Trichophyton concentricum

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Trichophyton concentricum
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Eurotiomycetes
Order: Onygenales
Family: Arthrodermataceae
Genus: Trichophyton
Species:
T. concentricum
Binomial name
Trichophyton concentricum
R. Blanch (1896)
Synonyms

Trichophyton concentricum is an anthropophilic dermatophyte believed to be an etiological agent of a type of skin mycosis in humans, evidenced by scaly cutaneous patches on the body known as tinea imbricata. This fungus has been found mainly in the Pacific Islands and South America.

Contents

Growth and morphology

Trichophyton concentricum produce dense, slow-growing folded colonies which are mostly white to cream colored on Sabouraud's dextrose agar and their hyphae are normally branched, irregular and septate with antler tips resembling T.schoenleinii. The production of conidia is unusual, however when present, microconidia and macroconidia are smooth walled with a diameter of approximately 4 microns and 50 μm respectively. [1] Due to its resemblance to macroconidia, hyphae are sometimes falsely identified as macroconidia. These fungi are also considered to be osmotolerant because of their ability to grown small colonies on 5% NaCl media and are. Hair perforation assays are generally negative with T. concentricum and growth is poor at 37 °C. [2] While T. concentricum is considered to be independent of external vitamin sources, growth is more robust with thiamine supplementation. This characteristic feature is commonly used to distinguish between T. concentricum and T. schoeleinii. [3] Overall, the natural habitat and growth of T. concentricum is not well understood and further studies are required.[ citation needed ]

Reproduction

Trichophyton concentricum reproduces sexually via its ascospores which are produced internally in vacuoles called asci (sing. ascus), found in pouches known as ascomata (sing. ascoma). [4] The asexual form of T. concentricum is composed of irregularly arranged filaments with chlamydoconidia and microaleurioconidia. [5]

Pathology and treatment

Imbricated lesions of T. concentricum on the back of an Indonesian patient. COLLECTIE TROPENMUSEUM Tinea Imbricata (huidschimmel) in ver gevorderde staat TMnr 10006761.jpg
Imbricated lesions of T. concentricum on the back of an Indonesian patient.

Trichophyton concentricum is an anthropophilic dermatophyte, meaning, humans are its primary host. Disease may result from close contact with the spores and filaments of T.concentricum or contact and sharing of household items with an infected person since it is communicable.[ citation needed ] It is usually contracted during childhood and causes a non-inflammatory chronic tinea corporis known as tinea imbricata, otherwise known as Tokelau. This is characterized by concentric rings of overlapping scales called papulosquamous patches which may exist for an individual's lifetime. While these lesions appears to affect mostly the trunk region of the body, it may affect any other area. There has been rare occurrences where the nails, skin and palms are affected but it has not been known to invade hair. [2] Most lesions begin on the face and subsequently spread to larger areas of the body. Pruritus has been the most common symptom of infection and it is most severe in warm and humid climates. Tinea imbricata has been known to cause hypopigmentation and hyperpigmentation. [5] Susceptibility to this infection has been reported to be hereditary with both dominant and recessive inheritance patterns. [6] [7] Environmental and immunological factors have also been implicated as playing a role in susceptibility to this fungus. [5] Tinea imbricata can co-exist with other maladies and this may result in varied clinical presentations.[ citation needed ]

Scrapings from lesions can be stained with 10% potassium hydroxide for visualization under microscope. The medium Sabouraud's dextrose agar is commonly used for colony growth and is treated with antibiotics to prevent bacterial contamination. [5] Colonies growth is usually observed in 1–2 weeks at 25 °C. Identification using polymerase chain reaction is also possible, this provides an accurate rapid diagnosis. [8]

Treatment of tinea imbricata is usually with griseofulvin combined with a topical imidazole agent which is administered until cured. [9] Treatment with griseofulvin or terbinafine has also been successful when combined with a keratinolytic agent, such as a topical cream. Griseofulvin which is administered orally, serves to disrupt fungal mitosis, hence prevents the division and spread of fungal cells . Compared to griseofulvin, azole and allylamine agents have not been found to be as effective in treating tinea imbricata. [10] [5] However, griseofulvin has not shown to be effective as a prophylactic agent to prevent tinea imbricata. [11] The eradication of T.concentricum is believed to be difficult due to high recurrence and presence in remote rural areas.

