Trichophyton tonsurans is a fungus that causes tinea capitis (scalp ringworm) infection worldwide, with high endemicity in Latin America (mainly northern Brazil), Mexico, and Africa. Because of changes in worldwide travel and immigration trends, the prevalence of T. tonsurans infections has increased in the United States and Canada in recent decades. T. tonsurans is responsible for most pediatric tinea capitis cases in the United States.
According to studies, T. tonsurans-related tinea capitis cases have increased significantly in recent years. Research carried out in the vicinity of San Francisco between 1974 -1994, for example, found a substantial rise in T. tonsurans infection. T. tonsurans comprised 41.6 % of cases in the 1970s but climbed to 87% in the 1990s.
Although the precise means of T. tonsurans dissemination is unknown, transmission is frequently associated with families, schools, other institutions, or barbershops. Interaction with infected individuals and the use of shared assets and amenities like mattress pillows, couches, rugs, and even pets can result in the transmission of T. tonsurans.
Children are most vulnerable to tinea capitis triggered by this species, whereas adult infections often present as tinea corporis.Because of its endurance in indoor environments and potential to be spread by asymptomatic carriers, Trichophyton tonsurans has been identified as a significant pathogen generating family and institutional outbreaks. Notably, T. tonsurans was identified from contact sports athletes in a Japanese investigation, with most strains hailing from judo practitioners.
These strains were classified into three subtypes relying on the non-transcribed spacer (NTS) section of the ribosomal RNA gene, having subtype I being the most common.Furthermore, tinea unguium (nail infections) is more common in older people, but tinea capitis is more common in youngsters. In 2019, the incidence of T. tonsurans nail infection was around 6% in older individuals & 1.4% in youngsters.
Classification and Structure:
Kingdom: Fungi
Phylum: Ascomycota
Class: Eurotiomycetes
Order: Onygenales
Family: Arthrodermataceae
Genus:Trichophyton
Species:Trichophyton tonsurans
Hyphae: Multicellular, tubular structures that branch and form a mycelium network. The hyphal cells are septate with cross-walls that divide them into segments. They have a 2-4 µm diameter and a length of 10-20 µm.
One or two nuclei per hyphal cell are spherical, ellipsoidal, or slightly irregular in shape. The nuclei have a 0.6-1.5 µm diameter and contain condensed chromatin.
Cell wall:Trichophyton tonsurans have a two-layered cell wall. The internal layer is thick (0.08-0.11 µm), moderately electron-dense, while the external layer is thin (0.02-0.03 µm), dark, loose, and often interrupted with an irregular contour. The cell wall gives support & protection to the cell.
Vacuoles: One or more vacuoles per hyphal cell are small (0.3-0.5 µm) and can be single or polymorphic in shape. The vacuoles contain membranous fragments, fibrillar and granular materials, or protein globules. They perform functions such as storage, digestion, or osmoregulation.
Trichophyton tonsurans produce various types of spores for reproduction. These include conidia and chlamydospores. Conidia are asexual spores formed by budding or fragmentation of hyphae. They can be further classified as microconidia and macroconidia.
Trichophyton tonsurans is a member of the Arthroderma vanbreuseghemii complexity with a negative (-) mating type, whereas Trichophytonequinum has a positive (+) mating type. These two varieties are conspecific, meaning they belong to the same biological species. AndT. tonsurans 30-kDa allergen is also identified, which triggers immediate hypersensitivity.
According to research, Trichophyton tonsurans isolates from diverse places have been discovered to have different molecular kinds. For example, six molecular kinds (A to F) were discovered in Japan between 2011 and 2015. kind A was linked to Brazil, Type B to Mexico, Type C to Africa, Type D to North America, Type E to Europe, & Type F was entirely novel to the region.
Trichophyton tonsurans strains that include NBRC5928, CN01111901, LSEMBox12-1126, & LSEMBox17-1636 have aided in the understanding of its virulence & genetic features.
Trichophyton tonsurans are harmful due to the presence of numerous virulence genes. These are some examples:
CarbM14 is a gene that encodes a subtilisin-like protease involved in the degradation of keratin and other proteins found in host tissues or the immune system.
