Phylogeny Analyses Of Clinical Sporothrix Species In China

Sporotrichosis is an acute or chronic subcutaneous mycosis, which canbe acquired by a traumatic contact with Sporothrix contaminated vegetationor soil, and through cat contact or scratches. Sporothrix schenckii had longbeen believed to be the unique causal agent of sporotrichosis since it wasfirst described by Benjamin Schenck in1898. Identification was madeprimarily based on morphological characters. Recently, with molecularphylogenetic analysis, S. schenckii was discovered to be a complex of atleast six phylogenetic species. The correlation was revealed betweengeographical distribution and genotypes among species of Sporothrix. Thevirulence levels and antifungal susceptibility were also different amongSporothrix species.Sporotrichosis has a global distribution. In China, it is more frequentlyencountered in northeast provinces including Jilin, Heilongjiang, andLiaoning. The causal agents were identified as Sporothrix schenckii by morphological identification, but they showed variable clinical phenotypesand antifungal susceptibility. Hence the study of sporotrichosis agent inChina is significant toward understanding the geographical distribution andthe treatment of sporotrichosis.The aims of this study were to collect a wide range representativestrain of pathogens causing sporotrichosis in China, and confirm theiridentity through phylogeny analyses using the ITS rDNA and β-tubulinsequences.In this study, we investigated the molecular phylogeny of64clinicalisolates which were identified as Sporothrix schenckii sensu lato bymorphological characters. All of the strains were isolated from patientsfrom several provinces in China. The phylogeny was inferred by DNAsequence analyses based on datasets of the ITS and a combined ITS andpartial β-tubulin region. Reference sequences were retrieved from GenBank.The maximum parsimony (MP) analysis was performed using PAUP v.4.0b10. The results showed that all of the isolates clustered in a distinctclade with the type strain of Sporothrix globosa.The data in our study showed that the sporotrichosis cases in Chinawere caused by S. globosa rather than S. schenckii, and it is demonstratedthat ITS and β-tubulin are efficient to distinguish species in S. schenckiispecies complex. With the increasing multilocus sequence data in thisgroup, efficient molecular diagnosis protocols using specific primers should be developed to enable a rapid and accurate identification of clinicalSporothrix species.