Epidemiology

Trichophyton concentricum is endemic to the Pacific Islands and southeast Asia, particularly in the indigenous hill tribe people. 9-18% of individuals in these regions are affected. Cases of T. concentricum infection among the South and Central American indigenous people has also been reported. Infections among Europeans are rare. The vast range of climates in the endemic regions has led to speculations about the existence of two strains: a thermotolerant strain which lives between 28 and 30 degrees Celsius and a thermo-sensitive strain which lives between 20 and 25 degrees Celsius. However, no evidence has been found to support this theory. [5]

Tinea imbricata has been found in equal proportions in males and females and distributed equally among all age groups. The disease affects mostly pure race and lack of proper hygienic conditions have been shown to increase risk of infection. [5] Additionally, dietary conditions, hygiene, environment, immune considerations, and genetics are factors believed to play a role in susceptibility. [12]

Related Research Articles

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Dermatophyte is a common label for a group of fungus of Arthrodermataceae that commonly causes skin disease in animals and humans. Traditionally, these anamorphic mold genera are: Microsporum, Epidermophyton and Trichophyton. There are about 40 species in these three genera. Species capable of reproducing sexually belong in the teleomorphic genus Arthroderma, of the Ascomycota. As of 2019 a total of nine genera are identified and new phylogenetic taxonomy has been proposed.

<span class="mw-page-title-main">Tinea capitis</span> Cutaneous fungal infection of the scalp

Tinea capitis is a cutaneous fungal infection (dermatophytosis) of the scalp. The disease is primarily caused by dermatophytes in the genera Trichophyton and Microsporum that invade the hair shaft. The clinical presentation is typically single or multiple patches of hair loss, sometimes with a 'black dot' pattern, that may be accompanied by inflammation, scaling, pustules, and itching. Uncommon in adults, tinea capitis is predominantly seen in pre-pubertal children, more often boys than girls.

<span class="mw-page-title-main">Dermatophytosis</span> Fungal infection of the skin

Dermatophytosis, also known as ringworm, is a fungal infection of the skin. Typically it results in a red, itchy, scaly, circular rash. Hair loss may occur in the area affected. Symptoms begin four to fourteen days after exposure. Multiple areas can be affected at a given time.

<span class="mw-page-title-main">Onychomycosis</span> Medical condition

Onychomycosis, also known as tinea unguium, is a fungal infection of the nail. Symptoms may include white or yellow nail discoloration, thickening of the nail, and separation of the nail from the nail bed. Fingernails may be affected, but it is more common for toenails. Complications may include cellulitis of the lower leg. A number of different types of fungus can cause onychomycosis, including dermatophytes and Fusarium. Risk factors include athlete's foot, other nail diseases, exposure to someone with the condition, peripheral vascular disease, and poor immune function. The diagnosis is generally suspected based on the appearance and confirmed by laboratory testing.

<span class="mw-page-title-main">Kerion</span> Medical condition

Kerion or kerion celsi is an acute inflammatory process which is the result of the host's response to a fungal ringworm infection of the hair follicles of the scalp that can be accompanied by secondary bacterial infection(s). It usually appears as raised, spongy lesions, and typically occurs in children. This honeycomb is a painful inflammatory reaction with deep suppurative lesions on the scalp. Follicles may be seen discharging pus. There may be sinus formation and rarely mycetoma-like grains are produced. It is usually caused by dermatophytes such as Trichophyton verrucosum, T. mentagrophytes, and Microsporum canis. Treatment with oral griseofulvin common.

<i>Trichophyton rubrum</i> Species of fungus

Trichophyton rubrum is a dermatophytic fungus in the phylum Ascomycota. It is an exclusively clonal, anthropophilic saprotroph that colonizes the upper layers of dead skin, and is the most common cause of athlete's foot, fungal infection of nail, jock itch, and ringworm worldwide. Trichophyton rubrum was first described by Malmsten in 1845 and is currently considered to be a complex of species that comprises multiple, geographically patterned morphotypes, several of which have been formally described as distinct taxa, including T. raubitschekii, T. gourvilii, T. megninii and T. soudanense.