Sub2: It also encodes a subtilisin-like protease, which aids in the degradation of keratin and other proteins in host tissues or the immune system.
CER: It encodes a cerato-platanin protein that can cause inflammation and tissue damage when activated on host cells.
URE: It encodes a urease enzyme that hydrolyzes urea and produces ammonia. This process can raise the pH level, making the atmosphere more conducive to fungus development.
T. tonsurans invades the hair shaft after infecting the host, causing hair damage & sporulation within the hair. It causes the hair to burst and curl, resulting in a black dot on the head in the case of tinea capitis.
During T. tonsurans pathogenesis, the fungus creates proteases that hydrolyze structural proteins, specifically keratin present in hair. Peak protease production occurs while the sporulation phase of the infection, which generally occurs between days 18 to 22. The production of protease & the subsequent degradation of keratin triggers the breakdown of the hair structure.
T. tonsurans can create melanin, an antioxidant molecule that shields the fungus from harmful UV rays. This melanin generation is especially critical for the fungus’ survival in sunny areas where infection is common.
The lesion may be a raised border with limited hair loss in the initial stages of T. tonsurans infection. However, when the illness spreads, infected hairs drop off at the scalp surface, resulting in the scaly look & appearance of short hair stubs. Twisted hairs are sometimes seen in keratotic follicular papules. Inflammatory reactions like edema, abscesses, or severely inflammatory kerion are also possible. While hair can grow back, some scars may remain.
The interaction between T. tonsurans and host epithelial cells is facilitated by carbohydrate-specific adhesins that recognize sugars on the surface of host cells. This recognition process is essential for the immune response, allowing the host to identify the pathogen.
Studies have indicated that T. tonsurans may evade the mannose receptors on dendritic cells and macrophages, thus preventing an effective immune response. This evasion mechanism interferes with the recognition of the pathogen and inhibits the activation of cytotoxic immune responses, contributing to the establishment of the infection.
The activation of innate immunity is a crucial element of the immunological response to T. tonsurans. On the other hand, it has been shown in studies to down-regulate receptors that involve Toll-like receptors (TLRs), human beta-defensins (HBDs), & TLR4, all of which are important for initiating the proper immune response. T. tonsurans‘ manipulation weakens the host’s ability to establish an effective defense against the virus, contributing to Dermatophytosis’s chronic nature.
T. tonsurans infection is mediated by cell-mediated immunity, which involves T lymphocyte activation. Chronic dermatophytosis infections have been linked to decreased T cell cytotoxic responses to the fungal antigen. On the other hand, healthy people have an effective cytotoxic reaction that damages the fungal hyphae. Restoring cell-mediated immunity may be critical for more effective dermatophytosis treatment.
Trichophyton tonsurans induce Dermatophytosis, which can present in various clinical manifestations depending on the location and severity of infection. Tinea capitis & tinea corporis are the most prevalent manifestations.
Tinea capitis usually affects the scalp and is marked by scaling, alopecia (hair loss), erythema (redness), and, on rare occasions, pustules or inflamed nodules known as kerions. Tenderness may accompany these kerions, causing severe discomfort.
Tinea corporis is a skin infection that manifests as annular (ring-shaped) lesions with elevated borders & a transparent core.Tinea barbae, which affects the beard area, & tinea faciei, which affects the face, are two types of Trichophyton tonsurans infection.
Tinea manuum is an infection of the hand, whereas tinea pedis is an infection of the foot, sometimes known as athlete’s foot. Tinea unguium is a nail infection that causes coloring, thickness, and brittleness. Topical steroids might alter the clinical appearance in some situations, resulting in tinea incognito.
Culture method: Dermatophyte Test Medium/ DTM is a specialized agar medium that contains inhibitors to suppress the growth of bacteria and other fungi while promoting the growth of Trichophyton species. It typically consists of a basal medium, such as Sabouraud dextrose agar supplemented with cycloheximide (to inhibit the growth of non-dermatophyte fungi) and phenol red. It contains the substrate, such as casein or hair, as a nutrient source for dermatophytes.
