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The authors report a case of tinea capitis in a woman aged 49, with a previous history of discoid lupus erythematosus. The pathogenic agent was Microsporum canis. The patient was cured after two months therapy with griseofulvin and local antimycotics.
The susceptibility of 28 strains of Microsporum canis to griseofulvin, to ketoconazole and to a combination of both antifungal drugs was determined. Griseofulvin proved to be more active than ketoconazole. The combination of both antifungal agents was found to exert an additive effect.
An atypical strain of Microsporum canis isolated from a two-year-old boy with tinea corporis is described. When cultured on Lactritmel agar the strain presented the typical pigment of M. canis without developing characteristic macroconidia. After 6 weeks, scarce, rudimentary, fusiform macroconidia 120-150 microns long developed on Lactritmel and Sablac microcultures. In vitro, the strain developed hair perforating organs. Experimental inoculation of a healthy volunteer produced a tinea with typical fluorescence and endoectothrix attack. After isolation the strain remained stable. These results differ from the results reported by English and Tucker. This is the first atypical strain of M. canis reported in Venezuela.
Scanning electron microscopy (SEM) is at present considered a good way to observe the morphological alterations induced by an antifungal on pathogenic fungi. Owing to its high precision, low voltage scanning electron microscopy (LVSEM) improves the quality of observations. The Microsporum canis morphology alterations induced by naftifine at a concentration of 0.9 microgram ml-1 (10 times the minimum inhibitory concentration (MIC) for 7 days were studied in LVSEM. The young lateral ramifications and the aborted buds take on a granulous aspect. These granulations can be localized as brassard shapes around hyphae. The mycelial filaments often appear irregularly swollen with bulbous tips. Macroconidia are selectively covered with a microfibrillar network. In addition, LVSEM on control samples reveals pavimentous angular structures on the macroconidial surface and fine granulations on the filament surface of M. canis unknown until now. A cytological study with transmission electron microscopy (TEM) of filaments altered by naftifine permitted us to observe the disorganization of cell wall fibrillar structure, an excessive plasma membrane undulation and an intracytoplasmic accumulation of large vesicles with probably lipidic contents.
The effect of sodium sulphite, cysteine, glutathione, mercaptoethanol and dithioerythritol (0.1-10 mmol l-1) on the activity of proteases of Microsporum gypseum was studied using azocasein, cross-linked bovine serum albumin and keratin as substrates. With the substrate without disulphide bonds (casein) no stimulation was found, and reducing agents inhibited proteolysis in most cases. With the remaining two substrates, all substances enhanced the activity of proteases probably through the cleavage of the substrate disulphide bonds. Sulphite was more effective than the four used thiols and enhanced the activity against serum albumin up to 3.2 times and against keratin up to 2.9 times. Using sulphitolysed sheep wool, keratinolytic activity increased after sulphitolysis of more than 20% of disulphide bonds. With the fully sulphitolysed wool the activity increased 43 times. The obtained results support the author's hypothesis on keratin degradation by sulphite excretion prior to attack by fungal proteases. Stimulation of proteolysis and keratinolysis by cleavage of disulphide bonds is not specific for dermatophytic proteases because trypsin and pronase behaved similarly in the experiments.
Microsporum canis is one of the most common zoophilic dermatophytes. If transmitted to humans, inflammatory lesions may develop, e.g. on the scalp. M. canis was isolated from a 5-year-old boy living in a suburban area who suffered from a long-standing, mildly inflammatory lesion on the scalp that had been treated for several months with anti-eczematous regimens. There had been no contact with animals, e.g. cats or dogs, in the previous months, but the lesions had developed a few weeks after the family had bought a used car from a dog owner. Indeed, M. canis could be grown on contact plates from the car's interior. This case illustrates that attention should be paid to the often neglected diagnosis of M. canis-induced tinea capitis and to unusual routes of infection.
Twenty-six sporulating strains of lyophilized microscopic fungi of the genera Epidermophyton, Microsporum, Paecilomyces and Trichophyton have been maintained at 2-8 degrees C for 8-14 years. In 23 strains the number of viable particles reduced less than 10-fold during this period compared with immediately after lyophilization. The viability of other three investigated strains ranged from 3.4% to 7.1% in comparison with the original values.
Microsporum nanum Fuentes 1956 has been identified in scrapings from a skin lesion in a patient in Karonga District, Malawi, Africa. We believe that this is the first such identification from the African continent. The patient had a single skin lesion in his popliteal fossa and was known to rear pigs.
Data collected from multiple trials with 110 fresh and preserved clinical isolates of Trichophyton mentagrophytes var. mentagrophytes, T. violaceum, T. rubrum, T. verrucosum, Microsporum canis and Epidermophyton floccosum revealed that production of macroconidia depends on glucose and thiamine concentrations in the medium. Optimal macroconidia production was obtained at the critical concentrations of 5 g l-1 glucose and 0.6 g l-1 thiamine when the two compounds were used in combination. The same conditions also encouraged macroconidia production in aconidial strains of T. verrucosum. Cutaneous inoculation in immunocompetent laboratory rabbits further enhanced the macroconidia producing capacity of the tested strains. Emphasis was placed on the occurrence of dysgonic/atypical strains of M. canis, which readily reverted to their typical phenotypes after growth on medium supplemented with 0.6 g l-1 thiamine, a process greatly augmented after cutaneous animal inoculation. It was verified that selective exogenous factors affect macroconidial production and that the dysgonic group of M. canis constitutes an epidemiologically significant group in the Greater Athens area. This is the first report of the occurrence of such M. canis strains from Greece.
