Hui Zhang1, Zhongkai Shi2, Qiwen Yang1, Yu Chen1, Yingchun Xu3. 1. Microbiology Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China. 2. Department of Clinical Laboratory, Heilongjiang Provincial Hospital, Haerbin, Heilongjiang 150036, China. 3. Microbiology Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China. Email: xycpumch@139.com.