Microsporum gallinae

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Microsporum gallinae
Microsporum gallinae.png
Microsporum gallinae colony growing in petri dish
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Eurotiomycetes
Order: Onygenales
Family: Arthrodermataceae
Genus: Microsporum
Species:
M. gallinae
Binomial name
Microsporum gallinae
(Mégnin ex Guéguen) Grigorakis (1929)
Synonyms

Epidermophyton gallinaeMégnin (1881)
Trichophyton gallinae(Mégnin ex Guéguen) Georg (1952)

Contents

Microsporum gallinae is a fungus of the genus Microsporum that causes dermatophytosis, commonly known as ringworm. [1] Chickens represent the host population of Microsporum gallinae but its opportunistic nature allows it to enter other populations of fowl, mice, squirrels, cats, [2] dogs and monkeys. [3] Human cases of M. gallinae are rare, and usually mild, non-life-threatening superficial infections. [2]

Taxonomy and naming

Microsporum gallinae was first identified in 1881 by Megnin from chicken favus, [4] and named Epidermophyton gallinae. [5] It was later transferred from the Epidermophyton genus, and classified in the Trichophyton genus, as T. gallinae. [4]

The identification of rough-walled macroconidia, a hallmark of the Microsporum genus, lead to the dermatophyte being classified as M. gallinae. [1] [4] There is still debate about the phylogenetic placement of this dermatophyte, but the accepted name is Microsporum gallinae. [5] Analysis of its DNA sequences by PCR shows M. gallinae is most closely related to Microsporum vanbreuseghemii and Arthroderma grubyi , both are also zoophilic fungi. [3] [6]

Distribution

Microsporum gallinae is distributed throughout the world, with cases reported in: Europe, the Middle East, South America, North America, Africa and Japan. [2] The fungus seems to be isolated more often in areas with high humidity and temperature. [3]

Morphology

In culture, M. gallinae produces a white, satiny colony. [7] [8] The colony appears flat with radial folds and irregular edges as it grows in culture [7] The colony reverse produces a strong pigmentation that changes from pink to a deep red and diffuses through the growth medium. [5] [7] [8] Optimal growth of M. gallinae occurs at 26-28 °C, [3] and no special nutritional requirements are necessary for its growth. [9] Additionally, M. gallinae is urease positive. [9]

During sporulation, septate hyphae, [2] [7] with macroconidia with tappered tips, and club shaped microconidia are present. [7] [8] [10] The addition of thiamine or yeast extracts promotes sporulation of M. gallinae. [7] Hair invasion observed in M. gallinae is large spored ectothrix type, meaning that the spores form outside of the hair shaft. [5]

Pathogenicity

Microsporum gallinae is a cosmopolitan zoophilic fungi that very rarely affects humans. [10] It obtains nutrients from keratin-rich skin, nails and hair, releasing enzymes during its digestion that elicit a host immune response as seen in ringworm. [11] [12] Microsporum gallinae infection is diagnosed by culturing the scrapings from skin lesions. [9]

Chickens

Microsporum gallinae causes a superficial infection [13] that forms white lesions on the wattles and combs of chickens. [1] [10] Lesions may spread to the head and neck. [2] The feathers are normally not affected by the dermatophyte, although some feather loss can occur. [1] Roosters and chicks tend to be more susceptible to the infection, with fighting cocks having the highest rates of M. gallinae dermatophytosis. [2] Although, it tends to resolve with treatment, the M. gallinae infection may become chronic. [1] The lesions can also become infected with bacteria, complicating the infection. [1] In some cases, it can resolve naturally without treatment; however, the infection may persist for weeks prior to clearance. [5]

Humans

Microsporum gallinae has been isolated from the scalp, and smooth skin in human populations. [10] Microsporum gallinae infections are most commonly tinea capitis and tinea corporis. [3] Very few human cases of M. gallinae infection have been reported, none of which were life-threatening. [9] Of the reported cases, individuals ranged from 3–96 years old. [3] They had cutaneous lesions on the glabrous skin or the scalp. [3] These localized lesions are frequently accompanied by itching. [2] [9] The cutaneous manifestations are very similar to those of Microsporum canis therefore many cases of Microsporum gallinae could have been unreported. [3]

In rare cases, immunocompromised individuals form severe dissemination on the skin, instead of small localized lesions [3] as a result of handling infected animals. [2] [9] Only one case of extensive dermatophytosis was reported involving M. gallinae infection of a person with AIDS. [2] [3] [9]

Treatment

The treatment of M. gallinae involves both topical and oral antifungals. [1] [3] Topical antifungals, such as: Terbinafine, [3] Tolnaftate, [1] and orally administered Griseofulvin [1] [9] have been used successfully to treat M. gallinae infections in humans and animals.

