrophytes var. erinacei is a zoophilic dermatophyte transmitted by hedgehogs which human infections manifest as highly inflammatory and pruritic eruptions. Methods We report a 21‐year‐old woman who presented with a two‐week history of a pruritic scaly erythematous plaque on the nose. The patient had kept hedgehogs as pets, and one had bitten her on the tip of the nose two months prior to the appearance of the nasal lesion. Results Fungal culture from the scales on the tip of the patient’s nose was compatible with T. mentagrophytes var. erinacei. The strains isolated from cultures made from samples taken from the noses and ears of the pet hedgehogs were morphologically similar to the strain isolated from the patient. Morphological identification was confirmed by sequencing the internal transcribed spacer. The lesion was diagnosed as tinea faciei, and therapy was initiated with topical and systemic terbinafine 250 mg/day for eight weeks, which resulted in complete improvement. Conclusions Trichophyton mentagrophytes var. erinacei is the most common dermatophyte isolated in hedgehogs. Usually T. mentagrophytes var. erinacei infection manifests as an extremely inflammatory and pruritic eruption that is confined to the site of contact with the hedgehog. Although the identification of T. mentagrophytes by traditional methods is possible, identification by ITS region analysis is a fast, simple, and increasingly available method. The increasing frequency of the practice of keeping exotic animals as pets has resulted in the emergence of several zoonotic diseases that can potentially be transmitted to humans.     

Tinea capitis among children and adolescents in the Farwaniya region of Kuwait

Analysis of 325 patients (182 males, 143 females) of mycologically proven tinea capitis (TC) seen over a period of two years from January 2001--December 2002 in the Farwaniya region of Kuwait is presented in this study. The age range was 8 months to 17 years. Peak incidence was observed in the 3-14 year age group (79.6%). Positive family history and contact with pets were noted in 22% and 36.7% of the cases, respectively. The non-inflammatory 'gray patch' variety was the most common clinical type, seen in 163 (50.2%) children, followed by the black-dot variant in 100 (30.2%) patients. A significant proportion of the cases (16.6%) had the uncommonly reported seborrheic dermatitis or dandruff like pattern. Highly inflammatory kerion was encountered infrequently (2.5%). Seven species of dermatophytes were isolated; Trichophyton violaceum in 135 (41.5%), followed by Microsporum canis in 89 (27.4%), Microsporum audouinii in 48 (14.8%), Trichophyton mentagrophytes var. mentagrophytes in 31 (9.5%), Trichophyton verrucosum in 15 (4.6%), Trichophyton tonsurans in 6 (1.9%) and Microsporum gypseum in 1 (0.3%) patient. T. violaceum was the most common fungus responsible for the black-dot variety (89/100) and kerion (4/8) patients. Three cases of kerion (33.3%) grew T. verrucosum. M. canis was the most common species isolated from the 'gray patch' cases (79/163; 48.5%) followed by almost equal prevalences of T. violaceum (16.6%), M. audouinii (15.3%), and T. mentagrophytes var. mentagrophytes (12.3%). Among the seborrheic type of cases, M. audouinii was the most common fungus isolated in 20/54 (37%) followed by T. violaceum in 15 (27.8%), T. mentagrophytes var. mentagrophytes in 9 (16.7%), M. canis in 8 (14.8%) and T. verrucosum and T. tonsurans in one (0.3%) patient each. The results are significantly different from those in earlier studies in Kuwait.     

An unusual clinical presentation of tinea faciei caused by Trichophyton mentagrophytes var. erinacei

Trichophyton mentagrophytes var. erinacei, the natural host of which is the hedgehog, has been found to cause highly inflammatory and pruritic eruptions, including tinea manuum, tinea corporis, nail infection, kerion, scalp infection, and tinea barbae. To our knowledge, however, no reports have been made of tinea faciei caused by Trichophyton mentagrophytes var. erinacei in the English language literature. We provide here the case of tinea faciei caused by Trichophyton mentagrophytes var. erinacei.     