When Trichophyton tonsurans is inoculated onto DTM, it utilizes the substrate and produces enzymatic activity that changes the medium’s color. Typically, the medium starts as a reddish-orange color. As the fungus grows and metabolizes the substrate, it releases alkaline by-products, causing the medium to turn yellow or pink.Colonies exhibit variable colors, including white, yellow, gray, tan, or brownish. The surface texture of the colonies can also vary, appearing powdery, suede-like, or granular.
Direct microscopy of clinical specimens, such as skin scrapings or hair samples, allows for observing fungal structures. Trichophyton tonsurans typically produce septate hyphae, long, tubular structures with cross-walls. These hyphae may show branching and form a network called mycelium. Microscopic examination can also reveal the presence of spores, such as conidia or chlamydospores, which are reproductive structures of the fungus.
PCR assay: In Trichophyton tonsurans, a PCR test can be constructed by targeting the nuclear ribosomal internal transcribed spacer 1 (ITS1) region, positioned between the 18S and 5.8S rDNA. Fungal DNA is isolated from culture colonies or hairbrush samples and used as a template in a PCR process.
The PCR primers selectively bind to the ITS1 region of Trichophyton tonsurans DNA, enabling target sequence amplification. Trichophyton tonsurans can be confirmed by examining the PCR results, allowing for a quick and reliable diagnosis of the fungal infection. This test provides a reliable and specific approach for detecting T. tonsurans from clinical isolates or hairbrush samples, allowing the infection to be identified and managed immediately.
LAMP assay: Specific primers are constructed in the LAMP assay to detect various areas on the target gene of Trichophyton tonsurans. This test uses a strand displacement reaction & runs at a constant temperature, eliminating the need for complicated procedures. The LAMP process needs mixing the sample, primers, and DNA polymerase, then executing a 70-minute incubation period.
Using loop primers has been shown to cut reaction time even further. The LAMP assay for T. tonsurans uses a commercial DNA amplification kit at a particular temperature. Trichophyton tonsurans can be detected and differentiated using the amplification & dissociation processes. The incubation time is set at 70 minutes for proper diagnosis.
Avoiding direct contact with infected people, their belongings, and contaminated surfaces can help lower the risk of transmission. Personal goods such as combs, brushes, hats, & towels should not be shared.
Cleaning and sanitizing surfaces that encounter possibly infected people, like shower floors, gym equipment, & locker rooms, regularly can aid in the elimination of fungal spores & the prevention of their spread.
Wearing breathable shoes and socks that drain away moisture can help lower the risk of fungus infections. It is also critical to avoid wearing snugly fitted shoes or moist garments for extended periods.
Trichophyton tonsurans is a fungus that causes tinea capitis (scalp ringworm) infection worldwide, with high endemicity in Latin America (mainly northern Brazil), Mexico, and Africa. Because of changes in worldwide travel and immigration trends, the prevalence of T. tonsurans infections has increased in the United States and Canada in recent decades. T. tonsurans is responsible for most pediatric tinea capitis cases in the United States.
According to studies, T. tonsurans-related tinea capitis cases have increased significantly in recent years. Research carried out in the vicinity of San Francisco between 1974 -1994, for example, found a substantial rise in T. tonsurans infection. T. tonsurans comprised 41.6 % of cases in the 1970s but climbed to 87% in the 1990s.
Although the precise means of T. tonsurans dissemination is unknown, transmission is frequently associated with families, schools, other institutions, or barbershops. Interaction with infected individuals and the use of shared assets and amenities like mattress pillows, couches, rugs, and even pets can result in the transmission of T. tonsurans.
Children are most vulnerable to tinea capitis triggered by this species, whereas adult infections often present as tinea corporis.Because of its endurance in indoor environments and potential to be spread by asymptomatic carriers, Trichophyton tonsurans has been identified as a significant pathogen generating family and institutional outbreaks. Notably, T. tonsurans was identified from contact sports athletes in a Japanese investigation, with most strains hailing from judo practitioners.
These strains were classified into three subtypes relying on the non-transcribed spacer (NTS) section of the ribosomal RNA gene, having subtype I being the most common.Furthermore, tinea unguium (nail infections) is more common in older people, but tinea capitis is more common in youngsters. In 2019, the incidence of T. tonsurans nail infection was around 6% in older individuals & 1.4% in youngsters.
