Gut bacteria influence Blastocystis sp. phenotypes and may trigger pathogenicity.

Area of Science:

• Microbiology
• Human Gut Microbiome
• Parasitology

Background:

• The role of intestinal microbiota in various diseases is established, but its influence on other infective organisms remains understudied.
• Blastocystis sp. is a common human intestinal parasite with a debated pathogenic potential.

Purpose of the Study:

• To investigate the association and interaction between Blastocystis sp. and the human intestinal microbiota.
• To determine if the intestinal microbiota influences the phenotype and pathogenicity of Blastocystis sp. ST3.

Main Methods:

• Comparison of gut microbiomes in Blastocystis sp.-free and Blastocystis sp. ST3-infected individuals (symptomatic and asymptomatic).
• Inferred metagenomic analysis to assess microbial functions.
• Co-culture experiments of Blastocystis sp. isolates from symptomatic and asymptomatic individuals with bacterial suspensions.

Main Results:

• Blastocystis sp. ST3 infection alters bacterial composition and microbial richness, particularly in asymptomatic individuals.
• Co-culturing Blastocystis sp. from a symptomatic individual with bacteria from an asymptomatic individual led to increased parasite growth and reduced pathogenicity.
• Blastocystis sp. infection influences microbial functions but has minimal impact on overall microbiota diversity.

Conclusions:

• The human gut microbiota plays a significant role in modulating the pathogenicity of Blastocystis sp.
• Bacterial interactions can transform asymptomatic Blastocystis sp. into a pathogenic form.
• This study provides a basis for understanding the variable pathogenic role of Blastocystis sp. observed in different studies.