IN VITRO SUSCEPTIBILITY OF DERMATOPHYTES TO ANTIFUNGAL DRUGS: A COMPARISON OF TWO METHODS

Background. There is an evidence that some fungal strains are resistant to certain antimycotic drugs with resulting therapeutic failures. Unlike testing of antibacterial agents, the activity of these drugs against the given fungal strains is not tested routinely. The paper presented is an approach to such a procedure. Methods. The minimum inhibitory concentration (MIC) values obtained using the dilution method were compared with the diameters of growth inhibition zones using the disk-diffusion method. Seven antifungal drugs (graiseofulvin, natamycin, naftifine, clotrimazole, bifonazole, miconazole, ketoconazole) were tested with 80 fungal strains, including Trichophyton rubrum, T. mentagrophytes, Microsporum canis, and Epidermophyton floccosum. Results. The majority of fungal strains were inhibited by griseofulvin at concentrations not exceeding 10 mg/L. The least susceptible was T. mentagrophytes. The most effective drug was naftifine, and the least effective was natamycin. Naftifine inhibited 98.75% of the strains tested at a concentration not exceeding 1.0 mg/L. An increase of the MIC value was accompanied by a decrease in the growth inhibition diameter. The relation was statistically significant. Conclusions. T. rubrum strains are more susceptible to antifungal drugs than T. mentagrophytes. Naftifine proved to be the most effective drug in dermatophytoses. Natamycin is a useful drug against yeast-like fungi but not against dermatophytes. The disk-diffusion method of fungal susceptibility assessment yields data consistent with results obtained from the dilution method and is recommended for routine use because of its simplicity.     

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.     

Epidemiology of dermatophyte infection in Auckland, New Zealand

This report describes the epidemiology of culture-proven dermatophyte infection in Auckland, New Zealand. The authors undertook a retrospective review of laboratory data for the period from June 1999 to July 2002. There were 10 004 dermatophyte isolates. The most common isolates were Trichophyton rubrum (69%) and Trichophyton mentagrophytes (19%). Microsporum canis was mainly isolated from children. The prevalence of T. mentagrophytes increased with patient age (P < 0.001). Trichophyton rubrum was most common in those aged between 20 and 59 years. The incidence of culture-proven dermatophyte infection was 2.9/1000 population for the year 2000, and the incidence increased with patient age (P < 0.001). It is concluded that dermatophytes causing superficial mycoses in the Auckland region are essentially similar to Australia and other Western countries, although some new organisms are seen as a result of the migration of people from other countries. The incidence of local dermatophyte infection increases with age.     

Epidemiological aspects of Trichophyton rubrum var. raubitschekii in Japan

Trichophyton rubrum var. raubitschekii is a rare anthropophilic dermatophyte isolated around the world from tinea corporis, tinea cruris, tinea pedis and tinea unguium. In this study, the isolation rate of T. rubrum var. raubitschekii was studied in 200 cases of tinea pedis and tinea unguium in Japan. The 200 clinical isolates were shown to be of downy type as their colonies on Sabouraud's dextrose agar were white to cream, suede‐like to downy, with a yellow‐brown to wine‐red reverse, and they produced few macroconidia. The type strain of T. rubrum var. raubitschekii (CBS 100084) and one clinical isolate (KMU 8337; isolated at Kanazawa) of downy type tested positive for urease, but the reference strain of T. rubrum (CBS 392.58) and the remaining 199 clinical isolates tested negative. Further epidemiological investigations are required to study human cases of infection with the granular type of T. rubrum and T. rubrum var. raubitschekii in Japan.     

Signature polymorphisms in the internal transcribed spacer region relevant for the differentiation of zoophilic and anthropophilic strains of Trichophyton interdigitale and other species of T. mentagrophytes sensu lato

Background Dermatophytes are the main cause of superficial mycoses in humans and animals. Molecular research has given useful insights into the phylogeny and taxonomy of the dermatophytes to overcome the difficulties with conventional diagnostics. Objectives The Trichophyton mentagrophytes complex consists of anthropophilic as well as zoophilic species. Although several molecular markers have been developed for the differentiation of strains belonging to T. mentagrophytes sensu lato, correct identification still remains problematic, especially concerning the delineation of anthropophilic and zoophilic strains of T. interdigitale. This differentiation is not academic but is essential for selection of the correct antimycotic therapy to treat infected patients. Methods One hundred and thirty isolates identified by morphological characteristics as T. mentagrophytes sensu lato were investigated using restriction fragment length polymorphism (RFLP) and sequence analysis of the polymerase chain reaction‐amplified internal transcribed spacer (ITS) region of the rDNA. Results Species of this complex produced individual RFLP patterns obtained by the restriction enzyme MvaI. Subsequent sequence analysis of the ITS1, 5.8S and ITS2 region of all strains, but of T. interdigitale in particular, revealed single unique polymorphisms in anthropophilic and zoophilic strains. Conclusions Signature polymorphisms were observed to be useful for the differentiation of these strains and epidemiological data showed a host specificity among zoophilic strains of T. interdigitale/Arthroderma vanbreuseghemii compared with A. benhamiae as well as characteristic clinical pictures in humans when caused by zoophilic or anthropophilic strains. The delineation is relevant because it helps in determining the correct treatment and provides clues regarding the source of the infection.     

