New Insights on Classification, Identification, and Clinical Relevance of Blastocystis spp

Abstract

SUMMARY Blastocystis is an unusual enteric protozoan parasite of humans and many animals. It has a worldwide distribution and is often the most commonly isolated organism in parasitological surveys. The parasite has been described since the early 1900s, but only in the last decade or so have there been significant advances in our understanding of Blastocystis biology. However, the pleomorphic nature of the parasite and the lack of standardization in techniques have led to confusion and, in some cases, misinterpretation of data. This has hindered laboratory diagnosis and efforts to understand its mode of reproduction, life cycle, prevalence, and pathogenesis. Accumulating epidemiological, in vivo, and in vitro data strongly suggest that Blastocystis is a pathogen. Many genotypes exist in nature, and recent observations indicate that humans are, in reality, hosts to numerous zoonotic genotypes. Such genetic diversity has led to a suggestion that previously conflicting observations on the pathogenesis of Blastocystis are due to pathogenic and nonpathogenic genotypes. Recent epidemiological, animal infection, and in vitro host-Blastocystis interaction studies suggest that this may indeed be the case. This review focuses on such recent advances and also provides updates on laboratory and clinical aspects of Blastocystis spp.

Identification of Blastocystis subtypes in clinical stool samples from Sao Paulo City, Brazil

“…is the most common intestinal parasites found in human feces and are considered an emerging parasite with a worldwide distribution (Tan, 2008). The clinical features associated with blastocystosis range from non-specific intestinal symptoms to cutaneous disorders and the severity of these diseases varies from acute to chronic infections, a possible reason for these differences is genetic diversity (Tan, 2008;Tan et al 2010;Scanlan, 2012).…”

“…infections remains unknown in many parts of the world. Recent studies have provided further information regarding ST distribution among human populations (Tan, 2008;Alfellani et al 2013); however, very few studies have been conducted in Latin America (Santín et al 2011). To date, a small number of studies subtyping Blastocystis (Malheiros et al 2011;David et al 2015;Ramírez et al 2016) (Garcia, 2001), considering positivity in at least one of the parasitological methods.…”

“…is usually detected using conventional parasitological methods such as the direct method, concentration method with formalin-ether and stained smears Tan, 2008). Culturing methods have been regarded as the gold standard for the detection of Blastocystis sp., because although these methods show high sensitivity (Yoshikawa et al 2011;Zhang et al 2012).…”

“…Culturing methods have been regarded as the gold standard for the detection of Blastocystis sp., because although these methods show high sensitivity (Yoshikawa et al 2011;Zhang et al 2012). Polymerase chain reaction (PCR) amplification of Blastocystis DNA from cultures or feces is thought to be the most sensitive detection method (Tan, 2008). DNA-based methods have been developed to identify genetic variation between Blastocystis sp.…”

Prevalence and genetic diversity of Blastocystis in family units living in the United States

“…Blastocystis is a single-celled microbial eukaryote that is commonly found in the intestinal tract of a diverse range of non-mammalian and mammalian hosts including humans Alfellani et al, 2013a;Tan, 2008). As a consequence of the controversial and unresolved role of Blastocystis in human intestinal disease and the increased awareness of the importance of the gut microbiome (and specific components of the gut microbiome) in human health and disease, research into Blastocystis has increased greatly in recent years (Andersen and Stensvold, 2015;Guinane and Cotter, 2013;Roberts et al, 2014;Scanlan, 2012;Scanlan and Stensvold, 2013;Sekirov et al, 2010).…”