Classification and Structure:
Kingdom: Fungi
Phylum: Ascomycota
Class: Eurotiomycetes
Order: Onygenales
Family: Arthrodermataceae
Genus:Trichophyton
Species:Trichophyton tonsurans
Hyphae: Multicellular, tubular structures that branch and form a mycelium network. The hyphal cells are septate with cross-walls that divide them into segments. They have a 2-4 µm diameter and a length of 10-20 µm.
One or two nuclei per hyphal cell are spherical, ellipsoidal, or slightly irregular in shape. The nuclei have a 0.6-1.5 µm diameter and contain condensed chromatin.
Cell wall:Trichophyton tonsurans have a two-layered cell wall. The internal layer is thick (0.08-0.11 µm), moderately electron-dense, while the external layer is thin (0.02-0.03 µm), dark, loose, and often interrupted with an irregular contour. The cell wall gives support & protection to the cell.
Vacuoles: One or more vacuoles per hyphal cell are small (0.3-0.5 µm) and can be single or polymorphic in shape. The vacuoles contain membranous fragments, fibrillar and granular materials, or protein globules. They perform functions such as storage, digestion, or osmoregulation.
Trichophyton tonsurans produce various types of spores for reproduction. These include conidia and chlamydospores. Conidia are asexual spores formed by budding or fragmentation of hyphae. They can be further classified as microconidia and macroconidia.
Trichophyton tonsurans is a member of the Arthroderma vanbreuseghemii complexity with a negative (-) mating type, whereas Trichophytonequinum has a positive (+) mating type. These two varieties are conspecific, meaning they belong to the same biological species. AndT. tonsurans 30-kDa allergen is also identified, which triggers immediate hypersensitivity.
According to research, Trichophyton tonsurans isolates from diverse places have been discovered to have different molecular kinds. For example, six molecular kinds (A to F) were discovered in Japan between 2011 and 2015. kind A was linked to Brazil, Type B to Mexico, Type C to Africa, Type D to North America, Type E to Europe, & Type F was entirely novel to the region.
Trichophyton tonsurans strains that include NBRC5928, CN01111901, LSEMBox12-1126, & LSEMBox17-1636 have aided in the understanding of its virulence & genetic features.
Trichophyton tonsurans are harmful due to the presence of numerous virulence genes. These are some examples:
CarbM14 is a gene that encodes a subtilisin-like protease involved in the degradation of keratin and other proteins found in host tissues or the immune system.
Sub2: It also encodes a subtilisin-like protease, which aids in the degradation of keratin and other proteins in host tissues or the immune system.
CER: It encodes a cerato-platanin protein that can cause inflammation and tissue damage when activated on host cells.
URE: It encodes a urease enzyme that hydrolyzes urea and produces ammonia. This process can raise the pH level, making the atmosphere more conducive to fungus development.
T. tonsurans invades the hair shaft after infecting the host, causing hair damage & sporulation within the hair. It causes the hair to burst and curl, resulting in a black dot on the head in the case of tinea capitis.
During T. tonsurans pathogenesis, the fungus creates proteases that hydrolyze structural proteins, specifically keratin present in hair. Peak protease production occurs while the sporulation phase of the infection, which generally occurs between days 18 to 22. The production of protease & the subsequent degradation of keratin triggers the breakdown of the hair structure.
T. tonsurans can create melanin, an antioxidant molecule that shields the fungus from harmful UV rays. This melanin generation is especially critical for the fungus’ survival in sunny areas where infection is common.
The lesion may be a raised border with limited hair loss in the initial stages of T. tonsurans infection. However, when the illness spreads, infected hairs drop off at the scalp surface, resulting in the scaly look & appearance of short hair stubs. Twisted hairs are sometimes seen in keratotic follicular papules. Inflammatory reactions like edema, abscesses, or severely inflammatory kerion are also possible. While hair can grow back, some scars may remain.
The interaction between T. tonsurans and host epithelial cells is facilitated by carbohydrate-specific adhesins that recognize sugars on the surface of host cells. This recognition process is essential for the immune response, allowing the host to identify the pathogen.
