Molecular Identification of Human Sporotrichosis in Korea

Background: Sporotrichosis is a common deep mycosis caused by the Sporothrix schenckii complex. Until 2016, no molecular studies had been conducted on these fungi, and all the included strains were reported as S. schenckii. However, investigations conducted in northeast China, Japan, and India revealed that S. globosa was the most prevalent Sporothrix species, whereas S. schenckii sensu stricto was reported very rarely. Objective: To investigate the accurate prevalent causative species of sporotrichosis among strains reported as S.schenckii in Korea. Methods: We isolated strains of Sporothrix spp. Prevalent in Korea from fungus collection centers or private collections and reviewed the available literature on molecular studies of strains from this region. We found five S. schenckii (1998-2016) and three S. globosa (2016-2018) strains. Ribosomal DNA internal transcribed spacer (ITS) sequences of these strains were compared with those of the S. schenckii complex strains. Results: The ribosomal ITS sequences of the eight strains were 100% identical with that of S. globose. No S. schenckii sensu stricto was found. In addition, a study on the molecular analysis of Korean S. schenckii published by Ishizaki et al. (2004) demonstrated that the eight strains were of the mitochondrial subtype group B (S. globosa). Thus, all the 16 strains examined within the Korean S. schenckii complex were determined to be S. globosa. Conclusion: In summary, S. globosa is the causative species within the tested Korean sporotrichosis cases reported between 1998 and 2018. Based on our analyses, S. globosa, and not S. schenckii, may be the predominant species in Korea.