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Blastocystis in a Liver Abscess: An Unusual Extraintestinal Location
Daniel Rodríguez-Zúñiga1, Belén Rivaya2, María Vanessa López-Peláez3
1Microbiology Department, Jove Hospital Foundation, Asturias, Gijón, Spain.
Abstract:
Blastocystis is a common anaerobic protist of uncertain pathogenicity that inhabits the human intestine. Rare cases reported in the literature suggest possible extraintestinal dissemination by unclear mechanisms. We followed a 43-year-old Peruvian woman presenting with low-grade fever and gastrointestinal symptoms who was diagnosed with a liver abscess by ultrasound and CT imaging. Identification of the causative agents was achieved through a combination of mass spectrometry, molecular methods (PCR and Sanger sequencing) and culture-based methods in blood, tissue and faecal samples. We detected gut-associated aerobic and anaerobic bacteria, including Escherichia coli, Eikenella corrodens and Bacteroides fragilis. Active forms of Blastocystis subtype ST1 were identified in the liver abscess fluid and successfully cultured in vitro. These findings suggest translocation of gut microbiota into the portal circulation as the underlying route of infection. Blastocystis can act as an opportunistic invasive microorganism in locations other than the intestinal tract.
Insights
Blastocystis, a common gut microbe, was found in a liver abscess, suggesting it can spread outside the intestine. This case highlights Blastocystis as a potential opportunistic pathogen in extraintestinal infections.
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.
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