Development of experimental sporothrichosis in a murine model with yeast and mycelial forms of Sporothrix schenkii

Márcia De Oliveira Nobre,Tatiana De Ávila Antunes,Vanessa Berg,Izamara Aparecida De Oliveira,Mário Carlos Araújo Meireles,Laerte Ferreiro,Cristina Gevehr Fernandes ,Thomaz Lucia

doi:10.22456/1679-9216.17160

Márcia De Oliveira Nobre, Tatiana De Ávila Antunes + Show 6 more

Open Access

https://doi.org/10.22456/1679-9216.17160

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Abstract

Sporotrichosis is a subcutaneous disease that affects both men and a variety of animals caused by the dimorphic fungus Sporothrix schenckii . The aims of this study were to observe differences in virulence between inocula containing the yeast (Y) or mycelial (M) forms, to compare the reactions induced by the two inocula injected in different anatomical sites, and to verify the possibility of horizontal transmission of the disease by contact between infected and healthy animals. All animals were observed during a period of nine weeks. Mice were inoculated subcutaneously in the paw pads and in the regions of the hip and shoulder joints. Another group of non-inoculated healthy mice was kept in direct contact with mice developing the subcutaneous lesions. Animals of groups Y and M developed lesions due to infections and clinical symptoms very characteristic of sporothrichosis. Lesions were more prominent and with longer duration when occurring in the pads than in any other site of inoculation. Non-inoculated mice remained healthy as it occurred to animals in the control group. The development of typical clinical symptoms for sporothrichosis in all inoculated groups suggests that no difference exists in virulence between the yeast and mycelial forms of the same isolated of S. schenckii . Moreover, the paw pads appear to be the site of choice for the inoculation for experimental sporotrichosis in the murine model. In addition, this study also showed that the contact with sick animals and contaminated materials is insufficient to transmit the infection to immune competent animals with intact skin.

Highlights

Sporotrichosis is a subcutaneous mycosis that has the dimorphic fungus Sporothrix schenckii as its causative agent
A small swelling at the inoculation sites was noted in 24 hours following the inoculation in all animals including the control group and that disappeared in 48 hours
In the forth week there was an evident reduction of lesions of group Y animals to 15% when group M had 50% of the animals still presenting the same clinical picture described above

Summary

Introduction

Sporotrichosis is a subcutaneous mycosis that has the dimorphic fungus Sporothrix schenckii as its causative agent. The habitat of the fungus is soil rich in organic matter but it grows in plants and tree bark in warm environments with high humidity [4]. The dimorphic organism is mycelial in the environment or in vitro in temperatures inferior to 37°C and yeast-like in vivo or in vitro at 37°C [6]. With this work we aimed to verify possible differences in the virulence between inocula of mycelial and yeast forms of S. schenckii comparing the reactions produced using three different sites of inoculation in mice. We tested the possibility of transmission of this mycosis from affected animals to healthy ones

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