Environmental Isolates of Sporothrix schenckii in China.

Restriction fragment length polymorphism (RFLP) in mitochondrial DNA (mtDNA) from 25 environmental isolates of Sporothrix schenckii from northeastern China was investigated. Based on the mtDNA-RELP patterns with Hae III, 6 isolates were confirmed to be S. schenckii, while the other 19 isolates were confirmed to be species distinct from S. schenckii. The mtDNA RFLP patterns of the 19 non-S. schenckii were identical to each other. The non-S. schenckii isolates could not be discriminated from S. schenckii by their macro- or micro-morphological features, and were not pathogenic in guinea pigs. Serological and delayed hypersensitivity cross-reactions were found between S. schenckii and the non-S. schenckii species, suggesting antigenic similarity. These results indicate that RFLP analysis of mtDNA is essential for the identification of environmental isolates of S. schenckii.