Probiotics should be considered when prescribing antibiotics, finds systematic review

Prescribers should consider recommending that patients take a course of probiotic supplements alongside antibiotics, a systematic review has concluded.

Results of the systematic review of 29 studies, published in the Journal of Medical Microbiology on 16 November 2022, showed that probiotics taken alongside antibiotics decreased diarrhoea and protected the diversity of bacteria in the gut.

The review considered papers that looked at the effect on the composition of bacteria in the gut of antibiotics, probiotics, and the two combined.

The studies all used 16S rRNA technology to assess the gut microbiome. Of the 29 studies, 11 looked at the effect of antibiotics, 11 looked at probiotics and 7 looked at antibiotics plus probiotics.

The antibiotic studies showed a decline in bacterial diversity in the gut after taking antibiotics. Certain genera and species, including the beneficial bacteria Faecalibacterium prausnitzii, were less common after people had taken antibiotics. Some studies showed that people’s gut microbiome took eight weeks or longer to recover.

Results from the probiotic studies were less clear. Only 4 of 11 studies showed an increase in bacterial diversity in the gut after taking probiotics. The authors of the review note that this could have been because people already had a varied gut microbiome before taking probiotics.

In five of the seven studies that added probiotics to antibiotics, patients were less likely to experience diarrhoea or other gastrointestinal symptoms if they were also taking probiotics. In four studies, the addition of probiotics helped to preserve bacterial diversity.

The researchers acknowledge that a wide diversity of methods used in the studies, including in types of antibiotics, types of probiotics and lengths of courses, make it harder to draw definite conclusions.

Review author Elisa Marroquin, assistant professor in the department of nutritional sciences at Texas Christian University, said the balance of the evidence pointed to prescribing probiotics alongside an antibiotic course.

“When participants take antibiotics, we see several consistent changes in some bacterial species. But when treatment was combined with probiotics, the majority of those changes were less pronounced and some changes were completely prevented.

“Considering the human data available up to this point, there does not seem to be a reason to withhold a prescription of probiotics when antibiotics are prescribed,” she said.

Commenting on the findings, Laura McCoubrey, a pharmacy PhD student at the UCL School of Pharmacy, said the study did not produce enough evidence that probiotics should be prescribed along with antibiotics.

“Based on this review, I don’t feel we can recommend a specific type of probiotic intervention,” she said.

“Instead, I would recommend that patients ensure they have enough prebiotic sources in their diets (i.e. fibre from fruit and veg) to promote the recovery of a healthy baseline microbiome.”

She said that the diversity of probiotics used, and their length of course, made it difficult to make a specific recommendation to patients who were keen to try probiotics.

“In the medium to long term, I think the future will involve personalised probiotic prescriptions. This would mean that individual patients’ microbiomes are sequenced, allowing prescribers to identify the specific microbial species that a patient may be lacking.”