Study shows antibiotics can alter stomach content for up to 8 years

By Stephen Beech

Antibiotics can alter the contents of your stomach for up to eight years, according to new research.

Even a single course of treatment with certain types of the prescription-only medicines may affect the composition of the community of bacteria living in the gut for several years, suggest the findings.

The study, published in the journal Nature Medicine, shows that some types of antibiotics can be linked to changes to the gut microbiome as long as four to eight years after treatment.

It is well documented that antibiotics can save lives when used to treat serious infections.

But previous studies have also indicated links between high antibiotic use and an increased risk of certain health conditions, including type 2 diabetes and gastrointestinal infections.

The reasons are not fully understood, but changes in the gut microbiome are believed to play a role.

It was already known that antibiotics have a short-term impact on the gut microbiome, but how long the changes persist was unclear.

An international research team, led by scientists in Sweden, has now found "strong" links between a person’s history of antibiotic use and the composition of their gut microbiome.

Study first author Dr. Gabriel Baldanzi said: “We can see that antibiotic use as far back as four to eight years ago is linked to the composition of a person’s gut microbiome today.

"Even a single course of treatment with certain types of antibiotics leaves traces.

“Antibiotic use is taken very seriously in Sweden, and country already have a strict antibiotic stewardship.

“People should continue to follow their doctor’s recommendations.

More from this section

Do you get heart palpitations when lying down?

What does the appendix do? Biologists explain the complicated evolution of this inconvenient organ

+2

Teens spend a third of school day on smartphones

"Having said that, our findings help shed light on other long-term consequences of antibiotics that are rarely considered.”

The research team analyzed drug register data alongside a detailed mapping of the gut microbiome of 14,979 adults living in Sweden.

The gut microbiome was compared between participants who had received different types of antibiotics and those who had not received any at all during the period.

The study was made possible by Sweden’s comprehensive prescribed drug register, which contains information on all antibiotics dispensed at pharmacies.

The researchers were then able to link the data to Swedish biobanks at Uppsala and Lund University containing gut microbiome data.

The research team found that the results differed substantially depending on the type of antibiotic used.

The strongest associations were observed for clindamycin, fluoroquinolones and flucloxacillin.

By contrast, penicillin V, the most commonly prescribed antibiotic for the treatment of infections outside hospitals in Sweden, was linked to small and short-lasting microbiome changes.

Study principal investigator Professor Tove Fall said: “The strong link between the narrow-spectrum flucloxacillin and the gut microbiome was unexpected, and we would like to see this finding confirmed in other studies.

"However, we believe that the findings of our study may help inform future recommendations on antibiotic use, especially when choosing between two equally effective antibiotics, one of which has a weaker impact on the gut microbiome,”

The research team acknowledged that the study only covered prescriptions from the previous eight years and that a longer follow-up period could provide further insights, and that the gut microbiome was sampled only once per participant.

But Fall, of Uppsala University, added: “We are currently collecting a second sample from almost half of the participants.

“This will enable us to gain an even better understanding of the recovery time and identify which gut microbiomes are more susceptible to disruption following antibiotic treatment.”