Phenotypic variation in Blastocystis sp. ST3.

Suresh Kumar Govind,Sanjiv Mahadeva,Tan Tian Chye,Nanthiney Devi Ragavan

doi:10.1186/1756-3305-7-404

Suresh Kumar Govind, Sanjiv Mahadeva + Show 2 more

Open Access

https://doi.org/10.1186/1756-3305-7-404

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Journal: Parasites & vectors	Publication Date: Aug 29, 2014
Citations: 64	License type: cc-by

Affiliation: University of Malaya

Abstract

BackgroundBlastocystis, is one of the most common human intestinal protozoan, which has many conflicting reports on its pathogenic role. Gut conditions which obviously varies in asymptomatic individuals, symptomatic and irritable bowel syndrome (IBS) patients in terms of gut flora, pH, osmotic pressure and water potentials could play an important role in its pathogenicity. The present study is the first study to investigate phenotypic characteristics of Blastocystis sp. ST3 isolated from asymptomatic, symptomatic and IBS isolates.MethodsA total of 8 Blastocystis isolates were obtained from four IBS patients (IBS1-4) and four symptomatic patients (S1-4) at a local gastroenterology clinic. Asymptomatic isolates (A1-4) were obtained from a field survey at a local village.ResultsAll 12 isolates were determined as subtype 3 (ST3). A1-4 isolates showed the highest peak growth followed by IBS1-4 isolates and S1-4 isolates for the growth profile. Parasites from IBS isolates (IBS1-4) showed the largest diameter with a mean 18.43 ± 2.22 μm compared to parasites of symptomatic isolates (isolates S1-4) 15.54 ± 3.02 μm and asymptomatic isolates (isolates A1-4) 11.76 ± 0.82 μm. The symptomatic isolates (average generation time: 9.87 ± 2.97 h) grew faster than the IBS isolates (average generation time: 7.56 ± 1.06 h) and asymptomatic isolates (average generation time: 5.97 ± 1.52 h). The parasites isolated from IBS isolates showed strong aggregation and clumping, which had seen reduced in parasites of isolates S1-4. No clumping was seen in parasites from A1-4. The outer surface of parasites in IBS isolates showed greater binding affinities towards FITC-labelled Concanavalin A (Con A) than symptomatic isolates and asymptomatic isolates. Scanning electron microscopy showed that in IBS isolates, the surface of Blastocystis showed a very coarse and intensely folded surface. The IBS isolates also exhibited a dense material and a thicker layer of surface coat can be seen compared to asymptomatic and symptomatic isolates.ConclusionThere have been no studies thus far providing evidence for phenotypic variation within a particular subtype. The present study is the first to demonstrate the phenomenon of gut environment facilitating adaptation of parasites possibly for survival leading to phenotypic differences for Blastocystis.

Highlights

Blastocystis, is one of the most common human intestinal protozoan, which has many conflicting reports on its pathogenic role
Blastocystis had been associated with irritable bowel syndrome (IBS) [24] and the consequence of gut conditions which obviously varies in asymptomatic individuals, symptomatic and IBS patients in terms of gut flora, pH, and osmotic pressure and water potentials has never been investigated
Genotyping of Blastocystis Based on polymerase chain reaction (PCR) amplification with the sequence tagged site (STS) primers, all the 12 isolates from 3 different groups, asymptomatic, symptomatic and IBS isolates amplified with the primer SB227 (~526 bp) [18] (Figure 1)

Summary

Introduction

Blastocystis, is one of the most common human intestinal protozoan, which has many conflicting reports on its pathogenic role. Gut conditions which obviously varies in asymptomatic individuals, symptomatic and irritable bowel syndrome (IBS) patients in terms of gut flora, pH, osmotic pressure and water potentials could play an important role in its pathogenicity. There have been 13 subtypes reported [15] with Blastocystis ST3 shown to be the highest in Thailand with prevalence rates between 41.7-92.3% [18]; Egypt54.55% [19]; Singapore- 78% [20]; Turkey- 75.9% [21]; Turkey-59.3% [22]; Germany- 21% [9] and France- 53.5% [23] These studies demonstrate the importance of subtype 3 in terms of its prevalence and its pathogenic implications. It is obvious that the severity would be obviously seen more in IBS than in the gut conditions of symptomatic or asymptomatic condition [25]

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