Studies have indicated that T. tonsurans may evade the mannose receptors on dendritic cells and macrophages, thus preventing an effective immune response. This evasion mechanism interferes with the recognition of the pathogen and inhibits the activation of cytotoxic immune responses, contributing to the establishment of the infection.
The activation of innate immunity is a crucial element of the immunological response to T. tonsurans. On the other hand, it has been shown in studies to down-regulate receptors that involve Toll-like receptors (TLRs), human beta-defensins (HBDs), & TLR4, all of which are important for initiating the proper immune response. T. tonsurans‘ manipulation weakens the host’s ability to establish an effective defense against the virus, contributing to Dermatophytosis’s chronic nature.
T. tonsurans infection is mediated by cell-mediated immunity, which involves T lymphocyte activation. Chronic dermatophytosis infections have been linked to decreased T cell cytotoxic responses to the fungal antigen. On the other hand, healthy people have an effective cytotoxic reaction that damages the fungal hyphae. Restoring cell-mediated immunity may be critical for more effective dermatophytosis treatment.
Trichophyton tonsurans induce Dermatophytosis, which can present in various clinical manifestations depending on the location and severity of infection. Tinea capitis & tinea corporis are the most prevalent manifestations.
Tinea capitis usually affects the scalp and is marked by scaling, alopecia (hair loss), erythema (redness), and, on rare occasions, pustules or inflamed nodules known as kerions. Tenderness may accompany these kerions, causing severe discomfort.
Tinea corporis is a skin infection that manifests as annular (ring-shaped) lesions with elevated borders & a transparent core.Tinea barbae, which affects the beard area, & tinea faciei, which affects the face, are two types of Trichophyton tonsurans infection.
Tinea manuum is an infection of the hand, whereas tinea pedis is an infection of the foot, sometimes known as athlete’s foot. Tinea unguium is a nail infection that causes coloring, thickness, and brittleness. Topical steroids might alter the clinical appearance in some situations, resulting in tinea incognito.
Culture method: Dermatophyte Test Medium/ DTM is a specialized agar medium that contains inhibitors to suppress the growth of bacteria and other fungi while promoting the growth of Trichophyton species. It typically consists of a basal medium, such as Sabouraud dextrose agar supplemented with cycloheximide (to inhibit the growth of non-dermatophyte fungi) and phenol red. It contains the substrate, such as casein or hair, as a nutrient source for dermatophytes.
When Trichophyton tonsurans is inoculated onto DTM, it utilizes the substrate and produces enzymatic activity that changes the medium’s color. Typically, the medium starts as a reddish-orange color. As the fungus grows and metabolizes the substrate, it releases alkaline by-products, causing the medium to turn yellow or pink.Colonies exhibit variable colors, including white, yellow, gray, tan, or brownish. The surface texture of the colonies can also vary, appearing powdery, suede-like, or granular.
Direct microscopy of clinical specimens, such as skin scrapings or hair samples, allows for observing fungal structures. Trichophyton tonsurans typically produce septate hyphae, long, tubular structures with cross-walls. These hyphae may show branching and form a network called mycelium. Microscopic examination can also reveal the presence of spores, such as conidia or chlamydospores, which are reproductive structures of the fungus.
PCR assay: In Trichophyton tonsurans, a PCR test can be constructed by targeting the nuclear ribosomal internal transcribed spacer 1 (ITS1) region, positioned between the 18S and 5.8S rDNA. Fungal DNA is isolated from culture colonies or hairbrush samples and used as a template in a PCR process.
The PCR primers selectively bind to the ITS1 region of Trichophyton tonsurans DNA, enabling target sequence amplification. Trichophyton tonsurans can be confirmed by examining the PCR results, allowing for a quick and reliable diagnosis of the fungal infection. This test provides a reliable and specific approach for detecting T. tonsurans from clinical isolates or hairbrush samples, allowing the infection to be identified and managed immediately.
LAMP assay: Specific primers are constructed in the LAMP assay to detect various areas on the target gene of Trichophyton tonsurans. This test uses a strand displacement reaction & runs at a constant temperature, eliminating the need for complicated procedures. The LAMP process needs mixing the sample, primers, and DNA polymerase, then executing a 70-minute incubation period.
