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Distribution of mating types among clinical isolates of the Microsporum gypseum complex
Abstract:
Forty-five clinical isolates of Microsporum gypseum were crossed with the + and - tester strains of Nannizzia gypsea, N. incurvata and N. fulva to determine their mating type. Thirty-two produced fertile gymnothecia when crossed with N. gypsea, of which 13 reacted as + and 19 as -. Ten produced fertile gymnothecia when crossed with N. incurvata, of which 7 reacted as + and 3 as -. The remaining 3 were sterile in all crosses with N. gypsea. N. incurvata and N. fulva. Of these 3, 2 were fluffy, degenerated cultures of M. gypseum, and the other one appeared to bae identical with the description of M. gypseum var. vinosum in cultural and morphological characteristics. There was approximately a 1:1 overall ratio of mating types among a total of 90 clinical isolates of M. gypseum in Japan on the basis of the above results and the data recently reported in the literature by other Japanese workers. The present results suggest that the ability to cause skin infection of humans by the soil-inhabiting organisms is approximately equal in the mating types and probably independent of sexuality.
Insights
Mating types of Microsporum gypseum were determined using tester strains. Results indicate an approximate 1:1 ratio of mating types in clinical isolates, suggesting equal human skin infection potential.
Area of Science:
- Medical Mycology
- Dermatophytosis
- Fungal Genetics
Background:
- Microsporum gypseum is a geophilic dermatophyte causing skin infections in humans.
- Understanding the mating types of M. gypseum is crucial for epidemiological and genetic studies.
- Previous research on mating types in Japanese clinical isolates is limited.
Purpose of the Study:
- To determine the mating types of clinical isolates of Microsporum gypseum.
- To investigate the ratio of mating types in a Japanese population of M. gypseum.
- To assess the relationship between mating types and the organism's ability to cause human infections.
Main Methods:
- Forty-five clinical isolates of Microsporum gypseum were crossed with tester strains of Nannizzia gypsea, Nannizzia incurvata, and Nannizzia fulva.
- Fertile gymnothecia production was observed to determine mating compatibility.
- Mating types (+ and -) were assigned based on successful crosses.
Main Results:
- Thirty-two isolates produced fertile gymnothecia with Nannizzia gypsea (+: 13, -: 19).
- Ten isolates produced fertile gymnothecia with Nannizzia incurvata (+: 7, -: 3).
- Three isolates were sterile across all crosses; two were degenerated cultures, and one resembled M. gypseum var. vinosum.
Conclusions:
- An approximate 1:1 ratio of mating types was observed among 90 clinical isolates of M. gypseum in Japan.
- The ability to cause human skin infections appears to be equally distributed between mating types.
- Sexuality and mating type may be independent of the organism's pathogenicity in humans.