Blastocystosis in patients with gastrointestinal symptoms: a case–control study

Abstract

BackgroundBlastocystosis is a frequent bowel disease. We planned to to evaluate the prevalence of Blastocystis spp. in patients who applied to the same internal medicine-gastroenterology clinic with or without gastrointestinal complaints to reveal the association of this parasite with diagnosed IBS and IBD.MethodsA total of 2334 patients with gastrointestinal symptoms composed the study group, which included 335 patients with diagnosed inflammatory bowel disease and 877 with irritable bowel syndrome. Patients without any gastrointestinal symptoms or disease (n = 192) composed the control group. Parasite presence was investigated by applying native-Lugol and formol ethyl acetate concentration to stool specimens, and trichrome staining method in suspicious cases.ResultsBlastocystis spp. was detected in 134 patients (5.74%) in the study group and 6 (3.12%) in the control group (p = 0.128). In the study group, Blastocystis spp. was detected at frequencies of 8.7% in ulcerative colitis (24/276), 6.78% in Crohn’s disease (4/59), 5.82% in irritable bowel syndrome (51/877), and 4.9% in the remaining patients with gastrointestinal symptoms (55/1122). Blastocystis spp. was detected at a statistically significant ratio in the inflammatory bowel disease (odds ratio [OR] = 2.824; 95% confidence interval [CI]: 1.149-6.944; p = 0.019) and ulcerative colitis (OR = 2.952; 95% CI: 1.183-7.367; p = 0.016) patients within this group compared to controls. There were no statistically significant differences between the control group and Crohn’s disease or irritable bowel syndrome patients in terms Blastocystis spp. frequency (p = 0.251, p = 0.133).ConclusionsBlastocystosis was more frequent in patients with inflammatory bowel disease, especially those with ulcerative colitis. Although symptomatic irritable bowel syndrome and Crohn’s disease patients had higher rates of Blastocystis spp. infection, the differences were not significant when compared to controls.

Comparative Prevalence of Blastocystis in Patients with the Irritable Bowel Syndrome and Healthy Individuals: A Case Control Study

“…Our results are in contrast with a study from the west of Iran (23) and other studies from Turkey, India, France, and Mexico which showed a higher prevalence of Blastocystis infection in IBS population compared to the control group (2,6,24,25), but similar to those reported studies from Thailand and Denmark (26,27). A notable feature of the current study is that the control group was selected from healthy people without GI symptoms, which it can be extended to the whole community in Ahvaz.…”

“…More than 100 years ago Blastocystis was described by Allexief, but its pathogenicity still remains controversial (4,5). The parasite was frequently reported in both healthy individuals and symptomatic patients (6). Gastrointestinal (GI) symptoms such as abdominal pain, watery diarrhea, vomiting, and flatulence have been attributed to the Blastocystis infection (7).…”

The Prevalence of Intestinal Parasites Is Not Greater Among Individuals With Irritable Bowel Syndrome: A Population-based Case-control Study

“…D fragilis has been detected in 4% to 35% of IBS patients 11,12,14 and Blastocystis has been reported to be more common in patients with IBS compared with controls at a prevalence of 16% to 53%, 12,14,15,18 although some studies have failed to confirm this. 13,17 Currently, the role of the parasites in GI symptomatology is unclear, partly because the prevalence of the parasites varies considerably between studies owing to differences in diagnostic approaches, small sample sizes, and lack of control groups.…”

“…[11][12][13][14][15][16][17][18] They are common parasites 19,20 and reported symptoms associated with D fragilis carriage include abdominal pain, loose stools, and diarrhea. 21 Blastocystis carriage may be associated with similar symptoms in addition to nausea, flatulence, and bloating.…”

Are Blastocystis species clinically relevant to humans?

“…Blastocystis carriage has been reported to be uncommon in patients with active ulcerative colitis (Petersen 2012) and rare in patients with Crohn's disease in Denmark but equivalent rates of carriage (around 6%) were seen in Turkey in IBD patients and healthy controls (Cekin et al 2012). Blastocystis has also been reported in association with active colitis with resolution of colitis with metronidazole therapy (Tai 2011).…”