Using loop primers has been shown to cut reaction time even further. The LAMP assay for T. tonsurans uses a commercial DNA amplification kit at a particular temperature. Trichophyton tonsurans can be detected and differentiated using the amplification & dissociation processes. The incubation time is set at 70 minutes for proper diagnosis.
Avoiding direct contact with infected people, their belongings, and contaminated surfaces can help lower the risk of transmission. Personal goods such as combs, brushes, hats, & towels should not be shared.
Cleaning and sanitizing surfaces that encounter possibly infected people, like shower floors, gym equipment, & locker rooms, regularly can aid in the elimination of fungal spores & the prevention of their spread.
Wearing breathable shoes and socks that drain away moisture can help lower the risk of fungus infections. It is also critical to avoid wearing snugly fitted shoes or moist garments for extended periods.
Trichophyton tonsurans is a fungus that causes tinea capitis (scalp ringworm) infection worldwide, with high endemicity in Latin America (mainly northern Brazil), Mexico, and Africa. Because of changes in worldwide travel and immigration trends, the prevalence of T. tonsurans infections has increased in the United States and Canada in recent decades. T. tonsurans is responsible for most pediatric tinea capitis cases in the United States.
According to studies, T. tonsurans-related tinea capitis cases have increased significantly in recent years. Research carried out in the vicinity of San Francisco between 1974 -1994, for example, found a substantial rise in T. tonsurans infection. T. tonsurans comprised 41.6 % of cases in the 1970s but climbed to 87% in the 1990s.
Although the precise means of T. tonsurans dissemination is unknown, transmission is frequently associated with families, schools, other institutions, or barbershops. Interaction with infected individuals and the use of shared assets and amenities like mattress pillows, couches, rugs, and even pets can result in the transmission of T. tonsurans.
Children are most vulnerable to tinea capitis triggered by this species, whereas adult infections often present as tinea corporis.Because of its endurance in indoor environments and potential to be spread by asymptomatic carriers, Trichophyton tonsurans has been identified as a significant pathogen generating family and institutional outbreaks. Notably, T. tonsurans was identified from contact sports athletes in a Japanese investigation, with most strains hailing from judo practitioners.
These strains were classified into three subtypes relying on the non-transcribed spacer (NTS) section of the ribosomal RNA gene, having subtype I being the most common.Furthermore, tinea unguium (nail infections) is more common in older people, but tinea capitis is more common in youngsters. In 2019, the incidence of T. tonsurans nail infection was around 6% in older individuals & 1.4% in youngsters.
Classification and Structure:
Kingdom: Fungi
Phylum: Ascomycota
Class: Eurotiomycetes
Order: Onygenales
Family: Arthrodermataceae
Genus:Trichophyton
Species:Trichophyton tonsurans
Hyphae: Multicellular, tubular structures that branch and form a mycelium network. The hyphal cells are septate with cross-walls that divide them into segments. They have a 2-4 µm diameter and a length of 10-20 µm.
One or two nuclei per hyphal cell are spherical, ellipsoidal, or slightly irregular in shape. The nuclei have a 0.6-1.5 µm diameter and contain condensed chromatin.
Cell wall:Trichophyton tonsurans have a two-layered cell wall. The internal layer is thick (0.08-0.11 µm), moderately electron-dense, while the external layer is thin (0.02-0.03 µm), dark, loose, and often interrupted with an irregular contour. The cell wall gives support & protection to the cell.
Vacuoles: One or more vacuoles per hyphal cell are small (0.3-0.5 µm) and can be single or polymorphic in shape. The vacuoles contain membranous fragments, fibrillar and granular materials, or protein globules. They perform functions such as storage, digestion, or osmoregulation.
Trichophyton tonsurans produce various types of spores for reproduction. These include conidia and chlamydospores. Conidia are asexual spores formed by budding or fragmentation of hyphae. They can be further classified as microconidia and macroconidia.
Trichophyton tonsurans is a member of the Arthroderma vanbreuseghemii complexity with a negative (-) mating type, whereas Trichophytonequinum has a positive (+) mating type. These two varieties are conspecific, meaning they belong to the same biological species. AndT. tonsurans 30-kDa allergen is also identified, which triggers immediate hypersensitivity.
