Remarkable Phenotypic Virulence Factors of Microsporum canis and Their Associated Genes: A Systematic Review.

Microsporum canis is a widely distributed dermatophyte, which is among the main etiological agents of dermatophytosis in humans and domestic animals. This fungus invades, colonizes and nourishes itself on the keratinized tissues of the host through various virulence factors. This review will bring together the known information about the mechanisms, enzymes and their associated genes relevant to the pathogenesis processes of the fungus and will provide an overview of those virulence factors that should be better studied to establish effective methods of prevention and control of the disease. Public databases using the MeSH terms "Microsporum canis", "virulence factors" and each individual virulence factor were reviewed to enlist a series of articles, from where only original works in English and Spanish that included relevant information on the subject were selected. Out of the 147 articles obtained in the review, 46 were selected that reported virulence factors for M. canis in a period between 1988 and 2023. The rest of the articles were discarded because they did not contain information on the topic (67), some were written in different languages (3), and others were repeated in two or more databases (24) or were not original articles (7). The main virulence factors in M. canis are keratinases, fungilisins and subtilisins. However, less commonly reported are biofilms or dipeptidylpeptidases, among others, which have been little researched because they vary in expression or activity between strains and are not considered essential for the infection and survival of the fungus. Although it is known that they are truly involved in resistance, infection and metabolism, we recognize that their study could strengthen the knowledge of the pathogenesis of M. canis with the aim of achieving effective treatments, as well as the prevention and control of infection.

Identification of Familial Infections Using Multilocus Microsatellite Typing in Tinea Corporis due to Microsporum canis.

Microsporum canis is a type of dermatophyte that causes zoonotic dermatophytosis in cats and dogs. We report three cases of tinea corporis due to M. canis from a single household with a domestic cat as a pet. The cases included a woman in her thirties (mother), a girl in her teens (older sister), and a girl in her teens (younger sister). Following sudden hair loss in the domestic cat, annular erythema with pruritus and scales appeared on the face, neck, and limbs of the older sister, younger sister, and mother, sequentially; they subsequently visited our hospital. Potassium hydroxide direct microscopy revealed filamentous fungi on all three women. In addition, short-haired colonies with a white to yellowish-white color and extending in a radial manner were found in cultures using a flat plate agar medium. A slide culture with the same medium indicated pointed spindle-shaped macroconidia with 7-8 septa. Therefore, the cases were diagnosed as tinea corporis due to M. canis. Genetic analysis of the cells of the cat and the mother, older sister, and younger sister using multilocus microsatellite typing (MLMT) indicated that all cases were classified into the same genotype, suggesting that the transmission route of these cases was familial. Here, we show that MLMT is useful in identifying the infection route in cases of tinea corporis due to M. canis.

Osteomyelitis by Microsporum canis and Staphylococcus spp. in cat (Felis catus) - case report.

BACKGROUND: Staphylococcus spp and Microsporum canis are zoonotic microorganisms which can cause infections and systemic diseases. The bone infection is usually caused by invasion of pathogen through the hematologic route. Mixed osteomyelitis caused by bacteria and fungi is rare, and to date, there have been no reports of mixed osteomyelitis with Staphylococcus spp. and Microsporum canis. CASE PRESENTATION: This essay reports an atypical presentation of mixed osteomyelitis (Staphylococcus spp. and Microsporum canis) in a domestic cat. A 15-month-old female Persian cat was presented to a veterinary service; the main complaint was the appearance of a nodule in the mandibular ventral rostral region. A radiographic exam performed on the animal showed proliferative and osteolytic bone lesions. The patient was submitted to a biopsy for histopathological evaluation, along with bacterial and fungal cultures. Results showed mixed osteomyelitis by Staphylococcus spp. and Microsporum canis. Microbial Sensitivity Test was performed to choose a more suitable treatment. Two surgical procedures were executed to resect and curette the lesion, and treatments with anti-inflammatory, antibiotic, and antifungal drugs were established, showing a positive clinical evolution. After 8 months of treatment, the patient's owner moved to a different city, and the animal was seen by other veterinarians, who followed along with the same treatment. However, due to complications and a diminishing quality of life over 4 years of diagnosis, the patient was euthanized. CONCLUSION: Given the above, mixed osteomyelitis is difficult to treat and can cause losses of life quality resulting death, especially in infections where M. canis is the agent causing the disease. Bacterial osteomyelitis is more frequently reported. But the lack of investigation of microorganisms other than bacteria, such as fungal cases, may imply in underdiagnosed cases. Treatment of osteomyelitis can be difficult considering the difficulties in isolating the pathological agent, resistance to the drug used, prolonged treatment time, and cost.

