Saccharomyces boulardii as therapeutic alternative in experimental giardiasis

J Appl Microbiol. 2021 Jul;131(1):460-469. doi: 10.1111/jam.14941. Epub 2020 Dec 9.


Aims: The objective of this study was to evaluate the effect of treatment with the probiotic Saccharomyces boulardii with or without metronidazole in experimental giardiasis.

Methods and results: The effect of treatment with S. boulardii with or without metronidazole on the intestinal mucosa, the antioxidant defence system and the parasitic load was determined in experimental giardiasis. Eight groups of animals with infection and/or treatment with the probiotic and/or drugs for 1 week after infection with Giardia lamblia were used. A reduction of approximately 90% in the parasitic load was observed in all the treated groups. Saccharomyces boulardii attenuated the damage caused by infection in the intestinal mucosa preserving its architecture and inhibiting the oxidative stress induced by parasite and metronidazole.

Conclusions: Saccharomyces boulardii was effective alone or in combination with metronidazole in resolving already established G. lamblia infection.

Significance and impact of the study: These results suggest the use of S. boulardii as an alternative treatment for giardiasis mainly in cases of resistance or intolerance to conventional treatment.

Keywords: Giardia lamblia; Saccharomyces boulardii; intestinal mucosa; metronidazole; oxidative stress; probiotic.

MeSH terms

  • Animals
  • Antiprotozoal Agents / therapeutic use*
  • Disease Models, Animal
  • Gerbillinae
  • Giardia lamblia / drug effects
  • Giardiasis / drug therapy*
  • Giardiasis / parasitology
  • Intestinal Mucosa / drug effects
  • Intestinal Mucosa / parasitology
  • Metronidazole / therapeutic use
  • Oxidative Stress / drug effects
  • Parasite Load
  • Probiotics / pharmacology
  • Probiotics / therapeutic use*
  • Saccharomyces boulardii / physiology*


  • Antiprotozoal Agents
  • Metronidazole