Evaluation of an Antibiotic Cocktail for Fecal Microbiota Transplantation in Mouse

Abstract

Objective: This study aimed to evaluate the effect of an antibiotic cocktail on gut microbiota and provide a reference for establishing an available mouse model for fecal microbiota transplantation (FMT) of specific microbes.

Design: C57BL/6J mice (n = 24) had free access to an antibiotic cocktail containing vancomycin (0.5 g/L), ampicillin (1 g/L), neomycin (1 g/L), and metronidazole (1 g/L) in drinking water for 3 weeks. Fecal microbiota was characterized by 16S rDNA gene sequencing at the beginning, 1st week, and 3rd week, respectively. The mice were then treated with fecal microbiota from normal mice for 1 week to verify the efficiency of FMT.

Results: The diversity of microbiota including chao1, observed species, phylogenetic diversity (PD) whole tree, and Shannon index were decreased significantly (P < 0.05) after being treated with the antibiotic cocktail for 1 or 3 weeks. The relative abundance of Bacteroidetes, Actinobacteria, and Verrucomicrobia was decreased by 99.94, 92.09, and 100%, respectively, while Firmicutes dominated the microbiota at the phylum level after 3 weeks of treatment. Meanwhile, Lactococcus, a genus belonging to the phylum of Firmicutes dominated the microbiota at the genus level with a relative abundance of 80.63%. Further FMT experiment indicated that the fecal microbiota from the receptor mice had a similar composition to the donor mice after 1 week.

Conclusion: The antibiotic cocktail containing vancomycin, ampicillin, neomycin, and metronidazole eliminates microbes belonging to Bacteroidetes, Actinobacteria, and Verrucomicrobia, which can be recovered by FMT in mice.

Keywords: antibiotic cocktail; fecal microbiota transplantation; gut microbiota; mouse model; pretreatment.

FIGURE 1

The cluster of fecal microbiota. (A) Experimental design drawing. Receptor mice had free access to antibiotic cocktails containing vancomycin (0.5 g/L), ampicillin (1 g/L), neomycin (1 g/L), and metronidazole (1 g/L) in drinking water. Feces were collected on the first day of the experiment (0 W), the first week of the experiment (1 W), the third week of the experiment (3W), as well as feces from donor mice (dM) fed with normal diet and feces from receptor mice (rM) when FMT ended over another 1 week. All mice were fed a normal diet. (B) β-diversity indices of unweighted_unifrac_distance. The redder color is, the farther distance is. dM, donor mice fed with a normal diet; FMT, fecal microbiota transplantation; PLS-DA, partial least squares discriminant analysis; rM, receptor mice transplanted with microbiota from dM.

FIGURE 2

The α diversity of fecal microbiota. (A) Chao 1. (B) Observed species. (C) PD whole tree. (D) Shannon. Data represented as mean ± SD (n = 24). Bars with different letters differ significantly (P < 0.05). Chao1, observed species, and PD whole tree are species richness indices, and the Shannon index reflects the diversity of gut microbiota. PD, phylogenetic diversity.

FIGURE 3

The relative abundance of fecal microbiota at the phylum level. (A) The relative abundance of microbes. (B) The ratio of Firmicutes to Bacteroidetes. Data represented as mean ± SD (n = 24). Bars with different letters differ significantly (P < 0.05). p_ represents microbial phylum.

FIGURE 4

The relative abundance of fecal microbiota at the genus level. Data represented as mean ± SD (n = 24). Bars with different letters differ significantly (P < 0.05). g_ represents microbial genus.

FIGURE 5

The diversity and relative abundance of fecal microbiota after FMT. (A) Observed species of fecal microbiota among donor mice (dM), mice treated with the antibiotic cocktail for 3 weeks (3W), and receptor mice (rM). (B) Effect of FMT on the relative abundance of fecal microbiota at the phylum level. (C) Effect of FMT on the relative abundance of fecal microbiota at the genus level. dM: donor mice fed with normal diet; FMT, fecal microbiota transplantation; rM, receptor mice with FMT from dM; p_ represents microbial phylum, g_ represents microbial genus.