The inhibitory effects of zinc oxide nanoparticles on clinical isolates of Microsporum canis in dogs and cats.

INTRODUCTION: Microsporum canis is the most common dermatophyte infecting pets and their owners, and its long duration of treatment and increasing rate of drug resistance have caused the attention of researchers to be directed towards the use of nanoparticles and new alternatives for treatment. This study investigated the antifungal effects of zinc oxide (ZnO) nanoparticles on clinical isolates of M. canis in dogs and cats and subtilisin 1 (SUB1) gene expression. MATERIALS AND METHODS: Zinc oxide nanoparticles were prepared using the wet chemical method at a concentration of 4000 ppm. Its antifungal potential was evaluated at concentrations of 62.5-4000 ppm by disk diffusion and microdilution methods against 10 isolates of M. canis. The effect of this product on SUB1 gene expression was investigated by quantitative real-time PCR method. RESULTS: The results of the disk diffusion test showed that the highest inhibitory diameter was at the highest concentration of ZnO nanoparticles (34 mm), and the inhibitory zone was observed in dilutions up to 250 ppm. The minimum inhibitory concentration (MIC) of ZnO nanoparticles was between 250 and 500 ppm, and the minimum fungicidal concentration was between 500 and 1000 ppm. There was a significant reduction in SUB1 gene expression in sub-MIC concentration (125-250 ppm) (p < 0.05). CONCLUSION: This study showed that ZnO nanoparticles have a concentration-dependent inhibitory effect on M. canis. Moreover, ZnO nanoparticles could decrease the expression of SUB1, an enzyme involved in fungi adhesion to the epidermis. Nevertheless, more studies must be done in the future to determine the possible side effects and safety of ZnO nanoparticles along with their efficacy in vivo.

In vitro virulotyping, antifungal susceptibility testing and DNA fingerprinting of Microsporum canis strains of canine and feline origin.

Microsporum canis is considered the common dermatophyte agent associated with ringworm in felines and canines. In the present study, we sampled n = 548 felines and canines for the probable isolation of M. canis. The rate of isolation from the cats and dogs was 70.27 % (52/74) and 1.68 % (8/474), respectively and Persian cats were found to be highly susceptible to M. canis infection. The strains were evaluated for their production of phospholipase, lipase, catalase, and hemolysis and their ability to grow at 35 â„ƒ. All the strains were identified as low producers of catalase and n = 17 strains exhibited high thermotolerance ability. Terbinafine was found to be the most effective antifungal drug and fluconazole was the least effective, in vitro. AFLP analysis revealed three genotypes of M. canis with 15 sub-clusters showing ≥ 90 % similarity and 7 sub-clusters exhibiting 100 % similarity. However, the phenotypic characters cannot be attributed based on the AFLP profiles.

Kerion Celsi in infants and children-A narrative review 2010-2023.

Kerion Celsi is an inflammatory, deep fungal infection of the scalp. It is rare in neonates but gets more common in children about 3 years and older. It represents with swelling, boggy lesions, pain, alopecia and purulent secretions. Secondary bacterial infection is not unusual after maceration. Extracutaneous manifestations include regional lymphadenopathy, fever and very rare fungemia. Id-reactions can occur. Diagnosis is based on clinical suspicion, clinical examination and medical history. Diagnosis should be confirmed by microscopy, fungal culture and molecular procedures. The most common isolated fungal species are anthropophilic Trichophyton (T.) tonsurans and zoophilic Microsporum (M.) canis, while geophilic species and moulds rarely cause Kerion Celsi. Treatment is medical with systemic and topical antifungals supplemented by systemic antibiotics when necessary, while surgery needs to be avoided. Early and sufficient treatment prevents scarring alopecia. The most important differential diagnosis is bacterial skin and soft tissue infections.

Subtilisin 3 production from Microsporum canis is independent of keratin substrate availability.

