Identification and Antifungal Susceptibility Profiles ofCandida nivariensisandCandida bracarensisin a Multi-Center Chinese Collection of Yeasts.
Candida nivariensisandC. bracarensisare two emerging cryptic species within theC. glabratacomplex. Thirteen of these isolates from 10 hospitals in China were studied for their species identification and antifungal susceptibilities. Phenotypic and molecular [rDNA ITS sequencing, D1/D2 sequencing and ITS sequencer-based capillary gel electrophoresis (SCGE)] and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) MS identification methods were compared for their performance in species identification. Twelve of 13 (92.3%) isolates were identified asC. nivariensisand one asC. bracarensisusing ITS sequencing as the reference method. Results obtained by D1/D2 sequencing and ITS SCGE were concordant with ITS sequencing results for all (100%) isolates. SCGE was able to subtype 12C. nivariensisinto four ITS SCGE length types. All isolates failed to be identified by the Vitek MALDI-TOF MS system (bioMérieux), whilst the Bruker MS system (Bruker Daltoniks) correctly identified allC. nivariensisisolates but using a lowered (≥1.700) cut-off score for species assignment; theC. bracarensisisolate was identified but with score <1.700. The Vitek 2 Compact system could not identify 11C. nivariensisand oneC. bracarensisisolate and misidentified the remainingC. nivarensisstrain as "C. glabrata." All isolates were susceptible-dose dependent to fluconazole [minimum inhibitory concentration (MIC) range 0.5-4 μg/mL] and were classed as susceptible to echinocandins (MICs ≤ 0.06 μg/mL). All 13 isolates had low MICs for other azoles (MICs ≤ 0.5 μg/mL), amphotericin B (MICs ≤ 2 μg/mL) and 5-flucytosine (MICs ≤ 0.25 μg/mL). Our results reinforce the need for molecular differentiation of species ofC. nivarensisandC. bracarensis. The performance of MALDI-TOF may be improved by adding mass spectral profiles (MSPs) into the current databases. The antifungal susceptibility profile of isolates should be monitored.
Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical SciencesBeijing, China; Graduate School, Peking Union Medical College, Chinese Academy of Medical SciencesBeijing, China.
Xin
X
Hou
Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences Beijing, China.
Meng
M
Xiao
Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research-Pathology West, Westmead Hospital, University of Sydney, Sydney NSW, Australia.
Sharon C-A
SC
Chen
Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences Beijing, China.
He
H
Wang
Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical SciencesBeijing, China; Graduate School, Peking Union Medical College, Chinese Academy of Medical SciencesBeijing, China.
Shu-Ying
SY
Yu
Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical SciencesBeijing, China; Graduate School, Peking Union Medical College, Chinese Academy of Medical SciencesBeijing, China.
Xin
X
Fan
Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research-Pathology West, Westmead Hospital, University of Sydney, Sydney NSW, Australia.
Fanrong
F
Kong
Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences Beijing, China.
Ying-Chun
YC
Xu
Candida bracarensis; Candida nivariensis; D1/D2 sequencing; ITS sequencer-based capillary gel electrophoresis (SCGE); ITS sequencing; antifungal susceptibility; matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF)