Can the Evidence-Based Use of Probiotics (Notably Saccharomyces boulardii CNCM I-745 and Lactobacillus rhamnosus GG) Mitigate the Clinical Effects of Antibiotic-Associated Dysbiosis?

Abstract

Dysbiosis corresponds to the disruption of a formerly stable, functionally complete microbiota. In the gut, this imbalance can lead to adverse health outcomes in both the short and long terms, with a potential increase in the lifetime risks of various noncommunicable diseases and disorders such as atopy (like asthma), inflammatory bowel disease, neurological disorders, and even behavioural and psychological disorders. Although antibiotics are highly effective in reducing morbidity and mortality in infectious diseases, antibiotic-associated diarrhoea is a common, non-negligible clinical sign of gut dysbiosis (and the only visible one). Re-establishment of a normal (functional) gut microbiota is promoted by completion of the clinically indicated course of antibiotics, the removal of any other perturbing external factors, the passage of time (i.e. recovery through the microbiota's natural resilience), appropriate nutritional support, and-in selected cases-the addition of probiotics. Systematic reviews and meta-analyses of clinical trials have confirmed the strain-specific efficacy of some probiotics (notably the yeast Saccharomyces boulardii CNCM I-745 and the bacterium Lactobacillus rhamnosus GG) in the treatment and/or prevention of antibiotic-associated diarrhoea in children and in adults. Unusually for a probiotic, S. boulardii is a eukaryote and is not therefore directly affected by antibiotics-making it suitable for administration in cases of antibiotic-associated diarrhoea. A robust body of evidence from clinical trials and meta-analyses shows that the timely administration of an adequately dosed probiotic (upon initiation of antibiotic treatment or within 48 h) can help to prevent or resolve the consequences of antibiotic-associated dysbiosis (such as diarrhoea) and promote the resilience of the gut microbiota and a return to the pre-antibiotic state. A focus on the prescription of evidence-based, adequately dosed probiotics should help to limit unjustified and potentially ineffective self-medication.

Keywords: Antibiotics; Diarrhoea; Dose; Dysbiosis; Probiotics; Strain-specificity.

Fig. 1

A diagrammatic representation of the concepts of antibiotic-associated dysbiosis and resilience. Eubiosis corresponds to a functionally stable state, indicated here as a trough. When the microbiota is perturbed by a variety of factors, collective resilience (a combination of microbiotic and host factors that have yet to be fully characterized) maintains the stable eubiotic state [–63]. However, this resilience may not be sufficient to counter the major perturbation caused by the administration of antibiotics—a perturbation that affects not only the microbiota but also the gut’s barrier functions and immune functions. The administration of antibiotics triggers a critical transition from eubiosis to dysbiosis—a less functional but meta-stable state [1]

Fig. 2

Mechanisms of action of the probiotic Saccharomyces boulardii CNCM I-745 in the context of antibiotic-associated dysbiosis. Antibiotics perturb the microbiota and the gut’s barrier functions and immune functions (left panel) [33, 37, 68, 70, 104]. The probiotic S. boulardii CNCM I-745 notably counters these perturbations and promotes a return to eubiosis by increasing microbial diversity, stimulating the microbial production of short-chain fatty acids (SCFAs), reinforcing the gut’s barrier functions and diminishing local inflammation (right panel) [–90]