Sporotrichosis Overview. Sporotrichosis is an infection of the skin caused by a fungus, Sporothrix schenckii. This fungus is related more closely to the mold on stale bread or the yeast used to brew beer than to bacteria that usually cause infections. The mold is found on rose thorns, hay, sphagnum moss, twigs, and soil. The infection is more common among gardeners, nursery workers, and farmers who work with roses, moss, hay, and soil. Once the mold spores move into the skin, the disease takes days or even months to develop.