25 Ago Prevalence, risk factors and subtypes of Blastocystis spp. in HIV infected patients in Italy

Blastocystis is an anaerobic unicellular protozoon. It is one of the most commonly encountered intestinal parasites in human faecal samples with uncertain impact on public health. We have recently acquired data concerning the prevalence and frequency of the Blastocystis subtypes (STs) in HIV positive Italian patients. A total of 108 HIV patients were enrolled between January 2016 and May 2017 and screened for intestinal parasites. Stool samples were examined by microscopy and subsequently subjected to DNA isolation and Sequence Tagged Site (STS)-PCR analysis. Potential etiological factors and clinical features were evaluated and compared between Blastocystis infected and non-infected individuals. The overall prevalence of intestinal parasites was 30.5%. Blastocystis was identified in stool samples of 28 patients (25.9%) using PCR assay. The detection rate was higher in men who have sex with men (MSM) (p=0.011) and Blastocystis was frequently associated with the concomitant isolation of other non-pathogenic parasites (p=0.0081). The most prevalent subtype was ST3 (55.5%) followed by ST1 (25.9%), ST2 (11.1%) and ST4 (7.4%). No association with gastrointestinal symptoms was observed (p=0.315). No correlation was found between the presence of Blastocystis and CD4 + T cell counts or ongoing anti-retroviral therapy (ART). This represents the first European study, which examines the prevalence of Blastocystis STs among HIV positive patients.