According to research, Trichophyton tonsurans isolates from diverse places have been discovered to have different molecular kinds. For example, six molecular kinds (A to F) were discovered in Japan between 2011 and 2015. kind A was linked to Brazil, Type B to Mexico, Type C to Africa, Type D to North America, Type E to Europe, & Type F was entirely novel to the region.
Trichophyton tonsurans strains that include NBRC5928, CN01111901, LSEMBox12-1126, & LSEMBox17-1636 have aided in the understanding of its virulence & genetic features.
Trichophyton tonsurans are harmful due to the presence of numerous virulence genes. These are some examples:
CarbM14 is a gene that encodes a subtilisin-like protease involved in the degradation of keratin and other proteins found in host tissues or the immune system.
Sub2: It also encodes a subtilisin-like protease, which aids in the degradation of keratin and other proteins in host tissues or the immune system.
CER: It encodes a cerato-platanin protein that can cause inflammation and tissue damage when activated on host cells.
URE: It encodes a urease enzyme that hydrolyzes urea and produces ammonia. This process can raise the pH level, making the atmosphere more conducive to fungus development.
T. tonsurans invades the hair shaft after infecting the host, causing hair damage & sporulation within the hair. It causes the hair to burst and curl, resulting in a black dot on the head in the case of tinea capitis.
During T. tonsurans pathogenesis, the fungus creates proteases that hydrolyze structural proteins, specifically keratin present in hair. Peak protease production occurs while the sporulation phase of the infection, which generally occurs between days 18 to 22. The production of protease & the subsequent degradation of keratin triggers the breakdown of the hair structure.
T. tonsurans can create melanin, an antioxidant molecule that shields the fungus from harmful UV rays. This melanin generation is especially critical for the fungus’ survival in sunny areas where infection is common.
The lesion may be a raised border with limited hair loss in the initial stages of T. tonsurans infection. However, when the illness spreads, infected hairs drop off at the scalp surface, resulting in the scaly look & appearance of short hair stubs. Twisted hairs are sometimes seen in keratotic follicular papules. Inflammatory reactions like edema, abscesses, or severely inflammatory kerion are also possible. While hair can grow back, some scars may remain.
The interaction between T. tonsurans and host epithelial cells is facilitated by carbohydrate-specific adhesins that recognize sugars on the surface of host cells. This recognition process is essential for the immune response, allowing the host to identify the pathogen.
Studies have indicated that T. tonsurans may evade the mannose receptors on dendritic cells and macrophages, thus preventing an effective immune response. This evasion mechanism interferes with the recognition of the pathogen and inhibits the activation of cytotoxic immune responses, contributing to the establishment of the infection.
The activation of innate immunity is a crucial element of the immunological response to T. tonsurans. On the other hand, it has been shown in studies to down-regulate receptors that involve Toll-like receptors (TLRs), human beta-defensins (HBDs), & TLR4, all of which are important for initiating the proper immune response. T. tonsurans‘ manipulation weakens the host’s ability to establish an effective defense against the virus, contributing to Dermatophytosis’s chronic nature.
T. tonsurans infection is mediated by cell-mediated immunity, which involves T lymphocyte activation. Chronic dermatophytosis infections have been linked to decreased T cell cytotoxic responses to the fungal antigen. On the other hand, healthy people have an effective cytotoxic reaction that damages the fungal hyphae. Restoring cell-mediated immunity may be critical for more effective dermatophytosis treatment.
Trichophyton tonsurans induce Dermatophytosis, which can present in various clinical manifestations depending on the location and severity of infection. Tinea capitis & tinea corporis are the most prevalent manifestations.
Tinea capitis usually affects the scalp and is marked by scaling, alopecia (hair loss), erythema (redness), and, on rare occasions, pustules or inflamed nodules known as kerions. Tenderness may accompany these kerions, causing severe discomfort.
Tinea corporis is a skin infection that manifests as annular (ring-shaped) lesions with elevated borders & a transparent core.Tinea barbae, which affects the beard area, & tinea faciei, which affects the face, are two types of Trichophyton tonsurans infection.
