Five-year China hospital invasive fungal surveillance net (CHIF-NET) study of invasive fungal infections caused by noncandidal yeasts: Species distribution and azole susceptibility

Abstract

Purpose: In this study, we report results from a 5-year surveillance for noncandidal yeast species causing invasive infections from 65 hospitals in China. Materials and methods: Species identification was carried out by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) supplemented by rDNA sequencing, and fluconazole and voriconazole susceptibilities of yeasts were determined by Clinical and Laboratory Standards Institute (CLSI) disk diffusion methods. Results: Overall, 884 noncandidal isolates belonging to 38 species were collected. Cryptococcus neoformans was the most common (75.6%), which also comprised 96.5% of the isolates from cerebrospinal fluid (CSF) and 62.6% from blood, followed by Trichosporon asahii (6.9%) and Rhodotorula mucilaginosa (5.1%). Fluconazole susceptibility and resistant rates were 74.1% and 9.7% for C. neoformans and 81.0% and 5.2% for T. asahii. Voriconazole exhibited good activity in comparison to these two species (99.5% and 98.3% of the isolates, were susceptible). However, 100% of the R. mucilaginosa isolates were resistant to both azoles. Other noncandidal yeast species showed reduced susceptibility to fluconazole (53.3%) but most were susceptible to voriconazole (94.3%). Over the 5 years, a decrease in the proportion of fluconazole-susceptible isolates was observed for C. neoformans (90%–67%, P<0.001) and other noncandidal yeast species (91%–66%, P<0.001). Moreover, the prevalence of azole-resistant R. mucilaginosa increased from 1% to 7% (P<0.001). Conclusion: The shift in azole susceptibilities in mainland China calls for continued surveillance for noncandidal yeasts.