Antibiotics can leave a long-term footprint on our gut microbiome: study

We have always known that antibiotics, life-saving drugs in serious infections, affect the composition of our gut microbiome (community of bacteria living in the gut). Now, scientists have found that certain types of antibiotics can be linked to changes that persist in the gut microbiome – and lower its diversity – for as long as up to four to eight years after treatment.

A lower diversity of gut microbiome species has been associated with a range of health conditions, such as obesity, diabetes and Inflammatory Bowel Disease, wrote scientists from Sweden in the journal Nature Medicine.

Clindamycin, fluoroquinolones and flucloxacillin had the strongest associations, Tove Fall, professor of molecular epidemiology at Uppsala University and principal investigator of the study, told The Hindu. “We saw large and long-lasting effects on the overall composition of these types including lower diversity and impact on individual bacteria types where some were reduced and others increased,” she added. 

The most commonly prescribed antibiotic to treat infections outside hospitals in Sweden – penicillin V – was linked to more short-lasting microbiome changes. 

For the study, researchers pored through Sweden’s National Prescribed Drug Register, while parallelly mapping the gut microbiome of 14,979 adults living in Sweden. Then they compared the microbiome of those who had had several types of antibiotics and those who had not received any at all for the study period.

While the reasons remain somewhat evasive, the antibiotic-catalysed changes indeed appear to leave a long-term footprint on the gut microbiome. “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,” the first author of the study, Gabriel Baldanzi, said in a press note.

The scientists believe these discoveries “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,” said Dr. Fall. “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,” she added. 

The researchers are now collecting a second sample from almost half of the participants to get a clearer understanding of the recovery time and identify “which gut microbiomes are more susceptible to disruption following antibiotic treatment,” said the paper.