Blastocystis in a Liver Abscess: An Unusual Extraintestinal Location

Area of Science:

• Microbiology
• Infectious Diseases
• Gastroenterology

Background:

• Blastocystis is a common intestinal anaerobic protist with debated pathogenicity.
• Extraintestinal dissemination of Blastocystis is rarely reported, with unclear mechanisms.

Purpose of the Study:

• To investigate the potential for Blastocystis to cause extraintestinal infections.
• To identify the causative agents of a liver abscess in a Peruvian woman.

Main Methods:

• Mass spectrometry, PCR, Sanger sequencing, and culture-based methods were used.
• Samples included blood, tissue (liver abscess), and fecal matter.
• Conventional and molecular techniques identified aerobic and anaerobic bacteria and Blastocystis.

Main Results:

• Blastocystis subtype ST1 was identified in the liver abscess fluid and cultured in vitro.
• Gut-associated bacteria including Escherichia coli, Eikenella corrodens, and Bacteroides fragilis were also detected.
• The findings suggest translocation of gut microbiota into the portal circulation caused the infection.

Conclusions:

• Blastocystis can translocate from the gut and act as an opportunistic pathogen.
• This case demonstrates Blastocystis ST1 causing an extraintestinal infection (liver abscess).
• Gut microbiota translocation is a plausible mechanism for such invasive infections.