Blastocystis hominis, a great unknown

Introduction: Blastocystis hominis is a protozoan that is most often found in the feces of people, both symptomatic and asymptomatic. This parasite has several controversies and uncertainties, especially in their pathogenicity. The ignorance or lack of importance given to this organism by health professionals is common but more and more studies support the involvement of the parasite in clinical pathology. The aim of this study is to review the epidemiological and clinical characteristics of all children with positive parasitological studies to Blastocystis hominis attended in the last five years in our health center.

Material and methods: a retrospective and cross-check of all stool cultures and parasitological studies in the past five years to children between 1 and 15 years old was performed and the epidemiological and clinical characteristics of patients positive for this organism were subsequently revised.

Results: in the past five years 530 parasitological and stool cultures were performed, 122 were positive (23.01%). The bacteria most frequently isolated were Campylobacter jejuni, followed by Salmonella enterica. Of enteroparasite positive samples, Blastocystis hominis was the most frequently isolated (24 cases). All children were native and had not traveled abroad, except a child who had been adopted in China. No patient had impaired immunity or comorbidities.

Conclusions: Blastocystis hominis is a microorganism to consider, and from the clinical point of view it seems reasonable to offer treatment to symptomatic patients in whom an alternative pathology was discarded.