<i>Trichophyton</i> Genus of Fungi

Trichophyton is a genus of fungi, which includes the parasitic varieties that cause tinea, including athlete's foot, ringworm, jock itch, and similar infections of the nail, beard, skin and scalp. Trichophyton fungi are molds characterized by the development of both smooth-walled macro- and microconidia. Macroconidia are mostly borne laterally directly on the hyphae or on short pedicels, and are thin- or thick-walled, clavate to fusiform, and range from 4 to 8 by 8 to 50 μm in size. Macroconidia are few or absent in many species. Microconidia are spherical, pyriform to clavate or of irregular shape, and range from 2 to 3 by 2 to 4 μm in size.

<i>Microsporum audouinii</i> Species of fungus

Microsporum audouinii is an anthropophilic fungus in the genus Microsporum. It is a type of dermatophyte that colonizes keratinized tissues causing infection. The fungus is characterized by its spindle-shaped macroconidia, clavate microconidia as well as its pitted or spiny external walls.

<span class="mw-page-title-main">Tinea imbricata</span> Medical condition

Tinea imbricata is a superficial fungal infection of the skin limited to southwest Polynesia, Melanesia, Southeast Asia, India, and Central America. The skin lesions are often itchy, and mainly in the torso and limbs. The name is derived from the Latin for "tiled" (imbricata) since the lesions are often lamellar. It is often treated with griseofulvin or terbinafine.

<span class="mw-page-title-main">Fungal folliculitis</span> Inflammation of hair follicles due to fungal infection

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<i>Microsporum gypseum</i> Species of fungus

Microsporum gypseum is a soil-associated dermatophyte that occasionally is known to colonise and infect the upper dead layers of the skin of mammals. The name refers to an asexual "form-taxon" that has been associated with four related biological species of fungi: the pathogenic taxa Arthroderma incurvatum, A. gypsea, A. fulva and the non-pathogenic saprotroph A. corniculata. More recent studies have restricted M. gypseum to two teleomorphic species A. gypseum and A. incurvatum. The conidial states of A. fulva and A. corniculata have been assigned to M. fulvum and M. boullardii. Because the anamorphic states of these fungi are so similar, they can be identified reliably only by mating. Two mating strains have been discovered, "+" and "–". The classification of this species has been based on the characteristically rough-walled, blunt, club-shaped, multicelled macroconidia. Synonyms include Achorion gypseum, Microsporum flavescens, M. scorteum, and M. xanthodes. There has been past nomenclatural confusion in the usage of the generic names Microsporum and Microsporon.

<i>Trichophyton mentagrophytes</i> Species of fungus

Trichophyton mentagrophytes is a species in the fungal genus Trichophyton. It is one of three common fungi which cause ringworm in companion animals. It is also the second-most commonly isolated fungus causing tinea infections in humans, and the most common or one of the most common fungi that cause zoonotic skin disease. Trichophyton mentagrophytes is being frequently isolated from dogs, cats, rabbits, guinea pigs and other rodents, though at least some genetic variants possess the potential of human-to-human transmission, e.g. Type VII and Type VIII. Particular genetic variants of the fungus have distinct geographic ranges.

<i>Microsporum canis</i> Species of fungus

Microsporum canis is a pathogenic, asexual fungus in the phylum Ascomycota that infects the upper, dead layers of skin on domesticated cats, and occasionally dogs and humans. The species has a worldwide distribution.

Microsporum nanum is a pathogenic fungus in the family Arthrodermataceae. It is a type of dermatophyte that causes infection in dead keratinized tissues such as skin, hair, and nails. Microsporum nanum is found worldwide and is both zoophilic and geophilic. Animals such as pigs and sheep are the natural hosts for the fungus; however, infection of humans is also possible. Majority of the human cases reported are associated with pig farming. The fungus can invade the skin of the host; if it is scratched off by the infected animal, the fungus is still capable of reproducing in soil.

<i>Microsporum gallinae</i> Species of fungus

Microsporum gallinae is a fungus of the genus Microsporum that causes dermatophytosis, commonly known as ringworm. Chickens represent the host population of Microsporum gallinae but its opportunistic nature allows it to enter other populations of fowl, mice, squirrels, cats, dogs and monkeys. Human cases of M. gallinae are rare, and usually mild, non-life-threatening superficial infections.

<span class="mw-page-title-main">Favus</span> Medical condition

Favus or tinea favosa is the severe form of tinea capitis, a skin infectious disease caused by the dermatophyte fungus Trichophyton schoenleinii. Typically the species affects the scalp, but occasionally occurs as onychomycosis, tinea barbae, or tinea corporis.