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

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References

  1. 1 2 3 4 5 6 7 8 9 Fonseca, Edwin; Leonel Mendoza (1984). "Favus in a Fighting Cock Caused by Microsporum gallinae". Avian Diseases. 28 (3): 737–741. doi:10.2307/1590243. JSTOR   1590243. PMID   6487194.
  2. 1 2 3 4 5 6 7 8 9 Murata, Michiko; Hideo Takahashi; Sana Takahashi; Yoko Takahashi; Hiroji Chibana; Yoshiteru Murata; Kazutoshi Sugiyama; Takashi Kaneshima; Sayaka Yamaguchi; Hitona Miyasato; Masaru Murakami; Rui Kano; Atsuhiko Hasegawa; Hiroshi Uezato; Atsushi Hosokawa; Ayako Sano (2013). "Isolation of Microsporum gallinae from a fighting cock in Japan". Medical Mycology. 51 (2): 144–149. doi:10.3109/13693786.2012.701766. PMID   22809243.
  3. 1 2 3 4 5 6 7 8 9 10 11 12 Miyasato; Yamaguchi; Taira; Hosokawa; Kayo; Sano; Uezato; Takahashi (2011). "Tinea corporis caused by Microsporum gallinae: First clinical case in Japan". The Journal of Dermatology. 38 (5): 473–478. doi:10.1111/j.1346-8138.2010.01090.x. PMID   21352324. S2CID   20249376.
  4. 1 2 3 Silva, Margarita; Benham, Rhoda W. (December 1952). "Nutritional Studies of the Dermatophytes with Special Reference to Trichophyton Megnini Blanchard 1896 and Trichophyton Gallinae (Megnin 1881)". The Journal of Investigative Dermatology. 18 (6): 285. doi: 10.1038/jid.1952.55 .
  5. 1 2 3 4 5 TORRES, GLADYS; Georg, Lucille K. (1956). "A Human Case of Trichophyton Gallinae Infection". A.M.A. Archives of Dermatology. 74 (2): 191. doi:10.1001/archderm.1956.01550080077011. PMID   13353992.
  6. ↑ Gräser, Y; el Fari, M; Presber, W; Sterry, W; Tietz, HJ (April 1998). "Identification of common dermatophytes (Trichophyton, Microsporum, Epidermophyton) using polymerase chain reactions". The British Journal of Dermatology. 138 (4): 576–82. doi:10.1046/j.1365-2133.1998.02165.x. PMID   9640360. S2CID   8176357.
  7. 1 2 3 4 5 6 Howard, D.H (2002). Pathogenic Fungi in Humans and Animals (2nd ed.). CRC Press.
  8. 1 2 3 Campbell, C, E and D.W; Johnson; Warnock (2013). Identification of Pathogenic Fungi (2nd ed.). Wiley Blackwell.{{cite book}}: CS1 maint: multiple names: authors list (link)
  9. 1 2 3 4 5 6 7 8 Del Palacio, A (1992). "Widespread dermatophyosis due to Microsporum gallinae in a patient with AIDS-a case report from Spain". Clinical and Experimental Dermatology. 6 (17): 449–453.
  10. 1 2 3 4 Kwon-Chung, K.J.; Bennet, E.J. (1992). Medical Mycology (2nd ed.). Lea & Febiger.
  11. ↑ Babel, Dennis E.; Rogers, Alvin L. (June 1983). "Dermatophytes: Their contribution to infectious disease in North America". Clinical Microbiology Newsletter. 5 (12): 81–85. doi:10.1016/S0196-4399(83)80014-2.
  12. ↑ Weitzman, I; Summerbell, R.C. (April 1995). "The dermatophytes". Clin Microbiol Rev. 8 (2): 240–259. doi:10.1128/cmr.8.2.240. PMC   172857 . PMID   7621400.
  13. ↑ Aurora, Dilip K.; Libero Ajello; K.G.Mukerji, eds. (1991). Handbook of applied mycology. New York: Marcel Dekker. ISBN   0824784359.
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