Case Control Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Pharmacol Ther. Nov 6, 2017; 8(4): 201-207
Published online Nov 6, 2017. doi: 10.4292/wjgpt.v8.i4.201
Protozoan parasites in irritable bowel syndrome: A case-control study
Khaled A Jadallah, Laila F Nimri, Rola A Ghanem
Khaled A Jadallah, Department of Internal Medicine, King Abdullah University Hospital, Faculty of Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan
Laila F Nimri, Rola A Ghanem, Department of Medical Laboratory Sciences, Jordan University of Science and Technology, Irbid 22110, Jordan
Author contributions: Jadallah KA and Nimri LF designed the research; Jadallah KA recruited the cases; Ghanem RA recruited the healthy controls, gathered clinical data, and collected stool samples; Nimri LF and Ghanem RA performed stool processing and analysis; Jadallah KA and Nimri LF drafted the manuscript; all authors critically revised and approved the final version of the manuscript.
Supported by Deanship of Research, Jordan University of Science and Technology, No. 214/2013.
Institutional review board statement: The study protocol was reviewed and approved by the Institutional Review Board at King Abdullah University Hospital and by the Committee of Research on Human subjects at the Jordan University of Science and Technolog.
Informed consent statement: All study subjects signed a written informed consent prior to participation.
Conflict-of-interest statement: The Authors declare that they have no conflict-of-interest.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Khaled A Jadallah, MD, Associate Professor, Department of Internal Medicine, King Abdullah University Hospital, Faculty of Medicine, Jordan University of Science and Technology, Ramtha Str., Irbid 22110, Jordan. khaled-j@just.edu.jo
Telephone: +962-79-6673884 Fax: +962-2-7200624
Received: May 2, 2017
Peer-review started: May 3, 2017
First decision: June 15, 2017
Revised: June 15, 2017
Accepted: August 3, 2017
Article in press: August 4, 2017
Published online: November 6, 2017
Abstract
AIM

To investigate the putative role of protozoan parasites in the development of irritable bowel syndrome (IBS).

METHODS

The study included 109 IBS consecutive adult patients fulfilling the Rome III criteria and 100 healthy control subjects. All study subjects filled a structured questionnaire, which covered demographic information and clinical data. Fresh stool samples were collected from patients and control subjects and processed within less than 2 h of collection. Iodine wet mounts and Trichrome stained smears prepared from fresh stool and sediment concentrate were microscopically examined for parasites. Blastocystis DNA was detected by polymerase chain reaction, and Cryptosporidium antigens were detected by ELISA.

RESULTS

A total of 109 IBS patients (31 males, 78 females) with a mean age ± SD of 27.25 ± 11.58 years (range: 16 -60 years) were enrolled in the study. The main IBS subtype based on the symptoms of these patients was constipation-predominant (88.7% of patients). A hundred healthy subjects (30 males, 70 females) with a mean ± SD age of 25.0 ± 9.13 years (range 18-66 years) were recruited as controls. In the IBS patients, Blastocystis DNA was detected in 25.7%, Cryptosporidium oocysts were observed in 9.2%, and Giardia cysts were observed in 11%. In the control subjects, Blastocystis, Cryptosporidium and Giardia were detected in 9%, 0%, and 1%, respectively. The difference in the presence of Blastocystis (P = 0.0034), Cryptosporidium (P = 0.0003), and Giardia (P = 0.0029) between IBS patients and controls was statistically significant by all methods used in this study.

CONCLUSION

Prevalence of Blastocystis, Cryptosporidium and Giardia is higher in IBS patients than in controls. These parasites are likely to have a role in the pathogenesis of IBS.

Keywords: Blastocystis, Cryptosporidium, Protozoan parasites, Giardia, Irritable bowel syndrome

Core tip: A mounting body of evidence suggests that infections with protozoan parasites may be implicated in the pathogenesis of irritable bowel syndrome (IBS). However, previous studies from different geographic regions have yielded conflicting results. The present study investigates the infection rate of protozoan parasites in Jordanian IBS patients. Our results indicate that infection with Blastocystis, Cryptosporidium, and Giardia spp. may play a role in the pathogenesis of IBS in a significant proportion of patients. Testing for these parasites in cases of presumed IBS may offer new insights into the pathogenesis of IBS and thus improve its management.