Isolation of Sporothrix schenckii from the environmental sources of cutaneous sporotrichosis patients in Himachal Pradesh, India: results of a pilot study

Abstract

Himachal Pradesh, India is a known endemic area for cutaneous sporotrichosis. No attempt has been made to isolate Sporothrix schenckii, the causative fungus, from environmental sources in this region or in India as such. This prospective study was carried out to isolate Sporothrix schenckii from different environmental samples collected from the vicinity of cutaneous sporotrichosis patients. All patients of cutaneous sporotrichosis diagnosed during March 2005-February 2006 were studied. Twenty-one biopsy specimens and 62 environmental samples of soil, various thorns, corn-stalk, grass-blades and sphagnum moss were subjected to mycologic culture on Sabouraud's glucose agar. Sporothrix schenckii was identified by colony characteristics, lacto-phenol cotton blue mounts and demonstration of temperature dimorphism. These patients (F : M 15 : 6) were between 12 and 72 years of age and had cutaneous lesions for 45 days to 4 years. Lymphocutaneous and fixed cutaneous sporotrichosis was seen in 14 (66.6%) and 7 (33.3%) patients respectively. Extremities were involved in 16 (76.2%); and 5 (23.8%) patients had facial lesions. Ten (47.4%) biopsy specimens and six environmental (three soil, three corn-stalk) samples were culture-positive, which showed morphological characteristics suggesting Sporothrix schenckii. No variation in colony characteristics and mycelial morphology was observed in growth isolates from clinical or environmental samples. Temperature dimorphism was observed in all the 10 isolates obtained from the clinical specimens and in two isolates cultured from corn-stalk. Corn-stalks are evidently important sources of Sporothrix schenckii infection although subsequent contamination of wounds appears more important for development of clinical disease. Culture of Sporothrix schenckii from environmental sources may not be always possible to correlate with profile of injuries.