[Blastocystis hominis in patients at the Ruiz y Paez University Hospital from Bolivar City, Venezuela].

Blastocystis hominis is a polymorphic protozoan of discussed taxonomic position, which is currently associated with human intestinal disease. In order to determine the prevalence of the microorganism in a sample of hospitalized patients, a study was carried out from november 1996 to april 1997 on 100 adult patients of both sexes aged 20 to 79 years at the "Ruíz y Páez" University Hospital of Bolivar city, Venezuela. A coproparasitological study was carried out using direct examination and Faust method. Infection by parasites and/or commensals was demonstrated in 48 patients. The most frequent agent was B. hominis with a prevalence of 42.0%. We did not find a statistically association between sex (P > 0.05) or age (X2 = 3.52; d.f; = 3) and B. hominis infection. B. hominis was most frequently identified as the single parasite (88.1%), and with a number of less than 5 cells per 400X microscopic field (73.8%). The infection was more common in patients with base chronic-immunosuppressive diseases, the major one being cancer. Diarrhea was observed in 27.0% of cases. Due to its high prevalence, especially as a single agent, together with the particular immunological characteristics of the patients studied, a potential pathogenic role of the opportunistic type is suggested for B. hominis.