Characterization of Bacterial and Fungal Microbiome in Children with Hirschsprung Disease with and without a History of Enterocolitis: A Multicenter Study.

Philip K Frykman,Iliyan Iliev,Agneta Nordenskjöld,Vince A Funari,Akemi Kawaguchi,Anna L Granström,Zhi Cheng,David M Underhill,Thomas T Hui,Tomas Wester,Jie Tang,Reeta Prusty Rao

doi:10.1371/journal.pone.0124172

Abstract

Development of potentially life-threatening enterocolitis is the most frequent complication in children with Hirschsprung disease (HSCR), even after definitive corrective surgery. Intestinal microbiota likely contribute to the etiology of enterocolitis, so the aim of this study was to compare the fecal bacterial and fungal communities of children who developed Hirschsprung-associated enterocolitis (HAEC) with HSCR patients who had never had enterocolitis. Eighteen Hirschsprung patients who had completed definitive surgery were enrolled: 9 had a history of HAEC and 9 did not. Fecal DNA was isolated and 16S and ITS-1 regions sequenced using Next Generation Sequencing and data analysis for species identification. The HAEC group bacterial composition showed a modest reduction in Firmicutes and Verrucomicrobia with increased Bacteroidetes and Proteobacteria compared with the HSCR group. In contrast, the fecal fungi composition of the HAEC group showed marked reduction in diversity with increased Candida sp., and reduced Malassezia and Saccharomyces sp. compared with the HSCR group. The most striking finding within the HAEC group is that the Candida genus segregated into “high burden” patients with 97.8% C. albicans and 2.2% C. tropicalis compared with “low burden” patients 26.8% C. albicans and 73% C. tropicalis. Interestingly even the low burden HAEC group had altered Candida community structure with just two species compared to more diverse Candida populations in the HSCR patients. This is the first study to identify Candida sp. as potentially playing a role in HAEC either as expanded commensal species as a consequence of enterocolitis (or treatment), or possibly as pathobioants contributing to the pathogenesis of HAEC. These findings suggest a dysbiosis in the gut microbial ecosystem of HAEC patients, such that there may be dominance of fungi and bacteria predisposing patients to development of HAEC.

Highlights

Congenital aganglionic megacolon, more commonly known as Hirschsprung disease (HSCR), was first described by Harald Hirschsprung in 1887 [1]
With the advancement of molecular microbiological techniques, a PCR based methodology demonstrated that colonization of Bifidobacteria and Lactobacilli genera were decreased in HSCR patients who developed Hirschsprung-associated enterocolitis (HAEC), compared with those who did not develop HAEC [7], suggesting that the composition of the bacterial populations may play a role HAEC
Fecal specimens from multiple regions of the colon were obtained at the time of surgery and showed increased bacterial population diversity in the HAEC patients compared with HSCR patients

Summary

Introduction

Congenital aganglionic megacolon, more commonly known as Hirschsprung disease (HSCR), was first described by Harald Hirschsprung in 1887 [1]. A microbial role in the development of HAEC has been suspected since it was first described over 50 years, at present, no specific organisms have been identified [3] Both Clostridium difficile and rotavirus have been implicated as causative agents of HAEC, neither were consistently present in patients HAEC [4,5,6]. Fecal specimens from multiple regions of the colon were obtained at the time of surgery and showed increased bacterial population diversity in the HAEC patients compared with HSCR patients. These early data suggest the possibility that HSCR children who develop HAEC have a shift from predominant “symbioant” microbes to potentially harmful “pathobioant” referred to as dysbiosis. Dysbioses have been identified as playing an important role in other gastrointestinal conditions such as inflammatory bowel disease [9]

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