Dermatophytes are highly infectious fungi that cause superficial infections in keratinized tissues in humans and animals. This group of fungi is defined by their ability to digest keratin and encompasses a wide range of species. We investigated a critical adhesion protein, subtilisin 3, utilized by Microsporum canis during initial stages of infection, analyzing its production and expression under varying growth conditions. Additionally, as this protein must be expressed and produced for dermatophyte infections to occur, we developed and optimized a diagnostic antibody assay targeting this protein. Subtilisin 3 levels were increased in culture when grown in baffled flasks and supplemented with either l-cysteine or cat hair. As subtilisin 3 was also produced in cultures not supplemented with keratin or cysteine, this study demonstrated that subtilisin 3 production is not reliant on the presence of keratin or its derivatives. These findings could help direct future metabolic studies of dermatophytes, particularly during the adherence phase of infections.

PCR-based methods in detection and identification of dermatophytes in dogs and cats with suspected dermatophytosis in 2021 in Poland.

Dermatophytes from Microsporum, Trichophyton and Epidermophyton genera are divided into geophilic, zoophilic and anthropophilic species which cause skin infection in humans and wide group of animals, mainly mammals. Main species causing dermatophytosis in dogs and cats are Microsporum and Trichophyton. Conventional mycological diagnostic technique includes Saburaud Dextrose Agar (SAD) and others medium cultures, 10% KOH mount and direct microscopy of hairs and scraping. Molecular diagnostic become more frequent in veterinary practice due to shortening of waiting time. In this study we based on two PCR methods. The nested PCR amplified CHS1 gene for dermatophytes detection, and multiplex PCR coding ITS1 and ITS2 fragments for species identification of detected derpatophytes. Most frequently detected species was Microsporum canis, mainly in young cats. Geophilic Microsporum gypseum and anthropophilic Trichophyton rubrum was found primarily in dogs. Molecular methods in dermatophytosis identification are rapid in contrast to routinely, long lasting culture.

Nannizzia species causing dermatophytosis in cats and dogs: First report of Nannizzia incurvata as an etiological agent in Brazil.

Dermatophytosis is a superficial cutaneous infection, most commonly caused by fungal species such as Microsporum canis, Nannizzia gypsea (Microsporum gypseum), and Trichophyton mentagrophytes in dogs and cats. The zoonotic potential of these species is concerning, as companion animals are increasingly close to their owners. Therefore, the objectives of the study were to evaluate the current prevalence of Nannizzia-causing canine and feline dermatophytosis in Curitiba and Metropolitan Region, as well as perform phenotypic and phylogenetic characterizations of these isolates. Thus, 241 skin and fur samples from 163 dogs and 78 cats were analyzed from 2020 to 2021. The samples were obtained from animals of three sources: Veterinary Hospital of the Federal University of Paraná, animal shelters, and private clinics. The diagnosis was performed through phenotypic characterization and sequencing ITS rDNA region. Among 97 positive samples for dermatophytes, Nannizzia was identified in 14 (14.4%) samples, while other dermatophyte genera were found in the remaining 83 (85.6%) samples. Among the canine samples, nine (90%) were N. gypsea, and one (10%) was N. incurvata. Whereas in feline samples, three (75%) were N. gypsea, and one (25%) was N. incurvata. It was concluded that among 97 animals infected with dermatophytes, dogs (24.4%; 10/41) were significantly more affected by Nannizzia than cats (7.1%; 4/56) (P < .05). According to molecular analyses, the ITS rDNA region provided satisfactory results for species-level identification of Nannizzia, confirming the first report of N. incurvata as an etiological agent of canine and feline dermatophytosis in Brazil.

Nannizzia genus affected significantly more dogs (24.4%) than cats (7.1%) (P < .05). The ITS rDNA exhibited higher accuracy for identifying dermatophytes compared to phenotypic diagnosis, allowing the confirmation of the first reports of N. incurvata as an etiological agent of dermatophytosis in dogs and cats in Brazil.