Atypical Microsporum canis variant in an immunosuppressed child

A 10‐year old boy with X‐chromosomal adrenoleukodystrophy presented with scaly patches on the scalp and diffuse effluvium. He was on immunosuppressive therapy because of a chronic graft‐versus‐host‐reaction after allogenic bone marrow transplantation. At home he had been in contact with cats, rabbits and guinea pigs. Through Wood light and KOH examination, we confirmed the diagnosis of tinea capitis and started antimycotic therapy. The morphology of the culture first suggested Epidermophyton floccosum, Trichophyton mentagrophytes var. nodulare or Trichophyton tonsurans as possible causes for this infection. Further studies, however, revealed an atypical form of Microsporum canis infection.     

Primary cryptococcal cellulitis caused by Cryptococcus neoformans var. gattii in an immunocompetent host

Primary cutaneous cryptococcal infection is uncommon. The cutaneous manifestations are most often the result of dissemination from the central nervous system or lung, usually in an immunocompromised host; cellulitis is regarded as the rarest cutaneous form. Primary cutaneous cryptococcosis has occasionally been reported in the immunocompetent, the causative organism being Cryptococcus neoformans var. neoformans. We present a case of cellulitis of the right arm in a 75-year-old man caused by Cryptococcus neoformans var. gattii, a fungus which is endemic in Australia and an important cause of infection in the immunocompetent This is the first case described of a primary cutaneous infection due to Cryptococcus neoformans var. gattii The interesting ecology of this organism is discussed.     

Tinea capitis in Tripoli

Mycological examination of 600 cases of tinea capitis in Tripoli showed Trichophyton violaceum to be the most common isolate, followed by Microsporum canis, Trichophyton schoenleinii and Trichophyton mentagrophytes. The various clinical patterns which scalp ringworm may present is discussed and attention is drawn to the relatively common non-inflammatory seborrhoeic or dry scaly pattern.     

Molecular typing of Trichophyton mentagrophytes var. interdigitale isolated in a university hospital in Japan based on the non‐transcribed spacer region of the ribosomal RNA gene

Detecting intraspecies polymorphisms in fungi causing dermatophytoses is important in elucidating routes of infection and determining whether Tinea recurrence is caused by exacerbation or re‐infection. In fungi, the non‐transcribed spacer region (NTS) of the ribosomal RNA gene shows the greatest accumulation of base sequence mutations. We therefore assessed NTS sequences in 64 clinical isolates of Trichophyton mentagrophytes var. interdigitale, the second most common species of dermatophytes in Japan. These isolates were among the clinical isolates of dermatophytes in the Department of Dermatology, Kanazawa Medical University Hospital in 2006 and were obtained by morphological and molecular biological identification methods. DNA was extracted from each isolate, as well as from one isolate maintained in our department, to detect length polymorphisms at each of three variable loci, TmiS0, TmiS1 and TmiS2, of the NTS for subtyping. We observed seven patterns for TmiS0, six patterns for TmiS1 and three patterns for TmiS2. The combinations of these patterns enabled us to classify the 65 isolates into 15 types. The most prevalent, constituted 46% (30/65) of all isolates. Eleven types were new combinations, whereas the other four were previously described. These results suggest that this method may be used to determine the molecular epidemiology of T. mentagrophytes var. interdigitale in Japan, because it generated results rapidly and in a sensitive manner.     

Localization of solitary dermatophytic lesions in man]

The occurrence of three causative organisms of the so called intertriginous dermatophytoses--Epidermophyton floccosum, Trichophyton mentagrophytes var. interdigitale and T. rubrum--was compared according to the localization of the lesions. The differentiation of invasion into solitary and combined sites showed a prevalence of E. floccosum in solitary lesions and T. rubrum in combined lesions. In T. mentagrophytes var. interdigitale, the frequency of occurrence of both types of the lesions was approximately the same. The differences found suggest various adaptation-ability of dermatophytes to different parts of the body. The study of localization of solitary lesions is important from the epidemiological point of view because it assists in revealing the sources of dermatophytic infection and the ways of transmission.     

