1127 Infantile eczema is associated with campylobacter and roseburia subpopulations but not microbial diversity in stool samples of Chinese newborns

Wednesday, 14 October 2015
Hall D1 Foyer (Floor 3) (Coex Convention Center)

Ting Fan Leung, MD, FRCPCH, FAAAAI , Department of Paediatrics, Prince of Wales Hospital, Hong Kong, Hong Kong

Man Fung Tang, BSc , Department of Paediatrics, Prince of Wales Hospital, Hong Kong, Hong Kong

Jamie Sui-Lam Kwok, BSc , The Chinese University of Hong Kong, Hong Kong, Hong Kong

Wing Hung Tam, MD , Department of Obstetrics and Gynaecology, Prince of Wales Hospital, Hong Kong, Hong Kong

Hing Yee Sy, PhD , Department of Paediatrics, Prince of Wales Hospital, Hong Kong, Hong Kong

Christine Kit-Ching Tung, BSc , The Chinese University of Hong Kong, Hong Kong, Hong Kong

Kam Lun Ellis Hon, MD, FAAP , Department of Paediatrics, Prince of Wales Hospital, Hong Kong, Hong Kong

Gary WK Wong, MD , Paediatrics, Prince of Wales Hospital, Hong Kong

Stephen Kwok-Wing Tsui, PhD , The Chinese University of Hong Kong, Hong Kong, Hong Kong

Background: Gut microbiota is increasingly recognised to play crucial roles in the pathogenesis of asthma, obesity and autoimmune diseases. Faecal microbiome is likely ethnic and diet-specific, but such data is lacking in Asians. This study characterised faecal microbial compositions of Hong Kong Chinese infants.

Methods: Random stool samples were obtained from 4-week-old infants with eczema (n=15) and without any allergy (n=15) at 9 months. Genomic DNA extracted by PowerSoil DNA Isolation Kit (MO BIO Laboratories) was sequenced using Ion PGM Seqeuncing 200 Kit v2, Ion 318 TM Chip v2 on Ion PGM System (Ion Torrent). Reads from each patient were filtered for low quality (Phred <20). Microbial diversity was evaluated using Shannon-Weaver diversity index in Swedish (J Allergy Clin Immunol 2012;129:434-40). The taxonomic classification of the reads was assigned by BLASTn.

Results: 5 controls had insufficient DNA for sequencing. No significant association was detected between eczema and any bacteria with ≥1% relative abundance, including Bacteroides, Escherichia, Klebsiella, Bifidobacterium, Streptococcus and Lactobacillus. Among the less abundant genera (relative abundance <1%), Campylobacter was more abundant in cases (median 0.008%, IQR 0.003-0.022%) than controls (median 0.001%, IQR 0.001-0.004%) while Roseburia was less abundant in eczema (median 0%, IQR 0-0.063%) than controls (median 0.055%, IQR 0.002-0.270%). Nonetheless, Shannon-Weaver diversity index of stool microbiota at 4 weeks was similar between infants with eczema and non-allergic controls at 9 months (median [IQR]: 1.28 [0.94-1.93] versus 1.47 [1.31-1.80]; P = 0.698). Comparing microbial compositions in our newborns and Swedish, Escherichia coli was found among top 5 genera only in both our cases and controls whereas enterobacter only in Swedish newborns. Clostridium, parabacteroides and lactobacillus were found only in Chinese eczema and healthy Swedish newborns.

Conclusions: Campylobacter and Roseburia appear to be less frequently detected in stool of 4-week-old Chinese infants who subsequently develop eczema. Microbial diversity is not associated with eczema susceptibility. This study confirms ethnic-specific early-life faecal microbial compositions.

Funding: Research Committee Group Research Scheme (3110087) and Direct Grant for Research (2013.2.033), CUHK