Is Good Bacteria Still Good?

Many people make use of probiotics to help increase their gut health. Probiotics are defined as living bacteria that aid in your digestive system. Probiotics are considered to be good bacteria. But a recent study performed by a team of researchers at the Weizmann Institute of Science in Israel, including immunologist Eran Elinav, reveals new insights into our understanding of these good bacteria.

Probiotics are widely given to patients after they have gone through a round of antibiotic therapy. Antibiotics are often prescribed as a result of a severe infection to help the patient’s immune system in clearing the overall host bacterial load. But, as it is the nature of antibiotics, in addition to the elimination of the infection or harmful bacteria, the commensal bacteria in the gut die as well, this process is known as dysbiosis. An adverse outcome of dysbiosis is antibiotic-associated-diarrhea, causing extreme loss of fluids and electrolytes. Severe dehydration, untreated, can lead to death.

One of the proposed methods to reconstitute the gut bacteria is to take probiotics. However, Elinav and team recognize that this avenue has not been entirely researched for its efficacy. Most studies that have explored this question will utilize a stool sample to get an idea of the current microbiome. Elinav and team have asked the question, what is the difference in individuals that take probiotics after taking antibiotics when compared to individuals who do not take probiotics after antibiotics? The researchers also included the results of individuals who utilize an autologous (self) fecal microbiome transplant.

“We invasively examined the effects of multi-strain probiotics or autologous fecal microbiome transplantation (aFMT) on post-antibiotic reconstitution of the murine and human mucosal microbiome niche,” states the team.

The researchers found that antibiotics increased the probiotic colonization in the human mucosa but only slightly improved in mice. Interestingly, the team also discovered that when compared to spontaneous post-antibiotic recovery, probiotics seemed to cause a delayed and incomplete indigenous stool/microbiome environment. The autologous fecal microbiome transplant, however, resulted in a rapid and near-complete recovery in only a few days.

The results suggest probiotics used after antibiotic treatment may hinder the gut’s ability to return its microbiome to homeostasis quickly. 

Elinav shares that, “collectively, potential post-antibiotic probiotic benefits may be offset by a compromised gut mucosal recovery, highlighting a need of developing aFMT or personalized probiotic approaches achieving mucosal protection without compromising microbiome recolonization in the antibiotics-perturbed host.”

Additionally, though this study did not measure the clinical effects of the prolonged gut disturbances associated, previous studies make connections between alterations in the gut homeostasis to inflammation, obesity, and allergies. It is important to remember that when taking antibiotics to do so in a safe manner and heed the instructions provided by the physician prescribing them to avoid any adverse effects of the therapy may bring with it.

Sources: New Scientist, Cell, WebMD, MayoClinic