Microbiological and molecular diagnosis of deep localized cutaneous infection with Trichophyton mentagrophytes

We describe a healthy young woman with a localized deep dermal infection on the right side of the chest wall. It was caused by the dermatophyte Trichophyton mentagrophytes, and resolved after two pulses of oral itraconazole 200 mg twice daily for 1 week. As cultural and microscopic features did not enable a precise identification of the fungus, molecular investigation was undertaken. Patterns of HaeIII restriction digests of genomic DNA from the culture matched those from Arthroderma incurvata and A. benhamiae, which is the teleomorph of T. mentagrophytes var. mentagrophytes.     

Identification of several clinical isolates of dermatophytes based on the nucleotide sequence of internal transcribed spacer 1 (ITS 1) in nuclear ribosomal DNA.

Nucleotide sequences of internal transcribed spacer 1 (ITS 1) in nuclear ribosomal DNA from seven morphologically unidentified dermatophyte isolates were determined. The sequences were compared with those of typical isolates of Trichophyton (T.) mentagrophytes var. interdigitale, T. rubrum, and Epidermophyton floccosum. Two of the isolates were classified as T. rubrum and the other five as T. mentagrophytes var. interdigitale. The results did not conflict with identifications using other molecular techniques, including random amplification of polymorphic DNA (RAPD) analysis and restriction enzyme analysis of mitochondrial DNAs. Thus, the nuclotide sequence of ITS 1 is possibly a good molecular marker for identification of these major anthropophilic dermatophyte species.     

Comparison of hairbrush, toothbrush and cotton swab methods for diagnosing asymptomatic dermatophyte scalp carriage

Background Tinea capitis may also present as a minimal infection, termed carrier state. Anthropophilic dermatophytes (i.e. Trichophyton tonsurans and Trichophyton violaceum) have been generally associated with high rates of asymptomatic carriage. Objectives The aim of this study was to compare the efficacy of the hairbrush, toothbrush and cotton swab methods for diagnosing scalp carriage as well as to determine the prevalence and related dermatophyte species for both asymptomatic and symptomatic tinea capitis in Adana Province, Turkey. Patients and methods A screening study was carried out between February 2006 and May 2006, covering three schools and a total of 1560 children with 857 (54.9%) boys and 703 (45.1%) girls, aged between 7 and 17 years (10.6 ± 2.3 years). The diagnosis was made by using three of the methods mentioned above with inoculation onto Sabouraud glucose agar. Results Symptomatic tinea capitis was not detected in the study; however, 21 (1.3%) asymptomatic carriers, with 9 (42.9%) boys and 12 (57.1%) girls, aged 7 to 13 years (9.7 ± 1.9 years) were detected. The diagnosis was made via hairbrush in 13, via cotton swab in 4 and via toothbrush in 4. The mean age (P = 0.075) and gender differences were found to be statistically insignificant (P = 0.26). The most common isolated species was Trichophyton mentagrophytes var. mentagrophytes (90.4%) followed by Trichophyton audouinii (4.8%) and Microsporum gypseum (4.8%). Nine children had Arab origin (P = 0.005), and 12 had immigrated from the south‐eastern region of Anatolia, Turkey. The screening of 32 households of 21 children with asymptomatic carriage enabled the researchers to detect the carrier state in three mothers and one sister, resulting in a total of four households (12.5%), with T. mentagrophytes var. mentagrophytes isolated, by hairbrush method in three cases and cotton swab in one case. If the methods were to be used alone, the prevalence of asymptomatic carriage would be found as 1.0% (16 of 1592) in the hairbrush, 0.3% (4 of 1592) in the toothbrush and 0.3% (5 of 1592) in the cotton swab methods; whereas the combined use of these three methods could reveal a total prevalence of 1.6% (25 of 1592). The hairbrush method was significantly found to be more effective in detecting dermatophyte fungi than the toothbrush (P < 0.01) and the cotton swab methods (P < 0.05). There was also a statistically significant difference between the use of a single method and the combination of all other three methods (P < 0.005). Conclusions In summary, it was found that the prevalence of asymptomatic carriage did not cover symptomatic tinea capitis prevalence (1.6% vs. 0%), and the dominant species was zoophilic T. mentagrophytes (92%, 23 of 25). Asymptomatic carriage was not found to be related to age, gender and the coexistence of other dermatophytoses; however, race (Arab origin) was found to be the only risk factor. For laboratory diagnosis, no method was found to be nominated as a gold standard; hence, a combined use of diagnosing methods was suggested.