Predominance of subtype 3 among Blastocystis isolates from a major hospital in Singapore

Abstract

Blastocystis is an enteric protozoan parasite commonly found in humans and animals. Phylogenetic and genotypic analyses have shown that Blastocystis exhibits extreme genetic diversity, and humans are host to a number of zoonotic isolates. In the present study, the prevalence of Blastocystis in 276 stool samples from a hospital in Singapore was examined, and for the first time, riboprinting using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to determine the genetic diversity of the Blastocystis isolated from the Singapore population. The prevalence rate was determined to be 3.3% (9/276), and Blastocystis displaying two main ribotypes were isolated. As a comparison, we performed PCR-RFLP using two different published methodologies, and both methods allowed the isolates to be divided into two distinct groups based on their riboprint patterns. According to a recently proposed classification scheme, 78% (7/9) of the isolates were of subtype 3, while 22% (2/9) were subtype 1. The predominance of subtype 3 in an urbanized city state such as Singapore is in agreement with the idea that subtype 3 is a genotype of human origin.

Update on the Molecular Epidemiology and Diagnostic Tools for Blastocystis sp

“…There was a 78% incidence of ST3 and a 22% incidence of ST1. This prevalence of ST3 in humans in an urbanised area such as Singapore is consistent with the argument that ST3 is of human origin [38].…”

Comparison of Microscopy, Culture, and Conventional Polymerase Chain Reaction for Detection of Blastocystis sp. in Clinical Stool Samples

“…Many epidemiologic studies reported only further use of molecular analysis if there are samples positive by culture. 4,17,24,[28][29][30] An obvious conclusion is that these studies did not provide a true representation of the prevalence of Blastocystis infections in human population studies where some culture systems used may not enable certain strains of Blastocystis to grow.…”

“…1 Blastocystis is the most common parasite isolated from human stool samples in developing and developed countries. 2,3 Rates of infection vary from 3.3% in developed countries 4 to 53.8% in developing countries. 5 Blastocystis is found in humans and animals.…”

Identification of Blastocystis Subtype 1 Variants in the Home for Girls, Bangkok, Thailand

“…An apparently higher prevalence of the mixed infection of subtypes in this community also supported and strengthened the possibility of person-to-person transmission when compared with the prevalence of Blastocystis infection in other studies (20% versus 1.1-14.3%). [28][29][30] Zoonotic transmission of Blastocystis in this population could be possible. Multivariate analysis showed that the girls who did not wash their hands after contacting pets had a high risk of getting Blastocystis infection.…”