From the Guidelines
Blastocystis hominis is generally considered normal in stool and treatment is not typically recommended for asymptomatic individuals. The presence of Blastocystis hominis in stool can be a common finding, even in healthy individuals, and its pathogenicity remains controversial 1. According to the 2017 Infectious Diseases Society of America clinical practice guidelines for the diagnosis and management of infectious diarrhea, the detection of Blastocystis hominis and Dientamoeba fragilis in stool may be clinically relevant if symptoms persist, but in the absence of other pathogens, they may not be the cause of disease 1. Key points to consider when interpreting the presence of Blastocystis hominis in stool include:
- The organism is often a commensal that lives in the intestinal tract without causing symptoms in most people
- Treatment is typically not recommended for asymptomatic individuals who have Blastocystis detected in their stool samples
- If a person experiences persistent gastrointestinal symptoms like diarrhea, abdominal pain, or bloating, and Blastocystis is found in high numbers with no other cause identified, treatment might be considered
- The presence of Blastocystis in stool should be interpreted in the clinical context, as many healthy carriers never develop symptoms It is essential to consider the clinical context and the presence of other pathogens when determining the significance of Blastocystis hominis in stool, as stated in the guidelines 1.
From the Research
Blastocystis Hominis in Stool
- Blastocystis hominis is commonly found in the intestinal tract of humans 2
- The presence of Blastocystis hominis in stool can be associated with symptoms such as abdominal pain, diarrhea, nausea, and vomiting 3
- However, many Blastocystis infections remain asymptomatic, and the pathogenicity of this unicellular parasite is still controversial 2, 4
Treatment and Eradication
- Metronidazole is often used as the first choice of chemotherapeutic agent for treating Blastocystis hominis infection 2, 5, 4
- Other drugs such as trimethoprim/sulfamethoxazole and nitazoxanide have also been used to treat Blastocystis hominis infection 2, 4, 6
- Probiotics like Saccharomyces boulardii have also shown potential beneficial effects in eradicating Blastocystis hominis 3
- Eradication of Blastocystis hominis has been associated with the prevention of symptomatic Hashimoto's thyroiditis and chronic urticaria in some cases 5
Diagnosis and Prevalence
- Blastocystis hominis can be diagnosed through microscopic examination of stool samples after staining with iodine and culturing in an egg slant medium 2
- The prevalence of Blastocystis hominis in the general population is not well established, but it is commonly found in individuals with gastrointestinal symptoms 3, 6