Virulence differences between albino and pigmented Sporothrix schenckii isolates

Abstract

Objective This work compares the virulence between pigmented (P) and albino (A) filamentous forms of S. schenckii through experimental skin sporotrichosis. Material and methods Two original wild pigmented isolates (1 and 2) cultivated in yeast extract peptone dextrose (YEPD), were exposed to 300 erg/mm 2 of UV radiation in order to produce mutant albinos. Swiss albino mice were divided in four groups (P1, A1, P2 and A2) and inoculated in the right paw pad with 0.1 ml of solution (1 × 10 6cells/ml) and observed during nine weeks. Results The albino groups A1 (86%) and A2 (100%) presented intense inflammatory reactions in the inoculation point ( p < 0.01) in Week 2 after inoculation, while in the pigmented groups, around 70% of the animals presented multiple skin lesions in Week 4 ( p < 0.01). In the last three weeks of the experiment, 67% of the mice in group P1 demonstrated multiple skin lesions. S. schenckii was recovered from samples obtained in necropsy and the histological analysis revealed formation of granulomas with yeast-like cells in the central area of the lesion. Conclusion The results obtained in this experimental model permit the conclusion that there are virulence differences between pigmented and mutant albino isolates of S. schenckii in the development of experimental skin sporotrichosis.