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Cobuccio LG, Laurent M, Gardiol C, Wampfler R, Poppert S, Senn N, Eperon G, Genton B, Locatelli I, de Vallière S. Should we treat Blastocystis sp.? A double-blind placebo-controlled randomized pilot trial. J Travel Med 2023; 30:6849435. [PMID: 36440639 DOI: 10.1093/jtm/taac143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUND Blastocystis sp. is a worldwide-distributed protist colonizing the guts of humans and a great variety of animals. It is unclear whether it is just a commensal or an infectious parasite that prompts eradication.The main objective of this study was to evaluate the usefulness of metronidazole in patients with gastrointestinal symptoms harbouring only Blastocystis sp. In addition, we explored whether Blastocystis subtype or concomitant parasitic infection detected by polymerase chain reaction (PCR) may influence treatment outcome. METHODS We included adults with persistent gastrointestinal symptoms (>14 days) visiting a primary care physician and in whom stool microscopy revealed only Blastocystis sp. Eligible patients were randomized to receive 10 days of metronidazole or placebo, followed by a crossover if still symptomatic. The primary outcome was normal stool consistency. Secondary outcomes were the changes in other abdominal symptoms (bloating, flatulence, abdominal pain, number of daily bowel movements) and general wellbeing. After the clinical phase of the study, Blastocystis subtypes were determined by PCR sequencing and stool samples were tested for 11 other protozoa with an in-house PCR. RESULTS We screened 581 outpatients for inclusion, of which 50 met the eligibility criteria. There was no difference in the primary outcome, nor any of the secondary outcomes between the subjects treated with metronidazole and placebo.The most frequent Blastocystis subtypes were ST4 (11/36) and ST2 (10/36). The in-house PCR was positive for other protozoa in 25% (10/40) of the patients. We identified Dientamoeba fragilis in 5, Entamoeba dispar in 3 and Cyclospora cayetanensis in 2 patients. Stratified analysis according to Blastocystis subtype or the presence of other protozoa showed no significant difference in treatment outcome with metronidazole or placebo. CONCLUSIONS Among patients infected with Blastocystis sp., metronidazole, compared with placebo, was not better in improving gastrointestinal symptoms, irrespective of subtype or microscopically undetected coinfection with other protozoa.
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Affiliation(s)
- Ludovico Gennaro Cobuccio
- Travel Clinic, Centre for Primary Care and Public Health (Unisanté), Lausanne, Switzerland
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Marie Laurent
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Celine Gardiol
- Travel Clinic, Centre for Primary Care and Public Health (Unisanté), Lausanne, Switzerland
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Rahel Wampfler
- Diagnostic Center, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Sven Poppert
- Diagnostic Center, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Nicolas Senn
- Travel Clinic, Centre for Primary Care and Public Health (Unisanté), Lausanne, Switzerland
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Gilles Eperon
- Division of Tropical and Humanitarian Medicine, Geneva University Hospitals, Geneva, Switzerland
| | - Blaise Genton
- Travel Clinic, Centre for Primary Care and Public Health (Unisanté), Lausanne, Switzerland
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- Department of Research and Innovation, Centre for Primary Care and Public Health (Unisanté), Lausanne, Switzerland
| | - Isabella Locatelli
- Department of Research and Innovation, Centre for Primary Care and Public Health (Unisanté), Lausanne, Switzerland
| | - Serge de Vallière
- Travel Clinic, Centre for Primary Care and Public Health (Unisanté), Lausanne, Switzerland
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- Infectious Diseases Service, University Hospital, Lausanne, Switzerland
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