Related Experiment Videos
Variants of Sporothrix schenckii with attenuated virulence for mice
Renata Ferretti de Lima1, Guido Vidal Schäffer, Cintia de Moraes Borba
1Department of Mycology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, FIOCRUZ, CP 926, Rio de Janeiro, RJ 21045-900, Brazil.
Abstract:
Strains of Sporothrix schenckii preserved under mineral oil were examined for virulence in BALB/c mice. The mice were inoculated with S. schenckii conidia and development of cutaneous lesions, signs of inactivity, weight loss, survival rates, number of viable yeast cells in lung and spleen, splenomegaly and organ lesions were evaluated. After intravenous injection of 7.5 x 10(6) conidia, two of five S. schenckii strains were unable to induce systemic disease and to kill the mice, only producing cord-like lesions on the tail that regressed with mouse maturation. Very small numbers of viable cells isolated from the spleen confirmed the lower invasive ability of these strains when compared with other strains studied here. These results suggest a relationship between the attenuation of virulence and the storage method under mineral oil after long periods of time.
Insights
Mineral oil preservation of Sporothrix schenckii strains may attenuate their virulence. Long-term storage under mineral oil could reduce the invasive ability of S. schenckii, impacting its disease-causing potential in mice.
Area of Science:
- Medical Mycology
- Infectious Diseases
- Pathogen Virulence Studies
Background:
- Sporothrix schenckii is a fungus causing sporotrichosis, a disease with varied clinical presentations.
- Understanding factors affecting S. schenckii virulence is crucial for disease management and prevention.
- Preservation methods can potentially alter microbial characteristics, including pathogenicity.
Purpose of the Study:
- To investigate the impact of mineral oil preservation on the virulence of Sporothrix schenckii strains.
- To evaluate the infectivity and pathogenicity of S. schenckii after long-term storage.
Main Methods:
- BALB/c mice were inoculated intravenously with conidia from S. schenckii strains preserved under mineral oil.
- Virulence was assessed by monitoring cutaneous lesions, activity levels, weight loss, survival rates, and organ involvement (spleen, lungs).
- Viable yeast cell counts in the spleen and spleen size (splenomegaly) were quantified.
Main Results:
- Two of five tested S. schenckii strains showed significantly reduced virulence.
- These attenuated strains induced only regressing cutaneous lesions and failed to cause systemic disease or mortality.
- Lower numbers of viable yeast cells in the spleen confirmed the diminished invasive capacity of these preserved strains.
Conclusions:
- Long-term storage of Sporothrix schenckii under mineral oil may lead to attenuation of virulence.
- The mineral oil preservation method appears to be associated with a decreased ability of S. schenckii to cause systemic infection.
- Further research is warranted to elucidate the mechanisms behind this observed virulence attenuation.