Tiña por Nannizzia nana: caso clínico y revisión bibliográfica / Ringworm by Nannizzia nana: Clinical case and literature review

Introducción Las dermatofitosis humanas son el grupo más extendido de infecciones causadas por hongos. Estos son capaces de invadir los tejidos que contienen queratina de los animales. Nannizzia nana (N. nana) puede causar tiña en cerdos y que de manera excepcional puede producir infecciones en humanos. Métodos Realizamos una búsqueda en PubMed de artículos publicados desde el 1 de enero de 1990 hasta el 31 de marzo del 2022 para identificar casos adicionales. Los términos de búsqueda empleados fueron «Microsporum nanum» y «Nannizzia nana». Resultados Tras la revisión bibliográfica identificamos un total 16 casos de dermatofitosis por N. nana desde 1990. En la mayoría de los pacientes, el diagnóstico clínico fue tinea corporis y los antifúngicos más utilizados fueron terbinafina y griseofulvina. Conclusión N. nana es una especie de dermatofito aislada infrecuentemente en humanos, pero que representa una fuente potencial de dermatofitosis en personas que entran en contacto directo o indirecto con animales y con el suelo (AU)

Introduction Human dermatophytoses are the most widespread infections caused by fungi. These are capable of invading the keratin-containing tissues of animals. Nannizzia nana (N. nana) can cause ringworm in pigs and rarely cause infections in humans. Methods We conducted a search using PubMed for articles published from January 1, 1990 to March 31, 2022 to identify additional cases. The search terms used were “Microsporum nanum” and “Nannizzia nana”. Results After reviewing the literature, we identified a total of 16 cases of dermatophytosis due to N. nana since 1990. In most of the patients, the clinical diagnosis was tinea corporis and the most widely used antifungals were: terbinafine and griseofulvin. Conclusion N. nana is a dermatophyte species isolated infrequently in humans, but it represents a potential source of dermatophytosis in people who come into direct or indirect contact with animals and soil (AU)

Multilocus Microsatellite Analysis of the Molecular Epidemiology of Microsporum canis Isolated in Japan.

Microsporum canis, a major causative agent of zoonotic dermatophytosis, has become prevalent in Japan. Molecular epidemiological surveys using multilocus microsatellite typing (MLMT), a sensitive genotyping tool for fungi, have been conducted to reveal intraspecies polymorphisms of M. canis.The present study utilized MLMT optimized for Japanese strains of M. canis to analyze epidemic trends of fungal infection. Six individual loci were targeted; namely, MS1, 2, 4, 5, 6, and 7. Analysis of data from 1974 through 2022 identified 416 strains, which were sorted into 60 genotypes by MLMT.The major genotypes showed changes in dominance during this period-changes that may reflect historical increases and decreases in the numbers of patients infected with M. canis patients. The main origins of infection included animal breeders and pet stores, as well as stray cat communities. Forty-nine episodes of familial outbreaks and cohabitant animal infections were recorded, and genotypes responsible for each episode were determined. MLMT analysis is not only a robust tool to understand population structures, but likely the most suitable method for tracking M. canis infections.

Improved effectiveness of an increased dose of griseofulvin for treating Tinea capitis among refugee children in Israel: A retrospective cohort study.

BACKGROUND: Tinea capitis (TC), a fungal infection that occurs in children, is primarily caused by dermatophytes such as Trichophyton and Microsporum species. For Trichophyton species, treatment with terbinafine is considered more effective than griseofulvin treatment. Specific populations, such as refugee children, are more susceptible to TC. OBJECTIVE: This study aimed to describe and compare the response to treatment among Israeli and refugee children with TC. PATIENTS/METHODS: We retrospectively reviewed data collected on refugee and Israeli children with TC between January 2004 and January 2020. RESULTS: Overall, 3358 children with TC (refugees: 1497; Israelis: 1861) were identified. Among these, 86% of the refugee children had TC caused by Trichophyton violaceum, 65% of the Israeli children had TC caused by Microsporum canis and 83% of all children were treated with griseofulvin. Overall, 14% of the refugees showed a partial response to a griseofulvin dose of ≤25 mg/kg/day; however, they showed a complete response upon increasing the dose to ≥30 mg/kg/day. No significant adverse effects were observed. CONCLUSION: The over-crowded day care centres and dense living make refugee children more susceptible to TC than the general population, and griseofulvin dosage adjustment is necessary. TC, due to Trichophyton species, could benefit from receiving an increased dose of griseofulvin in a suspension form, which is cheaper than terbinafine.

The Epidemiology of Tinea Capitis in Guangxi Province, China.

