Review
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World J Gastroenterol. Jun 21, 2014; 20(23): 7403-7415
Published online Jun 21, 2014. doi: 10.3748/wjg.v20.i23.7403
Mycobacterium avium subspecies paratuberculosis causes Crohn's disease in some inflammatory bowel disease patients
Saleh A Naser, Sudesh R Sagramsingh, Abed S Naser, Saisathya Thanigachalam
Saleh A Naser, Sudesh R Sagramsingh, Abed S Naser, Saisathya Thanigachalam, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32816, United States
Author contributions: Sagramsingh SR led the literature search, and writing of the manuscript; other co-authors contributed significantly to data analysis, and writing and revision of the manuscript.
Correspondence to: Saleh A Naser, PhD, Professor, Graduate Coordinator, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Building 20, BMS 136, 4110 Libra Drive, Orlando, FL 32816, United States. saleh.naser@ucf.edu
Telephone: +1-407-8230955 Fax: +1-407-8230956
Received: February 28, 2014
Revised: April 9, 2014
Accepted: April 28, 2014
Published online: June 21, 2014
Processing time: 112 Days and 15.7 Hours
Abstract

Crohn’s disease (CD) is a chronic inflammatory condition that plagues millions all over the world. This debilitating bowel disease can start in early childhood and continue into late adulthood. Signs and symptoms are usually many and multiple tests are often required for the diagnosis and confirmation of this disease. However, little is still understood about the cause(s) of CD. As a result, several theories have been proposed over the years. One theory in particular is that Mycobacterium avium subspecies paratuberculosis (MAP) is intimately linked to the etiology of CD. This fastidious bacterium also known to cause Johne’s disease in cattle has infected the intestines of animals for years. It is believed that due to the thick, waxy cell wall of MAP it is able to survive the process of pasteurization as well as chemical processes seen in irrigation purification systems. Subsequently meat, dairy products and water serve as key vehicles in the transmission of MAP infection to humans (from farm to fork) who have a genetic predisposition, thus leading to the development of CD. The challenges faced in culturing this bacterium from CD are many. Examples include its extreme slow growth, lack of cell wall, low abundance, and its mycobactin dependency. In this review article, data from 60 studies showing the detection and isolation of MAP by PCR and culture techniques have been reviewed. Although this review may not be 100% comprehensive of all studies, clearly the majority of the studies overwhelmingly and definitively support the role of MAP in at least 30%-50% of CD patients. It is very possible that lack of detection of MAP from some CD patients may be due to the absence of MAP role in these patients. The latter statement is conditional on utilization of methodology appropriate for detection of human MAP strains. Ultimately, stratification of CD and inflammatory bowel disease patients for the presence or absence of MAP is necessary for appropriate and effective treatment which may lead to a cure.

Keywords: Mycobacterium paratuberculosis; Crohn’s disease; Culture; PCR; Johne’s disease; Inflammatory bowel disease

Core tip: The review manuscript describes the past, present and predicted future research accomplishments in the area of Crohn’s disease and Mycobacterium avium subspecies paratuberculosis. This is a highly debated area and Dr. Naser’s thoughts described in this review will fuel interest and discussions in inflammatory bowel disease research. The manuscript has been in preparation for a couple of years and it is of high quality.