1. Division of Pediatrics, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, P. R. China
2. Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, P. R. China
3. Department of Biochemistry, Genome, Environment and Microbiome Community of Excellence, State University of New York at Buffalo, Buffalo, NY, USA
4. Division of Infectious Diseases, Department of Pediatrics, Jacobs School of Medicine and Biological Sciences, University at Buffalo, State University of New York at Buffalo, Buffalo, NY, USA