The aim of this study was to analyze the epidemiological characteristics and pathogen spectrum of tinea capitis in Guangxi, southern China. A multicenter prospective descriptive study was conducted in 8 hospitals across Guangxi. From January 2019 to July 2022, one hundred seventy-one (171) patients diagnosed with tinea capitis were included. Demographic data, risk factors, and fungal data were collected. If necessary, species were further identified by morphological or molecular sequencing in the central laboratory. Of the 171 cases of tinea capitis, 74.3% occurred in patients aged 2-8 years. Children with tinea capitis were mainly boys (59.6%) and were more likely than adults to have a history of animal contact (44.2% vs. 33.3%) and zoophilic dermatophyte infection (76.9% vs. 46.7%, P = 0.008). The adults were mainly female (53%) and were more likely than children to have a history of infection with anthropophilic organisms (53.3% vs. 18.9%). The causative agents of tinea capitis in Guangxi were diverse, and the most common pathogen was Microsporum canis (M. cani, n = 98, 62%), followed by Trichophyton mentagrophytes (T. mentagrophytes n = 18, 11.4%) and Trichophyton tonsurans (T. tonsurans n = 12, 7.6%). In addition, tinea capitis caused by Nannizzia incurvata (N. incurvata) and Trichophyton verrucosum (T. verrucosum) was detected in the study. Notably, the proportion of patients with kerion in the study was 41.5% (n = 71), and most of those patients were children (n = 68), especially neglected children living in the rural mountainous areas of Guangxi, where they were unable to receive timely diagnosis and appropriate treatment. In conclusion, the causative agents of tinea capitis in Guangxi, South China, are diverse, and the incidence of kerion is high, indicating that diagnosis and treatment modalities in the region remain grossly inadequate. Clinicians and policy-makers should collaborate to adopt public health strategies to control the disease.

Comparative analysis of whole genomes and transcriptomes of Microsporum canis from invasive dermatophytosis and tinea capitis.

ABSTRACTGenomes of strains of the zoophilic dermatophyte Microsporum canis from invasive (disseminated and subcutaneous) and noninvasive (tinea capitis) infections were compared. Especially the disseminated strain showed significant syntenic rearrangements, including multiple translocations and inversions, and numerous SNPs and Indels in comparison to the noninvasive strain. In transcriptome analysis, both invasive strains were enriched for GO pathways related to components of the membrane, iron binding and heme binding, which possibly enables them to invade deeper into dermis and blood vessels. At 37 °C, invasive strains showed gene expression enriched for DNA replication, mismatch repair, N-glycan biosynthesis and ribosome biogenesis. The invasive strains were slightly less susceptible to multiple antifungal agents suggesting that acquired elevated drug resistance might be involved in the refractory disease courses. Patient with disseminated infection failed to respond to a combined antifungal treatment with itraconazole, terbinafine, fluconazole and posaconazole.

Fatal dermatophytic pseudomycetoma in a patient with non-HIV CD4 lymphocytopenia.

Dermatophytic pseudomycetoma is a rare invasive infection, involving both immunocompetent and immunocompromised individuals. Since the discovery of inherited immune disorders such as the impairment of CARD9 gene, extended dermatophyte infections are mostly ascribed to any of these host factors. This study is to present and explore the potential causes in a fatal dermatophytic pseudomycetoma patient. We present a chronic and deep pseudomycetoma caused by the common dermatophyte Microsporum canis which ultimately led to the death of the patient. Mycological examination, genetic studies and host immune responses against fungi were performed to explore the potential factors. The patient had decreased lymphocyte counts with significantly reduced CD4+ T cells, although all currently known genetic parameters proved to be normal. Through functional studies, we demonstrated that peripheral blood mononuclear cells from the patient showed severe impairment of adaptive cytokine production upon fungus-specific stimulation, whereas innate immune responses were partially defective. This is, to our knowledge, the first report of fatal dermatophytic pseudomycetoma in a patient with non-HIV CD4 lymphocytopenia, which highlights the importance of screening for immune deficiencies in patients with deep dermatophytosis.

Neglected Adult Tinea Capitis in South China: A Retrospective Study in Nanchang, Jiangxi Province, from 2007 to 2021.