Clinical and laboratory data from 22 children with tinea corporis and tinea capitis caused by Microsporum canis (10 tinea corporis, 12 tinea capitis), confirmed by microscopic examination and culture and partly pretreated with griseofulvin or terbinafine, are summarized. The children were treated consecutively with itraconazole in our clinic during 1994/95. The age of the children ranged between 4 and 13 years, with girls being affected much more frequently than boys. Oral, individually adapted, high-dose treatment of 5 mg itraconazole per kg body weight proved to be successful. In all 22 children, although pretreatment with griseofulvin or terbinafine was partly unsuccessful, fungal infections could be cured clinically and also were culture negative at control examinations. In 10 children with tinea corporis treatment was performed only for 4-14 (middle 11) days. In the children with tinea capitis itraconazole treatment was continued for 3-11 weeks. Among the six children without pretreatment, itraconazole solution was administered for 4-11 weeks (average 7.5 weeks). Of the patients in whom pretreatment was unsuccessful, four with griseofulvin and two with terbinafine, the duration of the subsequent oral treatment with itraconazole solution was 3-5 weeks (average 3.6 weeks). The drug seemed to be well tolerated-no significant side-effects occurred, with the exception of possible minor gastrointestinal disturbances in two patients. Laboratory values remained within normal limits.
Microsporum nanum was isolated from a case of tinea corporis in a 16-year-old boy. This is the first recorded case of human ringworm infection caused by M. nanum in India.
The in vitro activity of itraconazole against Microsporum canis was evaluated with 38 feline isolates. Based on the observed minimum inhibitory concentrations it can be concluded that the drug could be effective in the therapy of cats affected by M. canis ringworm.
Clinical isolates of Microsporum canis and M. gypseum from humans, dogs and cats were examined by random amplification of polymorphic DNA (RAPD) and Southern hybridization analyses. The RAPD band patterns of six clinical isolates of M. canis were identical to those of standard strains of Arthroderma otae. Of nine clinical isolates of M. gypseum seven and two isolates showed RAPD patterns identical to those of standard strains of A. gypseum and A. incurvatum respectively. Southern blot analysis using a probe (C3) obtained from A. otae DNA revealed that six clinical isolates of M. canis showed specific bands identical to those detected in the standard strains of A. otae. Of nine clinical isolates of M. gypseum, seven and two isolates showed bands hybridized by the C3 probe identical to those detected in A. gypseum and A. incurvatum respectively. Furthermore, the results from mating experiments on these nine clinical isolates of M. gypseum showed complete agreement with the results from RAPD and Southern hybridization analyses. These findings clearly indicate that RAPD and Southern hybridization analyses are very useful in the identification of clinical isolates of M. canis and M. gypseum.
The first four cases of onychomycosis due to Microsporum gypseum observed in Italy between 1990 and 1997 are reported. clinical manifestation was distal subungual onychomycosis in all cases. The lesions were asymptomatic in two patients. Three patients were treated with oral itraconazole (pulsed therapy) and the other with ciclopirox 8% nail lacquer. Clinical and mycological recovery was achieved in all cases. The cases are reported because of their rarity.
The present study deals with a case of a 40-day-old girl with kerion Celsi caused by Microsporum canis. The source of the infection were the parents who presented tinea corporis caused by M. canis. Systemic treatment was carried out with terbinafine and complete recovery was achieved. Tinea capitis is unusual in children during their first year of life and its evolution towards kerion is very rare in newborns.
A 51-year-old white male, native of Rio de Janeiro, Brazil, with advanced AIDS and in chronic use of imidazoles for oral candidosis, presented erythematous, desquamative, pruriginous plaques of 1 month evolution on the trunk, inguinal/crural region, and lower limbs. The diagnosis of dermatophytosis was based on the isolation of Microsporum gypseum from scales scraped from the skin lesions. The lesions regressed after 30 days treatment with itraconazole, 100 mg day(-1). After interruption of this antifungal, the mycosis recurred 2 months later, along with a toe onychomycosis also caused by M. gypseum. Attempted reintroduction of itraconazole at higher dose was unsuccessful. Patient responded well to treatment with terbinafine 250 mg day(-1) for 45 days. However, the medication had to be interrupted as a result of the emergence of a disseminated erythematous/papulous rash. Topical treatment with amorolfine cream was then performed, with a good clinical and mycological response.
The aim of the study was to analyze the Microsporum canis infections in the Rijeka area, Croatia, observed between 1990 and 2001. A total of 724 cases of dermatophytosis caused by M. canis were diagnosed in 320 individuals with the tinea capitis and 404 with tinea corporis. The M. canis infections constituted 32.8% of all dermatophytes isolated during the study period.
We report a case of tinea on the eyelid in a woman with psoriasis. Due to the history of psoriasis and clinical aspect of the lesion the diagnosis of psoriasis was suggested in the first place; however, laboratory examination revealed Microsporum gypseum. The patient was treated with oral itraconazole resulting in clinical and mycological cure. We emphasize the uncommon location of tinea caused by M. gypseum and the importance of searching for fungal infection on scaly lesions.