Selective Regional Alteration of the Gut Microbiota by Diet and Antibiotics

Abstract

The small intestinal microbiota has recently been implicated in contributing to metabolic disease. We previously demonstrated that diets rich in saturated milk fat have a particularly strong impact on the small bowel microbiota as opposed to more distal gastrointestinal (GI) regions. However, the impact of antibiotics and diet on the small bowel microbiota has not been clearly demonstrated. Thus, we sought to determine how diet and antibiotics interact in modulating the regional landscape of the gut microbiota. We conducted a study using male mice on a high fat (HF) or a low fat (LF) diet (n = 15/group) that received either water control (n = 5/diet), rifaximin, (nonabsorbable broad-spectrum antibiotic; n = 5/diet) or an antibiotic cocktail consisting of metronidazole, cefoperazone, vancomycin, and neomycin (Abx cocktail; n = 5/diet). 16S rRNA sequencing was performed on mucosal scrapings collected from the small intestine and cecum, as well as on stool samples. Interestingly, antibiotics had a significant effect on community composition throughout the small intestine, cecum and stool, whereas diet significantly affected only the jejunum and cecum microbiota. The antibiotic cocktail, regardless of diet, was most effective in increasing cecum size, reducing body fat percentage, and plasma lipid levels. Altogether, this study reveals a selective and divergent regional alteration of the gut microbiota by diet and antibiotics.

Apyrase-mediated amplification of secretory IgA promotes intestinal homeostasis

“…ABXs strongly affect microbial diversity and intestinal barrier function, leading to bacterial translocation of live commensal bacteria to the mesenteric lymph nodes (MLNs) (Knoop et al, 2016). A characteristic feature of reduced bacterial load after ABX treatment is cecum enlargement, which characterizes also GF animals (Devkota et al, 2012;Poteres et al, 2020). Analysis of cecum weight 4 days after recovery from ABX treatment revealed a pronounced increase of this parameter, as expected.…”

Jejunum: The understudied meeting place of dietary lipids and the microbiota

“…Specific bacterial strains, such as Clostridium, influence processes underlying intestinal lipid absorption (see section 5.4). Recently, by comparing the effects of diet (high fat versus low fat), broad-spectrum antibiotics and antibiotic cocktails, Poteres et al (2020) showed that antibiotics had an effect on the murine small intestine, caecum and faeces microbiota composition, while diet significantly affected only the jejunum and caecum microbiota, suggesting that diet has a selective regional impact on the gut microbiota [13]. In addition, Turnbaugh et al (2009) showed using humanized mice that switching from a low-fat, plant polysaccharide-rich diet to a high-fat, high-sugar "Western" diet shifts the composition of the microbiota within a single day and changes microbial metabolic pathways and gene expression along the length of the gut, including in the small intestine [116].…”

“…Recently, several papers demonstrated the existence of crosstalk among dietary lipids, the jejunum microbiota and the jejunal epithelium [8][9][10][11][12][13]. This review aims to highlight this currently understudied topic and to provide arguments regarding the need for future studies.…”

Dietary fatty acids in gut health: Absorption, metabolism and function

“…Through a comparison of the dietary effects, antibiotic cocktails and broad-spectrum antibiotics, Poteres et al. ( Poteres et al., 2020 ) revealed that antibiotics impacted the murine small intestine, faeces and caecum microbiota make-up, whereas dietary intake highly influenced caecum and jejunum microbiota, implying that dietary intake exerts specific and localized effect over gastro-intestinal microbiota. Thus, future exploration on how lipids influence the microbial content in human jejunum is needed to decipher the detailed relationship between microbiota, host, and diet.…”