Experiments in mice show that a regimen of low-fibre foods keeps the gut microbiome from bouncing back.

A low-fibre diet could hamper the recovery of a healthy gut microbiome after antibiotic therapy.

Kerwyn Casey Huang at Stanford University in California and his colleagues studied intestinal bacteria in mice whose guts had been populated with microbes from a human donor. For five days, the team treated the ‘humanized’ mice with common antibiotics, such as streptomycin and ciprofloxacin.

Gut-microbe density dropped up to 100,000-fold within half a day of the rodents beginning antibiotics. Certain microbial species began to recover by about the third day of antibiotics, but recovery was delayed in mice fed a fibre-poor diet.

The researchers also gave streptomycin to mice with rodent microbiomes and found that animals housed alone were slower to recover than those housed in groups. Streptomycin can eliminate different bacterial strains in different animals, so mice living communally might have reconstituted their gut microbiomes more quickly by taking up microbes from their roommates.

The authors suggest that the fibre-poor diets and highly sanitized environments common in Western society could hinder the recovery of the microbiome in humans who’ve taken antibiotics.