Correlation between gastrointestinal fungi and varying degrees of chronic hepatitis B virus infection Yu Chen, Zhenjing Chen, Renyong Guo, Nan Chen, Haifeng Lu, Shuai Huang, Jie Wang, Lanjuan Li ⁎ State Key Laboratory for Diagnosis and Treatment of Infectious Disease, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, PR China Received 10 December 2009; accepted 9 April 2010 Abstract This study aims to compare the diversity of intestinal fungal microbiota in patients with different degrees of chronic hepatitis B virus (HBV) infection. Culture-independent and culture-dependent methods were performed on 38 patients with hepatitis B cirrhosis, 35 patients with chronic hepatitis B, 33 HBV carriers, and 55 healthy volunteers. An overall fungal biodiversity of 37 different operational taxonomic units was found in the clone libraries; only Candida spp. and Saccharomyces cerevisiae were obtained by the culture-dependent analysis. There was a higher richness of fungal species in patients with hepatitis B cirrhosis than in patients with chronic hepatitis B, and the latter was higher than that in HBV carriers and healthy volunteers. There was little difference in enteric fungal diversity between HBV carriers and healthy volunteers. The results indicate that the diversity of enteric fungi was positively correlated with the disease progression of patients with different degrees of chronic HBV infection. © 2011 Elsevier Inc. All rights reserved. Keywords: 18S rDNA; Culture-independent method; Diversity; Intestinal fungi; HBV infection 1. Introduction Hepatitis B is a major global health problem. About 2 billion people have been infected with the hepatitis B virus (HBV), and more than 350 million have chronic liver infections. According to the Hepatitis B (2000) Fact Sheet of the World Health Organization, hepatitis B is endemic in China and other parts of Asia, where 8% to 10% of the adult population is chronically infected. Altered intestinal micro- biota is a common complication in liver disease (Norman and Pirlich, 2008). Human intestinal microecology plays an essential role in metabolic activities, immunity, and trophic function (Blaut and Clavel, 2007; Guarner and Malagelada, 2003). Human intestinal microbiota was recently understood to constitute a novel “organ” integral to human health and disease (Eckburg et al., 2005; O'Hara and Shanahan, 2006). The adult human gastrointestinal tract contains bacteria, archaea, yeasts, and filamentous fungi. To date, most molecular studies have characterized gastrointestinal bacterial diversity, but the fungal community has been largely neglected (Guarner and Malagelada, 2003; Rajilic-Stojanovic et al., 2007; Zoetendal et al., 2008). Due to the development of molecular biology instru- ments, such as polymerase chain reaction (PCR) amplifica- tion and small subunit ribosomal RNA-based technologies, a more comprehensive phylogenetic framework exists for identifying microbial diversity in intestinal microbiota. With the application of culture-independent methods, the diversity of bacteria within the human gut was documented to be approximately 800 species (Backhed et al., 2005) instead of 400 to 500 cultured bacterial species as previously assumed (Moore and Holdeman, 1974). The first culture-independent analysis of mammalian enteric fungi revealed unprecedented diversity and multiple fungal species in murine gut (Scupham et al., 2006). The latest research showed that the gastrointestinal eukaryotic Available online at www.sciencedirect.com Diagnostic Microbiology and Infectious Disease 70 (2011) 492 – 498 www.elsevier.com/locate/diagmicrobio ⁎ Corresponding author. Tel.: +86-571-87236458; fax: +86-571- 87236459. E-mail address: ljli@zju.edu.cn (L. Li). 0732-8893/$ – see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.diagmicrobio.2010.04.005