<i>Trichophyton verrucosum</i> Species of fungus

Trichophyton verrucosum, commonly known as the cattle ringworm fungus, is a dermatophyte largely responsible for fungal skin disease in cattle, but is also a common cause of ringworm in donkeys, dogs, goat, sheep, and horses. It has a worldwide distribution, however human infection is more common in rural areas where contact with animals is more frequent, and can cause severe inflammation of the afflicted region. Trichophyton verrucosum was first described by Emile Bodin in 1902.

<i>Epidermophyton floccosum</i> Species of fungus

Epidermophyton floccosum is a filamentous fungus that causes skin and nail infections in humans. This anthropophilic dermatophyte can lead to diseases such as tinea pedis, tinea cruris, tinea corporis and onychomycosis. Diagnostic approaches of the fungal infection include physical examination, culture testing, and molecular detection. Topical antifungal treatment, such as the use of terbinafine, itraconazole, voriconazole, and ketoconazole, is often effective.

References

  1. ↑ Rippon, John Willard (1982). Medical mycology : the pathogenic fungi and the pathogenic actinomycetes (2nd ed.). Philadelphia: Saunders. ISBN   978-0-7216-7586-2.
  2. 1 2 "Trichophyton concentricum". Mycology Online. Retrieved 17 October 2015.
  3. ↑ Lyon, Errol Reiss, H. Jean Shadomy, G. Marshall (2012). Fundamental medical mycology. Hoboken: Wiley-Blackwell. ISBN   9781118101773.{{cite book}}: CS1 maint: multiple names: authors list (link)
  4. ↑ Kwon-Chung, K.J.; Bennett, John E. (1992). Medical mycology. Philadelphia: Lea & Febiger. ISBN   978-0812114638.
  5. 1 2 3 4 5 6 7 Bonifaz, Alexandro; Archer-Dubon, Carla; Saul, Amado (July 2004). "Tinea imbricata or Tokelau". International Journal of Dermatology. 43 (7): 506–510. doi:10.1111/j.1365-4632.2004.02171.x. PMID   15230889. S2CID   45272404.
  6. ↑ Bonifaz, A; Archer-Dubon, C; Saúl, A (July 2004). "Tinea imbricata or Tokelau". International Journal of Dermatology. 43 (7): 506–10. doi:10.1111/j.1365-4632.2004.02171.x. PMID   15230889. S2CID   45272404.
  7. ↑ SERJEANTSON, S (1977). "Autosomal Recessive Inheritance of Susceptibility to Tinea Imbricata". The Lancet. 309 (8001): 13–15. doi:10.1016/s0140-6736(77)91653-1. PMID   63655. S2CID   27447510.
  8. ↑ Yüksel, Tuba; İlkit, Macit (2012-05-01). "Identification of rare macroconidia-producing dermatophytic fungi by real-time PCR". Medical Mycology. 50 (4): 346–352. doi: 10.3109/13693786.2011.610036 . ISSN   1369-3786. PMID   21954954.
  9. ↑ "Dermatophytosis". Mycology Online. University of Adelaide. Retrieved 26 October 2015.
  10. ↑ BUDIMULJA, U.; KUSWADJI, K.; BRAMONO, S.; BASUKI, J.; JUDANARSO, L.S.; UNTUNG, S.; WIDAGDO, S.; WYDIANTO, RHPRABOWO; KOESANTO, D.; WIDJANARKO, P. (April 1994). "A double-blind, randomized, stratified controlled study of the treatment of tinea imbricata with oral terbinafine or itraconazole". British Journal of Dermatology. 130 (s43): 29–31. doi:10.1111/j.1365-2133.1994.tb06091.x. PMID   8186139. S2CID   25842579.
  11. ↑ González-Ochoa, A; Ricoy, E; Bravo-Becherelle, A (1964). "Study of Prophylactic Action of Griseofulvin—Human Experimental Infection with Trichophyton Concentricum". Journal of Investigative Dermatology. 42: 55–59. doi: 10.1038/jid.1964.13 . PMID   14115870.
  12. ↑ Hay, RJ (1983). "Immune responses of patients with tinea imbricata". British Journal of Dermatology. 108 (5): 581–586. doi:10.1111/j.1365-2133.1983.tb01060.x. PMID   6849824. S2CID   23235387.
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