It is normal to identify low numbers of yeast cells in stool samples, says a clinical study published in Infectious Disease Reports. Some patients exposed to high levels of antibiotics exhibit high levels of yeast in stool samples but this finding does not appear to have any clinical significance.
High levels of yeast in the stool may be associated with inflammatory conditions, argues Carol A. Kumamoto in a review article published in Current Opinion in Microbiology. Kumamoto's opinion is based on the fact many patients suffering from gastrointestinal diseases such as Crohn's disease may have increased yeast in the stool. The author notes however that since many of these patients receive regular treatment with antibiotics, the level of yeast in the stool may be a side effect of the antibiotics.
Stool is tested for pathogenic organisms in cases of diarrhea that continue for several days, says the American Association for Clinical Chemistry. The test distinguishes between disease-causing organisms and the many organisms that are normally found in stool. The bacteria, fungi and yeast that normally inhabit the gastrointestinal tract are called normal flora. Pathogenic organisms usually enter the digestive tract via contaminated foods and beverages. The most common organisms that cause diarrhea are salmonella, shigella, campylobacter, certain strains of Escherichia coli and Clostridium difficile.