Candida isolates causing refractory or recurrent oropharyngeal candidiasis in 11 hospitals in China Shu-Ying Yu,1–3 Li Zhang,1,3 Sharon Chen,4 Fanrong Kong,4 Meng Xiao,1,3 He Wang,1,3 Xin Hou,1–3 Meng-Lan Zhou,1–3 Ge Zhang,1,3 Jing-Jia Zhang,1,3 Si-Meng Duan,1,3 Wei Kang,1,3 Ying-Chun Xu1,31Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, People’s Republic of China; 2Graduate School, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, People’s Republic of China; 3Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases (BZ0447), Beijing, People’s Republic of China; 4Centre for Infectious Diseases and Microbiology Laboratory Services, ICPMR –New South Wales Health Pathology, The University of Sydney, Westmead, New South Wales, AustraliaIntroduction: We studied the species distribution and antifungal susceptibilities of Candida isolates causing refractory or recurrent oropharyngeal candidiasis (OPC) in a multicenter study in China (2013–2016).Methods: Species identification was performed using the Bruker Biotyper (Bruker Daltonics, Germany) matrix-assisted laser desorption/ionization time of flight mass spectrometry system supplemented by internal transcribed spacer sequencing as required. Antifungal susceptibilities were determined by the Clinical and Laboratory Standards Institute document (CLSI) M27-A3 broth microdilution methodology.Results: A total of 558 non-duplicate Candida isolates comprising 10 species were obtained from 535 patients. Candida albicans was the most common species (89.6%), followed by C. glabrata (5.2%), C. tropicalis (2.9%), and C. parapsilosis (0.7%). Azoles were active against C. albicans with susceptibility rates of 96% and 95.8% for fluconazole and voriconazole, respectively. MIC50 values of C. albicans to fluconazole, voriconazole, itraconazole, and miconazole were 1, 0.03, 0.25 and 0.12 μg/mL, respectively, higher than those in previous studies of which OPC patients (corresponding MIC50 values of 0.25 , 0.015 , 0.06 , and 0.03 μg/mL). Except for itraconazole, the MIC50 and MIC90 values of 58 non-C. albicans to other azoles were two to threefold higher than C. albicans. Miconazole, amphotericin B, nystatin, and 5-flucytosine had good in vitro antifungal activity for all isolates.Conclusion: The study provides valuable data on the species distribution and antifungal susceptibility of oropharyngeal Candida isolates from geographically diverse areas of China. C. albicans remains the most common species but with increasing rates of azoles resistance.Keywords: oral candidiasis, Candida, identification, antifungal susceptibility