Gastroesophageal reflux and PPI exposure alter gut microbiota in very young infants

Abstract

Importance: Infants with symptomatic Gastroesophageal reflux are treated with pharmacological therapy that includes proton pump inhibitors (PPI) with clinical improvement. The alterations to gut microbiome profiles in comparison to infants without reflux is not known.

Objective: To determine the effect of PPI therapy on gut bacterial richness, diversity, and proportions of specific taxa in infants when compared to infants not exposed to acid suppressive therapy.

Design setting and participants: This cohort study was conducted at the Stony Brook Hospital in Stony Brook, NY between February 2016, and June 2019. Infants meeting inclusion criteria were enrolled in a consecutive fashion.

Results: A total of 76 Infants were recruited and 60 were enrolled in the study, Twenty nine infants met clinical criteria for reflux and were treated with PPI therapy: median [IQR] gestation: 38.0 weeks [34.7-39.6 weeks]; median [IQR] birthweight: 2.95 Kg [2.2-3.4]; 14 [46.7%] male) and 29 infant were healthy controls median [IQR] gestation: 39.1 weeks [38-40 weeks]; median [IQR] birthweight: 3.3 Kg [2.2-3.4]; 17 [58.6%] male); 58 stool samples from 58 infants were analyzed. There were differences in Shannon diversity between the reflux and control groups. The reflux group that was exposed to PPI therapy had increased relative abundance of a diverse set of genera belonging to the phylum Firmicutes. On the other hand, the control group microbiota was dominated by Bifidobacterium, and a comparatively lower level of enrichment and abundance of microbial taxa was observed in this group of infants.

Conclusions and relevance: We observed significant differences in both α- and β-diversity of the microbiome, when the two groups of infants were compared. The microbiome in the reflux group had more bacterial taxa and the duration of PPIs exposure was clearly associated with the diversity and abundance of gut microbes. These findings suggest that PPI exposure among infants results in early enrichment of the intestinal microbiome.

Keywords: dysbiosis; gastroesophageal reflux; infants; microbiome; proton pump inhibitors.

Figure 1

Intestinal microbiota differ in overall composition (β-diversity) with gastroesophageal reflux. Panels (A) and (B) compare subjects with and without reflux, while panels (C) and (D) stratify Reflux infants by PPI use. In panels (A) and (C), relative abundances of taxa are summarized at the genus level. Between-group differences in β-diversity were evaluated by permutational ANOVA, with significant results indicated by asterisks. The results of principal components analyses are shown in panels (B) and (D).

Figure 2

Microbial diversity (α-diversity) differs with gastroesophageal reflux. Violin plots compare richness (Chao1), evenness (Shannon H/Hmax), and Shannon diversity (H) of intestinal microbiota between infants with and without Reflux (panel A) and stratified by PPI use (panel B). Results of ANOVA tests are indicated by asterisks.

Figure 3

Individual taxa differing in relative abundance by Reflux status and PPI use. The left column of panels are volcano plots of fold-change (FC; Log2 transformed) vs FDR-corrected p-values (-Log10 transformed) ascertained by ALDEx2 analysis (See Methods). Vertical and horizontal dashed lines represent cutoffs of FC ≥1.5 and FDR-corrected p-value ≤0.1, respectively. The right column of panels are ALDEx2-calculated effect sizes of taxa meeting FC and FDR-corrected p-value cutoffs. In all panels, taxa enriched in the control group (CON) are highlighted in blue with FC and effect sizes less than zero, while taxa enriched in comparison groups (Reflux, PP ≤ 30 d, PPI > 30 d) are highlighted in red with FC and effect sizes greater than zero.