Abstract
BACKGROUND: Inflammatory bowel disease (IBD), of which Crohn's disease (CD) and ulcerative colitis (UC) are the two main clinicopathological subtypes, is a group of digestive system diseases of unknown etiology. Risk factors for IBD are environmental factors, genetics, and immune system agents. Mycobacterium avium subspecies paratuberculosis (MAP) is one of the most important infectious factors and a suspected cause of IBD. The present study aimed to determine the prevalence of MAP in both IBD patients and non-IBD people as well as to investigate the relationship between the presence of this bacterium and IBD. METHODS: A cross-sectional study was conducted during May-December 2017 among 146 IBD patients (32 with CD and 114 with UC) at the Motahari Clinic affiliated to Shiraz University of Medical Sciences, Shiraz, Iran. For comparison, the blood samples of 146 non-IBD volunteers (the control group) were tested for the presence of MAP using the polymerase chain reaction method (specific IS900 fragment). The data were analyzed using the SPSS software (version 19.0). The Kolmogorov-Smirnov test was used to evaluate the normal distribution of variables. The χ2 test was used to compare the qualitative variables between the groups. RESULTS: MAP was present in 104 (71.2%) IBD patients out of which 24 (75%) had CD and 80 (70.2%) had UC. In the control group, MAP was present in 63 (43.2%) non-IBD volunteers. There was a significant association between the presence of IBD and MAP (P<0.001). CONCLUSION: A high prevalence of MAP was observed in the South of Iran. MAP DNA was detected in the blood samples of CD and UC patients as well as non-IBD volunteers. The high prevalence of MAP indicated a possible role of MAP in stimulating IBD.