Tinea capitis (TC) in adults is much less frequently diagnosed in comparison to TC in children. In this study, we explored retrospectively adult TC in a specialized dermatology hospital, located in South China, during the years 2007-2021. Among 1037 TC cases, 168 (16.2%) patients were older than 18 years. The majority of adults with TC, 77.38% (130/168), were older than 40, with a peak in the age of 51-60 years (40/168, 23.81%). Before presenting at our hospital, many of patients did not got proper treatment due to misdiagnosis or simply did not consulted an appropriate clinic. 60.71% (102/168) of the patients reported symptoms lasting for more than 1 year and 29.76% (50/168) reported chronic scalp problems of at least 10 years. And 27.38% (46/168) of the patients had an immunocompromised status, including long-term use of corticosteroids shampoo, type 2 diabetes mellitus (DM), psoriasis vulgaris, rheumatoid arthritis, systemic lupus erythematosus or bullous pemphigoid. As for clinical presentation, 87.5% (147/168) of the cases presented as black dot type of TC and anthropophilic dermatophytes were the predominant etiology, with Trichophyton violaceum (126), T. tonsurans (15), T. rubrum (8) and T. shoenleinii (6). Grey patch type of TC (3.57%, 6/168) was seldom in Jiangxi Province and zoophilic/geophilic dermatophytes were rare. Our study indicates that anthropophilic Trichophyton species can cause long-lasting TC in adults. Not in all cases, the manifestation had symptom clearly indicating a dermatophyte-related TC. Thus, patients with long-lasting scalp inflammation, also older ones, should be examined for the presence of dermatophyte-related TC.

Kerion Celsi due to Microsporum canis in an Adult Woman, Treated Successfully with Fosravuconazole.

A 64-year-old woman presented with a fist-sized, severely painful lesion with scales, crusts, pustules, erythema with subcutaneous abscess, and hair loss on the left temporal region. Direct microscopic examination revealed a large number of spores around the hair, which indicated ectothrix hair invasion, and some hyphae were also found. Histopathological examination showed significant inflammatory cell infiltration from the dermis to the subcutaneous tissues and into the hair follicles, destruction of the hair follicles with granulomatous reactions, and fungal masses along the hair within the hair follicles. Microsporum canis was identified based on morphological features via culture method and molecular biological analysis of the internal transcribed spacer region DNA sequence. The patient was diagnosed with kerion celsi caused by M. canis. For treatment of kerion celsi, we chose an oral antifungal agent, fosravuconazole (FRVCZ), which has been available since 2018 only in Japan. Clinical symptoms were cured in 12 weeks without scarring. No side effects were observed during oral administration of FRVCZ. The results of our case and several previous reports suggest that FRVCZ is effective in treating various types of dermatomycoses.

Pediatric tinea capitis in Jilin Province: analyzing previous results from a new perspective.

OBJECTIVES: To investigate the current etiological, diagnostic, and therapeutic characteristics of tinea capitis in children in Jilin Province. METHODS: Sixty pediatric patients with tinea capitis were enrolled between August 2020 and December 2021. Data on calcofluor white (CFW) fluorescence microscopy, fungal culture, Wood's lamp examination, dermoscopy, treatment, and follow-up were collected and analyzed. RESULTS: 1. Of all the enrolled patients, 48 had a history of animal contact, mostly with cats and dogs. Fifty-one strains were isolated, of which 46 were Microsporum canis (M. canis). 2. All enrolled patients were examined using fluorescence microscopy, and 59 were positive. Forty-one cases of tinea alba were examined using Wood's lamp, and 38 were positive. Forty-two cases of tinea alba were examined using dermoscopy, and 39 demonstrated specific signs. Effective treatment manifested as a fading bright green fluorescence, decreased mycelial/spore load, reduced specific dermoscopic signs, and hair regrowth. 3. Treatment was terminated in 23 and 37 cases based on mycological and clinical cures, respectively. No recurrence occurred during follow-up. CONCLUSION: 1. M. canis is the predominant pathogen causing tinea capitis in children in Jilin Province. Animal contact is considered the main risk factor. 2. CFW fluorescence microscopy, Wood's lamp, and dermoscopy can be used to diagnose ringworms and follow-up patients. 3. Both mycological and clinical cures can be the endpoint of adequate treatment for tinea capitis.