Controversial Pathogen: Blastocystis hominis Prevalence from Patients Attending a Tertiary Care Hospital Lucknow

Blastocystis hominis (B. hominis) is one of the most common enteric parasite and a highly controversial protozoan parasite regarding its pathogenicity. It has been variably regarded as a commensal and as a pathogen. The aim of this study was to determine the prevalence of B. hominis in relation to sex and age. The purpose of this study was to get a clear idea about the existence of B. hominis in symptomatic patients and their pathogenic effect in absence of other known pathogen. The present study was conducted in the Department of Microbiology of a tertiary care Hospital in Lucknow, India. Samples were collected after taking informed consent. A total of 640 stool samples were examined microscopically Out of all the samples examined 139 samples were found to be positive for at least one parasite. Among them B. hominis was found in fecal material of 41 patients (29.4%). In the present study common symptoms associated with B. hominis infection were abdominal pain (100 %), diarrhea (78%), Nausea (65.8%), Loss of weight (43.9%), Vomiting (21.9%), Constipation (21.9%). All the 41(29.4%) patients were treated with metronidazole 250 to 500 mg BID for 5-7 days because of symptoms and the presence of B. hominis stool specimens. After 5-7 days of treatment, all patients became asymptomatic with stools negative for B. hominis on follow-up examinations.