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Experimental systemic dermatophytosis
Abstract:
Albino guinea pigs with abraded skin were inoculated cutaneously with 27 strains of dermatophytes from animals and humans. The same strains were inoculated i.v. in guinea pigs with intact skin. Zoophilic dermatophytes and human isolates of Trichophyton mentagrophytes var. granulare produced ringworm after cutaneous application. After i.v. inoculation, the fungus was reisolated from skin samples from a considerable number of animals with and without clinical ringworm lesions, and also from lungs, liver, and kidneys. In the lungs, hyphal aggregates were noted. Some strains produced generalized dermatophytosis affecting all parts of the skin and internal organs. T. mentagrophytes B32663, selected for further study, was inoculated i.v. in the guinea pig, rabbit, rat, mouse, and chicken. Ringworm lesions occurred in the guinea pig and rabbit; in the mouse, rat, and chicken other organs were involved. Administration by other routes did not produce a generalized infection. The infection was not self-limited and the deep-seated lesions may be responsible for the recurrence of infection.
Insights
Dermatophyte infections in guinea pigs can spread to internal organs after intravenous inoculation, causing generalized disease. This deep-seated infection may lead to recurrent ringworm, highlighting the need for effective treatment strategies.
Area of Science:
- Mycology
- Veterinary Dermatology
- Infectious Diseases
Background:
- Dermatophytes are fungi causing superficial skin infections.
- Understanding dermatophyte dissemination is crucial for effective treatment.
Purpose of the Study:
- To investigate the infectivity and dissemination of dermatophyte strains in animal models.
- To evaluate the course of dermatophytosis following different inoculation routes.
Main Methods:
- Cutaneous and intravenous inoculation of 27 dermatophyte strains in guinea pigs.
- Intravenous inoculation of a specific strain (T. mentagrophytes B32663) in multiple animal species.
- Reisolation of fungi from skin and internal organs; histopathological examination of lung tissue.
Main Results:
- Cutaneous inoculation caused ringworm with specific zoophilic and human strains.
- Intravenous inoculation led to systemic fungal presence in skin, lungs, liver, and kidneys, with or without visible lesions.
- Generalized dermatophytosis affecting skin and internal organs occurred with some strains.
- T. mentagrophytes B32663 caused systemic infection in guinea pigs, rabbits, rats, mice, and chickens, with varied organ involvement.
- Infection was not self-limiting, suggesting deep-seated lesions contribute to recurrence.
Conclusions:
- Intravenous inoculation of dermatophytes can result in systemic infections beyond the skin.
- The route of administration significantly influences the manifestation and dissemination of dermatophytosis.
- Deep-seated fungal lesions may underlie the recrudescent nature of dermatophyte infections.