Genotypic diversity and antifungal susceptibility of Scedosporium species from clinical settings in China

BACKGROUND: Scedosporium species have drawn significant interest as inhabitants of polluted soil and water and as cause of high mortality in near-drowning patients. So far, most cases have been reported from Europe and Australia, while knowledge on their prevalence and genotypic diversity from Asia is scant. OBJECTIVES: To increase the knowledge of the genetic diversity and in vitro antifungal susceptibility of Scedosporium species involved in human infections from China. METHODS: Here, we applied the ISHAM-MLST consensus scheme for molecular typing of Scedosporium species and revealed both high species diversity and high genotypic diversity among 45 Chinese clinical Scedosporium isolates. RESULTS: Among the five species, Scedosporium boydii (n = 22) was the most common, followed by S. apiospermum (n = 18), S. aurantiacum (n = 4) and S. dehoogii (n = 1). S. aurantiacum was reported for the first time from clinical samples in China. The predominant sequence types (STs) were ST17 in S. apiospermum, ST4 in S. boydii and ST92 in S. aurantiacum, including four novel STs (ST40, ST41, ST42 and ST43) in S. apiospermum. Based on the CLSI-M38 A2 criterion, voriconazole was the only antifungal compound with low MIC values (MIC₉₀  ≤ 1 μg/ml) for all Scedosporium isolates in our study. CONCLUSIONS: The genetic diversity of clinical isolates of Scedosporium species from China is extremely high, with S. boydii being predominant and S. aurantiacum being firstly reported here. VOR was the only antifungal compound with low MIC values for all Scedosporium isolates in our study, which should be recommended as the firstline antifungal treatment against scedosporiosis in China.