Blastocystis infection is associated with irritable bowel syndrome in a Mexican patient population

Abstract

In recent times, some common "non-pathogenic" parasites, such as Blastocystis and Dientamoeba fragilis, have been associated to the aetiology of irritable bowel syndrome (IBS), while host pro-inflammatory cytokine gene polymorphisms might have a role in the pathophysiology of the disease. Therefore, Blastocystis subtypes (ST), D. fragilis and gene promoter single nucleotide polymorphisms of interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α) in IBS patients and controls were studied. After giving written consent, 45 patients with symptoms of IBS according to the Rome III criteria and 45 controls were enrolled. DNA was extracted from peripheral blood for SNP analysis at position -174 for IL-6 as well as -238 and -308 for TNF-α. Blastocystis was more common in the IBS group (p = 0.043). Interestingly, D. fragilis was found more frequently in the control group (p = 0.002); Blastocystis ST1 and 3 were most frequent in both groups. Haploview analysis revealed linkage disequilibrium in TNF-α (p < 0.0001); however, none of the SNPs for IL-6 and TNF-α were found to be significantly related with IBS. The clinical and molecular approaches undertaken for the first time in Latin American IBS patients demonstrated an association with Blastocystis that supports a pathogenic role of this parasite in IBS Furthermore, co-infections with ST1 and ST3 were frequent; thus, the genetic diversity proposed within ST polymorphisms does not rule out that particular strains might be associated with disease. In addition, our results do not support a major contribution of IL-6 and TNF-α gene polymorphisms in the susceptibility to IBS.

Fecal calprotectin among patients infected with some protozoan infections

“…The single most commonly-identified organism was Blastocystis hominis, which until recently was regarded as a nonpathogenic organism. (Ramirez-Miranda et al, 2011)and (Jimenez-Gonzalez et al, 2012) Several recent studies, however, point to a moderately strong association between B hominis and symptomatic IBS, with some variation between geographic areas. (Yakoob et al, 2010a) and (Grazioli et al, 2006).…”

Treatment of Dientamoeba fragilis in Patients with Irritable Bowel Syndrome

“…Both compare the prevalence of D. fragilis in IBS-patients and controls. 35,36 One study found that D. fragilis was more prevalent in IBS-patients compared with controls (4% versus 0%), 35 whereas the other study showed the exact opposite (2% versus 27%). 36 Methodological differences make the results difficult to compare.…”

“…Clinical response rate in patients co-infected with Blastocystis was low, and we failed to eradicate D. fragilis and Blastocystis from two patients. Blastocystis has previously been associated to IBS, 27,35,36 and further studies into the relevance of this parasite in IBS are warranted. Because of the limitations of the study no firm conclusions can be made, and results can primarily serve a hypothesis-generating purpose.…”

“…Effect of eradication of D. fragilis on gastrointestinal symptoms has also been described in non-IBS populations. 26,34 Epidemiological studies report prevalence rates of D. fragilis in IBS patients of 2-4%, 35,36 with the one study finding an association between D. fragilis and IBS, 35 which was not confirmed by the other. 36 Therefore, the role of D. fragilis in IBS symptoms remains to be clarified.…”

Possible Association between Blastocystis hominis and Bowel Disorders among Iraqi Patients in Kirkuk Province

“…The interpretation of the results is attributed to the effects of environmental and emotional stress upon Iraqi people due to the bad security condition and the waste products of the s perhaps may participate in the induction of IBS in addition to the crucial role of infectious agents (Jimenez-Gonzalez et al, 2012;Eroglu et al, 2009). On the other hand, no previous study investigate the effect of infection with this parasite on BMI.…”