A single course of antibiotics can change the composition of oral and gut microbiomes for at least a year, according to a modelling study by UCL researchers.

Moreover, this change leads to a decrease in the number and types of microbes found in the gut, but an increase in the diversity of the oral microbiome. These patterns have been previously associated with poorer health, although the full impacts are not yet known.

The microbiome is the name given to the collection of 10-100 trillion microorganisms such as bacteria, viruses, fungi and microscopic animals that live all over our bodies, and how they interact with the environment around them.

Over 95% of the microbiome’s bacteria live in the gut. Maintaining a healthy gut with hundreds of species of bacteria is thought to be beneficial, but the impacts of antibiotic-driven shifts of the human microbiome have yet to be fully assessed.

“Though we don’t fully understand the exact role the microbiome plays in maintaining health, the effect of antibiotics is dramatic and are likely to be of some importance,” explained study author Professor Francois Balloux (UCL Genetics Institute).

Read more at UCL