Comparison between the Effect of Secondary Metabolic Products of Nutrient Medium and Modified Medium of Yeast Saccharomyces boulardii Against Different Bacterial Species

Abstract

Background: Saccharomyces boulardii yeast are characterized by their resistance to the acidic environment in the stomach and a high ability to survive in these conditions. S. boulardii produces metabolites that make it able to resist acidic environments, act as an anti-inflammatory, and stimulate the immune system, as well as its effectiveness against intestinal bacterial pathogens. Therefore, this study aimed to determine the effect of secondary metabolic products of the nutrient media and the modified media of the yeast S. boulardii against different bacterial species.

Methods: Yeast S. boulardii was obtained from the markets of Anbar city. The strains of the bacterial species isolated from burn patients were provided by the microbiology laboratory at the burn center at Ramadi Hospital, Anbar, Iraq. Bacterial strains Enterococcus faecalis, Staphylococcus epidermis, Escherichia coli, Serratia marcescens, and Pseudomonas aeruginosa were grown in nutrient agar media for 24 hours and surface spread in petri plate. The antibacterial activities of S. boulardii are tested by the agar diffusion method.

Results: In this study, the results indicate that S. boulardii yeast when grown in the modified media as the incubation period increases, the active substances that have positive antimicrobial activity against the five bacterial species increase. The results showed that the E. coli, P. aeruginosa, and S. marcescens bacteria are the most affected by S. boulardii yeast filtrate due to the modified media, especially at the incubation period of 168 hours, where the inhibition zone for these bacteria was 19 and 18 mm.

Conclusion: The study concluded that S. boulardii yeast proved effective in inhibiting five types of bacteria. In addition, the microbial activity of S. boulardii yeast against these bacteria was clear and high when grown in the modified media compared to its growth in the nutrient (natural) media.