Tinea manuum is an infection of the hand, whereas tinea pedis is an infection of the foot, sometimes known as athlete’s foot. Tinea unguium is a nail infection that causes coloring, thickness, and brittleness. Topical steroids might alter the clinical appearance in some situations, resulting in tinea incognito.
Culture method: Dermatophyte Test Medium/ DTM is a specialized agar medium that contains inhibitors to suppress the growth of bacteria and other fungi while promoting the growth of Trichophyton species. It typically consists of a basal medium, such as Sabouraud dextrose agar supplemented with cycloheximide (to inhibit the growth of non-dermatophyte fungi) and phenol red. It contains the substrate, such as casein or hair, as a nutrient source for dermatophytes.
When Trichophyton tonsurans is inoculated onto DTM, it utilizes the substrate and produces enzymatic activity that changes the medium’s color. Typically, the medium starts as a reddish-orange color. As the fungus grows and metabolizes the substrate, it releases alkaline by-products, causing the medium to turn yellow or pink.Colonies exhibit variable colors, including white, yellow, gray, tan, or brownish. The surface texture of the colonies can also vary, appearing powdery, suede-like, or granular.
Direct microscopy of clinical specimens, such as skin scrapings or hair samples, allows for observing fungal structures. Trichophyton tonsurans typically produce septate hyphae, long, tubular structures with cross-walls. These hyphae may show branching and form a network called mycelium. Microscopic examination can also reveal the presence of spores, such as conidia or chlamydospores, which are reproductive structures of the fungus.
PCR assay: In Trichophyton tonsurans, a PCR test can be constructed by targeting the nuclear ribosomal internal transcribed spacer 1 (ITS1) region, positioned between the 18S and 5.8S rDNA. Fungal DNA is isolated from culture colonies or hairbrush samples and used as a template in a PCR process.
The PCR primers selectively bind to the ITS1 region of Trichophyton tonsurans DNA, enabling target sequence amplification. Trichophyton tonsurans can be confirmed by examining the PCR results, allowing for a quick and reliable diagnosis of the fungal infection. This test provides a reliable and specific approach for detecting T. tonsurans from clinical isolates or hairbrush samples, allowing the infection to be identified and managed immediately.
LAMP assay: Specific primers are constructed in the LAMP assay to detect various areas on the target gene of Trichophyton tonsurans. This test uses a strand displacement reaction & runs at a constant temperature, eliminating the need for complicated procedures. The LAMP process needs mixing the sample, primers, and DNA polymerase, then executing a 70-minute incubation period.
Using loop primers has been shown to cut reaction time even further. The LAMP assay for T. tonsurans uses a commercial DNA amplification kit at a particular temperature. Trichophyton tonsurans can be detected and differentiated using the amplification & dissociation processes. The incubation time is set at 70 minutes for proper diagnosis.
Avoiding direct contact with infected people, their belongings, and contaminated surfaces can help lower the risk of transmission. Personal goods such as combs, brushes, hats, & towels should not be shared.
Cleaning and sanitizing surfaces that encounter possibly infected people, like shower floors, gym equipment, & locker rooms, regularly can aid in the elimination of fungal spores & the prevention of their spread.
Wearing breathable shoes and socks that drain away moisture can help lower the risk of fungus infections. It is also critical to avoid wearing snugly fitted shoes or moist garments for extended periods.
Both our subscription plans include Free CME/CPD AMA PRA Category 1 credits.
Digital Certificate PDF
On course completion, you will receive a full-sized presentation quality digital certificate.
medtigo Simulation
A dynamic medical simulation platform designed to train healthcare professionals and students to effectively run code situations through an immersive hands-on experience in a live, interactive 3D environment.
medtigo Points
medtigo points is our unique point redemption system created to award users for interacting on our site. These points can be redeemed for special discounts on the medtigo marketplace as well as towards the membership cost itself.
Community Forum post/reply = 5 points
*Redemption of points can occur only through the medtigo marketplace, courses, or simulation system. Money will not be credited to your bank account. 10 points = $1.
All Your Certificates in One Place
When you have your licenses, certificates and CMEs in one place, it's easier to track your career growth. You can easily share these with hospitals as well, using your medtigo app.
