Gut health key to avoiding runs from antibiotics: Study

If you have experienced a bout of the runs after taking antibiotics, the cause might lie in the health of your gut microbiome.

This is the ecosystem of organisms that live in a person's digestive system, and comprise various species of bacteria and fungi.

A study by researchers from Singapore General Hospital (SGH) and Singapore-MIT Alliance for Research and Technology (Smart) found that individuals with lower levels of the bacterium Faecalibacterium prausnitzii in their gut microbiome - one of the most abundant strains of bacteria in the human digestive system - were at a higher risk of getting diarrhoea after taking antibiotics.

The study took place over a four-week period in 2019 and involved 30 healthy participants who were prescribed a three-day course of orally administered amoxicillin-clavulanate, known more commonly as Augmentin.

Their stool samples were collected and analysed throughout the course of the study. Lower levels of the F. prausnitzii bacterium were found in those who had diarrhoea than in those who did not.

The finding is significant, as the onset of diarrhoea during a course of antibiotics can lead to patients stopping their medication prematurely and thus ineffective treatment, according to the study's co-author, Dr Shirin Kalimuddin, a consultant at the SGH department of infectious diseases.

"The problem is very real for patients who are unable to take amoxicillin-clavulanate because it gives them diarrhoea," she said.

"Knowing why may help us devise treatment strategies in the future to minimise or avoid such adverse effects."

The findings were published in the peer-reviewed scientific journal iScience last month.

Globally, a third of patients develop diarrhoea after being prescribed with amoxicillin-clavulanate, which is used in treating pneumonia, urinary tract infections as well as other infections.

As part of the study, the team developed a simple polymerase chain reaction test to determine the levels of the F. prausnitzii bacterium in the participants' stool samples.

This could help assess how prone a patient might be to developing diarrhoea if he were given broad-spectrum antibiotics such as Augmentin to treat an existing bacterial infection, said Dr Shirin.

The study's co-author, Professor Eric J. Alm, said: "People respond differently to medication. Understanding this response and the ability to predict those at risk will help guide the development of point-of-care diagnostics."

Prof Alm, who is the principal investigator at Smart's antimicrobial resistance interdisciplinary group, added that while much research had been conducted on how a patient's DNA might affect his response to medication, the effect of the person's gut microbiome is relatively less known.

A solution, in the form of dietary fibre, could help individuals looking to reduce their risk of suffering from diarrhoea after taking antibiotics.

Prof Alm said: "There're myriad health benefits from increasing your consumption of dietary fibre and that's probably the best recommendation for keeping a healthy gut ecosystem."